Efficacy of SMR-Beta Neurofeedback for Attentional Processes
David A. Kaiser and Siegfried Othmer
EEG Spectrum, Inc. Encino, CA
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The effect of sensorimotor or beta neurofeedback on attentional processes was investigated using the Test of Variables of Attention (TOVA) for 530 children and adults with attentional problems. EEG neurofeedback training produced significant improvement in measures of inattention, impulsivity, and response variability. The greatest improvements occurred for subjects who exhibited severe deficits prior to training. Three-quarters of all subjects exhibited significant clinical improvement (i.e., half a standard deviation increase in one or more measures). Three models which directly or indirectly address the efficacy of EEG neurofeedback were discussed.
In recent years EEG biofeedback training has been applied to an increasing number of psychological, neurological, and psychosomatic conditions (e.g., Fleischman, 1997; James & Folen, 1996; Byers, 1995; Tansey, 1993). Sensorimotor (SMR; typically 12-15 Hz) and beta (15-18 Hz) neurofeedback, a form of training designed to enhance intermediate frequency EEG instantaneous amplitudes, has been reported to improve epilepsy (Lantz & Sterman, 1988; Tozzo, Elfner, & May, 1988; Sterman & MacDonald, 1978), attention deficit hyperactivity disorder (ADHD) (Lubar, Swartwood, Swartwood, & O’Donnell, 1995; Rossiter & LaVaque, 1995; Lubar & Shouse, 1976), specific learning disabilities (Tansey, 1985; Linden, Habib, & Radojevic, 1996), and some conditions associated with ADHD such as bruxism, tics, and mood swings (Alhambra, Fowler, & Alhambra, 1995; Tansey, 1986). Minor closed head injury, multiple sclerosis, autism, chronic fatigue syndrome, and pre-menstrual syndrome, head a growing list of conditions reported by clinicians to be partly or fully remediated by SMR-beta neurofeedback training (cf. Othmer, in prep).
The apparent diversity of disorders impacted by SMR-beta neurofeedback training suggests a commonality of mechanisms for these conditions, a fact that should be addressed by any theory that attempts to identify the therapeutic mechanism of SMR-beta neurofeedback. Sterman (1982) proposed that SMR neurofeedback may restore regulated function of thalamocortical mechanisms associated with arousal. In particular, abnormal sensorimotor arousal or excitability may interfere with higher cognitive functions in a resource-limited competive model (Sterman, 1996). Abarbanel (1995) formulated a similar model of self-regulation in which attentional processing were modulated by thalamocortical and limbic circuitry. In his model long-term potentiation was responsible for any functional permanence associated with training. Both models presume SMR-beta neurofeedback impacts functions that modulate arousal (Sterman, 1982; Abarbanel, 1995). Both models readily address the symptomatology and possible mechanisms of ADHD and epilepsy. The primary symptoms of ADHD, inattention, impulsivity, or hyperactivity, are associated with decreased arousal in frontal cortex and subcortical regions (Zametkin et al., 1990; Mann, Lubar, Zimmerman, Miller, & Muenchen, 1991). The cortical hyperexcitability associated with epilepsy may reflect an arousal dyfunction, possibly due to a loss of integrity in the thalamic gating mechanism (Sterman, 1982). In addition to motor or vocal tics, sufferers of Tourette’s Syndrome often exhibit somnambulism, night terrors, and other disorders of arousal (Barabas, Matthews, & Ferrari, 1984). Attentional processes in particular appear to be uniquely sensitive to problems of arousal, and thus they serve to be a good measure of effectiveness in restoring such functions.
The Test of Variables of Attention (TOVA) is a continuous performance task that assesses attentional processes relative to a normative database. The TOVA provides a quantifiable measure of effectiveness of SMR and beta biofeedback training for improving specific attentional properties such as impulse control and response consistency. The lack of test-retest practice effects, the use of language-independent nonverbal stimuli, and an extended test length (22.5 min), all make the TOVA especially useful in evaluating treatment effects in an ADHD, learning disabled, or like population (Greenberg, 1987).
The purpose of the present study is to evaluate the efficacy of SMR-beta neurofeedback for children and adults suffering from attentional problems as measured by the TOVA.