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EEG Biofeedback Training for Attention Deficit Disorder: A Review of Recent Controlled Studies and Clinical Findings
Siegfried Othmer, Ph.D., David Kaiser, Ph.D., and Susan F. Othmer, B.A.
June, 1995
Page 2 of 3
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 Recent Findings of Controlled Studies
Several studies have surfaced recently which meet criteria for controlled studies, and which therefore are beginning to fill the vacuum. Michael Linden has performed two studies which have both documented statistically significant shifts in IQ scores, along with favorable behavioral changes, using training protocols derived from Lubar. In his first study, which involved a small group of 9 experimental subjects and 9 controls, Linden found an increase in I.Q. scores of 10 points, with a statistical significance of p < .05, using the Kaufman Brief Intelligence Test, or K-BIT (Kaufman, 1990) (Linden, in press). He also found an improvement in parental assessment of inattention, likewise with p < .05. Hyperactivity improved to where it was below the abnormal rating; however, the change was not statistically significant. Assessments used the SNAP rating scale (Swanson, 1981) and the IOWA-Conners rating scale (Atkins, 1987). Training protocol was reinforcement of 16-20 Hz, with concurrent inhibition of excess 4-7 Hz activity. Training extended over 40 sessions. The findings were replicated in a second study, which is currently in preparation for publication.
Henry A. Cartozzo reported on his thesis work at the annual meeting of the Association for Applied Psychophysiology and Biofeedback (Cartozzo, 1995), which involved a small controlled study of EEG Biofeedback for ADHD using a protocol derived from Lubar (augmentation of 12-15 Hz activity with inhibition of 4-7 Hz and 22-30 Hz, with placement at Cz). Training extended over thirty sessions. Using 8 subjects and 7 controls, Cartozzo found significant improvements in the subtests of the WISC-R intelligence test which are most closely identified with ADHD, namely Arithmetic, Digit Span, and Coding. Together with Information, which was not tracked, the above WISC-R subtests constitute the famous "ACID" test of ADHD.
The WISC-R results obtained in the Cartozzo study are shown in Table 1, with comparative data from previous studies (Tansey, 1990; Othmer, 1991). The WISC-R changes were found to be significant at the level of p < .01, whereas the control group showed no significant changes. The results also fall in line with the previous studies. How may we interpret these results? The three subtests are associated with a factor called "Freedom from Distractibility". And they are the ones most sensitive to difficulties in sequential processing. Hence, improvement in these scores can be interpreted in terms of improvement in the continuity of mental processing, in working memory, and in the ability to sustain attentional focus. These improvements would, in turn, be observed as a diminution of distractibility. A minor criticism may be advanced: The latest data suffer from the fact that the two groups were not matched in starting subtest scores. The control group had lower mean scores than the experimental group.
Figure 1.
Improvements in WISC-R subtest score for three independent studies (Cartozzo, 1995; Othmer, 1991; Tansey, 1990) employing similar EEG training protocols.
The Cartozzo study also found improvements in scores on a computerized continuous performance test, the T.O.V.A. (Test of Variables of Attention) (Greenberg). The improvement in attention score was significant at the level of p < .01. The control group showed no significant movement on that test. The study also found behavioral improvements, but scores remained in the abnormal range even after the training. Furthermore, the control group improved on most behavioral measures even more than the treatment group. All changes were significant. However, they failed to confirm the expected interaction with treatment condition. On the other hand, amplitudes in the 4-7 Hz regime did decline with the training, whereas they increased in the control group. Amplitudes within the training band of 12-15 Hz did not change significantly over the course of training. The biofeedback cohort was given feedback via a PAC-Man like object which encoded the feedback signal in terms of its brightness and velocity through a maze. The control group was given the conventional PAC-Man game for the same number of sessions.
