EEG analysis of healthy adults in the highlands of Xining

An EEG analysis of 400 healthy adults in Xining, Qinghai Province, about 2260 meters above the sea level was made. A comparison of the data with those obtained from a healthy group of adults in the Beijing flatlands was carried out. It was found that (1) the incidence of abnormal EEG of the examinees in Xining was higher (32.25%) than that in Beijing, (2) the index in Xining was lower than that in Beijing, (3) the slow waves occurred more frequently in the Xining group, (4) the spikes were seen in 9.25% of the examined subjects and the sharp waves in 3.0% of the examined subjects in Xining, and (5) the physiological reactions were not so sensitive in the Xining group.