Abstract
In order to record directly the period (viz. frequency) of alpha-rhythm of human EEGs, the authors have designed an apparatus consisting of electrotachometric units, which were inserted into the circuit of a routine EEG recording machine. By this means, it is easily possible to measure the frequency of alpharhythm quantitatively and qualitatively in absolute values. Preliminarily technical notes on this apparatus and several findings obtained from normal subjects by practical application were reported in this paper.
