Basic concepts and clinical findings in the treatment of seizure disorders with EEG operant conditioning.

Two issues concerning sensorimotor EEG operant conditioning, or biofeedback, as a therapeutic modality for the treatment of seizure disorders are the focus of this review. The first relates to the question of whether relevant physiological changes are associated with this procedure. This question is addressed through review of an extensive neurophysiological literature that is likely unfamiliar to many clinicians but that documents both immediate and sustained functional changes that are consistent with elevation of seizure thresholds. The second focuses on the clinical efficacy of this method and whether it should carry the designation of "experimental". This designation is challenged through an assessment of over 25 years of peer-reviewed research demonstrating impressive EEG and clinical results achieved with the most difficult subset of seizure patients.

Limitations of the American Academy of Neurology and American Clinical Neurophysiology Society paper on QEEG.

The AAN/ACNS report is misleadingly negative regarding the current status of quantitative EEG and tends to discourage its development and use with other related clinical problems. There have been many excellent studies showing that QEEG can be useful for the evaluation and understanding of mild traumatic brain injury, learning disabilities, attention deficit disorders, alcoholism, depression, and other types of substance abuse. In fact, Hughes and John recently provided in this Journal an extensive and detailed review of the use of QEEG in psychiatric disorders. The bias of the AAN/ACNS report is also evident when contrasted to the outstanding review of the clinical utility of QEEG by the American Medical EEG Association, which clearly articulates the opposite points in many cases and concludes that QEEG has reached maturity. At present, the most one can say is that there are legitimate scientific debate and differences of opinion concerning the utility of QEEG, as there are in many other areas of medicine. The AAN/ACNS article should not be considered the definitive opinion. Too many implications for health care are at stake. The debate and research may continue without withholding valuable help from the public. We hope that revised guidelines will be drafted in such a way as to encourage the development of quantitative EEG and brain mapping rather than discourage future research support and use of QEEG with patients. Furthermore, we strongly feel that this technology should be available to, and be explored and used by, nonphysicians who are properly trained and certified.

Psychological defense mechanisms and electroencephalographic arousal.

The aim of this study was to examine the relationship between psychological defense as measured by the Kragh tachistoscopic Defense Mechanisms Test (DMT), and general arousal properties of the individual as measured with electroencephalogram (EEG). The DMT assesses defense by presenting neutral and threatening pictures with very short exposure times. EEG characteristics were measured in the 8-12 Hz EEG frequency band during DMT testing. Twenty-one male subjects participated in the study. All were US Air Force personnel on active duty. Personnel with high defense mechanisms, defined in this connection as slow perception of the threat, tended to have higher cortical arousal after Stimulus exposure than the subjects with low defense mechanisms. The differences occurred mainly with new stimulus material without any threatening content. The differences in arousal response to novel stimuli may contribute to an understanding of the relationships between the Kragh DMT test and performance in life-threatening situations.

Suppression of EEG rhythmic frequencies during somato-motor and visuo-motor behavior.

In a previous study of simulated vehicle performance we found that stationary visual attention and body movements alone produced selective effects on topographic EEG frequency patterns. In the present study we focus on an expanded set of these task components. EEG, EOG and ECG data were recorded from 21 subjects during instructed driving movements and during visual scanning tasks ranging from a stationary to a rapidly moving simulated driving display. Spectral analysis was calculated on ten 2-Hz, partially overlapped frequency bands between 6 and 17 Hz. Body movements produced a selective bilateral suppression of 11-15 Hz activity localized to medial somatosensory cortex, while both slow and rapid visual scanning tasks produced a similar bilateral suppression of 11-15 Hz activity localized to temporo-parietal sites. A generalized suppression of 7-11 Hz activity was also found during the fastest visual scanning task. There were no significant differences in ECG between tasks. Other human and animal findings consistent with these functional observations are discussed.

Physiological origins and functional correlates of EEG rhythmic activities: implications for self-regulation.

Recent neurophysiological findings in relation to thalamocortical mechanisms for sensory processing, together with established anatomical and expanding functional evidence, have provided a rational theoretical framework for the interpretation of normal and abnormal EEG rhythmic activities. This perspective is integrated here with earlier animal studies which were the foundation for many current applications of EEG self-regulation as a clinical tool. Basic evidence concerning the origins, frequency modulation, and functional significance of normal EEG rhythmic activities is reviewed here in an effort to provide guiding principles for the interpretation of clinical abnormalities and their remediation with EEG feedback training.

Concepts and applications of EEG analysis in aviation performance evaluation.

Quantitative studies of the human EEG during signal detection, flight simulation and actual flight performance tasks are reviewed here from the perspective of basic animal research on the neurophysiological and functional correlates of relevant rhythmic patterns. Evidence is examined which relates distinct EEG frequency changes to psychomotor behavior, signal processing and intrinsic attentional modulation during complex performance. Findings indicate that the EEG can provide a valid and objective index for mental effort but, in addition, may reveal task-related cognitive resource allocation, task mastery and task overload.

