Dementia of the Alzheimer type and multi-infarct dementia: a clinical description and diagnostic problems.

Patients who had Alzheimer's disease-senile dementia of the Alzheimer type (AD/SDAT) or multi-infarct dementia (MID) were compared with a group of controls. Demented patients had approximately the same degree of dementia and the same duration of illness. The MID group had a significantly higher mean age than the AD/SDAT group. Sixty-three per cent of the AD/SDAT patients were free of other diseases, while 65 per cent of the MID patients had cardiovascular disease. Thirty per cent of the MID patients had a history of previous depression, while only 5 per cent of the AD/SDAT patients had had depression. At the time of the investigation, however, AD/SDAT patients showed significantly more signs of depression than the MID patients. Focal neurologic signs were found in 70 per cent of the MID patients and only 6 per cent of the AD/SDAT patients. The electrocardiogram was normal for every AD/SDAT patient, while 75 per cent of the MID patients had abnormal ECGs. Electroencephalography showed generalized slow frequencies in 79 per cent of the AD/SDAT patients and localized slow frequencies and abnormalities in 65 per cent of the MID patients. Computed tomography of the brain showed that MID patients had significantly greater dilation of the ventricular system, while cortical atrophy did not differ significantly among the three groups. Homovanillic acid in the cerebrospinal fluid was significantly lower in the AD/SDAT group as compared with controls.