White matter, MS, & disconnection syndromes

Question 1

What is the most prominent artery supplying the cerebral white matter?

Answer 1

Lenticulostriate

Question 2

Factors of MS that are related to cognitive impairment

Answer 2

Duration of illness, atrophy, total lesion volume, physical impairment, enlarged cerebral ventricles, CC atrophy, cerebral hypometabolism

Question 3

Corona radiata

Answer 3

Rich mass of white matter within each hemisphere above the internal capsule

Question 3

Central pontine myelinolysis (CPM)

Answer 3

Related to too rapid correction of sodium deficiency; leads to longstanding dementia or death

Question 4

Psychiatric symptoms of white matter dementia

Answer 4

Irritability, depression, apathy, psychosis

Question 5

Adrenoleukodystrophy

Answer 5

Generalized loss of myelin in the brain & adrenal insufficiency; posterior pattern of affected white matter

Question 5

White matter disease is associated with what type of memory disturbance?

Answer 5

Poor retrieval but intact encoding

Question 5

What type of aphasia is most closely associated with white matter disease?

Answer 5

Conduction aphasia

Question 5

How has white matter damage been implicated in schizophrenia?

Answer 5

Research suggests that schizophrenia may result from disrupted frontal lobe connectivity related to oligodendriaglial dysfx and death resulting in abnormalities in myelin laying down & maintainence

Question 6

Relapsing/remitting course of MS

Answer 6

Specific periods of relapse followed by periods of remission; most common type in the early years

Question 6

Secondary progressive course of MS

Answer 6

Initially relapsing/remitting course followed by progression with or without occasional relapses, minor remissions, & plateaus

Question 6

Typical areas of preserved functioning in MS

Answer 6

Memory storage, encoding, recognition, simple auditory span, motor skill & implicit learning, language skills (other than fluency), basic visuospatial functions

Question 7

Lhermitte’s sign

Answer 7

Electrical sensation radiating down extremities or back upon cervical flexion; seen in MS

Question 8

How are MS lesions related to cognition?

Answer 8

Extent of plaques & total lesion area is related to cognitive function, but, in general, location of plaques is not predictive

Question 9

What toxin is associated with 2-3 weeks delayed demyelination?

Answer 9

Carbon monoxide

Question 10

Impairments associated with white matter dementia (Filley)

Answer 10

Slowness of cognition, poor sustained attention/vigilance, visual-spatial deficits, memory retrieval deficits, exec dysfx

Question 11

Factors associated with better MS prognosis

Answer 11

Young age (

Question 12

Metachromatic leukodystrophy

Answer 12

Disorder of myelin metabolism that usually begins in infancy

Question 13

White matter is most prominent in which lobe of the brain?

Answer 13

Frontal lobe

Question 14

Sympathetic apraxia in Broca’s aphasia

Answer 14

Apraxia of command mvmts of the LH, due to disconnection of L language area & motor assoc. cortices from R motor association cortices

Question 15

Cognitive impact of commissurotomy

Answer 15

L neglect, right-ear dominancy in dichotomous listening tasks, inability to name objects in L hand but can pick up with L hand if named, R constructional apraxia, spatial acalculia, cannot cross-replicate hand postures, difficulty naming points touched on L side of body, R-sided verbal anosmia, double hemianopia, hemialexia

Question 17

What cognitive domains are spared in white matter dementia?

Answer 17

Language (word finding deficits but not aphasic), no extrapyramidal symptoms, normal procedural memory

Question 18

Primary progressive course of MS

Answer 18

Continued decline

Question 19

What are the symptoms of Hallervorden-Spatz syndrome?

Answer 19

Progressive rigidity beginning in the legs, choreathetoid movements, dysarthria, dystonia, emotional & mental deterioration (visuospatial & memory)

Question 20

Marchiafava-Bignami disease

Answer 20

Rapidly progressing degeneration/demylination of CC that is associated with cognitive deterioration, emotional disturbances, confusion, hallucinations, tremor, rigidity, & seizures Associated with excessive consumption of red wine

Question 21

Progressive relapsing course of MS

Answer 21

Progressive disease from onset with clear acute relapses, periods between relapses are characterized by continuing progression

Question 21

What is the most common & debilitating complaint among patients with MS?

