Applied Neuroscience Flashcards
Name some frontal tests
Similarities Lexical fluency Luria motor test Go/on go test Cognitive estimates test Trail making test Alternative pyramids Proverb interpretation Frontal release signs Digit span
What is the similarities test?
Comparing two objects to test the ability of categorisation and not a description of common parts.
This tests abstract ability.
What does the similarities test.. test?
Frontal lobe
Abstract ability
What is the lexical fluency test?
Naming items such as animals - category fluency or
generation of words starting with letters FAS (word fluency).
What does lexical fluency test?
Speed and accuracy
Ability to shift from one set of objects to the next
Frontal lobe
What is the luria motor test?
Fist palm edge.
What does Luria motor test.. test?
Motor planning
Exectition
Error correction
Frontal lobe
What does the go/on go test.. test?
Response inhibition
Absence of perseveration
Resistance to interference
What is the cognitive estimates test?
E.g. How tall is an average English woman?
Uses questions that need abstract not mere factual thinking.
Give examples of tests that test abstract ability
Similarities Test
Cognitive estimates test
What is the trail making test?
Firstly, simple number sequence used to join dots.
Secondly, use alternating numbers and letters - more sensitive to frontal lobe dysfunction.
What does trail making test?
Frontal lobe Visuomotor tracing Attention Conceptualisation Set shifitng
Name some parietal tests
Copying shapes Identifying fingers Calculation ability Graphesthesia Right Left orientation Stereognosis Two point discrimination Visual inattention
Describe the copying shapes test.
Ability to draw shapes and construct geometrical patterns.
Describe the identifying fingers test.
Test the ability to recognise the touched finger when eyes are closed.
Test ability to correctly show ones index, middle and ring fingers.
Interlocking fingers test - ability to copy examiners interlocking fingers.
What does identifying fingers test.. test?
Dominane parietal damage causes finger agnosia as part of Gerstmann syndrome.
What is the calculation ability test?
Tests simple mathematical function.
What if often intact in calculation ability even if parietal dysfunction?
Recognition and use of numbers - arithmetic ability.
What does calculation ability test.. test?
Dominant parietal damage can cause acalculia as part of Gerstmann syndrome.
Describe Right left orientation test
Test for ability to touch right ear lobe with left index finger when eyes closed.
What does Right left orientation test.. test?
Dominant parietal damage can cause right-left disorientation as part of Gerstmann syndrome.
What is the stereognosis test?
Ability to recognise objects by palpation, without visual inspection.
What does stereognosis test?
Bilateral parietal function - somatosensory cortices.
What does the two point discrimination test.. test?
Cortical sensation
Bilateral somatosensory cortical function
Describe the visual inattention test
Letter or star cancellation task
Line bisection test
Draw a person/tree tasks
What are you looking for in the visual inattention test?
Hemineglect - feature of parietal lesions.
Signs and symptoms of unilateral front lobe lesion
Contralateral spastic hemiplegia
Elevation of mood, increased talkativeness, tendency to joke inappropriately (Witzelsuch)
Frontal release signs (grap/suck reflexes)
Anosmia
Signs and symptoms of left frontal lobe lesion
Motor speech disorder with agraphia with or without oro-buccal apraxia
Loss of verbal fluency with persevaration
Signs and symptoms of bilateral frontal lobe lesions
Bilateral hemiplegia
Spastic bulbar palsy
Abulia (indecisiveness, lack of drive)
Decomposition of gait and sphincter incontinence
Combination of grasping, sucking, obligate imitative movements, ulitization behaviour
Specific frontal syndromes?
Pseudo depressive
Dysexecutive
Pseudo psychopathic
What is a gelastic seizure?
Epileptic fit of incessant laughter, from left prefrontal seizure
Signs and symptoms of unilateral parietal lobe lesion
Corticosensory syndrome and sensory extinction
Mild hemiparesis
Homonymous hemianopia or inferior quadrantanopia
Sign of right parietal lobe lesion
Neglect of opposite side of external space
Sign of left parietal lobe lesion
Gerstmann syndrome
What is Gerstmann syndrome?
Dysgraphia
Dyscalculia
Finger agnosia
Right-left confusion
What causes Gerstmann syndrome?
Lesion in left parietal lobe
Signs and symptoms of bilateral parietal lobe lesions
Spatial disorientation and visual spatial defects
Bilateral ideomotor and ideational apraxia
Tactile agnosia
Balint syndrome
Signs of unilateral temporal lobe lesion
Homonymous upper quadrantanopia Wernickes aphasia Degrees of amusia and/or visual agnosia Dysnomia IMpairment auditory verbal learning
Signs of bilateral temporal lobe lesions
Hallucinations Dreamy states with uncinate seizures Emotional and behavioural changes Disturbance of time perception Korsakoff amnesic defect (hippocampaal formations) Apathy and placidity Hypermetamorphospia - compulsion to attend to all visual stimuli Kluver-Bucy syndrome
Signs of Kluver-Busy syndrome
Hyperorality
Hypersexuality
Blunted emotional reactivity
Where is the lesion in homonymous upper quadrantanopia?
