Introduction to Alzheimer’s Disease

The prevalence of Alzheimer’s disease is 10% in those over 65 years of age.  Alzheimer’s disease equally affects men and women.  In Alzheimer’s disease there is atrophy of cerebral cortex; that is a loss of cortical and subcortical neurones.  Also, in Alzheimer’s disease there is the accumulation of senile plaques containing the protein β-amyloid (which is a neurotoxin) and of neurofibrillary tangles.

In Alzheimer’s disease, there is a striking and disproportional loss of the neurotransmitter acetylcholine (Ach), but this is not the only loss in Alzheimer’s disease.  There is also a loss of tryptaminergic (5-HT), glutaminergic (glutamate) and neuropeptide neurotransmission.

Alzheimer’s disease is well known for giving an impairment of cognitive abilities.  This impairment is gradual in onset but relentless (keeps getting worse).  There is impairment of short-term memory – progresses from decreased ability to calculate, decreased visuospatial skills, decreased ability to use common objects/tools,  to decreased arousal/alertness.   Death occurs, 6-12 years after onset, usually due to complications of the immobility associated with the latter stages of the disease.