Multiband topographic EEG analysis of a simulated visuomotor aviation task.

Topographic EEG spectral magnitudes from 19 cortical sites were compared in 15 adult male subjects during performance of a simulated flight task and during control conditions which attempted to separately evaluate functional components of this task. Four conditions were studied, including eyes closed, a visual control, a motor control and a simulated landing task requiring integration of both visual and motor components. Each condition was repeated twice in a counterbalanced replicated measures design. A linked-ear EEG reference was used and spectral magnitudes calculated for 6 frequency bands. Decisions concerning band width and spectral transform were empirically determined. Findings indicated no significant differences between replications. A broad posterior cortical suppression of all frequencies was observed in the visual control condition. Anterior sites were affected only in the 7-12 Hz range. Additional suppression was seen during the motor control condition but limited to frontocentral sites in the 11-13 Hz band. The flight task, however, produced a further suppression at centroparietal cortex in the 9-13 Hz range. The extraction of both attentional and motor components from this task suggests that the parietal EEG activation was specific to cognitive processing.

Effects of systemic atropine sulfate administration on the frequency content of the cat sensorimotor EEG during sleep and waking.

Sensorimotor electroencephalogram (EEG) frequencies in cats were evaluated with power spectral analysis before and after 3 doses of atropine sulfate. All doses of atropine tested caused enhanced EEG slow waves (0-7 Hz) and spindles (8-15 Hz) during waking immobility, and postdrug frequency profiles during slow-wave sleep and waking immobility were identical. With 0.75 mg/kg atropine, movement (head movement, locomotion) resulted in EEG desynchronization and reduced power in all frequencies less than 24 Hz. After 1.5 or 3.0 mg/kg atropine, power in low frequencies remained elevated during movement, but power in spindle frequencies was significantly reduced compared with other states. During active REM sleep after 1.5 mg/kg atropine, power in spindle frequencies was significantly lower than that during quiet REM sleep. These results indicate that the sensorimotor cortical EEG in cats is under the control of multiple systems. At least 1 of these systems is active during movement, and its actions are resistant to muscarinic receptor blockade.

Polysomnographic sleep and waking states are similar in subsequent siblings of SIDS and control infants during the first six months of life.

Twenty-five subsequent siblings of infants who died of Sudden Infant Death Syndrome (SIDS) underwent 12-h overnight polygraphic recordings during the first week of life and at 1, 2, 3, 4, and 6 months of age. The polygraphic tracings from these infants were compared with those from 25 infants without a family history of SIDS. One dozen sleep and waking parameters were examined including state transition probabilities, the ratio between quiet sleep (QS) and active sleep (AS), the incidence and duration of sustained states and the stability of an infant's sleep and waking during the first half year of life. Variability within and between infants was marked with a reduction of variability in measures of QS at 3 months and of AS at 4 months of age. The similarities between subsequent siblings of SIDS and control infants far outweighted the differences. However, subsequent siblings exhibited a tendency, once asleep, to remain asleep longer than controls. This finding was observed in a comparison of 20 infants in each group. When five infants were added to each group, infants in both groups tended to awaken equally from QS, but once in AS the subsequent siblings tended to proceed into QS instead of awaken as the controls did.

Future perspectives for applied psychophysiology and biofeedback.

Current circumstances in both the health science and health care delivery systems in our country have created serious problems for health professionals, particularly for those of us in the relatively young field of biofeedback. At the same time, recent and emerging developments in the neurosciences and in technologies for biological measurement offer exciting new opportunities for the applied psychophysiology upon which our field is based. Examples of these developments include the elucidation of potential neurophysiological mechanisms that may mediate the psychophysiology of immune system responses, and technical achievements leading to on-line, noninvasive magnetic resonance imaging of brain neurochemistry. The issue of perspective is raised in relation to our response to both the challenge and the opportunities of our times.

Sleep and waking states in infancy: normative studies.

Twelve-hour polygraphic recordings were obtained in 20 normal healthy term infants at 1 week of age, at monthly intervals up to 4 months, and at 6 months of age. Each minute of these recordings was coded into active sleep (AS), quiet sleep (QS), wakefulness (AW), or indeterminate (IN) based on polygraphic and behavioral variables. For each state, a dozen variables were computed with the help of a laboratory computer. Together these variables describe trends in the development of sleep and wakefulness in the laboratory: an increase in QS and a concomitant decrease in AS, an increase in sustained episodes of these states, and continuous sleep onset in AS throughout this time span. Considerable variability appears to characterize immature sleep patterns, but a reduction in variability was noted between 3 and 4 months of age. The number of sustained sleep-state episodes and the percentage of AS and IN proved to be stable characteristics of individual infants. The large variability among and within infants sheds doubt on the usefulness of polygraphic monitoring of sleep states for early detection of abnormalities.