Unilateral temporal lobe
What is Geschwind syndrome?
Personality change reported in all epilepsy patients.
Pathology underlying Geschwind syndrome?
Due to lost connectivity among cerebral areas.
Symptoms of Geschwind syndrome?
Hypergraphia Circumstantiality Interpersonal viscosity Hyperreligiosity Hyposexuality
What is the most common aura in epilepsy?
Autonomic
Give e.g. of autonomic auras
Salivation
Vertigo
What is a forced thinking aura?
Individual has a compulsion to think on a certain restricted topic
What is evocation of thought aura?
Intrusion of stereotyped words or thoughts
Name auras of temporal lobe epilepsy
Autonomic sensations Forced thinking Evocation of thought Sudden obstruction to thought flow Panoramic memory Psychic seizures Uncinate crises Transient dysphagia Strong affective experiences Dostoevsky's epilepsy
What is Doestoevsky’s epilepsy?
Temporal lobe aura - ecstatic content
Common emotions in strong affective experiences aura?
Fear and anxiety
What is the uncinate crises aura?
Hallucinations of taste and smell associated with dream like reminiscence and altered consciousness
What is psychic seizures aura?
Isolated auras with hallucinations, depersonalisations, micropsia or macropsia, deja vu/jamais vu
What is panoramic memory aura?
Recall of expansive memories in incredible detail
Signs of unilateral occipital lobe lesions
Contralateral homonymous hemianopia - central/peripheral
Elementary (unformed) hallucinations
Visual object agnosia
Visual illusions - metamorphosis and hallucinations
What are elementary hallucinations often due to?
Irritative unilateral occipital lobe lesions
Which sign is more common right right-sided occipital lobe lesion?
Visual hallucinations
Which signs are common in unilateral occipital lobe lesion involving deep white matter or splenium of corpus callosum?
Alexia
Color-naming defect
Signs of bilateral occipital lobe lesions
Cortical blindness (pupils reactive) Anton syndrome Achromatopsia - loss of perception of colour Prosopagnosia Simultanagnosia Balint syndrome
What is Anton syndrome?
Denial of cortical blindness
Visual anosognosia
What signs are more common in parieto-occipital lesions?
Simultanagnosia
Balint syndrome
What sign is more common in temporo-occipital lesion?
Prosopagnosia
What is the most widely used intelligence test in clinical practice?
Wechsler Adult Intelligence Scale
Age range for Wechsler Adult Intelligence scale?
16-89 y/o
What age is Wechsler Preschool and Primary scale used for?
4-6.5 years of age
What is the Wechsler Adult intelligence scale composed of?
11 subtests:
6 verbal
5 performance
Lead to verbal, performance and combined IQ
What are the verbal tests in the Wechsler Adult intelligence scale?
Similarities Arithmetic Digit span Vocabulary Information Comprehension
What are the performance tests Wechsler Adult intelligence scale?
Picture arrangement Block design Picture completion Digit symbol Matrix reasoning
What are hold tests in Wechsler Adult intelligence scale?
Resistant to age-related decline. May be sensitive for organic brain damage.
What are the hold tests in Wechsler Adult intelligence scale?
Vocabulary
Information
Picture completion
Object assembly/matrix test
What are the non-hold tests in Wechsler Adult intelligence scale?
Block design
Digit span
Similarities
Digit symbol
How are the scores from hold and non-hold tests derived in Wechsler Adult intelligence scale?
Using a deterioration quotient
What is the Raven’s progressive matrix?
IQ test that is independent of education of cultural influences.
What tasks are used in Raven’s progressive matrix?
Visuospatial problem-solving (Performance IQ)
What ability is resistant to organic brain damage?
Reading
What is used to estimate premorbid IQ?
National adult reading test
What does the National adult reading test.. test?
Previous word knowledge prior to becoming ill
What is the stroop test?
Measures set shifting abilities and response inhibition
What does the stroop test.. test?
Frontal function
Ability to pay selective attention
What does the Wisconsin Card Sorting Test.. test?
Abnormal in people with frontal lobe damage/caudate and some schizophrenics
Method of Wisconsin Card Sorting test
Stimulus of cards of different colour, form and number.
Present to patients to sort into groups according to principle e.g. sort by colour, ignore form and number.
Which four tests.. test set-shifting ability and thereby executive functioning?
