Quantitative indexes of computed tomography in dementia and normal aging.

Quantitative indexes of compute tomography were compared in 28 patients with Alzheimer dementia and in 30 elderly persons with no history of neurologic disease. Age-corrected ventricle-brain ratios were abnormal for half of the dementia patients, whereas only a single subject in the control group had ventricles outside the limits of normal variation. Measurement of the distance between the third ventricle and Sylvian fissure indicated that the dementia patients had significantly more atrophy in this area. Employment of quantitative indexes standardized for age may aid in differentiating cerebral atrophy associated with dementia from that associated with normal aging.