Neural sciences Flashcards
A 64-year-old lady, on physical examination exhibits symptoms suggestive
of a movement disorder with associated speech defi cits. This clinical
presentation is classifi ed as ‘hypokinetic dysarthria’ by her neurologist. It is
associated with
A. Parkinson’s disease
B. Huntington’s disease
C. Spasmodic dysphonia
D. Multiple sclerosis
E. Myasthenia gravis
The answer is Parkinson’s disease. Bradykinesia or hypokinesia is a motor feature of
Parkinson’s disease. Dysarthria is a defi cit in the motor aspect of speech. It is usually secondary
to a motor neurological defi cit. Dysarthria can affect not only articulation, but also phonation,
breathing, or prosody (emotional tone) of speech. Total loss of ability to articulate is called
anarthria, whereas dysarthria usually involves the distortion of consonant sounds. The Mayo
Clinic classifi cation of dysarthria divides dysarthria into six basic types, each one corresponding
to a predominant motor disorder: fl accid (lower motor neurone disorders), spastic (upper
motor neurone disorders), ataxic (cerebellar lesions), hypokinetic (parkinsonian), hyperkinetic
(choreiform/tic disorders), and mixed. Mixed dysarthrias are seen in conditions with multiple
motor lesions, for example mixed spastic–ataxia of multiple sclerosis or mixed spastic–fl accidity
of amyotrophic lateral sclerosis. Speech therapy may be of substantial benefi t to many dysarthric
patients.
A 32-year-old man is diagnosed with a right-sided hemiparesis. On
examination, his speech shows non-fluent aphasia. His comprehension is
intact, but repetition is impaired. He is most likely to have
A. Transcortical motor aphasia
B. Transcortical sensory aphasia
C. Conduction aphasia
D. Broca’s aphasia
E. Wernicke’s aphasia
D. Testing a person’s speech is usually done in three steps. The fi rst step is to test for the
fl uency of speech. Non-fl uent output is characterized by a paucity of verbal output (usually
10–50 words per minute), whereas fl uent aphasics have a normal or even exaggerated verbal
output (up to 200 words or more per minute). Lesions of the motor (Broca’s) area produce
a non-fl uent aphasia. Assessment of language comprehension is the second step. Patients with
focal lesions limited to the left frontal lobe (Broca’s area) will have preserved comprehension
(Broca’s and transcortical motor aphasia). Patients with left posterior temporal or parietal
involvement will show impaired comprehension (Wernicke’s, global, transcortical sensory, and
isolation aphasias). The third step is to evaluate repetition. Transcortical aphasias usually have an
intact repetition. Patients with Broca’s, Wernicke’s, or conduction aphasia typically show impaired
repetition. In conduction aphasia, speech is fl uent (as in Wernicke’s aphasia) but comprehension is
intact (unlike Wernicke’s aphasia
A patient presents with features suggestive of Gerstmann’s syndrome. He also has aphasia. Which of the following is the most likely type of aphasia with which he may present? A. Transcortical sensory aphasia B. Transcortical motor aphasia C. Anomic aphasia D. Global aphasia E. Broca’s aphasia
A. Transcortical sensory aphasia is similar to Wernicke,s aphasia but is distinguished by the
retained ability to repeat. Lesions causing transcortical aphasias do not disrupt the perisylvian
language circuit from Wernicke’s area through the arcuate fasciculus to Broca’s area. Instead, they
interrupt connections from other cortical centres into the language circuit (hence the name
transcortical). These areas include the dominant angular gyrus, posterior middle temporal gyrus,
and periventricular white matter pathways of the temporal isthmus underlying these cortical
areas. When this results from involvement of the angular gyrus, it is frequently accompanied
by Gerstmann’s syndrome, constructional apraxia, and other evidence of the angular gyrus
syndrome.
Regarding aphasia, which of the following statements is true?
A. Broca’s aphasia presents with logorrhoea.
B. Neologism is a feature of Broca’s aphasia.
C. Paragrammatism is a feature of Wernicke’s aphasia.
D. Pure word deafness is associated with loss of naming.
E. Involvement of the posterior cerebral artery leads to global aphasia
C. Paragrammatism is seen in Wernicke’s aphasia. Speech is characterized by being empty
of meaning, containing verbal paraphasias, neologisms, and jargon productions. Most patients
with Wernicke’s aphasia have no elementary motor or sensory defi cits. A right homonymous
hemianopia may be present. Patients may be unaware of the defi cit and may present with
paranoia, as they do not realize why others do not understand them. The presence of
paragrammatism may be diffi cult to distinguish from formal thought disorder in schizophrenia.
In contrast, Broca’s aphasia shows agrammatism. In this case, the speech pattern is non-fl uent;
on examination, the patient speaks hesitantly, often producing the principal, meaning-containing
nouns and verbs but omitting small grammatical words and morphemes. This pattern is called
agrammatism or telegraphic speech, for example: ‘I go home’ or ‘wife here morning’. Reading is
often impaired in Broca’s aphasia despite preserved auditory comprehension. Broca’s aphasia
is associated with right hemiparesis, hemisensory loss, and apraxia of the non-paralysed left
limbs. Due to the awareness of the defi cit, patients with Broca’s aphasia may be more prone to
depression. Pure word deafness is a syndrome of isolated loss of auditory comprehension and
repetition, without any abnormality of speech, naming, reading, or writing. It is caused by bilateral,
or sometimes a unilateral, lesion, isolating Wernicke’s area from input from both Heschl’s gyri.
A lesion representing most of the territory of the left middle cerebral (not posterior circulation)
artery leads to a global aphasia.
Which of the following is true regarding acquired defects in reading
and writing?
A. Alexia without agraphia is called acquired illiteracy.
B. Alexia without agraphia is seen in association with Gerstmann’s syndrome.
C. Anomic aphasia is associated with Gerstmann’s syndrome.
D. Transcortical aphasia is due to lesions in the arcuate fasciculus.
E. Alexia without agraphia is seen in posterior cerebral artery stroke.
E. Pure alexia without agraphia is associated with left posterior cerebral artery stroke,
with infarction of the medial occipital lobe, often the splenium of the corpus callosum, and often
the medial temporal lobe. Alexia is the acquired inability to read. Patients with alexia without
agraphia can write but cannot read their own writing. Alexia with agraphia is sometimes called
acquired illiteracy. Alexia with agraphia is seen in angular gyrus lesions and is associated with
Gerstmann’s syndrome. It is seen in stroke of the angular branch of the middle cerebral artery.
Transcortical aphasias are analogues to the syndromes of global, Broca’s, and Wernicke’s aphasias,
with intact repetition. Lesions producing transcortical aphasias disrupt connections from other
cortical centres into the language circuit. Lesions to the arcuate fasciculus (usually in either the
superior temporal or inferior parietal regions) present with conduction aphasia
The clinical sign of fi nger–nose ataxia is seen in lesions of which of the following structures? A. Superior colliculus B. Inferior colliculus C. Pyramidal decussation D. Inferior olivary nucleus E. Thalamus
D. Inferior olivary lesions lead to appendicular ataxia which can be tested using the fi nger–
nose test. The inferior olivary nucleus serves motor coordination via projecting climbing fi bres
to the cerebellum. Isolated lesions of superior colliculus result in defective visual saccades. Subtle
auditory defects are noted in similar lesions of the inferior colliculus. Pyramidal decussation
carries corticospinal fi bres; damage to the corticospinal fi bres rostral to (above) the pyramidal
decussation results in contralateral motor defi cits, while lesions below the decussation result in
ipsilateral defi cits. Thalamic damage often results in sensory defi cit syndromes
A patient is observed to be repeating the phrases or words spoken by the
examiner. Which of the following can cause this phenomenon?
A. Transcortical motor aphasia
B. Transcortical sensory aphasia
C. Mixed transcortical aphasia
D. Huntington’s disease
E. All of the above
E. Echolalia is the phenomenon where the patient repeats words or phrases said by the
examiner; palilalia is the phenomenon where the patient repeats words or phrases that he
has uttered himself. In patients who develop both phenomena, echolalia precedes the onset of
palilalia. Common causes of echolalia include the transcortical aphasias and disorders that affect
the basal ganglia–frontal circuit. Echolalia could be due to a frontal executive defi cit, leading to
failure of environmental autonomy and resulting in echoing of perceived environmental stimuli.
Palilalia should be distinguished from stuttering and logoclonia (repetition of the fi nal syllable of
spoken words). Echolalia may be observed as part of speech disturbances in catatonic states
Neuropsychiatric Interview (NPI) is often employed in patients with
dementia or cognitive deterioration to detect psychiatric and behavioural
problems. Which of the following is not tested by the NPI?
A. Thought disturbance
B. Perceptual disturbance
C. Affective disturbance
D. Abnormalities in sleep pattern
E. Disorientation
E. Orientation is a measure of cognitive function. NPI is used for the assessment of thought
disturbance, perceptual disturbances, affect, abulia, agitation/aggression, disinhibition, appetite
disturbance, sleeping pattern, and aberrant motor activity in patients with dementia/cognitive
defi cits. It does not test cognitive functions such as memory or orientation
Regarding handedness, which of these statements is true?
A. The population can be divided into two categories: right and left handed.
B. 60% of the population are right handed.
C. 75% of right-handed people are left-hemisphere dominant for language.
D. 60% of left-handed people are left-hemisphere dominant for language.
E. Left-handed people are less likely than right-handed ones to have bilateral language
representation.
D. Hemispheric dominance is clinically inferred by handedness. It is a peripheral indicator
of cerebral hemispheric language lateralization. Handedness is now considered to exist as a
continuum, from extreme unilateral hand dominance on one end to ambidexterity on the other.
In this respect, the Edinburgh Handedness Inventory is a semiquantitative measurement of
handedness. It is thought that at least 90% of the human population is right-handed. Of these,
95% are left-hemisphere dominant. Approximately 10% of the human population is left-handed
and of these at least 60% are left-hemisphere dominant. Left-handers are more likely to have
bilateral language representation.
A patient with a history of traumatic brain injury undergoes
neuropsychological testing. In part A of the test he is asked to connect
numbered circles on a paper as fast as he can in correct order, using a pen.
In part B of the same test the same task is repeated but numbers and
alphabets occur in alternate sequences. Which of the following statements
is correct with regard to this test?