Trail Making Test
Wisconsin Card Sort Test
Hayling Test (sentence completion)
Bixton task
What is the most widely used memory test battery for adults?
Wechsler Memory Scale-Revised
What does the Wechsler Memory Scale-Revised test for?
Yields a memory quotient which is corrected for age and approximates the WAIS IQ.
In amnesic conditions, a disproportionately low MQ but preserved IQ is seen.
What does the Wechsler Memory Scale-Revised consist of?
Verbal paired associate Paragraph retention Visual memory for designs Orientation Digit span Rote recall of alphabet Counting backwards
What is the Benton Visual Retention Test?
Short term visual memory test
What does the Benton Visual Retention Test consist of?
Presentation of geometric figure for 1- seconds, after which patient attempts to draw figure from memory.
What does the Bender Visual Motor Gestalt Test.. test?
Visuomotor coordination - both adults and children
What did Halstead and Reitan create?
Battery of tests to determine location of specific brain lesions.
Name the tests created by Halstead and Reitan.
Category Test Tactual performance test Rhythm test Finger-oscillation test Speech-sounds perception test Trail making test A and B Critical flicker frequency Time sense test Aphasia screening test Sensory-perceptual test
What are the components of consciousness?
Arousal - wakefulness
Awareness - attentional processing
What does arousal depend on?
ARAS - Ascending Reticular activatinv system
What does the ARAS do?
Via thalamic intralaminar nuclei, synchronises rhythmical bursts of neuronal activity (20-40Hz) from the thalamocortical connections.
arousal is proportional to these.
What is required for maintenance of attention?
Intact right frontal lobe
What can lesions in ARAS lead to?
Small lesions of ARAS = stuporous state
Large bilateral lesions at cortical level = depression in altertness
What is the pathology in most patients in stupor?
Diffuse organic cerebral dysfunction
Describe stupor in a patient
Appear to be asleep but when vigorously stimulated, will manifest alertness by ocular movement.
What happens if you do caloric testing in organic stupor?
Reveal tonic deviation
What happens if you do caloric testing in psychiatric stupor?
Ocular nystagmus
What damage leads to akinetic mutism?
Diencephalic or bilateral anterior cingulate damage.
Lesion that interferes with reticular/cortical integration but spares corticospinal pathways.
Signs of akinetic mutism?
Immobility
Eye closure
Little or no vocalisation
Absence of spastcity and rigidity
What pathology results in vegetative state?
Isolated actions of ARAS and thalamus in absence of higher cortical influence due to extensive cortical damage.
Signs of vegetative state
Spasticity and rigidity of limbs.
Pathology of Locked in syndrome
Total paralysis below level of third nerve nuclei.
Due to infarction of ventral pons, pontine tumours, pontine haemorrhage, central pontine myelinolysis, HI or brain stem encephalitis.
Signs of locked in syndrome
Patients open eyes and elevate and depress eyes on command, but horizontal eye movements lost.
No other voluntary movement possible.
Clinical tests for attention
Serial 7s
Digit span
Spelling ‘world’ backwards
Recite months of year/days of week in reverse order.
Why is reverse-order mont of year measure of sustained attention?
Highly over-learned sequence
What does digit span depend upon?
Working memory
What conditions is digit span impaired in?
Delirium
Focal left frontal damage
Aphasia
Moderate to severe dementia
What is normal digit span?
7+/-2
Varies with age and general intelligence.
5 is normal in elderly.
What is considered normal time orientation?
Being inaccurate by 2 days or less
What is included in person orientation?
Name
Age
DOB
When is disorientation to ones own name seen?
Psychogenic amnesia
What is orientation to place affected?
Reduplicative paramnesia, seen in delirium
What does executive function include?
Planning initiation Sequencing Coordinating Error detection/correction Set shifting Termination
What does executive function depend upon?
Dorsolateral frontal lobe
Intact frontal-subcortical circuits
What is impulsivity a result of?
Response inhibition - seen in inferior frontal pathology.
How can impulsivity be tested?
Go-No-Go task.
Describe the Go-No-Go task.
Examiner instructs patient to tap once in response to single tap and withhold a response for two taps.
When asking a patient to copy a short sequence of alternating squares and triangles, what are you testing?
Ability to switch task
Inhibition of appropriate or persevative responses
What does the cognitive estimates test.. test?
Will result in bizarre/improbable responses in patients with frontal or executive dysfunction.
What does questioning the similarity between two conceptually similar objects assess?
INferential reasoning
How does information go from the visual cortex towards the temporal or parietal cortex?
Dorsal (‘where’) stream
Ventral (‘what’) stream
What does the dorsal stream link?
Visual information with spatial position and orientation in parietal lobe
What does the ventral stream link?
