For better than 25 years, the health care treatment modalities known as Biofeedback have demonstrated efficacy in the treatment of numerous human maladies. From treatment of panic and other anxiety related disorders, to medical disorders including Migraine, Raynauds, and Incontinence, patients have demonstrated that the utilization of Biofeedback procedures can be effective in creating subtle, yet powerful bodily changes ranging from vasodilation, heart rate and blood pressure change, to muscular rehabilitation in eliminating chronic pain resulting from physical injury. One treatment arena that has been disappointing for Biofeedback proponents has been the treatment of depression.
Richard J. Davidson, in his edited text Brain Asymmetry (1995), has authored a research literature review titled Cerebral Asymmetry, Emotion, and Affective Style. In this review, he traces a stream of research and convincingly concludes that right hemisphere frontal lobe Alpha Wave activity is correlated with certain emotional and physical functions, e.g. mood, approach vs. avoidance behavior, separation anxiety, and immune system function. However, this body of research does not address the effect of intentional right hemisphere frontal lobe Alpha enhancement on emotional experience, function, and style. From an empirical standpoint, the implications of this review are that such EEG training might shift the experience of depressed mood in a positive direction.
While there are no reports of well controlled group studies to support the effectiveness of EEG Biofeedback in the treatment of depressive disorders, there is a growing body of anecdotal case reports suggesting its efficacy. These preliminary findings not only indicate that depressed patients can learn to shift and enhance alpha amplitudes in the right frontal region, but that the patients' depressed mood subsides, and is replaced with a clearer and more optimistic emotional and thought process. Furthermore, patients skilled in this alpha shift, often report substantial mood elevation within the confines of a single session.
This growing body of preliminary data suggest that individuals diagnosed with both Dysthymia and with Major Depressive Disorders can alter and improve their mood disturbance through EEG Biofeedback training. The EEG skill building sessions may last from 30 to 45 minutes each, and preliminary findings suggest that four to seven sessions per week produce the most efficacious results. Less frequent sessions may produce a between session rebound depressive experience. In early sessions, and while the Alpha shifting skill is developing and becoming effective, the Neurofeedback sessions tend to produce rather dramatic mood elevation which may last from 24 to 72 hours. While individual differences in the number of sessions is expected, preliminary reports suggest that 30-40 sessions may be required to finalize the skill developing and normalizing processes. As with other forms of Biofeedback, session frequency can be reduced as proficiency and permanence are attained. Home practice is encouraged, both to enhance skill level, and generalize the effect to environments other than the clinician's office.
This protocol employs a computerized mathematical procedure, subtracting Alpha amplitudes, right from left hemispheres. The client receives visual and/or auditory reinforcement when crossing the difference threshold set by the clinician. For example, in the shaping process the therapist may set this threshold to a 1 microvolt difference, such that a tone sounds when the right hemisphere Alpha amplitude exceeds left hemisphere amplitude by one microvolt. The required amplitude, Right vs. left hemisphere, is gradually increased by the therapist, facilitating the patient's learning process in the direction of significant right hemisphere, frontal lobe dominance. The frontal lobe cortical EEG activity is monitored through two surface electrodes placed bilaterally. The active sensors are complimented by two ground/reference sensors.
As with any Biofeedback skill building protocol, controlled research needs to confirm the suspected value of the procedure. The efficacy of this and like protocols will be determined through the studies on the horizon.