Computerized Tomographic Scanning and the Diagnosis of Dementia

To the Editor: We agree with Fox et al., who reported in the issue of February 22 that computerized tomography of the head (CT scan) is a test of limited value for predicting the severity or outcome of dementia in the elderly. They correctly point out the fundamental reasons for the lack of correlation between cerebral atrophy and mental impairment; we would like to add another reason — the clinical heterogeneity of the dementing illnesses. In approximately 50 per cent of patients with dementia, the cause remains undetermined even after extensive workup.¹ These patients, usually labeled as having cortical atrophy.