Visual information to store of semantic knowledge in temporal lobes
What are disorders of visuospatial function?
Neglect
Constructional apraxia
What results in neglect?
Lesions in right hemisphere - usually inferior parietal or prefrontal
What results in left sided personal/extrapersonal neglect?
Damage to right parietal lobe
Which parietal lobe damage rarely results in neglect?
Left-sided
Which visuospatial side gets bilateral parietal lobe representation?
Right
How can neglect be discovered?
Simultaneous bilateral sensory or visual stimulation
Having patient bisect lines of variable lengths
Letter and star cancellation tasks
What is anosognosia?
Extreme form of neglect - patient will deny they are hemiplegic or that the affected limb belongs to them
What are apraxias?
Deficits in dressing and constructional ability
What do copying 3D shapes/clock test?
Constructional ability - will also highlight neglect
How to test dressing apraxia?
Ask patient to put on clothing that has been turned inside out
Classification of memory according to duration?
Immediate - seconds
Recent - minutes/days
Remote - months/years
Classification of memory according to encoding?
Explicit - semantic/episodic
Implicit
What is implicit memory?
Includes skills and procedures
What is semantic memory?
Memory for word meanings and general knowledge.
What is episodic memory?
Events
What does episodic memory depend on?
Hippocampal-diencephalic system
What is episodic memory important for?
Personal memories
What type of memories are anterograde and retrograde memories?
Episodic
What is working memory?
Limited capacity that allows us to retain information for a few seconds.
What is the working memory made up of?
Central executive system and 2 buffer systems.
What is the central executive system of working memory made up of?
Attention system
Dorsolateral prefrontal
What are the 2 buffer systems in working memory?
Visuospatial sketchpad
Phonological loop
What does the visuospatial sketchpad depend on?
Right hemisphere
What does the phonological loop depend on?
Left hemisphere
What is left hippocampus important for in memory?
Encoding declarative verbal memories
What is right hippocampus important for in memory?
Encoding non-verbal memories
Where is navigational memory?
Hippocampus
What is the hippocampal place code?
Pattern of cellular activation in hippocampus that corresponds to animals location in space
Does unilateral hippocampal lesion affect memory?
Rarely - hippocampus is able to compensate
Relevance of amygdala in memory?
Rates emotional importance of experience and regulates level of hippocampal activity accordingly.
Emotional memory and emotional face processing.
Helps in memory consolidatino depending on emotional input.
What does amygdalar damage result in?
Loss of fear conditions in monkeys and loss of maternal behaviour
What structures are associated with new learning?
Diencephalic structures such as dorsal medial nucleus of thalamus and mamillary bodies
Give e.g. of diencephalic amnesia (when diencephalic structures are damaged)
Korsakoff syndrome
Which type of memory stays in tact in most types of memory loss?
Procedural
E.g. of disease in which procedural memory is lost but declarative memory is intact
Parkinsons
What structures are thought to be involved in non-declarative procedural memory storage?
Cerebellum
Striatum
Amygdala
Motor area of neocortex
What is the key area for semantic memory?
Anterior temporal lobe
What is long-term potentiation?
Strengthening connection between two neurons on repeated communication
What is the neuronal basis of memory?
Long-term potentiation
What mediates long-term potentiation?
NMDA mediated calcium entry in glutamate neurons
What does learning result in, on a microscopic level?
Increases branching and synapse formation
Influences neurogenesis
Define anterograde amnesia
Forgetting newly encountered information from time of lesion
Define retrograde amnesia
Loss of memory of past events that happened before lesion was sustained
How does anterograde amnesia present
Forgetting appointments, losing items at home, inability remember conversations leading to repeated questions.
How does retrograde amnesia present?
Forgetting past events such as jobs, holidays, unable to remember a route and getting lost
E.g. of damage resulting in pure anterograde amnesia
Hippocampal damage:
herpes simplex encephalitis
Focal temporal lobe tumours or infarction
Characteristics of transient global amnesia
Pronounced anterograde and variable retrograde amnesia
Characteristics of memory lacunes
Repeated brief episodes of memory loss
What is Ribots law of retrograde amnesia?
Dissolution of memory is inversely related to recency of event.
i.e. recent memories are more likely to be lost than more remote in organic amnesia
What is semantic dementia?
Variant of frontotemporal dementia
How does semantic dementia present?
Patients complain of loss of words.
Vocabulary diminishes and patients use words such as ‘thing’ instead.
Parallel impairment in appreciating meaning of individual words.
What pathology is semantic dementia associated with?
Atrophy of anterior temporal lobe, usually left
How can working memory deficits present?
Lapses in concentration and attention e.g. losing ones train of thought, inability to process complex task as copmonents not retained long enough to be processed.