One hesitates to propose video games as a remedy for the disregulated behaviors of ADHD on the basis of the above behavioral improvements! There is a better interpretation of these findings. The Cartozzo study restricted itself to a single protocol in the study. This was unfortunate, since it is already known that different children may need different protocols (Lubar, 1991). The result is that some children improve while others do not, or may even deteriorate in behavior. This manifested itself in an increase (near-doubling) in the standard deviation of scores in the experimental group (whereas the standard deviation remained unchanged in the controls). The behavioral changes were reduced in statistical significance because of this increase in dispersion of the data.
Finally, Aubrey Fine and Larry Goldman of California Polytechnic Institute in Pomona (Cal Poly) reported preliminary results on their controlled study of ADHD at the 1994 annual meeting of the American Psychological Association in a poster presentation. This study involved two experimental groups, one getting EEG biofeedback, and a second obtaining cognitive training with a computerized tool (Captain's Log). A third group was a wait-list control. Because this was an initial study of a survey nature, the intake criteria were quite inclusive. Children were admitted who had been diagnosed not only with ADHD but also with seizure disorder, Tourette Syndrome, and depression. Most were already under medical management for these conditions. Some 80% of the group were medicated, 15% of them with more than one medication. Some of the remaining 20% of children were on summer drug holiday.
Because of the multiple objectives of the research study, assessment tools included the Wide Range Assessment of Memory and Learning, Stroop Color and Word Test, Kagan Familiar Figures Test, and the Grooved Pegboard Test. For ADHD assessment, the Conner's CPT and the Gordon Diagnostic System were employed, in addition to several parent questionnaires (Child Behavior Checklist, Home Situations Questionnaire, Child Attention Profile, Revised Conner's Questionnaire, and Social Skills Assessment).
Few of the academic skills tests revealed statistically significant improvement in either of the experimental conditions (12/51). Of course, the population had not been selected for deficiencies on those measures in the first instance, so it is difficult to judge the import of this finding. With respect to the ADHD assessments, the Conner's CPT showed improvement in omissions (inattention), commission errors (impulsivity), and response time. However, so did the control group! No statistically significant interaction with treatment condition was identified. The Gordon Diagnostic System did not yield significant change.
Parental Assessments, however, indicated some significant favorable changes. The Conner's Questionnaire yielded improvement on the impulsive-hyperactivity scale at the p < .01 level for the EEG training contingent. This finding is taken to be highly significant for several reasons. First, the behavioral improvement was identified in a population that was largely already medicated for ADHD, as stated above. Secondly, it was identified after only 20 training sessions, which is generally acknowledged to be insufficient to achieve a full resolution of ADHD with EEG training (Lubar, personal communication). Thirdly, it was identified by parents strictly on the basis of the home environment, since the first 20 training sessions were conducted over the summer months. For many of the children, the home environment is not as challenging as the school environment, so it would be harder to observe a change. And finally, a significant number of children were able to reduce their medications over the course of the EEG training. A maintenance of behavioral scores in the face of reduced medication dose should also be judged an improvement, but would not show up in the above statistics.
Part of the experimental group in the Cal Poly study was selected for an additional 20 sessions of training. The remainder of the group was composed of those who had essentially met the objectives of the training, and those who had not made significant progress in the first 20 sessions to merit continued training. The latter two groups were each a quarter of the total, so that about half (12) was selected for more training. In fact, only about 7 actually undertook the additional 20 sessions and subsequent retest. The results of testing after 40 sessions showed continued progress, as illustrated in Table 2, with four measures reaching significance at p < .05, and two reaching significance at p < .01 (hyperactive index of Conner's, and the depression scale of the child behavior checklist).
Figure 2.
Effect of 20 and 40 Sessions of EEG Biofeedback on Conner's Questionnaire Scale B (Learning Problems); Scale C (Psychosomatic); Scale D (Impulsive Hyperactivity); and Scale F (Hyperactivity); and on the Child Behavior Checklist depression and delinquency scales.
The last of the three groups may be regarded as "non-responders" in the usual sense. The case can be made that the experimental data should be evaluated also on the basis of a division between "responders" and "non-responders", as is typical in drug studies
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