Alzheimer's Disease


A chronic, progressive, neurologic disorder characterized by degeneration of the neurons in the cerebral cortex and subcortical structures, resulting in irreversible impairment of intellect and memory.


Causes and Incidence The cause is unknown, although theories involving genetic links, neurotransmitter deficiencies, viruses, aluminum poisoning, autoimmune disease, and viruses have been advanced. Alzheimer's disease is the fourth leading cause of death among the elderly in the United States. Approximately 3% of individuals over 65 years of age show signs of the disease; the proportion climbs to 20% in those over 80 years of age. The incidence is higher in women.


Disease Process Selective neuronal cells, primarily those involved in the transmission and reception of acetylcholine, degenerate in the cerebral cortex and basal forebrain, resulting in cerebral atrophy of the frontal and temporal lobes, with wide sulci and dilated ventricles. Senile plaques and neurofibrillary tangles are present. The basic pathophysiologic processes accompanying the brain damage are unknown.





Short-term memory loss, impaired insight/judgment, momentary disorientation, emotional lability, anxiety, depression, decline in ability to perform activities of daily living (ADLS)



Apraxia, ataxia, alexia, astereognosis, auditory agnosia, agraphia, prolonged disorientation, progressive memory loss (longand shortterm), aphasia, lack of comprehension, decline in care abilities, insomnia, loss of appetite, repetitive behavior, socially unacceptable behavior, hallucinations, delusions, paranoia



Total dependence in ADLs, bowel and bladder incontinence, loss of speech, loss of individuation, myoclonic jerking, seizure activity, loss of consciousness


Potential Complications

The end stage of Alzheimer's disease invites complications commonly associated with comatose conditions (e.g., skin breakdown, joint contractures, fractures, emaciation, aspiration pneumonia, infections).


Diagnostic Tests

Definitive diagnosis can be made only through autopsy. 


Clinical evaluation     

Any of the above manifestations  after depression, delirium, and other dementia disorders (e.g., head injury, brain tumor, alcoholism, drug toxicity, arteriosclerosis) have been ruled out; family history


Mental status examination  

Decreased orientation, impaired  memory, impaired insight/ judgment, loss of abstraction/ calculation abilities, altered mood



Brain atrophy; symmetric, bilateral, ventricular enlargement



Slowed brain wave activity,   reduced voltage



Medications for treating specific symptoms or behavioral manifestations (i.e., antidepressants, stimulants, antipsychotics, sedatives); experimental drugs include cholinergic, dopamine, and serotonin precursors; neuropeptides; and transcerebral dilators



Structured, supportive, familiar environment; orientation and cueing program for daily tasks; safety program; family support and counseling; respite care; institutionalization when home care is no longer possible



Excerpted from Mosby's Medical Encyclopedia

Copyright (c) 1994-5, 1996, 1997 The Learning Company Inc. All Rights Reserved