A. This is called letter cancellation task.
B. This test is not sensitive to progressive cognitive decline in dementia.
C. Part A of the test corresponds more closely to executive functioning than part B.
D. Patients with traumatic injury perform this test slower than average.
E. This is purely a test of selective attention.
D. This test is called the trail making test. It is not only a test of attention, but it also tests
visuomotor tracking and cognitive fl exibility (part B). Trail making test A requires the subject to
connect numbered dots. Trail making test B requires the subject to connect alternating alphabets
and numbers. This tests the ability to shift mental sets and hence to some extent corresponds to
executive functioning. This has been shown to be sensitive to change in patients with progressive
cognitive decline (e.g. dementia). Patients with traumatic brain injury perform slower on trail
making tests.
Which of the following matches is incorrect regarding amnestic syndrome
and site of lesion?
A. Wernicke–Korsakoff syndrome–thalamic nuclei
B. Herpes simplex encephalitis–anterior temporal cortex
C. Crutzfeld–Jakob disease–diffuse cortical
D. Anterior communicating artery stroke–medial temporal cortex
E. Complex partial seizures–hippocampal damage
D. Medial temporal cortex is not supplied by the anterior communicating artery; it is
supplied by the posterior cerebral artery. The anterior communicating artery supplies the basal
forebrain and striatum. Wernicke–Korsakoff syndrome is usually associated with nutritional
causes, where the thalamic nuclei (especially dorsal medial thalamus) are involved, leading to
anterograde amnesia and confabulation. Herpes simplex encephalitis (HSE) is another cause
of anterograde amnesia where anterior temporal lobes are often involved. Whether amnesia
is predominantly verbal or non-verbal is determined by the side of lesion and the cerebral
dominance. In CJD (Creutzfeldt–Jacob disease) diffuse cortical damage occurs. Amnesia of
complex partial seizures is related to recurrent hippocampal damage and sclerosis
Which of the following is a component of the triad in Balint’s syndrome? A. Visual neglect B. Achromatopsia C. Prosopagnosia D. Simultanagnosia E. Anosognosia
D. Balint’s syndrome consist of a triad of oculomotor apraxia (defi cits in the orderly
visuomotor scanning of the environment), optic ataxia (inaccurate manual reaching toward visual
targets), and simultanagnosia. Pathologically, Balint’s syndrome is produced by bilateral parietooccipital
lesions. Simultanagnosia is the inability to integrate visual information in the centre of
gaze with more peripheral information. The patient gets stuck on the detail that falls in the centre
of gaze without scanning the visual environment for additional information. They typically ‘miss
the forest for the trees.’ This leads to a signifi cant disturbance in object identifi cation. A patient
with Balint’s syndrome when shown a table lamp and asked to name the object may look at its
circular base and call it an ash tray!
Features of Gerstmann’s syndrome include all of the following except
A. Dysgraphia
B. Finger agnosia
C. Dysarthria
D. Inability to distinguish left from right
E. Acalculia
C. Dysarthria is not a feature of Gerstmann’s syndrome. Full Gerstmann’s syndrome, though
rarely reported, consists of left–right disorientation, fi nger agnosia, dysgraphia, and dyscalculia.
The lesion is mostly attributed to a dominant parietal lobe dysfunction. When all the components
are present the syndrome reliably localizes to the dominant angular gyrus. Gerstmann himself
thought that the inability to calculate was because of the fact that children learnt to count with
their fi ngers and the dysgraphia was due to problems with differential fi nger movements—both
being secondary to fi nger agnosia. Gerstmann noted that the greatest trouble in fi nger agnostics
was with distinguishing second, third, and fourth fi ngers. Screening for full Gerstmann’s syndrome
should be performed on patients who show any single component.
Blindsight is a feature of which of the following focal cortical syndromes? A. Balint’s syndrome B. Geschwind’s syndrome C. Charcot–Willibrand syndrome D. Anton’s syndrome E. Central achromatopsia
D. Anton’s syndrome features blindness and denial of blindness, that is the patient is blind
but denies sightlessness. The syndrome is most commonly associated with bilateral lesions of the
occipital cortex. Blind sight is a paradoxical syndrome seen in patients with cortical blindness.
It is the ability of the person to orient towards visual stimuli while there is no conscious visual
perception. This is due to the fact that 20 to 30% of fi bres of the optic tract are directed to
non-geniculate destinations, such as the superior colliculi and pretectal region of the brainstem.
It is thought that some visual processing occurs in this non-geniculate system. This phenomenon
is not demonstrable if the blindness is the result of pregeniculate lesions. Geschwind’s syndrome
refers to personality changes proposed to be due to disconnection of brain areas noted in
those with temporal lobe epilepsy. The Charcot–Wilbrand syndrome, or irreminiscence, is
characterized by the inability to generate an internal mental image or revisualize (imagine) an
object. The patients have more diffi culty in generating objects through drawing than in copying
model fi gures. It is usually secondary to bilateral parietal lobe lesions. Central achromatopsia
refers to loss of colour vision due to occipital lobe lesions.
A patient is not able to perform sequential motor acts despite intact comprehension, muscle power, and ability to perform single-step commands. He is exhibiting A. Ideational apraxia B. Ideomotor apraxia C. Conceptual apraxia D. Conduction apraxia E. Dissociation apraxia
A. Ideational apraxia (IDA) is an inability to correctly sequence a series of acts that lead to
a goal. Asking the patient to carry out a multistep, sequential task, such as preparing a sandwich for
work, is a good test of IDA. It is most often associated with degenerative dementia and delirium.
Ideomotor apraxia is probably the most common type of apraxia. Patients with ideomotor
apraxia make spatial and temporal errors when performing learned, skilled movements including
pantomimes, imitations, and using actual objects. When pantomiming the use of a screwdriver,
patients with ideomotor apraxia may rotate their arm at the shoulder and fi x their elbow. In
right-handed individuals ideomotor apraxia is almost always associated with left-hemisphere
lesions. A variety of structures, including the corpus callosum, the inferior parietal lobe, and the
premotor areas, may be involved. Patients with ideomotor apraxia can imitate actions of others
(using tools/objects) but have diffi culty pantomiming (in the absence of tools/objects). In patients
with conduction apraxia, imitation is worse than pantomiming. The site of the lesion has not been
localized (unlike conduction aphasia). Patients with conceptual apraxia make tool-selection errors.
Which of the following is true about limb-kinetic apraxia?
A. Tasks such as fi nger tapping and pegboard are typically unimpaired.
B. Picking up objects using pincer grasp is spared.
C. It usually affects the hand that is ipsilateral to a hemispheric lesion.
D. The lesion is localized to the contralateral premotor cortex.
E. Patients typically present with an inability to perform multistep motor task
D. Limb-kinetic apraxia most often occurs in the limb contralateral to a hemispheric lesion,
usually to the premotor cortex. Patients with limb-kinetic apraxia demonstrate a loss of deftness
and ability to make fi nely graded, precise, independent fi nger movements. These subjects will not
be able to use a pincher grasp to pick up a penny. They will have trouble rotating a coin between
the thumb, middle fi nger, and little fi nger.
A 55-year-old man fi nds it diffi cult to recognize faces. On further testing, his ability to discriminate faces and match faces is intact. The most likely condition he is suffering from is A. Apperceptive prosopagnosia B. Associative prosopagnosia C. Apperceptive visual object agnosia D. Simultanagnosia E. Central achromatopsia
B. The term agnosia was originally introduced by Freud. In general, patients with agnosia
have clinical feature of impaired recognition of sensory stimuli despite normal sensory pathways.
Agnosia represents a disorder of higher-order sensory processing. There is an impaired ability
to recognize the nature or meaning of sensory stimuli. This is usually modality specifi c. There
are two basic categories of agnosia. Apperceptive agnosia involves impaired generation of
the minimal integrated percept necessary for meaningful recognition. This defect, leads to
the formation of an inadequate minimal object recognition unit (i.e. the minimum information
required to meaningfully interpret the percept). For example, a “pencil” is initially perceived
as—”long, thin, pointed at one end, etc”, before a meaning (“it is a pencil—it is used to write”)
is attributed to the percept. Patients are unable to distinguish visual shapes and so have trouble
recognizing, copying, or discriminating between different visual stimuli. Associative agnosia involves
defective association of meaning with percepts. The defect is in associating a correctly perceived
percept with its meaning. Patients can describe visual scenes and classes of objects but still fail to
recognize them. Patients suffering from associative agnosia are still able to reproduce an image
through copying. Anosognosia refers to being unaware of a neurological state/illness. Abulia refers
to loss of drive or motivation seen in cingulate lesions.
Which of the following is true regarding episodic memory?
A. Episodic memory is implicit and non-declarative.
B. Episodic memory loss is not seen without medial temporal lesions.
C. Episodic memory loss can present as anterograde or retrograde amnesia.
D. Episodic memory applies only to events of personal signifi cance.
E. Episodic memory is more often preserved than semantic memory in dementia
C. Memories of specifi c experiences formed in specifi c contexts are called episodic, for
example the meal one had 3 weeks ago at a restaurant. Episodic memory is explicit, that is it is
consciously acquired (we know how and where we acquire it) and declarative, that is it can be
consciously recalled. Episodic memory depends largely on the integrity of the medial temporal
lobe, but there are other structures that are involved in episodic memory. These include the
frontal lobe, basal forebrain, retrosplenial cortex, presubiculum, fornix, mammillary bodies,
mammillothalamic tract, anterior nucleus of the thalamus, etc. Damage to any one of these
structures can result in defi cits in episodic memory. Hence episodic memory loss cannot be said
to be characteristic of a medial temporal lesion. Episodic memory impairment could manifest as
anterograde or retrograde amnesia. Anterograde amnesia refers to impairment in new memory
formation and retrograde amnesia refers to the loss of previously acquired memories. Episodic
memory applies to both personal and public events. In most dementias, semantic memory loss
occurs at later stages than episodic memory loss.