Pathology in which structures leads to working memory deficits?
Basal ganglia
White matter diseas
Characteristics of dissociative amnesia
Memory of important recent events that is partial, patchy and selective.
Episodic memory loss - retrograde only
What is the problem in dissociative amnesia?
Complete unavailability of memories which were formed normally and previously accessible.
Forgotten events are generally traumatic or stressful.
Define aphasia
Higher-level language defect despite intact hearing, sound production and articulation mechanisms.
What is anomia?
Naming defects
Where is sound from the ears transmitted to?
Wernicke’s area
Auditory association cortex that processes language component
What is Broca’s area?
Higher motor area of language production
Where do signals from Broca’s area go on to?
To motor area to coordinate delivery of language via tongue, lips and vocal cords
What are the three components of language?
Fluency
Comprehension
Repitition
What does fluency of language depend upon?
Intact Broca’s area and its forward connections
What does language comprehension depend upon?
Intact Wernicke’s area and its connection with association cortex and sensory input
Which component of language requires no higher-level processing?
Repitition
When can repetition occur?
When Broca’s, Wernicke’s and arcuate fasciculus are intact.
What is lost in Wernicke’s sensory aphasia?
Repetition
Comprehension - reading and writing
Naming
What is left intact in Wernicke’s sensory aphasia?
Fluency
What is lost in Broca’s motor aphasia?
Fluency
Repetition
Naming
What is left intact in Broca’s motor aphasia?
Comprehension
What is lost in Conduction aphasia?
Repetition
Naming
What is left intact in Conduction aphasia?
Fluency
Comprehension
What is left intact in Transcortical sensory aphasia?
Fluency
Repetition
What is lost in Transcortical sensory aphasia?
Comprehension
What is kept intact in Transcortical motor aphasia?
Repetition
Comprehension
What is lost in transcortical motor aphasia?
Fluency
Naming
How does Broca’s aphasia present?
Speech is nonfluent; appears laboured with many interruptions and pauses.
Function words are most affected.
Abnormal word order and agrammatism.
Speech is telegraphic.
E.g. of Broca’s ahasia
I see…. the dotor, dotor sent me…. Bosson.
How does Wernicke’s aphasia present?
language output is fluent but highly paraphasic, sometimes with string of neologisms and circumlocutions - jargon aphasia.
Speech contains large number of function words but few nouns/verbs.
Output is voluminous but uninformative, like schizophrenic speech disturbance.
What is pure word deafness?
Patient can speak, read and write fluently but comprehension is impaired only for spoken language.
What damage leads to pure word deafness?
Bilateral (or left sided with disrupted connections to non-dominant circuit) damage to superior temporal pole
What is pure word blindness?
Alexia, no agraphia
patient can speak and comprehend normally, and write spontaneously, but reading comprehension is impaired.
Damage leading to pure word blindness.
Left posterior cerebral artery affecting splenium of corpus callosum and left visual cortex
What is pure word dumbness?
Spoken language cannot be produced clearly but patient can comprehend language, read and write.
What is pure agraphia?
Isolated inability to write while everything else is preserved.
Define apraxia
Varying combination of the following disturbances in order of progressive dysfunction:
Failure to produce correct movement in response to verbal command
Failure to correctly imitate movement performed by examiner
Failure to perform movement correctly in response to seen object
Failure to handle object correctly
Damage related to apraxia?
Left parietal and frontal lobes
What is isolated limb apraxia diagnostic of?
Corticobasal degeneration
Functional classification of apraxia
Constructional apraxia
Ideational/conceptual
Ideomotor (most common)
Define constructional apraxia
Inability to construct elements into meaningful whole
E.g. of constructional apraxia
Unable to draw or copy simple diagrams or figures
Localization of constructional apraxia?
Right cerebral hemisphere, often parietal lobe
Define ideational/conceptual apraxia
Impairment in carrying out a sequence of actions requiring use of various objects in correct order.
Localization of ideational/conceptual apraxia
Left parieto-occipital and parietotemporal regions
Definition of ideomotor apraxia
Disorder of goal-directed movement.
Patient knows what to do but not how to do it.
E.g. of ideomotor apraxia
Patient uses own fingers to represent toothbrush when asked to brush teeth.
Improves on imitation and use of actual tool.
Tool more effective than gestures.
Localization of ideomotor apraxia
Mainly left hemisphere; frontal and parietal association areas.
What results in bilateral ideomotor apraxia?
Unilateral lesions of left hemisphere in right-handed patients, usually less severe in left limb.
Regional classifications of apraxia
Buccofacial
Limb-kinetic
Define buccofacial apraxia
Inability to coordinate and carry out facial and lip movements such as whistling, winking, coughing on command.
