Cognitive Dysfunction and Dementia

Question 1

Define: Agnosia, Agraphia, Alexia.

Answer 1

Agnosia - failure to recognize or comprehend perceived stimuli (i.e. prosopagnosia)

Agraphia - inability to write (implies you’ve been able to before)

Alexia - inability to read (implies you’ve been able to before)

Question 2

Define anomia, anosognosia, neglect

Answer 2

Anomia - difficulty finding words

Anosognosia - difficulty to recognize illness / lack of awareness of one’s disability

Neglect - Inattention to stimuli from one side of the visuospatial environment

Question 3

Define aphasia, apraxia, dysarthria

Answer 3

Aphasia - inability to understand and use language (higher order language deficit)

Dysarthria - motor inability to speak (movement deficit) / inability to articulate

Apraxia - impairment of skilled movement upon command or attempted mimicry despite comprehension and normal motor function

Question 4

How is repetition affected in Broca’s, Wernicke’s, conduction, and global aphasia?

Answer 4

All impaired

In conduction aphasia -> loss of arcuate fasciculus = this is the primary defect. Can formulate thoughts and say things, but bad at repeating things -> requires Wernicke and Broca strong communication

Global aphasia is just total knockout

Question 5

How do transcortical motor / transcortical sensory aphasia differ from other aphasias?

Answer 5

Transcortical motor - affects frontal lobe around Broca’s area. Similar symptoms except repetition is intact (Broca’s area not affected)

Transcortical sensory - affects temporal lobe around Wernicke’s area. Similar symptoms except repetition is intact (Wernicke’s area not affected)

Question 6

What is transcortical mixed aphasia also called and what characterizes it?

Answer 6

Also called pure echolalia

• > patient has intact Wernicke’s, Broca’s, and arcuate fasciculus but frontal and temporal lobes are damaged
• > can only repeat, nonfluent speech production and comprehension
• > analogous to transcortical version of global aphasia.

Question 7

When is anomia typically seen?

Answer 7

It is common with all aphasia and often the only sign of mild or resolving aphasia.

Question 8

What is aprosodia and what causes it?

Answer 8

A-prosody - inability to see intonation and emphasis in speaking
-> cannot detect affective or emotional content of speech

Prosody perception occurs in the superior temporal gyrus of the nondominant hemisphere (analogous to Wernicke)

Prosody expression occursin the inferior frontal gyrus in the nondominant hemisphere (analogous to Broca)

Question 9

What does a dominant parietal lobe lesion cause?

Answer 9

Gerstmann’s syndrome
- think of someone trying to count their fingers
Tetrad:
-Finger agnosia - cannot identify finger named by examiner or recognize which finger has been touched / moved
-Left-right disorientation
-Acalculia
-Agraphia - writing impairment

Question 10

How is left-right disorientation tested?

Answer 10

Best via crossed pointing
-> have patient point to right foot with left hand. Makes it more difficult when you have to think of two directions at once

Question 11

Why does acalculia occur in Gerstmann’s syndrome?

Answer 11

Usually due to aphasia -> inability to perceive and hold numbers in recent memory for calculation

However, true anarithmetria can happen

Question 12

What will lesion of the nondominant parietal lobule cause?

Answer 12

Contralateral neglect, often with anosognosia of the issue.

If it affects more superior portion can cause constructional apraxia (difficulty drawing objects like clockface) or dressing apraxia (poor processing of spatial information so cannot put clothing on well)

Question 13

What is cortical blindness vs Anton’s syndrome?

Answer 13

Cortical blindness - no visual perception due to cortical deficit in occipital lobes

Anton’s syndrome - cortical blindness + visual anosognosia -> patient maintains that they can see. Probably due to disconnection syndrome between visual cortex and visual integration cortices

Question 14

What is Balint’s syndrome? What is notably preserved?

Answer 14

Triad:
1. Oculomotor apraxia - cannot gaze effectively via saccadic eye movements

2. Optic ataxia - can’t reach out to a visual target accurately (i.e. finger to nose on someone else, but could do on themselves easily since proprioception is intact)
3. Simultanagnosia - visual inattention, can’tt ell whole from the parts. Often associated with prosopagnosia.

Basically similar in reasoning to Anton syndrome, and Anton may recover thru Balint’s.

Color vision is notably preserved.

Question 15

What is achromatopsia and what causes it?

Answer 15

Loss of color vision in all or part of the visual field, due to inferior occipital lobe lesions (where color vision is sent thru from visual cortex)

Question 16

What is prosopagnosia and what is it caused by?

Answer 16

Inability to recognize faces, but generally difficulty recognizing specific members of a general class of objects on basis of minor variations (i.e. a farmer and his cows, a bird watcher and species of birds)

Disorder of visual cueing of memories -> they can tell you what goes with what, but can’t name that person or thing
-> fusiform gyrus normally implicated

Question 17

What is visual agnosia?

Answer 17

Ability to see and describe an object’s features without being able to recognize / name it, as well as associate it with its function

Patient does not have anomia - i.e. they can tell you what a glove is

They can even draw the object and match it to a drawing or picture

i.e. man who took his wife for a hat

Question 18

What are the four types of memory?

