A Rationale for Neurofeedback Training
Siegfried Othmer, Ph.D. Chief Scientist, EEG Institute
Given that nature is parsimonious, it is reasonable to conjecture that this same organizational principle applies to the regulation of physiological states, such as states of organismic arousal and activation. Congruence between mechanisms of perceptual organization and of the organization of states may mandate that a single organizational principle underpins both functions. If so, the relevant frequency domain for such organization of state is lower than that for the representation of percepts, given the greater persistence of such states and the larger spatial scale associated with them. Evidence for a role of rhythmicity in the organization of percepts may be seen in the well-known 40-Hz EEG activity. Corresponding evidence for the organization of states can be found in the dynamics of the well-known alpha rhythm and of the sleep spindle.
Neurofeedback: Operant conditioning on EEG rhythmic patterns
Giving further evidentiary support is the effect on arousal and activation when the observed rhythmicity of the neuronal ensembles, as discerned from the EEG, is subject to explicit operant conditioning. Both central arousal and autonomic arousal can be modulated in real time purely by rewarding change in the instantaneous rhythmicity exhibited by the EEG using real-time frequency domain analysis. The arousal level achieved is determined by the part of the frequency spectrum that is reinforced.
Further, the effect of long-term operant conditioning on EEG parameters has been shown to have clinical effects in terms of remediating those conditions that involve significant disregulations of central or autonomic arousal. Among such conditions are the depression and anxiety disorders, various sleep disorders, and pain syndromes such as migraines.
Additionally, operant conditioning of EEG spectral components has been shown effective in remediating Attention Deficit Hyperactivity Disorder and its principal comorbidities, e.g., the disruptive behavior disorders and Tourette Syndrome. This may be by virtue of the coupling of vigilance and attentional focus to physiological arousal. Alternatively, it may be because attentional state is likewise mediated by the rhythmic properties of the EEG, in a manner similar to the management of arousal.
Efficacy for the more disruptive behavior disorders, as well as for more severe emotional dysfunctions such as Reactive Attachment Disorder, Asperger's Syndrome, and Autism demonstrates that the EEG training addresses regulation in the affective realm as well. It appears, therefore, that the EEG training addresses with comparable facility disregulations in the arousal, attentional, and affective realm, and hence should be considered as part of any therapeutic program that comprehensively addresses such disorders.
Efficacy of EEG biofeedback for seizures suggests that the technique enhances nervous system stability even in the context of local disturbances such as seizure foci, resulting in a heightening of the seizure threshold. Efficacy for the symptoms of traumatic brain injury may similarly be seen in terms of ordering of timing properties of the EEG that may have become disrupted due to the injury. Often head injury symptoms are strictly functional in character, leaving no evidence on structural measures. The restoration of more optimal rhythmic functioning may be a condition of the restoration of function.
State management in the time and frequency domain
In the above, a central role is posited for the rhythmic organization of neuronal firing activity in terms of the management of state. In general, the organization of state requires linkages to be established between different brain regions, and rhythmicity may lie at the core of effective interaction and communication between different brain regions. Attention Deficit Disorder may be an externally visible "symptom" of disregulation of internal brain mechanisms subserving attentional focus, vigilance, orientation to novelty, and habituation. More generally, it may be a symptom of internal disregulation in the ordering of sequential and of parallel processing. This externally visible symptomatology could be seen as a paradigm for a comparable "internal ADHD," in which brain regions are not properly brought into collaboration, hence leading to a wide range of behavioral outcomes with reduced predictability and higher variability.
If one were to pick the singular dominant feature of ADHD it might very well be variability itself-the lack of predictability of behavior given the circumstances. Thus the core issue of ADHD may be a particular kind of central nervous system disregulation. If rhythmicity in the EEG is the marker for such organization, this could give rise to the hope that the reordering of rhythmic properties of the EEG, and the ordering of communication linkages between different brain regions, could represent a fundamental remedy for symptom clusters such as ADHD.
The same concepts may be seen as operative in the realm of arousal regulation and affect regulation as well. Thus, affect regulation is mediated by communication between certain subcortical nuclei and specific cortical regions. These communication pathways too are likely to be subject to rhythmic organization of some type. In fact, consideration of these principal "axes" of neurophysiological function-arousal, attention, and affect-allows one to cover much of the ground encompassed in the DSM IV. From the perspective of neurophysiology, then, many of these conditions can be seen as grounded in disregulation of fundamental control mechanisms. In the bioelectrical domain of brain regulation, EEG rhythmicity appears to play a central role, and serves as both an indicator of brain functional integrity as well as a measure of dysfunction when it exists. Restoration of appropriate dynamics of EEG rhythmicity through operant conditioning may then result in complete symptom remission. Thus, insofar as disregulation characterizes the disorder, then re-regulation constitutes a remedy.
Neurofeedback for the unstable brain
There is one large category of conditions for which EEG neurofeedback has shown efficacy, and which are not encompassed in the above. These are disorders which may be seen as arising out of fundamental instabilities in CNS regulation: seizures; bipolar disorder; schizophrenia; Panic Disorder; and Dissociative Identity Disorder. With respect to these disorders, the EEG training can be seen as stabilizing the CNS, and hence raising the operative threshold for kindling the instabilities.
Disregulation is the problem; self-regulation is the solution
The disorders referred to above as instabilities, together with the categories previously mentioned, jointly cover the vast majority of conditions listed in the DSM-IV. Empirical evidence exists that all of these disorders can be moved toward normalization of behavior with EEG neurofeedback. It is therefore proposed that most mental disorders may be regarded as disorders of disregulation, and that both psychopharmacology and neurofeedback act to restore more appropriate self-regulation. In this perspective, the brain is regarded as a multi-dimensional control system required to maintain its own stability entirely through self-regulatory techniques.
The most cogent example of the brain's susceptibility to disregulation in the frequency domain is photic epilepsy. Here the cortical driving attributed to periodic optical modulation is sufficient to drive the brain into the instability of a seizure or a migraine or into nausea. The rhythmic patterns observed in subclinical seizure activity also support the view that seizure susceptibility and rhythmic disorganization are coupled.
The operative domain of pharmacology is those conditions which involve long-term, steady-state disregulation (dysthymia, generalized anxiety). Pharmacology is less optimal when it is needed to address instabilities on short timescales. Neurofeedback, on the other hand, addresses itself with equal facility to the steady-state conditions responsive to pharmacological intervention and to what have been termed instability conditions. It appears, therefore, that neurofeedback is potentially even more comprehensive in its scope of action than pharmacological agents. This broad range of applicability supports the view that the primary source of disregulation is to be looked for in the brain's control mechanisms in the time domain.
In summary, we are confronting a scientific revolution in which the neurosciences are discovering the role of rhythmicity in organizing brain timing, in the same timeframe in which clinicians are discovering the practical implications of operant conditioning of EEG rhythmic properties. The remediation of psychopathologies thus effected demonstrate the central role of rhythmic mechanisms in brain self-regulation for a variety of functions, including in particular-but not limited to-central and autonomic arousal, attention, and affect.