Localization of buccofacial apraxia.
left inferior frontal lobe and insula
Commonly accompanies aphasia caused by lesion of Broca’s area.
Define limb-kinetic apraxia?
Loss of hand and finger dexterity resulting in inability to connect or isolate individual movements.
What does limb-kinetic apraxia result in?
Affects use of tools, gestures, particularly finger movements.
Localization of limb-kinetic apraxia?
Dominant frontoparietal or primary motor cortex.
What is visual agnosia?
Failure of object recognition despite adequate perception
What happens in appreceptive visual agnosia?
Patients have normal vision but cannot identify and name objects
they can name objects by description or touch.
Pathology leading to appreceptive visual agnosia?
Bilateral occipitotemporal infarction
What happens in associative visual agnosia?
Stored semantic knowledge is affected.
Pathology leading to associate visual agnosia?
Lesions of anterior left temporal lobe
How to test for visual agnosia?
Assess visual object naming/description and tactile naming, naming described objects and providing semantic information about unnamed items.
What is prosopagnosia?
Ability to recognise familiar faces.
Pathology leading to prosopagnosia?
Face processing is a bilateral function, more key areas on right.
Associated with bilateral or right-sided lesions of occipital-temporal junction (fusiform gyrus).
What is the fusiform gyrus?
Occipital-temporal junction
What is achromatopsia?
Loss of ability to discriminate colours
Pathology resulting in achromatopsia?
Medial occipitotemporal damage due to left posterior cerebral artery infarct
What is colour agnosia?
Loss of ability to retrieve colour information stored in semantic knowledge base e.g. what colour is a banana?
Damage leading to colour agnosia?
Left occipito-temporal damage
What is colour anomia?
Disorder of colour naming despite intact perception and colour knowledge.
Damage leading to colour anomia?
Disconnection of language structures in temporal lobe from visual cortex.
What is acalculia?
Inability to read, write and comprehend numbers.
What are the symptoms of Balint syndrome?
Simltanagnosia
Optic Ataxia
Oculomotor apraxia
What results in Balints syndrome?
Bilateral superior-parietoocipital damage (disruption to dorsal ‘where’ strand linking visual and parietal association areas).
Possible causes of Balints syndrome?
CO poisoning
Infarct
Alzheimers
What is simultanagnosia?
Inability to attend to more than one item at a time
What is optic ataxia?
Inability to guide reaching or pointing despite adequate vision
What is oculomotor apraxia?
Inability to voluntarily direct saccades to a visual target
Lesion resulting in Gerstmann syndrome
Lesinos in dominant angular and supramarginal gyri (parietal lobe)
Symptoms of Antons syndrome
Denies any deficit
Damage in Antons syndrome
Bilateral occipital damage
Damage in Marchiafava-Bignami disease?
Symmetrical demyelination and necrosis of corpus callosum and adjacent anterior commissure.
Signs in Marchiafava-Bignami disease?
Sudden onset stupor/coma/seizures.
Chronic onset of dementia and/or gait problems
Stereotypical patient who gets Marchiafava-Bignami disease?
Alcoholics drinking red wine
What is the only sensory nerve to have no thalamic relay?
Olfactory
What does unilateral anosmia suggest?
Lesion affecting olfactory nerve filaments, bulb, tract or stria
Describe cortical representation for smell
Bilateral in piriform cortex
Given the fact that cortical representation of smell is bilateral, what type of lesion would not cause any olfactory impairment?
Unilateral lesion distal to decussation of olfactory fibres (temporal/uncinate)
What can cause unilateral anosmia?
Frontal meningiomas
E.g. of diseases causing hyposmia
Early feature in Parkinsons and Alzheimers
Where is the lesion in unilateral blindness?
Anterior to optic chiasm (optic nerve or retina)
Where is the lesion in bitemporal hemianopia?
Optic chiasm
E.g. of diseases causing bitemporal hemianopia?
Pineal tumours
Cranipharyngioma
Lesion causing left-sided homonymous hemianopia?
Lesion of right optic tract, lateral geniculate body, optic radiations and striate cortex
Lesion causing right-sided homonymous hemianopia
Lesions of left retro-chiasmatic structures
Pathology causing enlargement of blind spot?
Any process causing disc swelling
Lesion causing superior quadrantanopia?
Optic irradiation lesion at temporal lobe of contralateral side
Lesion causing inferior quadrantanopia?
Optic irradiation lesion at parietal lobe of contralateral side
What causes cortical blindness?
Occipital cortex lesion
Bilateral posterior cerebral artery occlusion
What diseases does funnel vision occur in?
Glaucoma
Retinitis pigmentosa
Post-papilloedema optic atrophy
Bilateral occipital infarcts with macular sparing
What is tunnel vision?