During bedside cognitive testing, a 40-year-old patient is asked to give the years when World War II took place. Which of the following memories is tested here? A. Procedural memory B. Episodic memory C. Semantic memory D. Implicit memory E. Non-declarative memory
C. Semantic memory describes memories for general information which is unrelated
to other information, for example dates in history, the colour of our national fl ag, or the
characteristics of different species of dinosaurs (encyclopaedic facts). Semantic memory is explicit
and declarative (see explanation to the previous question). In the most general sense, semantic
memory refers to all of our knowledge of the world; however, semantic memory is more usually
tested in the context of naming and categorization tasks. It is localized to the inferior lateral
temporal lobes. The frontal lobes are responsible for providing information to, and retrieving
information out of, the semantic memory banks
A 35-year-old woman recently separated from her boyfriend of 5 years was
brought to the A&E with loss of memory. On examination, her memory
loss is specifi c to events associated with her boy friend. But she remembers
other events that took place around the same time. She is most probably
suffering from
A. Localized amnesia
B. Selective amnesia
C. Generalized amnesia
D. Continuous amnesia
E. Systematized amnesia
E. The woman described in the question probably suffers from dissociative amnesia, in
this case precipitated by the stress of separation. Systematized amnesia is the loss of memory
for a certain category of information such as material relating to one’s family or a particular
person. In this case, her boy friend. Localized amnesia is the condition where the individual fails
to recall events that occurred during a circumscribed period of time. In selective amnesia the
person can recall some but not all events during a circumscribed period of time. Generalized
amnesia is characterized by a failure to recall all of a person’s past life. There may be dissociation
between explicit and implicit memory, for example the person may retain all his learned skills,
but completely forget who he is or his past (a la Jason Bourne in the Bourne trilogy). Continuous
amnesia is a condition featuring an inability to recall events subsequent to a specifi c time up to
and including the present.
Cummings JL and Mega MS
After an enjoyable evening with friends at a pub, Tom calculates the cost
of the number of drinks that he had, subtracts the total from the value of
money he gave the bartender, and calculates the change that is due. The
system of memory that enables such calculation is
A. Episodic memory
B. Semantic memory
C. Procedural memory
D. Working memory
E. Retrograde memory
D. Working memory describes the ability to temporarily hold information in mind
and manipulate it as required by circumstances, for example doing mental arithmetic. It may
be phonological, such as keeping a phone number in mind for as long as it takes to dial or
visuospatial, such as following a mental map while cycling to work. Baddeley described a central
executive system in working memory, which is central to manipulation of the data held in the
‘phonological loop’ or the ‘visuospatial sketchpad’. In short, working memory is what allows us
to mentally add up the cost of the number of pints of lager we had at the pub, subtract the total
from the value of the money we give the bar tender, and calculate the change that is due to us.
Prefrontal cortex is the most important structure for working memory, due to the extensive
role played by the central executive; other structures involved include posterior parietal cortices.
Disturbances of working memory can result in anterograde disturbances to other systems
of memory as well, because intact working memory is generally required for the encoding of
information. Episodic memory may be particularly affected
Which of the following conditions does not show predominant abnormality in procedural memory? A. Parkinson’s disease B. Huntington’s disease C. Progressive supranuclear palsy D. Olivopontocerebellar degeneration E. Early Alzheimer’s disease
E. Procedural memory describes the ability to learn and perform tasks without
conscious thought. This is disturbed in conditions that involve subcortical basal ganglia
structures such as Parkinson’s disease, Huntington’s disease, progressive supranuclear palsy,
and olivopontocerebellar degeneration. Procedural memory defi cits may also be found in
depression and OCD. In conditions such as Alzheimer’s disease, mild cognitive impairment, Lewy
body dementia, vascular dementia, the frontal variant of frontotemporal dementia, encephalitis,
Korsakoff ’s syndrome, traumatic brain injury, hypoxic–ischaemic brain injury (including cardiac
bypass surgeries), temporal lobe surgery, seizures, vitamin B12 defi ciency, hypoglycaemia, transient
global amnesia, and multiple sclerosis, episodic memory is more likely to be impaired. Mood,
anxiety, and psychotic disorders may also show episodic memory disturbances. Finally, episodic
memory impairment may be a side-effect of treatment with anticholinergic drugs and ECT.
Semantic memory may be disturbed in conditions such as Alzheimer’s disease, the temporal
variant of frontotemporal dementia, traumatic brain injury, and encephalitis. Working memory
is disturbed in most of the conditions listed above. Working memory is also impaired in anxiety,
depression, schizophrenia, OCD, ADHD, other psychiatric states, and medications. Finally,
impairments in working memory occur as part of normal ageing.
A patient who had developed a pyloric stenosis following ingestion of
sulphuric acid develops a confusional state, ophthalmoplegia, and ataxia.
Which of the following is not true?
A. A CT scan may reveal bilateral hypodense areas in the medial thalamus.
B. The patient may present with diffi culty in learning new information.
C. Administration of thiamine in the acute phase may prevent the emergence of chronic
amnesic syndrome.
D. Confabulation is most common in the early stage of the amnesic syndrome.
E. The patient’s memory of events before the onset of amnesia is always normal.
E. The condition described is Wernicke–Korsakoff syndrome. Although the common
cause for the syndrome is malnutrition secondary to alcohol use, a number of other conditions
including hyperemesis during pregnancy, gastrectomy, pyloric stenosis, etc. are associated. In
addition to diffi culty learning new information, patients with Korsakoff ’s syndrome usually have
a retrograde amnesia which could extend back up to several years prior to the onset of the
syndrome. Patients usually remain amnesic for 1–3 months after onset and then begin to recover
gradually over a 10-month period; 25% recover completely and 25% have no demonstrable
recovery. CT scan may reveal bilateral hypodense areas in the medial thalamus in patients
with acute Wernicke’s encephalopathy, and mamillary body atrophy may be demonstrated by
MRI in some patients with chronic Korsakoff ’s syndrome. Confabulation is common during
the early phases of Korsakoff ’s syndrome but is unusual in the chronic phase of the condition.
Administration of thiamine during the acute Wernicke’s phase may prevent emergence of
Korsakoff ’s syndrome. Once the memory defect is established, however, thiamine has little effect
except to prevent further deterioration.
Which of the following is the least valuable clinical indicator of severity of
head injury?
A. Duration of retrograde amnesia
B. Glasgow Coma Scale
C. Duration of unconsciousness
D. Neurological lesions noted using an MRI
E. Duration of post-traumatic amnesia
A. There are several clinical indicators that predict severity of a head injury. They include
duration of retrograde amnesia, the depth of unconsciousness as assessed by the worst score
on the Glasgow Coma Scale (GCS), the duration of coma, neurological evidence of cerebral
injury, using an MRI or EEG, and the duration of post-traumatic amnesia. Of these, the least useful
clinical indicator is the duration of retrograde amnesia. Duration of post-traumatic amnesia is the
best marker of outcome. Patients with a post-traumatic amnesia of less than 1 week will have
minimal disability, while duration of more than 1 month is suggestive of enduring and signifi cant
disability. Other predictors of a bad outcome include previous head injury, older age, APOE e4
status, and alcohol dependence. Head injury can be classifi ed as mild wherein a GCS score
of 13 to 15 is likely to be associated with only a short duration of loss of consciousness (less
than 20 minutes) and a short post-traumatic amnesia (less than 24 hours). In moderate head
injury, GCS score 9 to 12 is likely to be associated with loss of consciousness of more than a
few minutes but less than 24 hours and a post-traumatic amnesia of more than 1 day but less
than 1 week. In severe head injury, a GCS score 3 to 8 is likely to be associated with a loss of
consciousness of more than 1 day or a post-traumatic amnesia of more than 1 week.
A 24-year-old patient is admitted to a head injury unit following a road
traffi c accident. He recovers well from acute neurological defi cits but
is diagnosed with post-concussion syndrome. Which of the following
statements pertaining to his condition is true?
A. There is a consistent relationship between severity of injury and the presence of postconcussion
syndrome.
B. Diplopia is an early symptom of post-concussion syndrome.
C. CT scans show brain lesions in up to 50% of patients in the fi rst week.
D. Psychological factors are more likely to play a role in illnesses of shorter duration.
E. There is no association between the presence of symptoms and compensatory claims
B. The term post-concussion syndrome (PCS) is used to describe a cluster of symptoms
that results in severe disability following mild head injury. There is no consistent relationship
between the prevalence of PCS and the severity of head injury. Sometimes a similar constellation
of symptoms may be seen in moderate and severe injury, where it is more likely to be attributed
to the actual brain damage. Symptoms are usually vague, but early symptoms may include
neurological complaints such as diplopia, dizziness, etc. Additional symptoms include cognitive
impairment, fatigue, anxiety, depression, and irritability. In general, most neurological symptoms
will have resolved by 2 to 6 months. Several observations support an organic basis, for example
diffuse microscopic axonal injury on post mortem, macroscopic brain lesions evident in 8–10%
of individuals on CT scan, subtle abnormalities on EEG, etc. Psychosocial factors play a part
in the syndrome, especially in those lasting longer than 1 year. This is greatest in those with
very mild head injuries and very chronic symptoms. There is an association between severity
of post-concussion symptoms and seeking compensation, but very few improve even after the
compensation.
A 30-year-old man who was involved in a road traffi c accident was
unconscious for 10 minutes. His CT scan was normal and he is now
conscious, but complaining of a bad headache. The family is concerned
about him developing seizures as his father has a history of epilepsy. What is
the next line of action?
A. Start phenytoin for 1 to 2 weeks
B. Start prophylactic carbamazepine for a year
C. Start long-term benzodiazepines
D. An abnormal EEG in this patient is an indication for starting prophylactic antiepileptic
medication
E. Antiepileptics are not indicated
E. Anticonvulsants are not indicated at this point in time, especially since the patient has
no symptoms suggestive of seizures. About 2 to 5% of all patients with mild, closed head injury
tend to develop long-term seizure disorder. This rises to about 10 to 20% in patients with severe,
closed head injury. A higher incidence of seizures has been seen in patients with depressed skull
fractures (15%), haematomas (30%), and penetrating brain wounds (50%). Early seizures, within
the fi rst week, are relatively benign and are only weak predictors of later epilepsy. This patient has
a mild, closed injury, and he is at a low risk for developing seizures, despite positive family history.
Randomized controlled studies have shown that the use of anticonvulsants does not prevent the
development of post-traumatic epilepsy beyond the fi rst week after injury. There is a limited role
for genetic predisposition in developing post-traumatic epilepsy. Those with the ApoE-ε4 allele
may be at higher risk for post-traumatic epilepsy
A 25-year-old patient presented with a history of recurrent, unilateral visual
disturbances that resolved completely, on-and-off episodes of pins and
needles in her left hand, and recent-onset bladder disturbances. Which of
the following statements regarding this illness is true?
