Ancoli S., Kamiya J. Methodological Issues in Alpha Biofeedback Training

Biofeedback and Self-Regulation, Vol. 3, No. 2, 1978, 25 р.Current controversies concerning outcomes of EEG alpha feedback training
are at least in part due to methodological differences among different
studies. The aim of this paper is to provide future and present researchers in
this field with an analysis of methods used in most of the studies published
from 1968 to 1976, and to comment on those methodological issues we
think most important. These include alpha assessment, training schedules,
and uni- versus bidirectional training. This analysis is accomplished in part
by a series of tables listing 45 studies and the detailed methodologies used. It
is believed that the probabilities of successful feedback enhancement of
alpha can be substantially improved by incorporating the following suggestions:
(a) employing at least four training sessions, (b) the use of continuous
rather than dichotomous feedback, supplemented by periodic quantitative
scores of progress, and (c) using training trials of at least 10 minutes"
duration.
This paper attempts to help resolve some of the controversies in the field of
alpha biofeedback training. Long before feedback training was developed,
it was known that alpha activity was suppressed by visual and oculomotor
processes. Many of the details of this relationship have been investigated in
a wide variety of studies (Fenwick & Walker, 1969; Jasper & Shagass, 1941;
Mulholland, 1969).