DISORDERS OF COGNITIVE FUNCTION - mums.ac.ir

DEMENTIA

A.R.ALEHASHEMI MD

ASSISTANT PROFESSOR OF NEUROLOGY

MSHDIAU

2016 dec

A radical claim…..

Learn to think…..

…….Think to learn

TITELS

CONSCIOUSSNESS

COGNITION

DEMENTIA

DEFINITION

CLASSFICATION

TREATABLE CAUSES

CONSCIOUSSNESS

Awareness of self & the environment

Consciousness

Two components of conscious behavior

– Arousal- appearance of wakefulness

– Content- the sum of cognitive and affective function

Level of consciousness

Requires NL function of either:

– Bilateral hemispheres

– Reticular activating system (RAS) in the brain stem

Content of Consciousness (COGNITION)

Cerebral cortex

– Emotions

– Memory

– Attention

– Reasoning

– Self-awareness

– Spatial relationships

– …

Dementia

DEMENTIA

Age-specific prevalence of dementia

0

10

20

30

40

50

60

70

80

90

100

% a

ffec

ted

65-69 70-74 75-79 80-84 85-89 90-94 95-99

Age

Definition

Acquired generalized and often progressive impairment of cognitive function that affects the content, but not the level, of consciousness.

Two types of Dementia

Cortical Disorder affecting the cortex, the outer portion or layers of the brain.

Alzheimer’s and Creutzfeldt-Jakob are two forms of cortical dementia

Memory and language difficulties(Aphasia) most pronounced symptoms.

Two types of Dementia

Subcortical

Dysfunction in parts of the brain that are beneath the cortex.

Memory loss & language difficulties not present or less severe than cortical.

Huntington’s disease and AIDS dementia complex.

Changes in their personality and attention span.

Thinking slows down.

DSM-V Criteria for Dementia:

1. The gradual onset and continuing decline of cognitive function from a previously higher level, resulting in impairment in social or occupational function

DSM-V Criteria for Dementia:(cont.)

2. Impairment of recent memory (the inability to learn new information), and at least one of the following:

a) Language (word-finding difficulties) b) Disturbances of praxis (inability to execute skilled motor activities in the absence of weakness)

c) Disturbances of visual processing (visual agnosia and constructional disturbances)

d) Disturbances of executive function (including abstract reasoning and concentration)

DSM-V Criteria for Dementia:(cont.)

3. The cognitive deficits are not due to other psychiatric disease, neurologic diseases, or systemic diseases, and the deficits do not exclusively occur in the setting of delirium

Minimental status exam

ORIENTATION

REGISTRATION

ATTENTION & CALCULATION

RECALL

LANGUAGE

CONSTRUCTION

TOTAL 30

Mild Cognitive Impairment

MMSE 24-28 Problem with recollection Does not meet dementia criteria

Mild cognitive impairment (MCI)

MCI is a relatively recent term, used to describe people who have some problems with their memory but do not actually have dementia.

Some people (80%?) will be in the early stages of Alzheimer’s disease or another dementia. Others, however, will have MCI as a result of stress, anxiety, depression, physical illness or just an ‘off day’.

It is estimated that 15% of the population may be experiencing MCI.

Currently extensive research on MCI is ongoing.

At the moment there is not enough evidence to recommend any specific treatments.

Differential Diagnosis:

1. Alzheimer Disease (pure ~40%, + mixed~70%)

2. Vascular Disease, MID (5-20%)

3. Drugs , Depression

4. Ethanol

5. Medical / Metabolic Systems

6. Endocrine (thyroid, diabetes)

7. Neurologic , Nutritional (other primary degenerations, etc.)

8. Tumor, Toxin, Trauma

9. Infection

10. Amnesia, Autoimmune

TREATABLE OR REVERSIBLE CAUSES

~ 15% -20 of causes

NPH

IC mass lesion (Tumor, SDH)

B12 def.