A. The risk of her developing a major depressive disorder is 5–10% during her lifetime.
B. Her likelihood of developing suicidal ideation is similar to that in the general population.
C. She is 10 times more likely to develop a manic episode compared to the general
population.
D. Pathological laughing and crying is seen in around 10% of cases.
E. There is no risk of triggering a relapse of neurological condition with ECT.
D. This patient is most probably suffering from multiple sclerosis. The lifetime prevalence
of major depression in multiple sclerosis (MS) is around 50%. It is three to 10 times the rate in
the general population. Suicidal intent occurs in up to 30% of MS patients. This is linked to the
presence and severity of depression and degree of social isolation. Suicide rates in MS patients
are up to seven times higher than rates in the general population. Depression and suicide rates
are higher in MS than in most other neurologic disorders. In MS patients, the lifetime prevalence
of bipolar affective disorder is twice the prevalence in the general population. Pathological
laughing and crying is a syndrome that presents with inappropriate laughter without associated
happiness and inappropriate tears without associated sadness. Approximately 10% of MS patients
are affected, with varying degrees of severity. ECT is generally well tolerated by patients with MS,
but carries a risk of neurological relapse and exacerbation of the illness
Which of the following statements regarding cognitive impairment in
multiple sclerosis is true?
A. Cognitive defi cits are secondary to depressive symptoms.
B. Cognitive defi cits are closely related to physical disability and duration of illness.
C. Memory defi cits in multiple sclerosis are more apparent on recall compared to
recognition.
D. MMSE is a good test to screen for cognitive defi cits in multiple sclerosis.
E. Donepezil has not been found to be useful in improving memory in multiple sclerosis.
C. Around 50% of patients with MS have cognitive defi cits. Aphasia, apraxia, and agnosia,
which are characteristic of predominantly cortical diseases, are generally absent in MS, where
pathology is largely confi ned to subcortical white matter. Although patients with long-lasting
and advanced physical disability may also have severe cognitive impairment, the correlation
between cognitive dysfunction and disease characteristics (type and duration of MS) is usually
weak or modest. Cognitive defi cits are also independent of mood symptoms in MS. Defi cits in
working, semantic, and episodic memories have been reported. MS patients have diffi culty both in
acquiring and in retrieving information (although performance on recognition tests is better than
recall). Procedural memory is usually unaffected. Impaired attention and slowness of thinking is
another feature of MS. Frontal lobe defi cits may take the form of defi cits in conceptualization and
abstract thinking. At least one study has shown that donepezil is effective in improving cognitive
defi cits in MS.
Which of the following statements regarding pathological laughing and
crying is true?
A. It is always associated with motor defi cits such as pseudobulbar palsy.
B. Exaggerated crying and laughing is attributed to an underlying mood disorder.
C. Antidepressants have been found to be of no use in treatment.
D. It has been associated with frontal executive function defi cits.
E. By defi nition, patients cannot have a comorbid mood disorder.
D. Pathological laughter and crying is a symptom seen in MS, where approximately 10% of
MS patients are affected, with varying degrees of severity. This is similar to descriptions of the
pseudobulbar affect, although this symptom can be present without pseudobulbar palsy. Patients
are more likely to have frontally mediated cognitive defi cits. Commonly used scales to identify
and characterize this syndrome include the Pathological Laughter and Crying Scale and the
Centre for Neurologic Study–Lability Scale. The most common differential diagnosis is a mood
disorder, but patients with pathological crying exhibit the emotional display in the absence of a
pervasive and sustained elation or depressed mood. But when mood disorder and pathological
laughter and crying coexist, differentiation can be very diffi cult. TCAs and SSRIs have been found
to be effective in the treatment even if no depression is noted
Consciousness is preserved in which of the following types of seizures? A. Tonic–clonic seizures B. Simple partial seizures C. Status epilepticus D. Absence seizures E. Complex partial seizures
B. Epilepsy is a common disorder, affecting approximately 1% of the population and
may involve individuals of any age. Seizures are convulsions that may be produced by a wide
variety of events, including alcohol and drug withdrawal syndromes, hypoglycaemia, transient
cerebral anoxia, and epileptic syndromes. Epilepsies are characterized by recurrent seizures and
their classifi cation is based on seizure type, age of onset, intellectual development, fi ndings on
neurological examination, and results of neuroimaging studies. Seizures are broadly classifi ed into
partial and general forms. Partial seizures are further divided into simple and complex. In simple
partial seizures consciousness is preserved; complex seizures are characterized by disturbances in
consciousness. Partial seizures pertain to one half or one particular area of the brain. Generalized
seizures involve both hemispheres from the beginning of the seizure but, at times, they may
be secondary to spread from a partial seizure. Tonic–clonic seizures and absence seizures are
examples of primary generalized seizures. They are usually associated with a loss of conscious
awareness.
A 45-year-old lady developed recurrent seizures with aura, automatism,
and lip smacking. Ictal EEG showed spike and sharp waves complex along
the right temporal region. Which of the following statements regarding her
diagnosis is not true?
A. The aura itself constitute a simple partial seizure.
B. This presentation is highly suggestive of complex partial seizure.
C. There is an increased chance of this lady developing mania in her lifetime.
D. A right-sided focus increases the risk of depression compared to mania.
E. There is a fi ve-times increase in the risk of suicide compared to the general population.
D. Left-sided foci are associated with an increased risk of depression and right-sided foci
with an increased risk of mania. Mood disorders are the most common type of psychopathology
encountered in patients with epilepsy. Prevalence rates of depression range from 30 to 50% in
patients with epilepsy. With intractable disorders, up to 60% have lifetime histories of depressive
syndromes. In contrast to the incidence of depression in epilepsy, the incidence of mania and
bipolar disorder are at normal or near-normal levels. Some retrospective chart reviews state a
lifetime prevalence of 20%. The incidence of suicide in epilepsy patients is fi ve to 10-fold greater
than in the general population. In those with temporal lobe epilepsy, suicide rates are around
25 times that of the general population
Features suggestive of Geschwind’s syndrome include all except A. Circumstantiality B. Hypographia C. Hyper-religiosity D. Viscosity E. Increased aggression
B. Geschwind’s syndrome is an eponymous syndrome of interictal behaviour/personality
disorder which has been described in temporal lobe epilepsy (TLE). Clinical features of this
syndrome include preoccupation with philosophical and religious concerns, anger, excessive
emotionality, viscosity (noted especially in speech), circumstantiality, altered sexuality, and
hypergraphia. Recent reviews state that personality traits, rather than a personality disorder per
se, seems more likely in these disorders and they tend to resemble the cluster C category of
disorders in DSM-IV
A 23-year-old patient previously diagnosed with epilepsy presents to
casualty with intractable seizures following the breakup of a relationship.
She has been compliant on her medications. The neurologist suspects
psychogenic non-epileptic seizures. Which of the following statements is
true with regard to her condition?
A. A postictal prolactin elevation of two times the baseline level is reliable in diagnosing
true seizures.
B. Up to 80% of patients with seizures have psychogenic non-epileptic seizures.
C. Less than 5% of cases with intractable seizures have psychogenic non-epileptic seizures.
D. Presence of tongue bite and incontinence is diagnostic of true seizures.
E. Video EEG recording is the gold standard for diagnosing psychogenic non-epileptic
seizures.
E. Psychogenic non-epileptic seizures were previously referred to as ‘pseudoseizures’. They
are seizure-like behavioural events that occur in the absence of abnormal electrical discharge
in the brain. The gold standard for diagnosis is video-EEG monitoring. People who present with
non-epileptic seizures commonly have comorbid epilepsy. Nearly 30 to 50% of patients who
have non-epileptic seizures have epilepsy and 20 to 60% of patients who have epilepsy have
non-epileptic seizures. The average age of onset is between 20 and 30 years and it is three times
more common in women than men. Prevalence rates of a history of sexual abuse in non-epileptic
seizures range from 25 to 75%. An elevated prolactin level (usually two times baseline or three
standard deviations above normal) could be due to seizures or any neurological event, such as
syncope. Some patients with pseudoseizures may have modest elevations in prolactin levels.
A normal prolactin may not always be diagnostic of pseudoseizures, since it is frequently normal
in partial seizures and sampling may be mistimed following convulsions
Early onset of major depression is most commonly associated with stroke
pertaining to which of the following regions of the brain?
A. Right anterior
B. Right posterior
C. Left anterior
D. Left posterior
E. Bilateral posterior
C. Historically, left anterior stroke has been associated with depression. This has been
questioned in more recent times—including a few meta-analyses that did not show such a
relationship. The laterality hypothesis of poststroke depression may hold true only in the acute
stage of illness of less than 2 months’ duration. As time passes, the chance of getting a depressive
episode is equal in all kinds of stroke. Major depression occurs in approximately 10–25% of
patients. Anxiety occurs without depression in up to 10%. Apathy occurs in 20% of patients.
Anosognosia with denial of illness is present in 25–45% of patients, particularly those with right
posterior lesions. Catastrophic reactions appear in approximately 20% and emotional lability is
present in 20%. The mean duration of major depression appears to be about 9 months, but can
be chronic, lasting for years in hospitalized patients.
A 67-year-old business man is admitted to a stroke unit. He is having
signifi cant aphasia. He has episodes of anger outburst when someone tries
to communicate with him. Which of the following is false regarding this
‘catastrophic reaction’?
A. Family history of psychiatric disorders is more common in those with catastrophic
reaction.
B. It is associated with the presence of major depression.
C. The reaction is mostly secondary to the presence of aphasia.
D. Patients are more likely to have a personal history of psychiatric disorders.
E. Higher frequency of basal ganglia lesions may be seen.
C. Goldstein instigated the term ‘catastrophic reaction’ to describe a cluster of symptoms
characterized by aggressive outbursts in patients with brain injury. It was ascribed to the inability
of the person to cope with the physical/cognitive defi cit. An important study with respect to
catastrophic reaction was conducted by Starkstein et al. in 1993. The major fi ndings of this study
are as follows. Catastrophic reaction occurs in around 20% of stroke patients. It is associated
with a personal and family history of psychiatric illness. It is also signifi cantly associated with the
presence of poststroke depression. It is more common in anterior subcortical lesions and lesions
involving the basal ganglia. The reaction is not merely a frustration reaction to the presence of
aphasia or cognitive defi cits; it could be present as a symptom on its own or as a behavioural
symptom in a subgroup of depressed patients with anterior subcortical damage.