Answer 18

1. Registration / working memory - your attention span (can only remember it as long as you are thinkin about it)
2. Short-term memory - recall within minutes
3. Long-term memory - requires consolidation
4. Motor skills and conditioned reflexes

Question 19

What are the portions of the brain responsible for each type of memory?

Answer 19

Working memory - frontal cortex

Short-term memory and longterm memory - hippocampus and neocortex

Motor skills / conditioned reflexes - cerebellum / neocortex

Question 20

What is Ribot’s law?

Answer 20

More recent memories are more affected by retrograde amnesia than are more distant memories

Question 21

What areas of the brain are typically affected in an amnestic syndrome?

Answer 21

Medial temporal lobes (hippocampus), anterior thalamic nucleus, or mammillary bodies

Remember, papez circuit goes hippocampus->fornix->mamillary bodies-> mammillothalamic tract-> anterior nucleus of the thalaus

Question 22

What are the symptoms of amnestic syndrome?

Answer 22

Mixture of anterograde and retrograde amnesia which will improve as the lesio resolves
-> patient will be left with a memory gap

Question 23

What is transient global amnesia?

Answer 23

An acute onset transient anterograde amnesia which is usually benign, but leaves a permanent memory gap during that period

There will be a full recovery of anterograde memory

Question 24

What is psychogenic amnesia also called and what psychiatric problem often accompanies it?

Answer 24

Dissociative amnesia

-> often accompanied by dissociative fugue - abrupt travel or wandering during period of dissociative amnesia

Question 25

What are the symptoms of dissociative amnesia?

Answer 25

Inability to recall personal information and past, with intact memory for recent events (how it is differentiated from other amnesias)
-> usually occurs secondary to longterm trauma or stress

Question 26

What is mild neurocognitive disorder define? “pre-dementia”

Answer 26

Modest cognitive decline in one or more cognitive domains:
Complex attention
Executive function
Learning and memory
Language
Perceptual-motor
Social cognition

Range of 1-2 standard deviations below normal, but do not interfere with function and are not due to another mental disorder or delirium

Question 27

How does major neurocognitive disorder differ from mild?

Answer 27

Major will have greater than 2 standard deviations below normal function in at least one of the domains, with significant impairment in function

Also called dementia

Question 28

What are two important tests for evaluation of dimentia?

Answer 28

Mini Mental Status Exam - requires copyright

Montreal Cognitive Assessment - MoCA - free to use

Question 29

What scale helps distinguish vascular dementia from other kinds of dementia? How does it work / what is it looking for?

Answer 29

Modified Hachinski Ischemic Score. Score >7 = vascular dementia

-> Asks about abruptness of onset, stepwise deterioriation, presence of risk factors for CVAs, and focal neurologic signs which would not be present in other causes of dementia

Question 30

What occurs pathologically in Lewy body dementia?

Answer 30

Deposition of eosinophilic inclusions of alpha-synuclein (Lewy bodies) primarily in the cortex, causing a dementia (if Lewy bodies were in basal ganglia, it would primarily cause Parkinsonianism)

Question 31

What are the clinical features of Lewy body dementia? What precipitates symptoms?

Answer 31

Changes in attention and alertness that fluctuate greatly

Frequent visual hallucinations

Parkinsonism within 1 year of dementia onset

Symptoms precipitated by antipsychotics and antinausea drugs (metoclopramide) which are D2 receptor antagonists -> worsen parkinsonism

Question 32

How do you tell Parkinson’s disease from Lewy body dementia?

Answer 32

In Parkinson’s, dementia is a late feature - typically 10+ years after clinical disease onset

In Lewy body dementia, dementia often appears before Parkinsonian symptoms (early-onset)

Question 33

Give a familial prion disease which isn’t fatal familial insomnia.

Answer 33

Gerstmann-Straussler-Scheinker

Question 34

Give a few subacute encephalopathies which resemble dementias?

Answer 34

Medication effects, alcohol
Metabolic encephalopathies (i.e. hepatic, renal), vitamin deficiencies, thyroid problems, chronic subdural hematoma, vasculitic encephalopathy, depression (can cause pseudodementia)

Question 35

What are a few routine tests which should be done to rule out other causes of dementias?

Answer 35

Serum B12, LFTs, thyroid function tests, depression screenings, BUN/creatinine, etc

Question 36

Is EEG and CT routinely done for evaluation of dimentia?

Answer 36

No - EGG just shows generally slowing in all dementias

CT - usually just shows cortical atrophy and hydrocephalus ex vacuo

Question 37

When would a lumbar puncture be done for evaluation of dementia?

Answer 37

Presence of infection / tumor, or very rapid progression

-> reasonable suspicion that an etiology might be detected by CSF examination

Question 38

Give the three acetylcholinesterase inhibitors which can be used in Alzheimer’s.

Answer 38

Donepezil - done a puzzle
Rivastigmine - reverse the stigma
Galantamine - Alzheimer’s GALA

Question 39

What treatments can slow disease progression in Alzheimer’s?

Answer 39

Memantine - NMDA receptor antagonist

Vitamin E - antioxidant supplementation