EEG IN SUCCESSFUL AGING - A 5-YEAR FOLLOW-UP-STUDY FROM THE 8TH TO 9TH DECADE OF LIFE

Fifteen out of 25 successfully aged individuals completed a 5 year EEG follow-up study from the eighth to ninth decade of life with comprehe nsive neuropsychological investigation. One subject suffered from stro ke and one developed symptoms of dementia during the follow-up. Of 13 subjects who completed the follow-up as being healthy, MRI showed subt le enlargement of ventricles or subarachnoid spaces and mild signal hy perintensities in a few regions in 2 subjects. General cognitive decli ne was not observed (WAIS-R IQ: 113.4 at entry, 114.3 five years later ). There were no EEG dominant frequencies below 8 c/sec and no more ba ckground slowing than a few theta waves per 10 sec, either at entry or 5 years later. Intermittent slowing was observed in 9 subjects at ent ry and in 8 subjects 5 years later. The prevalence of intermittent slo wing was suggested to increase with advancing age when compared to pre vious studies with younger elderly. However, intermittent slowing occu rred only a few times in an EEG test and lasted for less than 2 sec. M oreover, the presence of intermittent slowing did not correlate with a ny neuropsychological decline or any MRI change. This type of intermit tent slowing was regarded as non-specific and clinically silent.