Comparative Study of Feedback Method in an Alpha Enhancement Paradigm

Abstract

The performance of subjects receiving integrated, binary, and proportional feedback during an occipital alpha enhancement task are contrasted in the present study. 45 subjects were randomly assigned to one of three feedback groups. Auditory feedback was used in all three groups. The treatment sequence for subjects in each group included a 5 minute baseline period followed by a 3 minute "free play" period and 5 consecutive 3 minute feedback training periods. Alpha activity was defind as EEC activity between 8 and 13 Hz (measured with eyes closed). Feedback for the integrated and binary groups was a 550 Hz tone. Subjects in the integrated group received 5 seconds of feedback if their cumulative integrated alpha during the previous 5 second period was greater than or equal to 50% of the value obtained by averaging sixty 5 second periods of cumulative integrated alpha measured during the base- line period. The binary group subjects received feed- back when their alpha production exceeded the mean alpha amplitude obtained during the baseline period. Feedback for the proportional group consisted of a tone which varied linearlly between 300 (no alpha) and 700 (maximum alpha) Hz. Results indicated that alpha enhancement in the integrated feedback group was significantly greater than that of the other two groups. The treatment effect was significant only for the integrated feedback group.