Behavior, Cortical Function, and Dementia

Question 1

What is memory?

Answer 1

The ability to learn and then recall information after different periods of time

Question 2

What is “immediate” memory?

Answer 2

The pre-requisite state of attentiveness required for learning something

Question 3

How can you determine if “immediate” memory is intact? If it appears to not be intact, what are possible causes?

Answer 3

Patient should be alert and awake enough to immediately repeat or recite a sequence of 5 numbers spoken out loud

Excessive sleepiness
Sedation from medications
Systemic illness diffusely inhibiting cortical function
Lesions affecting the RAS more directly

Question 4

Impaired ___ precludes any reliable testing of recent or remote memory as well as other cortical functions.

Answer 4

Attention

Question 5

What is recent or “short-term” memory?

Answer 5

Ability to recall information after several minutes of retention

Question 6

How is short-term memory tested?

Answer 6

Patient is given 3 items to repeat aloud and instructed to recall them 5 minutes later on command

Question 7

What is remote or “long-term” memory?

Answer 7

Ability to recall past events hours, weeks, or even years afterward

Question 8

How is long-term memory tested?

Answer 8

Ask a prior address or anniversary date for which the correct answer is known

Question 9

Memory function depends on what pathways?

Answer 9

Bilateral pathways involving the temporal lobe and thalamus, specifically hippocampus -> fornix -> mammillary body -> anterior thalamic nucleus

Question 10

What causes amnesia in Wernicke-Korsafoff syndrome?

Answer 10

Bilateral thalamic and mammillary body lesions; caused by thiamine deficiency in malnourished alcoholics

Question 11

What are 2 other causes of bilateral hippocampal lesions causing amnesia?

Answer 11

Anoxia

Herpes simplex encephalitis

Question 12

What is apraxia?

Answer 12

The inability to conceptualize and perform a skilled, learned, motor act on command

Question 13

What kind of lesions may cause gait apraxia (inability to walk on command)?

Answer 13

Prefrontal lobe lesion

Question 14

What kind of lesions may cause a constructional (cannot draw a house or copy a drawing) or dressing (cannot put on and button a shirt) apraxia?

Answer 14

Posterior cortical lesions, especially involving the parietal lobe

Question 15

What is agnosia?

Answer 15

Impaired recognition of perceived stimuli caused by lesions of sensory association cortex

Question 16

Lesions of particular lobes of the cerebral hemispheres often involve what 4 general etiologies?

Answer 16

Head trauma
Stroke
Tumor
Dementia

Question 17

Presentation of patients with pre-frontal or frontal lobe syndrome?

Answer 17

Listless, apathetic, unconcerned
Poor hygiene, incontinence
Poor judgment and disinhibition -> outbursts, rude humor, inappropriate sexual behavior
Executive functions are impaired (poor planning and performance of multistep or novel tasks, lack of creative thinking, limited attention, motor perseveration)
Gait apraxia
Paratonia
Frontal lobe release signs

Question 18

What is paratonia?

Answer 18

Increased limb tone or resistance is felt as the examiner moves the patient’s limb more rapidly

Question 19

What are frontal lobe release signs?

Answer 19

Previously normal findings during infancy when myelination of descending inhibitory pathways was incomplete -> sucking reflex, rooting reflex, palmar and plantar grasps

Question 20

Presentation of syndromes of the temporal lobes?

Answer 20

Amnesia (bilateral hippocampal lesions)
Cortical deafness (bilateral auditory cortex lesions)
Kluver-Bucy syndrome (limbic system)
Unilateral lesion of superior-posterior dominant temporal lobe -> Wernicke’s aphasia

Question 21

Presentation of syndromes of the parietal lobes?

Answer 21

Asterognosis
Agraphesthesia
Extinction on double simultaneous stimulation
Impaired spatial relationships between the body and its surrounds if lesion of the non-dominant parietal lobe -> anosognosia (unaware of hemiparesis), hemispatial neglect

Question 22

What is Gerstmann’s syndrome?

Answer 22

Agraphia
Right-left disorientation
Dyscalculia
Finger agnosia

Question 23

What causes Gerstmann’s syndrome?

Answer 23

Lesion of the supramarginal or angular gyrus of the dominant parietal lobe

Question 24

Presentation of occipital lobe syndromes?

Answer 24

If enough bilateral visual cortex is involved -> cortical blindness

Question 25

What type of lesion causes visual agnosia?

Answer 25

Bilateral temporo-occipital lesions

Question 26

Key features of delirium?

Answer 26

Fluctuating levels of attention and motor activity, with alternating agitation/hyperactivity and obtundation/stupor

Moods and emotions may vary

Hallucinations are often reported

Tremulousness, asterixis, myoclonus, ataxia, dysarthria

Question 27

What is dementia?

Answer 27

General term for a diffuse impairment of cortical function which usually evolves less abruptly over a longer period of months to years, and impedes the daily function of the patient

Question 28

Work-up for dementia?

Answer 28

Standardized cognitive testing such as the MMSE or neuropsych testing

Brain scan (preferably MRI) -> chronic subdural hematomas, brain tumors/abscesses, multiple infarctions or hemorrhages, NPH
LP if unexplained fever and headache (could be chronic meningitis)
HIV (younger patients)

All: CBC, CMP, B12, thyroid

Question 29

Most common type of dementia in the US?

Answer 29

Alzheimer’s

Question 30

Pathogenesis of Alzheimer’s?

Answer 30

Degenerative disease, where specific types of neurons are gradually destroyed by metabolic changes unrelated to infection, ischemia, or immune system abnormalities

Excessive accumulation of beta-amyloid in the form of extracellular amyloid or senile cortical plaques. Deposition leads to formation of intraneuronal neurofibrillary tangles, consisting of microtubule-associated tau protein

Question 31

What is typically the earliest finding in Alzheimer’s?

Answer 31

Memory loss

Question 32

What are the major tauopathies?

Answer 32

Alzheimer’s dementia
Progressive supranuclear palsy
Corticobasal degeneration
Frontotemporal lobar dementia

Question 33

Manage Alzheimer’s?

Answer 33

Slow deteriorating coarse by enhancing the cholinergic system with ACEIs (donepezil, rivastigmine, or galantamine)

May add memantine later (NMDA antagonist that opposes the excitotoxic effects of glutamate in the CNS)

May need sedatives and antipsychotics to control behavioral symptoms