Were examined 56 normal subjects, with an average age of 21,268 years. Of these, 19 were born in the sea, in the mountains 30 and 7 on the mountain. In the present communication it is only the results of electroencephalographic examination. The criteria for the classification of the results of the electroencephalogram (EEG) are described into four types; the overall results were: 60.7% normal EEGs; electroencephalograms dysrhythmic 25.0%; electroencephalograms limits 5.4%; abnormal electroencephalograms 8.9%. It is emphasized here that the EEG classified as dysrhythmic be considered as normal special reactivity; electroencephalograms limits are questionably abnormal; Finally, it is noted that when speaking of abnormal EEG that is not to say pathological EEG. The 33.9% of those tested did not show slow waves during hyperventilation. Of this group 10.5% were coastal, mountain were 73.7% an...