Which of the following statements about poststroke depression is true?
A. Younger age predisposes to poststroke depression.
B. Cortical atrophy prior to stroke predisposes to poststroke depression.
C. Male sex is a risk factor for poststroke depression.
D. Lower educational status is a risk factor for poststroke depression.
E. Lower socioeconomic status is a risk factor for poststroke depression
B. On the basis of the fact that not all patients with a left anterior or a right posterior lesion
develop depression, other premorbid factors were studied by Starkstein et al. Along with the
presence of family history of affective disorders in those who developed poststroke depression,
they also found that there was no signifi cant relationship between the presence of depression
and demographic variables such as age, sex, education, socioeconomic status, etc. Presence
of premorbid cortical atrophy was found to be a risk factor for depression. Similarly, cortical
atrophy also predicts mania.
A 67-year-old patient with stroke has left inferior quadrantanopia, left
hemineglect, and dressing apraxia with mild hemiparesis on neurological
examination. Which artery is most likely to be involved in the stroke?
A. Posterior cerebral artery
B. Middle cerebral artery
C. Anterior cerebral artery
D. Common carotid artery
E. Internal carotid artery
B. The middle cerebral artery supplies most of the cortical grey matter, including the
parietal cortex. The inferior parietal lobe includes the upper part of the optic radiation which
carries fi bres from upper half of the retina and hence lesions of this area produce inferior
quadrantanopia. Parietal lobe damage also explains the hemineglect, mild hemiparesis, and
dressing apraxia. Carotid artery syndrome usually presents with amaurosis fugax, the feature
distinguishing it from the middle cerebral artery syndrome. Amaurosis fugax is transient, painless
monocular blindness, usually due to emboli either from the large arteries or the heart itself.
Occlusions of the coronaries usually occur at the bifurcation of the common carotid.
Which of the following stages of sleep is characterized by more than 50% delta activity in the EEG? A. Stage 1 NREM B. Stage 2 NREM C. Stage 3 NREM D. Stage 4 NREM E. REM sleep
D. Stage 4 NREM sleep is characterized by more than 50% delta activity. When the delta
activity ranges from 20 to 50%, the person is in stage 3 NREM sleep. K complexes and sleep
spindles along with delta waves of less than 20% is noted in stage 2. Stage 2 is also the longest
sleep stage through the night, comprising almost 50% of adult sleep. Stage 1 is characterized by
gradual slowing of the alpha wave (less than 50% alpha activity). This is the sleep onset. Stage W
(wakefulness) is characterized by predominantly alpha waves posteriorly with low voltage mixed
frequency beta waves anteriorly. REM sleep constitutes around 20–25%. Normally, much less time
is spent in stage W and stage 1.
All the following are features of REM sleep except A. Low brain oxygen consumption B. High cerebral blood fl ow C. Penile erection D. Absent electrodermal activity E. Dream-like mental state
A. Characteristics of REM sleep include variable heart and breathing rate, high oxygen
consumption and cerebral blood fl ow, penile erections (morning erections due to high levels
of REMs), increased vaginal blood fl ow and uterine activity, absent electrodermal activity,
poikilothermic state, and dream-like mental activity. In contrast, NREM sleep is characterized
by regular, slow heart and breathing rate, low cerebral blood fl ow and O2 consumption, absent
penile blood fl ow, and thought-like mental activity. Muscular tone is maintained in NREM sleep
and atonia is seen in REM.
Regarding sleep terror, which of the following statements is false?
A. It is associated with REM sleep disturbance.
B. Vocalizations may occur during the episode.
C. There is usually amnesia for these episodes.
D. It becomes exacerbated by sleep deprivation.
E. It is associated with psychopathology in adults.
A. Characteristics of REM sleep include variable heart and breathing rate, high oxygen
consumption and cerebral blood fl ow, penile erections (morning erections due to high levels
of REMs), increased vaginal blood fl ow and uterine activity, absent electrodermal activity,
poikilothermic state, and dream-like mental activity. In contrast, NREM sleep is characterized
by regular, slow heart and breathing rate, low cerebral blood fl ow and O2 consumption, absent
penile blood fl ow, and thought-like mental activity. Muscular tone is maintained in NREM sleep
and atonia is seen in REM.
Sleep terrors occur in slow-wave sleep (stage 3 and 4) unlike nightmares which occur
in REM sleep. Sleep terrors are characterized by a sudden arousal with intense fearfulness, often
associated with a sharp scream. The subject may sit up in bed, may vocalize unintelligibly, and
waking the individual leads to confusion. There is amnesia for the episode and unlike nightmares
it is very rarely associated with vividly recalled dreams and images. A familial pattern has been
reported. In children, night terrors may be transient but in adults they may be associated with
other psychopathology.
A 25-year-old man complains of excessive daytime sleepiness. He loses
balance and falls down every time he laughs at a joke. He also complains
of seeing ‘ghosts’ while falling asleep. Which of the following is likely to be
found in this patient?
A. A sleep-onset slow wave stage
B. Excess of hypocretin in the hypothalamus
C. Seizure activity on electroencephalography
D. Episodes of sleep paralysis
E. Absence of REM on polysomnography
D. This patient is likely to have narcolepsy. Narcolepsy is a disorder of unknown aetiology.
It consists of the tetrad of excessive day time sleepiness, cataplexy, sleep paralysis, and hypnagogic
hallucinations. Polysomnography typically shows sleep-onset REM stage. Cataplexy refers to
sudden loss of muscular tone, often seen in association with emotional reactions in those with
narcolepsy. An abnormality in the hypocretin neurones in the lateral hypothalamus has been noted
in those with narcolepsy. Hypocretin (orexin) is a highly excitatory peptide hormone secreted
from the hypothalamus. This is necessary to maintain wakefulness and it also increases appetite.
Narcolepsy, especially cataplexy, is considered to be a hypocretin defi ciency syndrome. SSRIs and
TCAs remain the treatment of choice currently. Modafi nil is also being tried as a treatment
All of the following increases the risk of developing dementia in those with
Parkinson’s disease except
A. Older age group
B. Greater severity of motor disturbances
C. Longer duration of Parkinson’s disease
D. Being female
E. Signifi cant functional disability
D. Dementia is estimated to occur in 27% of patients with Parkinson’s disease (PD).
Dementia has been associated with older age, greater PD severity, hallucinations, longer duration
of PD, greater disability, and male gender. Causes of dementia in PD include Lewy body pathology,
dopamine depletion, coexisting AD, and other conditions. Reduced fl uorodopa uptake in the
frontal cortex and caudate nucleus, and in mesolimbic pathways are predictors of cognitive
impairment. Temporoparietal cortical hypometabolism also predicts cognitive impairment.
Donepezil has been found to be useful in two separate double-blind trials in patients with PD.
Which of the following is considered as a ‘Parkinson plus’ syndrome? A. Wilson’s disease B. Fredreich’s ataxia C. Progressive supranuclear palsy D. Amyotrophic lateral sclerosis E. Guillain–Barré syndrome
C. Progressive supranuclear palsy is considered as a Parkinson plus syndrome. It is
distinguished from Parkinson’s disease by the presence of early broad-based and stiff gait
disorder (axial greater than limb rigidity in extension) with backward falls, and supranuclear
gaze palsy with slow vertical saccades and diffi culty looking down (and hence the falls). Falls
are very common in these patients and are an important cause of morbidity. Patients are
prone to develop various psychiatric complications, including cognitive dysfunction and mood
disorders. Cholinesterase inhibitors have not been particularly useful in treating patients with
progressive supranuclear palsy associated dementia. Other Parkinson plus syndromes include
multisystem atrophy (called Shy–Drager syndrome when associated with autonomic failure),
olivopontocerebellar atrophy, and corticobasal degeneration.
A 64-year-old man presents with sudden-onset blindness that started as a
‘curtain coming down’ and he lost his vision completely for a few minutes.
Within 15 minutes this improved and was restored to full, normal vision.
The origin of emboli in this case is most likely to be at
A. Posterior cerebral artery
B. Anterior cerebral artery
C. Internal carotid artery
D. Anterior communicating artery
E. Middle cerebral artery
C. In this case the origin of emboli must be at the internal carotid artery. The ophthalmic
artery, a branch of the internal carotid artery, is blocked transiently, producing the symptoms
described in the question. This is called as amaurosis fugax which translates to ‘fl eeting darkness’.
It is related to transient but sudden monocular visual loss as a result of decreased retinal
circulation. It is a type of transient ischaemic attack and could be a harbinger of a cerebrovascular
accident. Compromise of posterior circulation usually leads to cortical blindness, often with
macular sparing.
A 21-year-old lady is found wandering at a public place. She is unaware of
her address or any other personal details. She was admitted and later found
to be on the missing persons register at a police station 100 miles away.
After 4 weeks, she regains normal memory and remembers having lost her
mother in a fi re accident 6 weeks ago. Which of the following is true about
the nature of her memory problems?
A. Total amnesia for past events may be seen during the episode.
B. No amnesia for the episode will be present following recovery.
C. A vascular aetiology is most likely.
D. Inability to learn new materials will be seen during the episode.
E. Episodes are often accompanied by other neurological symptoms.
A. The given history is consistent with dissociative fugue. Fugue states are associated with
stressful life events wherein total amnesia for the recent past can be seen. More often the
amnesia related to dissociation is circumscribed to events of personal importance. During the
fugue, the patient may retain normal functional activities and may even learn new verbal and nonverbal
materials. Following recovery from the fugue, one may not remember the activities carried
out during the fugue state.
A 63-year-old man with alcohol dependence suffers a serious head injury.
On recovery he is found to have unusual behaviours. When a tooth brush
is placed in front of him, he immediately begins to brush his teeth, even in
entirely inappropriate contexts. He is exhibiting
A. Alien hand syndrome
B. Klüver–Bucy syndrome
C. Utilization behaviour
D. Executive dysfunction
E. Balint’s syndrome
C. This is an example of utilization behaviour. A patient with utilization behaviour will be
forced to ‘utilize’ objects presented to him despite the absence of obvious need for such usage.