Hypothyroidism

Syphilis

Depression(PSEDUDEMENTIA)

Clinical course:

The rate of progression depends upon the underlying cause.

The duration of history helps establish the cause of dementia: Alzheimer‘s disease is slowly progressive over years, whereas encephalitis may be rapid over weeks. Dementia due to cerebrovascular disease appears to occur ’stroke by stroke‘.

Estimate MMSE as a function of time

0

5

10

15

20

25

30

-10 -8 -6 -4 -2 0 2 4 6 8 10

Estimated years into illness

MM

SE

sco

re

AAMI / MCI DEMENTIA

Alzheimer’s Disease (AD)

Alzheimer’s Disease (AD)

Alzheimer’s Disease (AD)

Epidemiology

– Most common degenerative disease of the brain

– 10% of people over age 65 years have AD

– 20% of persons > 80 years

– 30% of > 90 years old

– Male = Female

Histopathology:

Macroscopic: – Atrophy, mostly temporoparietal and frontal

Microscopic – Loss of neurones and synapses – Neurofibrillary tangles (NFTs) – amyloid plaques ( Neurotic plaques) – Granulovsacular degeneration

Chemistry – loss of neurotransmitters, especially

acetylcholine (ACh)

AD: a progressive CNS disorder with a characteristic pathology

Brain

atrophy

Senile

plaques

Neurofibrillary tangles

Katzman, 1986; Cummings and Khachaturian, 1996

Risk factors for AD:

Down’s

syndrome

Strong risk factors for AD*

Age

Down’s syndrome

Family history

Certain genes associated with increased risk but do not cause AD e.g. ApoE4

AD: spatial

impairments

Progressive loss of knowledge and organizational ability over 4 years

Dementia with Lewy bodies

Up to 20% of dementias

Lewy bodies diffusely through cortex

Markedly fluctuating cognitive impairment

Visual and/or auditory hallucinations

Paranoid delusions

Falls

Extrapyramidal features: rigidity & bradykinesia

Neuroleptic sensitivity: extrapyramidal S/Es

Dementia with Lewy bodies

Vascular dementia

Vascular dementia

Also called multi-infarct dementia (MID)

About 15-20%

Decline can be linear or step-wise

Vascular dementia

Step-wise decline - uneven steps, varying plateau

Earlier onset than AD and M > F

Sudden onset, stepwise deterioration

Hx of high BP, strokes

Evidence associated arteriosclerosis, eg coronary artery disease

Focal neurological symptoms and signs

Focal pathology on brain imaging

VAD -vs.- AD

Fronto-temporal dementia Pick’s disease

Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease

Transmissible: cornea transplants, intracerebral recording electrode implants, growth hormone

Rapidly progressive dementia

Etiologic agent: proteinaceous infectious particle (prion)

Creutzfeldt-Jakob disease (cont.)

Dementia

Psychiatric symptoms

Myoclonus

Extrapyramidal signs

Cranial nerve palsies

New Variant: bovine spongiform encephalopathy – Earlier onset (mean age, about 30 years)

– More prolonged course (median duration over 1 year)

– Prominent early psychiatric abnormalities, including depression and personality changes.

NORMAL-PRESSURE HYDROCEPHALUS

NPH

NORMAL-PRESSURE HYDROCEPHALUS

Sometimes called communicating (lateral, 3rd, 4th ventricles remain in communication) or nonobstructive hydrocephalus

Triad

– Dementia

– Gait apraxia

– Incontinence

Idiopathic or secondary (meningitis, SAH)

Memory defects, but rarely aphasia and agnosia

NORMAL-PRESSURE HYDROCEPHALUS (cont.)

Weeks-months Gait apraxia early, with weight bearing Pyramidal signs Urinary incontinence

Lp: normal or low opening pressure – Remove 30-50 cc; prognostication

CT scan or MRI: enlarged lateral ventricles without increased prominence of cortical sulci

Cisternography: delayed clearance

Rx: CSF shunting; VA,VP,LP

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