Absence of disparity between 2mm and 1mm fields on confrontation test.
Symptoms of cortical blindness
Bilateral homonymous hemianopia with small central field around point of fixation (macular sparing) or
complete blindness
How can one test the optic nerve?
Fundoscopy
Colour vision - Ishihara chart
Visual fields - confrontation test or perimetry
Acuity - Snellen chest
Where do afferent fibres in optic nerve go to?
Lateral geniculate bodies and relay to Edinger-Westphal nuclei via pretectal nucleus
Where is the Edinger-Westphal nucleis?
Midbrain
Where do efferent (parasympathetic) fibres go from Edinger-Westphal nucleus?
Via third nerve to ciliary ganglion and then to pupil.
Which nerve carries efferent fibres from the Edinger-Westphal nucleus?
3rd cranial nerve
What happens when one fixates on an object?
Convergence
Pupillary constriction
Which fibres carry convergence information?
Afferent fibres from optic nerve relay to convergence centre.
What does the convergence centre do?
Receives muscle spindle afferent fibres from extraocular muscles (mainly medial recti) which are innervated by the 3rd CN.
What is the efferent route from the convergence centre?
To Edinger-Westphal nucleus, ciliary ganglion and then to the pupils.
What is light-near dissociation?
Pupils that accommodate but do not reacte.
Causes of light-near dissociation?
Argyll Robertson pupil
Diabetes
Aldie pupil
When is Argyll Robertson pupil seen?
Neurosyphillis
What happens in Aldie pupil?
Peripheral pupillary defect producing tonic pupil.
What happens in absent light reflex?
Due to afferent defect in pupillary reflex pathway - possibly pretectal.
Where is the oculomotor nerve nucleus located?
Midbrain
What does CN III supply?
Levator palpebrae superioris
Superior, inferior and medial recti
Inferior oblique muscles
Signs of lesion of CN III?
Paralysis of ipsilateral upper eyelid and pupil
Patent cannot adduct, look up or down.
Pupil looks out (exotropia)
What does lesion of nucleus of third nerve result in?
Bilateral ptosis
Ipsilateral paralysis of upper eyelid and pupil.
What pathology results in diplopia in more than one direction?
Paralysis CN III
What diseases result in pupil-sparing CN III paralysis?
Diabetes
Vasculitis
Brainstem lesions such as MS
Where is the trochlear nerve nucleus located?
Midbrain
What does the trochlear nerve innervate?
Superior oblique muscle
Which nerve allows a person to visualise the tip of their nose?
Trochler
Path of trigeminal nerve?
From midbrain through pons (main sensory nucleus and motor nucleus) to cervical region (spinal tract of trigeminal nerve)
Function of trigeminal nerve
Sensory innervation of face
Muscles of mastrication
What supplies the corneal reflex?
Afferent - V nerve
Efferent - facial nerve
What does complete paralysis of CN V result in?
Sensory loss of ipsilateral face and weakness of mastication muscles.
Attempted opening of mouth results in deviation of jaw to paralyzed side.
What can lead to loss of corneal reflex?
Acoustic neuroma pressing on 5th nerve
Where is the CN VI nerve located?
Paramedian pontine region on floor of 4th ventricle
What does abducens nerve innervate?
Lateral rectus
Signs in CN VI palsy?
Double vision on horizontal gaze only - horizontal homonymous diplopia
Why is paralysis of CN VI a false localizing sign?
It may result from increased intra cranial pressure
Motor function of CN VII?
Motor supply to facial muscles from motor nucleus
Sensory function of CN VII?
Innervates skin of posteromedial aspect of pinna and around external auditory canal.
Taste senation of anterior 2/3 of tongue and relays to sensory nucleus tractus solitarius
Secrotomotor function of CN VII?
Parasympathetic relay to lacrimal, lingual and submandibular glands
Signs of lower motor neuron lesion of CN VII?
Complete ipsilateral facial paralysis
Facial draws to opposite side as patient smiles
Eye closure impaired
Ipsilateral palpebral fissue is wider
What causes LMN lesion of CN VII?
Bells palsy
Sign of UMN CN VII lesion?
Lower half of face is paralyzed
Eye closure is preserved
What is used to test CN VIII?
512 Hz tuning fork
How does CN VIII communicate balance?
Vestibular portion transmits information about linear and angular accelerations of the head from urticle, saccule and semicircular canals of membranous labyrinth to vestibular nucleus.
Result of Rombergs test if loss of CN VII
Patient will fall towards side of vestibular hypofunction
Diseases where Rombergs is positive
CN VIII dysfunction
Disease of dorsal column
Polyneuropathies
What is caloric testing?
Water testing
Normal caloric testing results
Cold water; nystagmus to opposite side.
