Focal left temporal slow EEG activity is related to a verbal recent memory deficit in a non-demented elderly population

Neuropsychological measures of memory and cognition and topographical quantitative EEG were obtained on 35 healthy, non-demented, right-handed, elderly subjects aged 60-81. All were free of medications which impair cognition. They were divided into a left temporal slow abnormality group (n = 9) and a control group (n = 26) on the basis of topographically normalized measures of both delta and theta activity for the left temporal lead T3. The group with left temporal slow activity was significantly deficient on measures of memory savings and memory losses derived from the Logical Memory (Story Recall) Test in the Wechsler Memory Scale--Revised. There were no significant differences between these two groups on the non-memory cognitive tasks. This predominant verbal recent memory deficit profile is reasonably similar to the neuropsychological deficit profile of very mildly demented Alzheimer patients. Because left temporal slow EEG activity is also the predominant EEG abnormality in mild Alzheimer patients, a prospective study should be done to determine if this abnormality in non-demented elderly subjects is most often a preclinical sign of Alzheimer's disease.