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EEG Biofeedback Training for Hyperactivity,
Attention Deficit Disorder, Specific Learning Disabilities,
and Other Disorders
Siegfried Othmer, Ph.D., and Susan F. Othmer
March, 1989
Page 1 of 5
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 INTRODUCTION
The technique of EEG biofeedback has been investigated by researchers for nearly 20 years. It is still relatively uncommon because its usage has been restricted largely to drug-refractory cases of epilepsy. It has also been investigated for use with minor neurological conditions such as hyperactivity , attention deficit disorder, and specific learning disabilities. Finally, its clinical application has broadened to include other conditions such as endogenous depression, sleep disorders, and the motor, sensory, cognitive and psychosocial dysfunctions attributable to minor closed head injury. In the latter applications, research backup is still meager. The clinical application of the technique is now outpacing the capability of research to provide the statistical underpinnings, on the one hand, and to evaluate testable models on the other.
EARLY RESEARCH BASIS of the EEG BIOFEEDBACK TECHNIQUE
Numerous research studies have confirmed the identification of a 12-14 Hz rhythm in the EEG of a number of species, observed over the Rolandic (sensorimotor) cortex. This rhythm is associated with inhibition of motor activity (Chase and Harper, 1971; Howe and Sterman, 1972; Sterman, 1977). It was labeled SensoriMotor Rhythm (SMR) for its location at the sensorimotor cortex. The rhythm has also been identified in humans. An increase in SMR in the EEG of cats by operant conditioning was subsequently demonstrated (Sterman and Wyrwicka, 1967; Wyrwicka and Sterman, 1968). Similar findings were observed in primates. One effect of such training in cats and in humans was to increase the incidence and duration of Rolandic sleep spindles, which occur in the identical spectral band (12-15 Hz) as the waking SMR, and in the same location. This is accompanied by more sustained periods of quiet sleep in both normal subjects and insomniacs (Sterman, Howe, and MacDonald, 1970).
It was also noted that paraplegics and quadraplegics exhibited larger than normal amounts of the sleep spindles, and reduced amounts of low frequency (4-7 Hz) EEG activity. Concomitantly, victims of spinal cord injury exhibit a relative dearth of epileptic behavior. Moreover, cats with cervical dorsal column transsections exhibited a heightened threshold for drug induced seizures. Finally, a case was observed in which an epileptic subject suffered a high cervical cord compression, and his clinical and EEG seizure activity subsequently disappeared (Sterman and Shouse, 1982). These findings suggested a correlation on the one hand between the quality of sleep and epilepsy (Sterman, 1976a) and on the other a fundamental relation between the relative incidence of SMR rhythm and that of seizures with a motor symptomatology. Reduction in 4-7 Hz power has also been demonstrated in monkeys during sleep, after administration of four anticonvulsant drugs. This suggests that excessive low frequency amplitude is indicative of insufficient cortical control, and is a concomitant of susceptibility to seizure onset; moreover, it can be impacted by the medication.
Following on such hypotheses, it was found as early as 1969 that after training for enhanced SMR rhythm in cats the threshold for seizure onset was increased for chemically induced seizures (Fairchild, 1974, Sterman, 1976b). Subsequently, EEG feedback training in poorly controlled epileptics yielded numerous reports of seizure reduction. In 1972, Sterman and Friar published a study of seizure reduction achieved in one person using SMR augmentation training only. There were, in addition, favorable personality changes as well: "Initially she was a quiet and unobtrusive person. She became more confident, outgoing, and interested in her appearance as time went on. She reported that she went to sleep faster, had a more refreshing sleep, and woke up faster in the morning." (Sterman, 1972). Sterman, MacDonald, and Stone achieved an average 66% reduction in seizure incidence in four epileptics using SMR enhancement training in combination with inhibition of excessive slow-wave activity in the 6-9 Hz regime (Sterman, 1974).
Finley, Smith, and Etherton achieved a factor of ten reduction in seizure incidence in a 13-year-old epileptic with an initial seizure rate of eight per hour. These results were achieved with SMR enhancement training in the 11-13 Hz range over some 6 months. There was a concomitant reduction in number of epileptiform discharges observable in the EEG (Finley, 1975). In a followup study after one year of SMR training, seizure incidence had decreased to one per 3 hours (Finley, 1976). Seifert and Lubar achieved significant seizure reduction for 5 of 6 subjects with three months of SMR training, although no significant change in SMR EEG amplitude was demonstrated. Excessive 4-7 Hz amplitudes were inhibited. Subjects were uncontrolled with near-toxic levels of anticonvulsants (Seifert, 1975). Lubar and Bahler used the same protocol with eight severely epileptic patients, and achieved seizure reduction with seven. Two were seizure-free for as long as a month after training. Others acquired the ability to block seizures. Severity and duration of seizures also decreased (Lubar, 1976).
The above studies and other similar ones were reviewed by Sterman (1982). The common elements were that they typically combined positive reinforcement of intermediate EEG frequencies (in the range of 8-25 Hz) with inhibition of lower frequencies (3-8 Hz), but differed in many aspects, such as electrode placement and reward criteria. Taking all the studies together indiscriminately, some 70% of subjects showed seizure reduction with the various experimental protocols.
Recently, Tozzo et al compared EEG biofeedback with relaxation training. Five of 6 drug-refractory epileptics were found to be able to reduce seizure incidence and severity with SMR augmentation training combined with theta (i.e., 4-7 Hz) inhibition. Two subjects benefited in seizure rate from relaxation training (Tozzo, 1988).
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