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Conversely, the subjects who remained aware of the environment . . . produced the smallest
amounts of alpha” (Brown, 1974, p. 333). One interpretation of this seeming paradox is that the
subjects entered a state of selective attention which did not require an alert, no-alpha EEG.
Possibly, the subjects were attending to being nonattentive during the feedback trials and
became less attentive to being nonattentive during the rest periods.
Alpha and Anxiety
There are indications that alpha production is related to anxiety (Nowak & Marczynski, 1981).
However, the use of alpha-biofeedback training to reduce anxiety has met with mixed success.
Hardt and Kamiya (1978) reported that with high trait anxiety subjects alpha training resulted in
anxiety reduction in proportion to alpha increases and anxiety increases in proportion to alpha
suppression. Watson, Herder, and Passini (1978) report long-term improvement in both state
and trait anxiety with alcoholics who participated successfully in alpha training. Plotkin and
Rice (1981), however, found that anxiety reduction was related more to perceived success in
the feedback task than to actual changes in alpha production. They thus attribute the
reductions in anxiety that occur during alpha feedback training to placebo effects.
In a study by Orne and Paskewitz (1974) subjects were given alpha feedback training and
were told that their alpha production would determine whether or not they would receive
electrical shock during periods signaled by a tone. Although the subjects indicated increased
physiological and psychological arousal during times of jeopardy, as measured by increased
heart rate, skin conductance responses, and reported subjective apprehension and anxiety,
their alpha production was not affected. These results indicate that a reduction in alpha
production is not a necessary consequence of increased anxiety or physiological arousal.
However, the results do not necessitate the conclusion that increased alpha production does
not reduce anxiety.
Therapeutic Applications of Alpha Training
Although there have been reports of unsuccessful attempts to utilize alpha biofeedback
training therapeutically (Hord, Lubin, Tracy, Jensma, & Johnson, 1976; Leib, Tryon, &
Stroebel, 1976; Mandelzys, Lane, & Marceau, 1981; Watson & Herder, 1980), positive results
have been reported with several therapeutic applications. Goldberg, Greenwood, and Taintor
(1976) reported that a decrease in illicit drug use accompanied learned control of alpha in four
chemically addicted subjects. Peniston and Kulkosky (1989) utilized alpha-theta brain-wave
training with alcoholics and reported long-term improvement in depression scores and
sustained prevention of relapse. Alpha training paradigms have been successful in reducing
seizures and abnormal brain rhythms in epileptics (Johnson & Meyer, 1974a; Rouse, Peterson,
& Shapiro, 1975; Sterman, 1973). Success has been noted in the treatment of migraine
headaches (Andreychuk & Skriver, 1975; Cohen, McArthur, & Rickles, 1980), although alpha
training was not found to be superior to other biofeedback strategies. The control of pain has
been found to be related to alpha production in meditators (Pelletier & Peper, 1977) and alpha-
biofeedback strategies have been found to facilitate control of chronic pain in conjunction with
hypnotic suggestion (Melzack & Perry, 1975) and stress inoculation training (Hartman &
Ainsworth, 1980). Mills and Solyom (1974) used alpha training successfully with five
ruminating obsessives and found that virtually no ruminations occurred during alpha, indicating
possibilities for further research and application of alpha training in this area. Alpha
suppression training has been successful improving performance on an arithmetic task with
mentally retarded subjects (Jackson & Eberly, 1982), and improving attention and reading
skills (Ludlam, 1981).
Binaural Beats and the Frequency-Following Response
As has already been seen, the alpha rhythm is influenced by many factors, both internal and
external. Environmental factors such as photic and auditory stimulation have been found to
influence alpha production in various ways. Flickering lights can entrain the electrical rhythms
of the brain through the frequency- following response. A more subtle example of the
frequency-following response occurs through binaural beats, an auditory brainstem response.
Photic Stimulation
Research clearly indicates the possibility of entraining specific frequencies of brain waves by
presenting subjects with frequency-specific flickering lights (Arinibar & Pfurtscheller, 1978;
Nogawa, Katayama, Tabata, Ohshio, & Kawahara, 1976; Regan, 1966; Williams & West,
1975; Yaguchi & Iwahara, 1976). For example, alpha-frequency brain waves may be entrained
by exposing subjects to a light stimulus flickering at a rate within the alpha frequency range.
The tendency for the electrical rhythms of the brain to become entrained to frequencies of
sensory stimuli in the environment is called the frequency-following response (Moushegian,
Rupert, & Stillman, 1978; Sohmer, Pratt, & Kinarti, 1977; Stillman, Crow, & Moushegian,
1978).
Auditory Stimulation
Research also indicates that auditory stimuli can be used to entrain the electrical rhythms of
the brain (Neher, 1961; Picton, Woods, & Proulx, 1978a; Picton, Woods, & Proulx, 1978b).
Auditory entrainment of cortical rhythms can occur through two different routes. One may
achieve entrainment through bursts of sounds such as through drum beats, or one may
achieve entrainment through the less direct and more subtle route of binaural beats.
The range of the electrical rhythms of the human cortex is 0 Hz to about 40 Hz. Since humans
have an auditory range of 20 to 20,000 Hz, it is not possible to directly entrain cortical rhythms
below 20 Hz with pure tones. However, the phenomenon of binaural beats, an auditory
brainstem response, allows the entrainment of frequencies below 30 Hz through the interaction
of pure tones within the superior olivary nuclei.
