Efficacy Results

Abstract /

  Introduction

  Method
  Results
  Discussion
  References

METHOD

Efficacy of SMR-Beta Neurofeedback for Attentional Processes

David A. Kaiser and Siegfried Othmer
EEG Spectrum, Inc. Encino, CA
November 1997

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RESULTS
Repeated measures analyses of variance (ANOVA) were used to evaluate the effect of group membership for three factors: medication, gender, and age. Medication refers to whether subjects took condition-specific medication at any time during their EEG biofeedback training. Medication information was only present for 324 subjects and only the data from these individuals were analyzed. No effect of medication, F (2,551)=1.884, ns ; gender, F (2,417)=0.949, ns ; nor age F (2,447)=3.754, p >.01; was found on the TOVA measures. As no significant differences were found between groups, all groups were combined into a single group. Repeated measures ANOVAs were then used to evaluate the effect of EEG biofeedback training on four dependent measures of the TOVA: Inattention (percent omission), Impulsivity (percent commission), Response Time, and Response Variability. Low scores were truncated at four standard deviations below normal (i.e., 40 points). Mean pre- and post-training TOVA scores are presented in Table 1.

Table 1.
Mean standard scores for TOVA measures before and after approximately 20 EEG biofeedback sessions for 324 subjects with attentional deficits .

 

Pre-Training

Post-Training
Inattention

83.4

91.7
Impulsivity

85.5

98.9
Response Time

89.9

88.4
Resp. Variability

79.7

86.6

EEG biofeedback training produced significant improvement in inattention scores; F (1,323)= 38.678, p <.001; impulsivity scores, F (1,323)= 191.266, p <.001; and variability of response time, F (1,323)= 32.175, p <.001. Results are even more dramatic when individual data are observed. As can be seen in Figure 1, only a handful of subjects demonstrated declines in impulsivity scores while the majority improved greatly and in proportion to pre-treatment values. Improvement extended above and beyond the normal range for many individuals.

Figure 1. Pre- and post-treatment TOVA impulsivity standard scores for 530 children, adolescents, and adults. Each line segment represents a single subject’s change from pre-training to post-training scores. The data are sorted by pre-training score. Improvement is indicated when the line segment rises above the pre-training value.

Those subjects with pre-treatment impulsivity scores less than two standard deviations below the mean (i.e., scores of 70 and below) improved more than 25 points in measures of inattention, F(1,92)=97.414, p<.001; and impulsivity, F(1,79)=107.451, p<.001. Improvement was less marked but still impressive in response time, F(1,60)=15.587, p<.001; and response variability, F(1,110)=80.249, p<.001 (see Figure 2). In all, EEG biofeedback training produced clinically significant improvement (i.e., half a standard deviation increase or more on one or more measures), in 75 % of all subjects, a value comparable to the approximately 70% response rate of psychostimulants (Cantwell, 1994; Barkley, 1990).

Figure 2. Pre- and post-treatment TOVA standard scores for all four dependent measures for subjects with pre-treatment deficits of two standard deviation or more below the mean.

Sixty-two subjects underwent an additional period of training after 20 sessions were completed. Understandably, these were individuals who had achieved only modest progress in 20 sessions. Impulsivity was found to improve from pre-treatment levels after 20 sessions and then continued to improve after 40 sessions. Response variability exhibited significant improvement only after 40 training sessions were completed (see Figure 3).

Figure 3. TOVA standard scores for 62 subjects at pre- treatment,
after 20 sessions, and after approximately 40 sessions.

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