An extreme form of this is seen in ‘environmental dependence syndrome’—the patient becomes
compelled to make use of all that is seen in his immediate environment resulting in an array of
serial complex behaviour. Klüver–Bucy syndrome occurs in the context of bilateral temporal
lobe damage. It is associated with hyperorality, inappropriate sexuality, and increased exploratory
behaviour (hypermetamorphosis). Alien hand syndrome refers to loss of control of limb
movements resulting in ‘automatic’ coordinated hand movements. The patient is usually aware of
this and may try to exercise control using the other hand. Balint’s syndrome is characterized by
oculomotor apraxia, optic ataxia, and simultanagnosia
The most probable site of a lesion for the patient described in
Question 47 is
A. Frontal lobes
B. Dominant parietal lobe
C. Occipitoparietal junctions bilaterally
D. Bilateral amygdala
E. Corpus callosum
A. Utilization behaviour is seen in patients with frontal lobe damage. Dominant parietal
lobe lesions result in apraxia, right–left confusion, acalculia, and fi nger agnosia. Balint’s syndrome
occurs in bilateral parieto-occipital damage.
A 32-year-old woman with complex partial seizures is referred to a
psychiatrist to exclude psychosis. She experiences olfactory hallucinations
and intense anxiety. Which of the following is not correct with regard to
complex partial seizures?
A. Temporal lobe is the most common site of origin.
B. Ictal hallucinations are often accompanied by emotional reactions.
C. Patients are often aware of the unreal nature of the hallucinations.
D. Irritability is the most common emotional reaction accompanying the aura.
E. Déjà vu is a well-known phenomenon occurring in complex partial seizures.
D. Temporal lobe is the most common site of origin of complex partial seizures; in very
few cases parietal focus has been demonstrated. When accompanied by hallucinations, intense
emotional reactions may be seen during the seizure. Fear is the most common emotion noted.
Curiously, patients are often aware of the unreal nature of their hallucinatory experiences, but
this awareness is not specifi c to complex seizures. Pathology of familiarity characterized by déjà
vu and jamais vu are commonly reported in temporal lobe epilepsy.
A 78-year-old woman presents with fl uent progressive aphasia with
preservation of new learning and orientation. On follow up she is observed
to have progressive diffi culties in understanding the meaning of words used
during normal conversation. She is most likely to have
A. Alzheimer’s dementia
B. Semantic dementia
C. Lewy body dementia
D. Broca’s aphasia
E. Vitamin B12 defi ciency
B. Progressive fl uent aphasia early in the course of a dementing illness is a feature of
semantic dementia. Semantic dementia is a type of frontotemporal degenerative disorder. The
pathological fi nding is predominantly frontotemporal degeneration with ubiquitin inclusions.
Motor neurone disease type inclusions may also be noted. Semantic memory refers to
representation of meanings, understanding concepts, and knowledge unrelated to temporal
events (cf. episodic memory). Focal cortical defi cits, especially progressive aphasia, can be
presenting features of Alzheimer’s disease but this is uncommon.
Which of the following can be used to test premorbid IQ in patients with neurological damage? A. National Adult Reading Test B. Rivermead Behavioural Memory Test C. Weschler’s Memory Scale D. Mini Mental State Examination E. Minnesota Multiphasic Inventory
A. The National Adult Reading Test (NART) has been widely used as a measure of
premorbid IQ. The usefulness of NART as a measure of premorbid IQ is based on two
assumptions:
1. Reading ability is relatively independent of brain damage.
2. Ability to read irregular words from a list is a strong predictor of intelligence in the normal
population.
Hence in those with brain damage, irrespective of the diagnosis, NART can be used to estimate
the most probable IQ level before becoming ill. However, the notion that the NART score is
relatively independent of brain damage has come under scrutiny of late. Studies in Alzheimer’s
dementia and Korsakoff ’s syndrome have indicated deterioration in reading ability, leading to an
underestimated premorbid IQ.
A 55-year-old man with history of long-standing, untreated hypertension
is brought to A&E by his wife following 3 hours of ‘confusion’. He was
repeatedly questioning her and was not able to remember what he was
doing 30 minutes ago. He is also unaware of events of the past 2 weeks,
despite remembering them until 3 hours ago. Neurological examination
is otherwise unremarkable and he has no psychiatric history. The episode
resolves by itself within 24 hours. Which of the following is false with regard
to his condition?
A. Immediate memory will be intact.
B. Anterograde amnesia will be predominant.
C. Patchy and inconsistent retrograde amnesia will be seen.
D. Visuospatial and problem-solving functions will be affected.
E. Rapid recovery occurs in most individuals.
D. This history is consistent with transient global amnesia (TGA). Sudden-onset amnesia
with inability to form new memories of current events and a variable degree of retrograde
amnesia is seen. The entire episode lasts for hours to days and on recovery the extent of
retrograde amnesia shrinks and almost intact memory for events that happened before the
episode is restored, but a dense amnesia persists for the events during the episode (24 hours in
this case) even after full recovery. During the episode itself, the procedural memory, visuospatial
functions, and problem-solving ability are intact; the patients may even be able to drive during the
episode.
Abnormalities in which of the following vascular territories is implicated in
the presentation described in Question 52?
A. Anterior cerebral circulation
B. Middle cerebral circulation
C. Posterior cerebral circulation
D. Cortical venous sinus outfl ow
E. Middle meningeal circulation
C. TGA is thought to be vascular in origin. Posterior cerebral circulation (vertebrobasilar
insuffi ciency) is implicated, which supplies signifi cant part of hippocampal and other medial
temporal regions. Migrainous or epileptic aetiology has not been entirely disproved. Obstruction
to cortical sinuses may be related to idiopathic intracranial hypertension in some cases. The
middle meningeal artery may be injured in skull fractures, often becoming a source of extradural
haematoma.
A patient with long-standing, uncontrolled type 2 diabetes presents with
anterior spinal artery occlusion. Which of the following sensations carried
by the spinal cord is most likely to be affected?
A. Proprioception
B. Vibration
C. Pain
D. Joint position
E. Light touch
C. The anterior spinothalamic tract is supplied by the anterior spinal artery. The
spinothalamic tract carries pain and temperature sensations. Posterior tracts such as dorsal
columns of gracilis and cuneatus carry joint sense, light touch, proprioception, and vibration
sensations. Infarction of the spinal cord usually involves the territory of the anterior spinal
artery—the ventral two-thirds of the spinal cord.
Which of the following structures is a part of cerebellum? A. Dentate nucleus B. Red nucleus C. Substantia nigra D. Subthalamic nucleus E. Insular cortex
A. The cerebellum has an external cortical grey matter and the deep cerebellar nuclei.
There are four deep nuclei: dentate, globose, emboli-form, and fastigial nuclei. Mossy fi bres and
climbing fi bres provide the major input into the cerebellum. Substantia nigra and subthalamic
nucleus are part of basal ganglia. Red nucleus is an upper brainstem nucleus seen at the level of
tegmentum. Similar to substantia nigra, red nucleus also contains iron pigments. It is involved in
motor coordination
Which of the following is true with respect to pseudobulbar palsy?
A. It is caused by diffuse brain stem damage.
B. It is often accompanied by fl accid tongue.
C. Jaw jerk is exaggerated.
D. It is seen in poliomyelitis.
E. Frontal release signs are inconsistent with the diagnosis
C. Pseudobulbar palsy is also known as spastic bulbar palsy. It usually results from
bilateral frontal damage. This may be due to vascular, demyelinating, or motor neurone disease
(amyotrophic lateral sclerosis). Diffuse brainstem damage (bulb) will produce lesions in the
cranial nerve nuclei, causing bulbar palsy. Pseudobulbar palsy is an upper motor neurone type of
lesion. Bulbar palsy produces lower motor neurone damage. Hence increased tone (producing
spastic tongue), exaggerated tendon refl exes (brisk jaw jerk), and lack of fasciculations are
notable. Diffuse frontal damage may produce frontal release signs. Poliomyelitis, diptheria, and
Guillain–Barré syndrome are known causes. The most common cause of progressive bulbar palsy
is motor neurone disease
Lesions of the subthalamic nucleus are associated with A. Chorea B. Hemiballismus C. Tics D. Epilepsy E. Visual neglect
B. Lesions of the subthalamic nucleus are associated with hemiballismus. Lesions of the
caudate nucleus are associated with chorea. Disturbances in the GABA system of caudate
nucleus are noted in Huntington’s disease. Similarly, damage to the caudate nucleus is implicated
in Sydenham’s chorea seen in streptococcal infection. Parkinsonian movement disturbances,
especially bradykinesia, are associated with damage to the substantia nigra
Which of the following neuropsychological tests is primarily used to detect errors in set-shifting capacity? A. Tower of London B. Rey Osterrieth Complex Figure Test C. Wisconsin Card Sorting Test D. Word Fluency Test E. Letter Cancellation Test
C. Set shifting is an executive function. In the Wisconsin Card Sorting Test, abstract
reasoning and fl exibility in problem solving are tested. In this test, cards of different colour, form,
and number are available. Patients are asked to sort the cards into groups according to varying
categories (colour only, form only, or number only) as requested by the examiner. This measures
the capacity for abstract thinking and set-shifting ability (cognitive fl exibility). Tower of London
is a problem-solving test; it involves frontal and basal ganglia function but does not directly test
set-shifting ability. Rey Osterrieth fi gure is a test of visual memory wherein a complex geometric
fi gure is given to be copied, followed by immediate reproduction from memory and reproduction
after a delay.
A 72-year-old man is afflicted with stroke. He is not able to identify objects
with their correct names but is able to demonstrate the usage correctly.
When the correct name is given to him, he is able to recognize it correctly.
He is suffering from
A. Motor aphasia
B. Apraxia
C. Anomic aphasia
D. Sensory aphasia
E. Abulia
C. Anomic (or nominal) aphasia presents with inability to name objects and body parts.
Patients have fl uent speech, intact repetition, intact comprehension, reading, and writing. Nominal
aphasia often presents together with, or may follow, recovery from other forms of aphasia.
Nominal aphasia is not very useful for lesion localization. It is also noted in early Alzheimer’s
disease.
The blood supply to the hippocampus comes from the A. Basilar artery B. Anterior communicating artery C. Anterior cerebral artery D. Anterior choroidal artery E. Lenticulostriate arteries
D. The blood supply to the rostral third of the hippocampus comes from the anterior
choroidal artery, which is a direct branch of the internal carotid artery. It does not take part in
the circle of Willis anastamosis. The occipital two-thirds are supplied by hippocampal branches,
the posteromedial choroidal artery, and the inferior temporal branches of the posterior cerebral
artery.