In 1839 H. W. Dove, a German experimenter, discovered the auditory effect of binaural beats
(Oster, 1973). He found that when two different frequencies of sound were presented, one to
each ear, a third frequency equal to the difference between the two frequencies was
experienced. This third, binaural beat is actually the result of the interaction of the two primary
tones within the auditory brainstem. For example, if a pure tone with a frequency of 400 Hz is
presented to one ear and a second tone of 410 Hz is presented to the other ear, a third
binaural beat with a frequency of 10 Hz will also be heard as a result of the interaction of the
two frequencies. Binaural beats can be generated at frequencies below 40 Hz and may be
used to entrain electrical rhythms of the brain to vibrate at the same frequency through the
frequency-following response (Dobie & Norton, 1980; Gerken, Moushegian, Stillman, & Rupert,
1975; Moushegian, Rupert, & Stillman, 1978; Smith, Marsh, & Brown, 1975; Smith, Marsh,
Greenberg, & Brown, 1978; Sohmer, Pratt, & Kinarti, 1977; Stillman, Crow, & Moushegian,
1978; Yamada, Yamane, & Kodera, 1977). Mediating processes through which the auditory
brainstem binaural beat may entrain the cortex are likely to include attentional and motivational
factors. Binaural-beat techniques are reportedly being used to successfully entrain specific
brain-wave frequencies for specific purposes (Atwater, 1988). Preliminary reports indicate that
the techniques may lend themselves to therapeutic applications. The combination of binaural
beats and brain wave biofeedback may also prove therapeutically useful in the future.
METHODOLOGY
The Pilot Study
A pilot study was implemented January 1989, in order to further define the parameters
necessary to test the utility of binaural beats in enhancing alpha production. The purposes of
the study were to determine (a) the effectiveness of the binaural- beat technique in enhancing
alpha production within a single session, (b) the effectiveness of the binaural-beat technique in
enhancing alpha production across sessions, and (c) the number of sessions necessary in
order for the binaural-beat technique to enhance the self-regulation of alpha in subjects.
Method
Subjects
Four volunteer students, one undergraduate female, one graduate female, one undergraduate
male, and one graduate male, were used ranging in age from 20-38. A total of eighteen
sessions of usable data was compiled. One subject completed six sessions, two subjects
completed five sessions, and one subject completed two sessions.
Procedure
The initial session included a discussion of a handout describing the components of the
“relaxation response” (Benson, 1975) and a brief introduction to the binaural-beat
phenomenon. Subjects were told that the experiment was designed to provide a binaural beat
to serve as the “mental device” (p. 27) in Benson’s paradigm. Subjects were reminded of the
importance of maintaining a passive attitude and focusing on the binaural beat before each
session.
The procedure for each session was the same; (a) subjects completed a brief pre-test of
subjective experience of relaxation and anxiety, (b) subjects were given instructions to relax
and breathe slowly and deeply for three to five minutes, (c) EEG activity was recorded while
subjects listened with eyes closed for seven minutes each to three conditions of sound–
artificially produced surf sounds, surf sounds with audible alpha-frequency binaural beats, and
surf sounds with subaudible alpha-frequency binaural beats, (d) subjects completed a brief
post-test of subjective experience of the procedure and levels of relaxation and anxiety.
Instruments
The binaural beats were produced by a Model 201B Hemi-Sync Synthesizer (“Instruction
Manual,” undated). EEGs were recorded bipolarly from occipital and temporal sites of both
hemispheres (T3, T4, 01, & 02 sites as per Jasper, 1958) by a Mind Mirror II EEG (Blundell,
undated; Cade & Coxhead, 1979).
Scoring
Average alpha ratios were computed for each condition of each session. Each of the 28
channels was sampled three times per second. For each condition a ratio of alpha/all
frequencies was computed. These ratios were utilized in the statistical analysis.
Results
Early in the study it became evident that methodological refinements were needed in order to
demonstrate any effects of the binaural beats. The analysis of variance of the data revealed
that there were no significant differences in alpha production either within sessions across
conditions or across sessions. Although alpha production was observed to increase in the
binaural-beats condition early in some sessions, a tendency was observed for the subjects to
move through alpha into desynchronized theta, indicating light sleep. Subjective reports of
“dozing off” corroborated these observations. These periods of light sleep, almost devoid of
alpha, affected the average alpha ratios.
Subjective reports indicated that the procedure was experienced as either pleasing and
relaxing or neutral. Open interviews revealed that one subject who was certain he had found
the key and was controlling his alpha was in actuality producing no more EEG alpha than
before.
DISCUSSION
Since the procedural conditions of the pilot study were insufficient to document that the alpha
binaural beats could stimulate increased alpha, the strategy of adding the biofeedback task
was conceived to provide subjects with an ongoing measure of success. It is conceivable that
with feedback, subjects will be able to discover successful strategies for letting the binaural
beats entrain their brain rhythms to the frequency of the stimulus.
The Study
Based on the results reported in the pilot study, the following study was conducted which
incorporates a feedback condition into the binaural-beat procedure. The feedback will