An Auditory Tracking Device Designed for Use in Conjunction with Continuous Eeg Recording

A tracking apparatus has been in use in this laboratory for some time which makes possible the continuous monitoring of performance and the continuous recording of the elecuo-encephalogram (EEG) simultaneously. In order to achieve this combination, the following restrictions had to be borne in mind: (a) for a study of alpha in the EEG the eyes must be closed and (b) for satisfactory measurement of EEG and other physiological variables it is important to record from S in a reclining or semi-reclining position. Our search of the literature failed to uncover a tracking task which met these necessary conditions, so the apparatus here described was designed. The resulting system employs the auditory modality for the cueing signals (the amount and direction of S's error is fed back to him via tones through a pair of earphones). Mechanically, the whole range of movement of the tracking control operated by S is limited to an angular displacement of less than 10 degrees of arc. In this, and in other mechanical features, the device resembles that described by Surwillo (4), providing nearly optimal conditions for muscle-potential recording. Electrically, our apparatus differs considerably from Surwillo's system.