Answer 21

Fatigue - affects up to 90%

Question 22

Charcot's triad

Answer 22

Nystagmus, dysarthria, tremor (associated with cerebellar dysfx)

Question 23

Pathology of MS

Answer 23

Multifocal areas of CNS white matter inflammation, demyelination with loss of oligodendrocytes & astrogliosis

Question 23

Pure word mutism

Answer 23

Lose capacity to speak but oral & reading comprehension & writing intact; due to separation of Broca's area from subcortical motor centers

Question 25

Risk factors for central pontine myelinolysis

Answer 25

Alcoholism, liver disease, malnutrition

Question 27

3 major groups of white matter pathways

Answer 27

Projection, commissural, association

Question 29

1st degree relatives of patients with MS are \_\_\_\_x more at risk than the general population?

Answer 29

6-8x

Question 31

Transsynaptic degeneration

Answer 31

Neuronal loss & reactive gliosis in neurons deprived of synaptic input by lesions in adjacent neurons

Question 32

Common affective/behavioral problems in MS

Answer 32

Depression, personality changes, anxiety

Question 33

Most common cognitive deficits in MS

Answer 33

Memory, complex attention/speed of info processing, exec fx, verbal fluency

Question 34

Disconnection syndrome (Geschwind)

Answer 34

Any disorder in which cortical areas that normally work in conjunction become isolated, involving interruption of info transfer

Question 35

Outcomes in childhood-onset MS

Answer 35

Increased risk of having deficits in at least 1 area of cognition, increased rate of need for educational assistance, 1/2 had psych diagnosis, little evidence of physical disability

Question 37

Proposed explanations for MS

Answer 37

Slow-acting virus, delayed reaction to a common virus, autoimmune reaction in which body attacks its own tissues

Question 39

How does MS risk vary by race/ethnicity?

Answer 39

Predilection for whites; Asian & black populations have low risk

Question 40

Transverse myelitis

Answer 40

Acutely evolving inflammatory-demyelinative lesion of the spinal cord, often an expression of MS

Question 41

Visual changes seen in MS

Answer 41

Optic neuritis, intranuclear ophthalmoplegia, Marcus Gunn pupil

Question 43

Which hemisphere has a greater proportion of white matter?

Answer 43

Right

Question 44

Overall prevalence of cognitive impairment in MS

Answer 44

40-70%; of those with impairment, 80% are mild

Question 45

How does immigration from a high-risk to a low-risk latitude affect MS risk?

Answer 45

Individuals carry with them some of the risk from their place of origin if they move after age 15

Question 46

How does childhood-onset MS differ from adult-onset?

Answer 46

Higher lesion burden on initial MRI, esp. in brainstem & cerebellum; however, T2-bright foci in younger children can vanish with repeat scans

Question 47

Describe the steps of myelogenesis (i.e., which areas of the brain are myelinated 1st, 2nd, etc.)

Answer 47

1) Primordial ('premature') fields are myelinated before birth (somesthetic cortex, primary visual, primary auditory) 2) Intermediate ('postmature') fields myelinate during first 3 monts (secondary association areas) 3) Terminal fields myelinate b/t 4th month and 14 yrs of age (classical association areas)

Question 48

Multiple sclerosis

Answer 48

Multifocal demyelinating disease that causes destruction of myelin sheath of nerve fibers along with sclerotic plaques that form in areas where demyelination has occurred & block or distort the normal transmission of nerve impulses

Question 49

Retrobulbar neuritis

Answer 49

Optic neuritis that occurs far enough behind the optic disk that no early changes of the optic disk are visible by ophthalmascope

Question 50

How do prevalence rates of MS change relative to the Equator?

Answer 50

Prevalence decreases systematically as latitude of habitation nears Equator