In early Alzheimer’s disease, widespread loss of nerve cells is most
pronounced in which of the following structures?
A. Layer III of cerebral cortex
B. Layer IV of entorhinal cortex
C. Layer I of cerebral cortex
D. Layer II of entorhinal cortex
E. Layer IV of cerebral cortex
D. Early in the Alzheimer’s disease neuronal loss is most pronounced in layer II of the
entorhinal cortex of the hippocampus. The parahippocampal gyri and subiculum are also affected.
This extends to anterior nuclei of the thalamus, septal nuclei, amygdala, and monoaminergic
systems of the brainstem are also depleted. The cholinergic neurones of the nucleus basalis of
Meynert are also reduced. In cerebral cortex, most pronounced loss occurs with respect to
pyramidal neurones and astrocytic proliferation follows as a compensatory or reparative process,
most prominently in layers III and V.
Glutamate-induced excitotoxicity is proposed as a cause of which of the following conditions? A. Huntington’s disease B. Crutzfeld–Jakob disease C. Wilson’s disease D. Korsakoff ’s syndrome E. Weber’s syndrome
A. Excessive stimulation of glutamate receptors leads to an increase in intraneuronal
calcium and nitric oxide. Calcium activates proteases that could destroy the neurone from
within. Memantine is an NMDA antagonist used in the treatment of Alzheimer’s disease, based
on the excitotoxicity hypothesis. This mechanism may be applicable for Parkinson’s disease too.
In Huntington’s disease, an expansion of the polyglutamine region of huntingtin takes place
due to the disease-causing mutation. Hence the mutant huntingtin protein accumulates in the
nuclei of neurones, preferentially in striatum and cortex. These aggregates may be directly
toxic to some extent, but predominant striatal loss, as opposed to cortical loss, may be due to
glutamate-mediated excitotoxicity. Huntingtin accumulation may render cells unusually sensitive
to glutamate-mediated damage
Which of the following is a feature of occlusion of the right-sided posterior
inferior cerebellar artery?
A. Left-sided loss of facial pain sensation
B. Left-sided loss of facial temperature sensation
C. Loss of pain sensation on the right side of the body
D. Loss of temperature sensation on the left side of the body
E. Mydriasis of the right eye
D. Posterior inferior cerebellar artery occlusion leads to Wallenberg’s syndrome. The
resulting signs and symptoms are attributed to infarction of a wedge of lateral medulla that
contains vestibular nuclei, descending sympathetic tract, spoinothalamic system (carrying pain
and temperature from contralateral side of body), descending fi fth nerve tract and nucleus, and
ninth and tenth nerve fi bres of same side. This leads to ipsilateral Horner’s syndrome (miopsis,
anhidrosis, and ptosis due to sympathetic damage), ipsilateral loss of face sensation (fi fth nerve
damage), dysphagia, hoarseness, loss of gag refl ex (ninth/tenth nerve damage), and contralateral
loss of pain and temperature over half of the body.
A 65-year-old man presents with memory diffi culties and loss of balance.
He has signifi cant, new-onset urinary incontinence. CT scan of the brain
shows dilated ventricles but no signifi cant widening of sulci. The most likely
diagnosis is
A. Normal-pressure hydrocephalus
B. Alzheimer’s dementia
C. Lewy body dementia
D. Benign intracranial hypertension
E. Alcoholic dementia
A. The age of the patient, the triad of memory diffi culties, loss of balance, and urinary
incontinence, and the neuroimaging fi ndings suggest normal-pressure hydrocephalus (NPH).
NPH is not a hydrocephalus in the true sense—there is no increase in intracranial pressure when
lumbar puncture is carried out. Following certain meningeal insults, secondary to subarachnoid
haemorrhage, head trauma, or resolved meningitis, an increase in intracranial pressure may
develop but reach a stable stage where formation of CSF diminishes and equilibrates with
absorption, which increases proportionate to the pressure. Once this equilibrium is reached
there must be a gradual fall in pressure, although at a high normal level. In some patients, this high
normal intracranial pressure of 150 to 200 mm H2O leads to manifestation of NPH.
During polysomnographic recording of a patient with sleep disturbances,
it is observed that his heart rate and blood pressure are lower than that
recorded during normal wakefulness. His muscle tone is also notably low.
Which of the following is true with respect to his physiological state?
A. Vivid memory of dreams occur at this stage.
B. If awakened from this stage there will be some degree of confusion.
C. Penile erection occurs automatically at this stage of sleep.
D. High cerebral blood fl ow is seen at this stage.
E. In adults, 25% of sleeping time is spent in this stage of sleep.
B. The presence of low heart rate, muscle tone, and blood pressure is suggestive of NREM
sleep. At this stage of sleep if a person is awakened, he will be confused. He may not recollect
the instance of awakening in the morning. A normal adult spends nearly 75% of sleep in various
NREM stages, while the remaining 25% is REM sleep. Penile erection, high cerebral blood fl ow,
and vividly recalled dreams are features of REM stage
The frequency of alpha waves seen in EEG recordings is A. >13 Hz B. 8–12 Hz C. 4–8 Hz D. 0.5–4 Hz E. <0.5 Hz
B. Alpha, beta, delta, and theta are four important wavelets in EEG when awake. Alpha waves
are predominant, especially posteriorly when the eyes are closed; they occur at a frequency of
8 to 13 Hz. Beta waves are sometimes seen in normal EEG over central, anterior regions; they
occur at a frequency higher than 13 Hz. Theta activity is seen infrequently when awake but often
when a subject is drowsy or sleeping. Excessive theta when awake is abnormal. Delta waves
(frequency less than 3.5 Hz) are normally seen only in deep sleep and are pathological if noted in
adult waking EEG. With ageing, slow waves become more common in EEG.
Diffuse fl attening of EEG with low-amplitude theta and delta waves is seen in A. Huntington’s disease B. Alzheimer’s dementia C. Hepatic encephalopathy D. Delirium tremens E. Crutzfeld–Jakob disease
A. Huntington’s disease is characterized by diffuse fl attening or loss of alpha waves in EEG.
In a study conducted in a group of 95 patients with Huntington’s chorea, 31 showed little activity
of any kind (fl at trace EEG) and in particular no alpha rhythm above 10 μV in amplitude was seen.
There was a statistically signifi cant association between cortical atrophy, especially the frontal
lobe, and a ‘low voltage’ EEG in the same study. Such low-voltage records, though not specifi c for
Huntington’s chorea, are rare in other neurological disorders
Which of the following functions is mediated by endogenous cannabinoids? A. REM sleep induction B. Motor coordination C. Peripheral sympathetic modulation D. Gut motility E. Mediation of intraocular pressure
E. Two types of cannabinoid receptors, central (CB1) and peripheral (CB2), have been
identifi ed. Both receptors bind to exogenously administered tetrahydrocannabinol (THC),
present in marijuana. Anandamide (from the Sanskrit word ‘ananda’ for bliss) is chemically
N-arachidonoylethanolamine (arachidonic acid and ethanolamine derivative). It is a weak
endogenous cannabinoid ligand. 2-arachnidonylglycerol is a strong endogenous ligand for the
cannabinoid receptor. Endogenous cannabinoids exhibit intraocular pressure-lowering effects.
They also decrease motor activity level and relieve pain. Anandamides are demonstrated in the
thalamus, with a putative role in pain-related neurotransmission.
A 22-year-old man is diagnosed with craniopharyngioma. He is experiencing
symptoms due to the tumour pressing upon adjacent brain tissue. Which of
the following visual defect is characteristic of this tumour?
A. Tunnel vision
B. Homonymous hemianopia
C. Binasal hemianopia
D. Bitemporal hemianopia
E. Superior quandrantonopia
D. Bitemporal hemianopia is secondary to chiasmatic lesions. Pituitary tumours
characteristically cause bitemporal hemianopia. Craniopharyngioma is a benign epithelioid
tumour arising from remnants of Rathke’s pouch at the junction of the infundibular stem and
pituitary. It lies above the sella turcica and so exerts pressure effects on the optic chiasm
leading to bitemporal hemianopia. Tunnel vision is a result of extensive peripheral fi eld defects.
Quadrantanopias usually result from damage to the optic radiation beyond the chiasma. Parietal
lesions result in inferior, while temporal lesions result in superior, quadrantanopia.
Priapism is a side-effect associated with which of the following? A. α1 receptor stimulation B. α2 receptor stimulation C. α1 receptor blockade D. α2 receptor blockade E. Nicotinic cholinergic stimulation
C. Priapism is defi ned as a persistent penile erection greater than 4 hours in duration,
which is unrelated to sexual stimulation or desire. Roughly 40 to 50% of patients who develop
priapism become impotent, even after surgical treatment. Drug-induced priapism accounts for
15–40% of all cases. Psychotropics associated with priapism include trazodone, phenothiazines,
butyrophenones, risperidone, and clozapine. Priapism results from decreased venous outfl ow
from the corpora cavernosa of the penis. This can be caused by obstruction of the venous system,
for example by blood dyscrasias such as sickle cell anaemia or by blocking the sympathetically
mediated (α1 receptor) detumescence. Hence the ability of a drug to block α1 receptors
correlates with its risk of priapism. This is especially true if the antiadrenergic effect is unopposed
by an equally strong anticholinergic effect. Sympathetic tone is related to detumescence while
parasympathetic tone is related to erection. For drugs with combined antiadrenergic and
anticholinergic activity, when antiadrenergic activity negates detumescence, the anticholinergic
activity will negate erection and so priapism will be rare.
Metacognitive abilities are proposed to be functions of the frontal lobe.
Metacognition refers to
A. Planning and sequential execution of motor acts
B. Ability to refl ect on one’s own cognitive processes
C. Problem-solving ability
D. Initiation and sustainment of motivation
E. Automatic cognitive processing without selected focus of attention
B. Metacognition refers to one’s knowledge concerning one’s own cognitive processes
and products of such processes. Metacognition is predominantly a function of prefrontal cortex.
Prefrontal damage leads to overestimation of abilities, lack of awareness of defi cits, and inability to
use feedback to change behaviour.
