Abstract
Approximately four million individuals over 65 years ofage sufferfrom some form of dementia. A majority of these people sufferfrom an Alzheimer's-type dementia. Brain alterations associated with this disease process include neurofibrillary tangles and senile plaques and reductions in concentrations of chemical messengers. Alzheimer's-type dementia is typified by a slow decline in intellect andpersonality. It is usually diagnosed after other possibilities have been excluded, and can be correctly diagnosed only upon autopsy. Over 12 of these chemical messenger systems have been examined in Alzheimer's disease. Brain tissue of autopsied Alzheimer's patients has revealed reductions in chemical messenger systems such as the cholinergic, noradrenergic, dopaminergic, serotoninergic, and recently, somatostatin and corticotropin. Treatment strategies based on the deficits of these chemical systems has been unremarkable to date. The only treatment that has yielded positive results thus far has been with a drug of the cholinergic system, physostigmine. However, side effects limit its use. A new brain scanning methodology called Positron Emission Tomography has revealed brain metabolic deficits in the parietal and temporal lobes of the brain in patients with mild to moderate Alzheimer's disease. Patients with severe Alzheimer's disease have brain metabolic deficits throughout their brain. Effective study ofAlzheimer's disease must encompass clinicalandpost-mortem studies that include brain chemical evaluations in addition to PET scanning. A combined approach willyield a better understanding of what Alzheimer's-type dementia is, how it progresses, and how it might better be treated.
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