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A Rationale for Neurofeedback Training
Siegfried
Othmer, Ph.D. Chief Scientist, EEG Institute
May, 2001
The brain must organize function on all behaviorally relevant timescales.
Moreover, it must maintain its own stability and integrity in the
general case. It is significant that the vast majority of resources
of the brain are invested in communicating with itself, and hence
in managing itself. (For example, more than 99% of cortical neurons
terminate on other cortical sites.) The organization of information-handling
in the brain is just beginning to be understood. However, one important
organizing principle that has emerged in recent years is the concept
of time-binding, the proposition that ensembles of neurons representing
specific percepts may be defined in terms of simultaneity in the
time domain, and of synchrony in the frequency domain.
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.
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