The ‘n-back test’ consists of making a response in accordance with a visual
or auditory stimulus presented ‘n’ items before the currently displayed
stimulus. This test is widely employed in neuroimaging paradigms primarily
to enable engagement of which of the following brain areas?
A. Frontal lobes
B. Occipital lobes
C. Cerebellum
D. Hippocampus
E. Amygdala
A. ‘N back’ test is a popular experimental paradigms for functional neuroimaging studies
of working memory. In this test subjects are asked to monitor a series of verbal or non-verbal
stimuli and to indicate when the currently presented stimulus is the same as the one presented
n trials previously. Using quantitative meta-analysis technique of normative functional imaging
studies, a broadly consistent activation of frontal and parietal cortical regions by various versions
of the n-back working memory paradigm has been demonstrated
Which of the following toxins has been used to simulate a model of
Parkinson’s disease?
A. Ketamine
B. Methyl phenyl tetrahydropyridine (MPTP)
C. Methylene dioxy methamphetamine (MDMA)
D. Vanillyl mandelic acid (VMA)
E. Hydroxy indole acetic acid (5HIAA)
B. MPTP occurred as an impurity when illicit synthesis of opioids was attempted by a
chemistry graduate student. He developed acute parkinsonian disease. Following detailed
investigations, animal models of Parkinson’s disease have been developed using MPTP as a
neurotoxin. VMA is a metabolite of epinephrine; 5HIAA is a metabolite of serotonin. MDMA
is the chemical name for ecstasy. Ketamine is a dissociative anaesthetic that stimulates sigma
receptors in brain. It is being increasingly used as a street drug.
How many layers are present in the laminar structure of the human cerebral cortex? A. Three B. Four C. Twelve D. Six E. Two
D. Human neocortex consists of a six-layered laminar structure. This cytoarchitectural
division has been largely adapted from Brodmann’s pioneering work. These six layers are
numbered from the top, that is the pial surface to the underlying white matter. In order, these are:
1. Molecular (or plexiform)
2. External granular layer
3. External pyramidal
4. Internal granular
5. Internal pyramidal (or ganglionic)
6. Multiform (or fusiform) layer.
The layers vary mostly in the size and density of pyramidal and stellate cells
Which of the following nuclei of the thalamus is primarily involved in the
relay of information for visual processing?
A. Supraoptic nucleus
B. Dorsomedial nucleus
C. Medial geniculate nucleus
D. Suprachiasmatic nucleus
E. Lateral geniculate nucleus
E. Lateral geniculate nucleus is the junction where axons of retinal ganglion cells terminate
after passing through uninterrupted via the optic nerve, optic chiasm, and optic tract. The medial
geniculate body is involved in auditory processing.
Which of the following cells are the only excitatory neurones in the cerebellum? A. Purkinje cells B. Basket cells C. Stellate cells D. Granule cells E. Golgi cells
D. Granule cells are the only excitatory neurones in the cerebellum. The cerebellar cortex
is a three-layered structure with the outermost layer containing two types of inhibitory neurones,
the stellate cells and basket cells. The middle layer has cell bodies of Purkinje cells (main output)
which are GABA-mediated and so are inhibitory in function. The innermost layer contains granule
cells, which are excitatory, and Golgi cells, which are inhibitory
Which of the following components of cognition is tested by the digit span task? A. Working memory B. Implicit memory C. Sensory memory D. Autobiographic memory E. Procedural memory
A. Working memory can be tested using digit span tasks. Using digit repetition forward,
a patient’s working memory capacity can be tested. Usually, a list of numbers (in no specifi c
pattern) is read aloud by the examiner and the patient is asked to repeat it immediately in same
order (forward span) or reverse order (backward span). Gradually, the length of the numeric
string is increased. Consistent error at a particular length is an indication for test termination. The
normal forward digit span is 7±2 for most adults. Backward span is more diffi cult and averages
around 5±2.
Ataxia can result from cerebellar lesions or posterior column lesions.
Though gait disturbances are predominant in both these conditions, which
of the following is seen in sensory ataxia but not cerebellar ataxia?
A. Nystagmus
B. Dysarthria
C. Loss of tendon refl exes
D. Absence of Romberg’s sign
E. Intact joint position sense
C. Sensory ataxia is due to posterior column disease, resulting from spinal cord lesions.
In this condition, loss of joint position sense and loss of tendon refl exes are seen. In cerebellar
ataxia, associated cerebellar signs such as dysarthria or nystagmus may be present. The corrective
effects of vision on balance and posture are seen in sensory ataxia. This is elicited by Romberg’s
test wherein swaying, which is almost absent when eyes are open and feet together, becomes
prominent on eye closure. In cerebellar ataxia, the patient may sway even with eyes open, which
worsens on eye closure
The ability of neurones to change the connection strength with other
neurones underlies the electrophysiological process called long-term
potentiation (LTP). Which of the following forms the neurochemical
basis of LTP?
A. Acetylcholine via nicotinic receptors
B. Substance P
C. Glutamate via NMDA receptors
D. Dopamine via D4 receptors
E. Cannabinoids via CB1 receptors
C. Long-term potentiation (LTP) is conceptualized as a more or less permanent increase
in synaptic effi cacy following high-frequency activity across the synapse. Glutamate via NMDA
receptor activation infl uences LTP. This may underlie changes in synaptic plasticity observed in
learning- and memory-related processes. LTP is proposed to be the cellular biological correlate
of long-term memory.
Which of the following is a major dopaminergic site? A. Nucleus basalis B. Ventral tegmental area C. Dorsal raphe nucleus D. Spinal interneurones E. Locus coeruleus
B. Most neurones from the ventral tegmental area of midbrain ascend in the medial
forebrain bundle and the nigrostriatal pathway. These neurones are rich in dopamine. The
dopamine neurones of the ventral tegmental area (VTA) are thought to play a central role
in reward, motivation, and drug addiction. Nucleus basalis of Meynert is a major cholinergic
site. Dorsal raphe nucleus is predominantly a serotonergic site. Locus coeruleus contains
noradrenergic neurones
Which of the following brain regions shows a preferential degeneration in Alzheimer’s disease? A. Nucleus basalis B. Ventral tegmental area C. Dorsal raphe nucleus D. Spinal interneurones E. Locus coeruleus
A. Nucleus basalis of Meynert contains a majority of cholinergic neurones. Apart from
hippocampal (entorhinal cortex) neuronal loss, selective loss of neurones in the nucleus basalis
has led to the pursuit of cholinergic theories of memory impairment in dementia. Currently
available pharmacological interventions largely target cholinergic defi ciency in Alzheimer’s
disease.
Processing of fear conditioning is associated with functions of the A. Planum temporale B. Heschl’s gyrus C. Amygdala D. Anterior pituitary E. Angular gyrus
C. SM, a patient with rare bilateral amygdala damage, was initially reported to lack the ability
to recognize fear from facial expressions. Since the report of her case, a number of lesion and
functional imaging studies have demonstrated the role of the amygdala in fear processing. It is
possible that the amygdala mediates spontaneous fi xations on the eyes when viewing expressions
of faces. Lack of such fi xation may lead to failure of spontaneous processing of fearful emotions
Which of the following enzymes involved in neurotransmitter synthesis is
directly affected by pyridoxine defi ciency?
A. Glutamate decarboxylase
B. Acetyl cholinesterase
C. Dopamine hydroxylase
D. Tyrosine hydroxylase
E. Tryptophan hydroxylase
A. Pyridoxine (vitamin B6) when phosphorylated to pyridoxal phosphate acts as a coenzyme
in the conversion of glutamic acid to GABA, mediated by the rate-limiting enzyme glutamate
decarboxylase. The pivotal role of this chemical interaction is evident from pyridoxine-dependent
seizures, which can occur in relation to mutations of chromosome 5q31. Dysfunction of this
enzyme leads to glutamate accumulation and excitatory damage via NMDA receptors
Which of the following brain areas has a relatively permeable blood–tissue interface? A. Anterior pituitary B. Hippocampus C. Subfornicular organ D. Cerebellum E. Lateral surface of frontal lobes
C. The circumventricular organs are midline structures around the third and fourth
ventricles. Pineal gland, median eminence, neurohypophysis, subfornical organ, area postrema,
subcommissural organ, organum vasculosum of the lamina terminalis, and the choroid plexus
are considered as circumventricular organs. These structures lack the blood–brain barrier seen
in other regions of brain. These areas enable the brain’s direct response to chemical challenges
in blood.
Which of the following terms refers to a substance that infl uences neuronal
activity and originates from non-synaptic sites?
A. Neurotransmitter
B. Neurotrophin
C. Neuromodulator
D. Second messenger
E. Neurohormone
C. A neuromodulator is a substance that enhances or diminishes the effect of
neurotransmitters but does not usually result in neuronal conduction changes on its own.
Substance P, enkephalin, cholecystokinin, somatostatin, and neuropeptide Y are examples
of neuromodulators. Neurotrophin is a substance produced to infl uence neuronal growth.
Neurohormones are substances released by neurones into the blood stream to infl uence
effector organs at distant sites, for example corticotrophin-releasing hormone.
Which of the following neurotransmitters act as a physiological antagonist for acetylcholine? A. Serotonin B. Substance P C. Neurokinin D. Norepinephrine E. Nicotine
D. Norepinephrine acts as physiological antagonist for acetylcholine. Physiological
antagonism is defi ned as the process wherein two chemical molecules that act through two
different receptor systems result in opposing actions in the body that tend to negate each other’s
physiological effect. Insulin and glucagon can be considered as physiological antagonists, to some
extent.
Which of the following is not a ligand-gated ion channel? A. Nicotinic cholinergic receptors B. GABAA receptors C. Glycine receptors D. NMDA receptors E. Muscarinic cholinergic receptors
E. Muscarinic receptors act via the G protein-coupled second messenger system. Nicotinic
cholinergic receptors operate via ligand gated channels that are permeable to Na+, K+ and
sometimes Ca2+. GABAA receptors are also ligand-gated ion channels that allow Cl– ions to pass
through, resulting in inhibitory activity. Glycine receptors are strychnine-sensitive ligand-gated
ion channels with inhibitory activity. Metabotropic receptors aside, most glutamate receptors
(NMDA, AMPA, and kainate) are ionotropic and allow Ca2+ transit (NMDA, AMPA) or Na+, K+
transit (kainate) via ligand-gated channels
