Electroencephalography, visual evoked potentials, and cerebral CAT-scan as diagnostic tools in senile dementia of Alzheimer type.

The usefulness of a cerebral computed tomogram (CAT-scan), an electro-encephalogram (EEG), and flash visual evoked responses (FVER) as diagnostic tools in dementia was studied in 36 mentally impaired and 32 unimpaired persons aged 75 yr and above, who were recruited from a random sample of elderly people living at home. The clinical diagnosis of dementia was made after a full psychogeriatric assessment supplemented by a follow-up 18 mo later. When the measures of cortical atrophy from a cerebral CAT-scan, the presence/absence of diffuse slow activity on a standard EEG, and FVER P200 and FVER P100 latencies were introduced in a logistic regression model, the clinical diagnoses being the dependent variable, an effective prediction of senile dementia of Alzheimer type (SDAT) was obtained (sensitivity 93%, specificity 86%, misclassification rate 12%). We conclude that the use of FVER, an EEG, and a cerebral CAT-scan may facilitate the diagnosis of senile dementia of Alzheimer type.