Cognitive Disorders

7.10.2006

DeliriumA. Disturbance of consciousness

i.e. Reduced clarity of awareness of the environment

Reduced ability to focus, sustain, or shift attention

B. Change in cognition E.g. Memory deficit, disorientation, language

disturbance

C. Disturbance develops over a short period of time (hours to days) and tends to fluctuate over the course of the day

D. Evidence that the disturbance is caused by the direct physiological consequences of a GMC, substance, or both

Facts about Delirium Prevalence: At any point in time…

0.4% of adults age 18 and older1.1% of adults age 55 and olderUp to 60% of nursing home residents

age 75 and older Gender: Males might be at higher risk Age of onset: Most common in the elderly and medically

ill Course: Develops over hours to days

Majority of cases resolve (could be hours, days, weeks, or months…)

Some cases progress to coma, stupor, or death

Increases risk of mortality for hospital patients

Causes of Delirium Psychoactive substances of abuse Medications other than above (e.g.

steroids) Infection, especially in the brain (e.g.

bacterial, viral, etc.) Toxins (e.g. heavy metals like mercury) Surgery Head injury Shock

DementiaA. Development of multiple cognitive deficits

manifested by both:1. Memory impairment (either old or new information)2. One or more of the following cognitive disturbances:

a. Aphasia (impaired speech)b. Apraxia (impaired ability to carry out motor activities)c. Agnosia (failure to recognize/identify objects)d. Disturbance in executive functioning (planning, organizing,

sequencing complex activities)

B. Cognitive deficits cause significant impairment in functioning and represent a significant decline from a previous level of functioning

Facts about Dementia Prevalence: 0.5-1% adults age 65 and above

10-15% adults age 85 and above20-25% adults 90 and above35-40% adults 95 and above

Gender: Slightly more common in females Age of onset: Typically in the elderly (depends

on cause) Course: Typically gradual onset, chronic,

progressive (depends on cause)

Causes of Dementia Alzheimer’s (Cause of 70% of dementias) Vascular lesions in the brain (reduces

blood flow to the brain) HIV Head trauma Parkinson’s Disease Huntington’s Disease Pick’s Disease Creutzfeldt-Jakob Disease

Alzheimer’s Disease: Forms Early Onset – develops prior to age 60

Runs more strongly in families Progresses more rapidly

Late Onset – develops at age 60 or later

Risk for developing Alzheimer’s increases with age

Alzheimer’s Disease: Pathology Neuropathology

Plaques, neurofibrillary tangles of tau protein Plaques of amyloid and protein

Protein that is present in all kinds of tissues Responsible for “housekeeping” Abnormal growth creates plaques Plaque count positively correlated with cognitive decline

Research in mice also implicate excessive iron in the brain

Small holes in neural tissue (granulovacuoles) Atrophy (“wasting away”) of the brain Firm diagnosis is only possible after death, at

autopsy

Alzheimer’s Disease: Pathology

Brain of someone with Alzheimer’sDisease – plaques, tangles, and overall brain atrophy are present

Brain of a healthy person

Alzheimer’s Disease: Genetics All Down syndrome kids get Dementia of

Alzheimer’s type Down syndrome due to trisomy on

Chromosome 21 Chromosome 21 is also linked to early onset

form of Alzheimer’s Disease Production of the amyloid protein is linked to

Chromosome 21 However, we don’t know if the amyloid

tangles are the cause of Alzheimer’s Disease or an additional symptom of the real cause…thus, we still don’t know if Chromosome 21 has a causal role in Alzheimer’s

Alzheimer’s Disease: Treatment No effective treatment exists to restore lost

functioning Behavioral therapy works to control

wandering, incontinence, inappropriate sexual behavior, and poor self-care behaviors

Drugs that enhance the availability of the neurotransmitter acetylcholine (acetylcholine depletion has also been found in Alzheimer’s patients) Slows, but doesn’t stop decline

Trying to pursue medications or vaccines that will clear away the tangles and plaques

Alzheimer’s Disease: Caregivers Caregivers of Alzheimer’s patients must

deal with the “social death” of the patient even before the actual physical death

Financial burden Chronic stress High risk for depression

Vascular Dementia Second most common cause of dementia (19% of

cases), more common in men Damage caused to specific areas of the brain Stroke – interruption of blood flow to the brain,

results in lack of oxygen to parts of the brain, which may die

Aneurism – rupture of blood vessels in the brain, blood floods the brain, pushing blood against the skull, crushing cells and killing parts of the brain

Abrupt, sudden onset of symptoms with fast decline

May be normal functioning in parts of brain not affected

Dementia due to HIV Researchers found that HIV could result in

the destruction of brain cells Causes generalized atrophy, edema

(swelling), inflammation, and patches of demyelination

May lead to psychotic phenomena as well 30-60% of untreated AIDS/HIV patients will

develop dementia Only 20% of AIDS/HIV patients who receive

antiviral treatment develop dementia

Huntington’s Disease Inherited disease caused by an autosomal

dominant gene 100% determined by your genes (i.e. if you

have the genes for it, you will develop Huntington’s Disease)

Age of onset: approximately 35 – 45 Progressive deterioration of motor skills,

personality, cognitive functions (dementia), and mood

Results in death within 10-20 years of developing symptoms

Parkinson’s Disease Slowly progressive neurological disorder More common in men Age of onset is typically between ages 50-70,

although Michael J. Fox developed symptoms at age 30

Causes rigidity, tremors, lack of balance, diminished small motor control, and difficulties communicating

Caused by both genetic and environmental factors

20-60% of cases result in dementia