EEG findings of local healthy elderly population and elderly dementia population

Abstract

To examine the EEG characteristics of the elderly people who participated in the medical checkup for dementia. Subjects were 402 elderly people in population-based dementia prevalence survey (2010) of Tone-Town, Ibaraki. EEG was recorded for 5 minutes in sitting position. EEG of 318 elderly people (166 males [age 77.5±7.8], 152 females [age 76.3±7.7]) were readable for interpretation. EEG abnormalities rate were 5.7% in Normal Control (NLC), 9.6% in Within Normal Limits (WNL), 18.5% in Mild Cognitive Impairment (MCI) and 42.9% in Alzheimer’s Disease (AD). Rate of less-than 9 Hz background activities were significantly low on NLC and significantly high on AD. The appearance of elderly-specific EEG finding was: Kappa rhythms 69.8%, Wicket spikes 3.5% and temporal slow waves of the elderly (TSE) 15.7%. The more the kappa rhythm appeared, the older the patients were. The frequency of background activities were related to the morbidity of dementia. Kappa rhythms may play a certain additional role in the age-related change within a brain.