Electroencephalography in subjects sixty years and over

Abstract

650 EEGs were examined in 466 normal subjects and patients over 60 years old. 1. 1. Abnormal EEGs were observed in 32.7% of normal subjects and in 44.5% of neurologically normal cases. The incidence of EEG abnormalities tended to augment with increasing decades in neurologically normal cases. The existence of high blood pressure did not seem to influence the incidence of EEG abnormalities either in neurological or non-neurological cases. 2. 2. In hemiplegic and hemiparetic patients who had survived more than one year after the apoplectic attack, EEGs were normal in 14.5% and 27%, respectively. No difference in the incidence of abnormal EEG was noted between right and left side paralysis; however, the correlation of the side showing more prominent EEG changes with the clinically paralysed side was significantly higher in right sided than in left sided paralysis in right-handed subjects. 3. 3. Alpha blocking was noted in 57.6% of neurologically normal subjects, decreasing significantly with increasing decade after the 6th, and was significantly lower in neurological patients than in subjects with no neurological manifestations. 4. 4. “Flat” EEGs were found in 8.6% of neurologically normal subjects and their incidence tended to decrease with increasing decade after the 6th. No significant difference was noted between neurologically normal and abnormal cases. 5. 5. The build-up after hyperventilation was poor in general, and was absent in 73% of 401 cases.