WISC-R
One concern with respect to the WISC-R is a practice effect on retest scores, with the result that many practitioners insist on a six-month retest interval. This criterion was adhered to in our study, with most retest intervals larger than nine months. We believe that the practice effect on the present data is in fact negligible, based on the following grounds: First, in one explicit determination of retest error with a sample of 300, after only a one-month interval only a 7-point IQ change was observed. (Wechsler, 1974) After some six to nine months, more extinction would be expected. Second, the concern about retest error diminishes if one is observing significant change in the WISC-R. In a number of the WISC-R subtests, the child is asked to stop after a certain number of errors, or by virtue of a time limit. On the retest, therefore, the child is exploring fresh ground if he is in fact doing significantly better than before. Third, significant gains were observed in those areas where long-term memory cannot have been an issue, such as Digit Span. Fourth, the gains were in fact least where a practice effect might be expected, such as Block Design and Object Assembly. Finally, we are dealing with a population which demonstrated poor visual retention in the pre-test.

The gains shown in the WISC-R are ascribed to a composite of factors. Alertness, attentiveness, and perseverance were clearly greater in the retest than before, in essentially all cases. Impulsivity was manifestly better, and test anxiety was reduced. However, there is abundant evidence for a broad range of improvements in those cognitive tasks which contribute to verbal comprehension and to perceptual organization: visual and auditory retention (Benton VRT and Digit Span), short and long-term memory (Information, Vocabulary), sequential processing (Arithmetic), inferential thinking (Similarities), verbal conceptualization and expressive language (Comprehension), visual perception (Picture Completion, Picture Arrangement), sequential processing (Coding), and visual-motor coordination (Tapping Test, Mazes).

Hence, the WISC-R improvements are attributed to a combination of behavioral and cognitive factors. Moreover, improvements in both areas appear to be directly attributable to the EEG training, rather than one being the incidental corollary of the other. The startling improvements in arithmetic score on the WISC-R, for example, are likely to be due to a combination of factors, such as improved attention span and improvements in sequential and symbolic processing skills, in addition to behavioral factors such as reduced anxiety or impulsivity.

WRAT
The results of the WRAT show a much larger dispersion than the WISC-R test results. Some children demonstrated great strides in reading and arithmetic achievement. Others were relatively unaffected. It should be noted that the WRAT is a test of achievement rather than of ability. It may take time (or educational therapy) for new cognitive skills to manifest themselves in higher academic achievement.

Benton VRT, and Tapping Subtest of Harris Tests of Lateral Dominance.

The Benton VRT shows perhaps the most striking evidence of an effect on a specific learning disability, as distinguished from general effects on attentional mechanisms. And the Tapping Subtest of the Harris Tests of Lateral Dominance is perhaps the most graphic demonstration and of an effect on hemispheric organization, and is arguably best understood in terms of remediation of a traumatically induced neurological deficit.

Mechanisms of Efficacy of EEG training
These findings are corroborative of a mechanism which remediates minor neurological deficits centrally. That is, the statistics of cortical activity, as manifested in the EEG, are assumed to be governed largely by the brain stem reticular formation and nonspecific thalamic nuclei. The effects of such training would be expected to be global, that is, not restricted to one hemisphere. The training apparently impacts on the processes which govern cortical activation, via a balance of excitatory and inhibitory mechanisms.

The breadth of impact of this technique implies a more universal mechanism than one specific to the motor system, or even to sensorimotor cortex. The fact that the same protocol can successfully address both symptoms of cortical hyperexcitability (seizures, motor and vocal tics, anxiety) and symptoms of underarousal (childhood depression, ADD) strongly suggests that EEG biofeedback may be a general method of achieving cortical regulation or stabilization in individuals where that is manifestly deficient.

Comparison of WISC-R Data with Tansey
A comparison has been made between the WISC-R results achieved in this study and those achieved by Tansey using SMR training at Cz. The results are shown in Figure 13. The comparison indicates that Tansey's population was relatively more severely impaired. The gains are significantly higher in our study group for Arithmetic, Picture Completion, and Comprehension. They are significantly lower for Object Assembly. The other subtests show comparable gains. If account is taken of the difference in pre-test scores, the implied preference for the present protocol emerges even more strongly.

Figure 13

Figure 13.
Comparison of WISC-R data from the present study using beta training with that published by Tansey (1990) for SMR training. A preference for beta training is indicated.

SUMMARY
In summary, we have documented by a variety of tests specific benefits in terms of cognitive function and academic competence of EEG training at sensorimotor cortex, and consisting of enhancement of activity in the 15-18 Hz spectral region, and suppression of excessive amplitudes in the 4-7 Hz and 22-30 Hz regions. The benefits of the training are ascribed to indirect stimulation of the central mechanisms which govern cortical activation. Striking improvements in symptoms of conduct disorder and oppositional/ defiant disorder were also noted in those cases where these were present, but were not quantitatively assessed. Sleep disorders and headache syndromes were also remediated. Follow-up data indicate the benefits of the training persist. A preference for beta training vis-a-vis SMR training for remediation of cognitive deficits, as originally reported by Lubar, appears confirmed.