Warm water; nystagmus towards same side.
Why is nucleus of CN IX and CN X called nucleus ambiguous?
Both are anatomically indistinuighable
Sensory function of CN IX?
Sensory innervation of posterior third of tongue and pharynx.
Motor funciton of CN IX?
Pharyngeal muscules - stylopharyngeus (with CN X)
Which CN is important for BP control?
IX
How is CN IX involved in BP control?
Vascular stretch afferents from aortic arch and carotid sinus travel via CN IX to nucleus solitarius
Signs of CN IX palsy
Loss of taste in posterior 1/3 of tongue
Loss of pain and touch sensation in 1/3 of posterior tongue, soft palate and pharyngeal walls
Where does CN X start?
Nucleus ambiguous
Which CN has the longest peripheral course?
CN X
Where does CN x stretch up to?
Splenic flexure of colon
Function of CN X
Motor supply to pharyngeal muscles, palatoglossus and larynex
Smooth muscle of tracheobronchial tree, oesophagus, Gi tract up to middle-distral 1/3 of transverse colon
Which pharyngeal muscle does CN X not supply?
Stylopharyngeus
Where is the somatic sensation carried by CN X?
Back of ear
External auditory canal
Parts of tympanic membrane, pharynx, larynx and dura of posterior foss
What innervates pharyngeal gag reflex and palatal reflex?
CN IX and X
What is the palatal reflex?
Elevation of soft palate and ipsilateral deviation of uvula on stimulation of soft palate
Sign of CN IX and X paralysis?
Pharyngeal gag reflex and palatal reflex will result in deviation of uvula to normal side (away from lesion)
Functino of CN XII
Motor innervation of all extrinsic and intrinsic muscles of tongue
Sign of CN XII palsy?
Tongue deviates to side of paralysis on protrusion
What is concussion?
Transient coma for hours followed by apparent complete clinical covery.
What is contusion?
Prolonged coma, focal signs and lasting brain damage.
Where does contusino occur?
Beneath (coup injury) or contralateral (contracoup injury) to site of impact.
Where is contre-coup contusion most common?
Orbito-frontal area and temporal tips where acceleration/deceleration forces cause brain to impact on bony protuberances of skull.
What type of HI occurs in bilateral orbitofrontal injury?
Behavioural dyscontrol syndrome
Mechanisms of traumatic brain injury
Axonal and neuronal damage from direct trauma
Shearing and rotational stresses on declerating brain
Brain oedema and raised ICP
Brain hypoxia and ischaemia
What causes diffuse axonal injury?
Differential motion of brain within skull resulting in shearing and stretching of axons
Difference between diffuse axonal injury and focal brain injury?
Diffuse axonal injury is more widespread with extensive lesions in white matter tracts.
What is diffuse axonal injury more often associated with (signs)?
Persistent vegetative state
Coma
Types of amnesia post head injury?
Post-traumatic amnesia
Retrograde amnesia
What is post-traumatic amnesia?
Anterograde amnesia for period of injury and period following injury until normal memory resumes
What is retrograde amnesia after HI?
Dense amnesia for period between last clearly recalled memory prior to injury and injury itself.
Normal post-traumatic amnesia time?
Minutes
What is used to assess HI severity?
GCS 24 hours after injury.
Length of coma
Post-traumatic amnesia
What is used to predict functional outcome after HI?
LOC
PTA
Poor prognostic factors with respect to psychiatric morbidity following HI?
Long duration of LOC Long PTA Elderly Chronic alcohol use Diffuse brain damage New onset seizures Focal damage to dominant lobe
Classification of mild HI
PTA <60 minutes
Functional outcome of mild HI?
May return to work in <1 month
Classification of moderate HI?
PTA between 1-24 hours
Functional outcome of moderate HI?
Return to work in 2 months
Classification of severe HI?
PTA between 1-7 days
Functional outcome of severe HI?
Return to work in 4 months
Classification of very severe HI?
Pta >7 days
Functional outcome of very severe hI?
May require >1 year to return to work
When is cognitive imppairment most likely after HI?
After closed HI with PTA lasting >24 hours
When is personality change most likely after HI?
HI to orbitofrontal lobe or anterior temporal lobe
What is post-concussional syndrome characterised by?
Headache
Dizziness
Insomnia
Irritability/emotional lability/anxiety/depression
Increased sensitivity to noise, light etc
Fatigue/poor concentration
When is schizophrenia-like psychoses (paranoia) likely after HI?
Right temporal and orbitofrontal injury
Prevalence of schizophrenia post HI?
2-5%
% in which post-traumatic epilepsy is seen?
5% closed HI
30% open HI (usually during first year)
Worsens progress
Where does working memory occur?
Frontal & parietal lobes