Neuropsychological assessment of subjects with uncontrolled epilepsy: effects of EEG feedback training.

A battery of neuropsychological tests was administered at baseline, postcontrol period, and posttraining period to 24 drug-refractory subjects with epilepsy participating in a study of sensorimotor electroencephalographic (EEG) normalization feedback training. Results revealed the following. First, subjects exhibited significant baseline deficits in psychosocial, cognitive and motor functioning. Second, certain tests discriminated subjects before training who were subsequently above and below the median in seizure reduction following EEG training. Subjects who showed the greatest seizure reduction performed better on a test of general problem-solving ability but not on other cognitive tests and worse on tests involving strong motor components and were more intact psychosocially. These subjects also took significantly fewer medications in combination than did less successful subjects. Third, improvement on several measures occurred following participation in the study. Cognitive and motor functioning improved only in subjects with the greatest seizure reduction and only after actual training as opposed to control conditions. Psychological functioning, as measured by the Minnesota Multiphasic Personality Inventory (MMPI) improved in both outcome groups. MMPI improvement, unlike cognitive improvement, was as likely to occur after control conditions, when seizure reduction had not yet occurred, as after EEG training. Thus, MMPI changes apparently reflected the nonspecific benefits of participation in this study.

Hemisphere-specific deficits on cognitive/perceptual tasks following REM sleep deprivation.

Current research and theory support the position that there are diurnal changes in the relative functional dominance of the hemispheres in the "normal" population. In one example of this position, Bakan (1978) has stated that REM sleep allows for right hemisphere dominance with a relative absence of left hemisphere interference. The present study involved pre- and postREM deprivation visual presentation of cognitive/perceptual performance tasks that had previously been demonstrated to have lateralizing value. Ten right-handed adult males each spent three nights in a sleep laboratory completing these tasks and a variety of questionnaires. After REM deprivation, performance decreased on right hemisphere tasks presented to the right hemisphere first. However, left-hemisphere-first presentation of one of the right hemisphere tasks (facial recognition) actually resulted in performance improvement after REM deprivation. This improvement was attributed to a suppression or diminution of capacity of the primary processing style of the left hemisphere. Results are further discussed in terms of Bakan's theory, the different processing "styles" of the two hemispheres, possible functions of REM and relationships of the biological cycles to possible shifts in cerebral laterality.

Sleep disruption with basal forebrain lesions decreases latency to amygdala kindling in cats.

Sleep deprivation enhances seizure susceptibility in experimental and human epilepsies. Because sleep abnormalities are also common in these populations, a possible explanation for this close association is that sleep deprivation activates seizures by enhancing existing sleep disturbances. The present experiment examined this hypothesis by comparing sleep-waking state percentages and the number of after-discharge-eliciting stimulations required to induce generalized tonic-clonic convulsions with the amygdala kindling model of epilepsy in 3 groups of cats (n = 5 each). One group consisted of experimental subjects who received bilateral lesions of the basal forebrain, a preoptic area long implicated in the generation of normal sleep state characteristics. A second group sustained unilateral lesions of the basal forebrain area. Since only bilateral destruction of this region produces sleep-waking cycle abnormalities, this group provided a lesion control. Finally, a third group had no lesion and provided a control which allowed normative assessment of sleep state patterns and seizure susceptibility in otherwise unmanipulated cats. The results were: cats without lesions showed a parallel development of seizure and sleep disorders, the latter indexed by progressive SWS and REM sleep deficits; cats with unilateral lesions showed identical trends in the development of sleep and seizure anomalies; and cats with bilateral lesions of basal forebrain displayed similar but more severe sleep disturbances than those evidenced by control subjects and also required fewer after-discharge stimulations to establish kindled convulsions.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in circadian sleep and waking patterns after somatosensory deafferentation in the cat.

The present study describes changes in circadian state pattern organization associated with somatosensory deafferentation in the adult cat. Nine animals, implanted for chronic monitoring of standard sleep state variables, were divided into 3 groups for study. Six cats received dorsal column transections at either a high (C1-C3, N = 3) or low (C5-T1, N = 3) cervical level. The remaining three served as intact controls. State evaluations of continuous 24 h polygraphic recordings disclosed a significant facilitation of alert waking and a suppression of slow wave sleep in animals with high cervical lesions; REM sleep was not affected. State pattern percentages for animals with low cervical lesions were comparable to those of intact controls; however, lesioned animals of both experimental groups showed changes in the frequency of occurrence and duration of individual sleep/wake episodes. These findings were interpreted in terms of the enhancement of intrinsic rhythmic discharge patterns over ventrobasal thalamocortical pathways.

'Kindling' a sleep disorder: degree of sleep pathology predicts kindled seizure susceptibility in cats.

Progressive sleep deficits accompanying the gradual development of a kindled seizure disorder in cats persist at least one month after kindling and correlate with subsequent seizure thresholds. These parallels between the two pathologies suggest the kindling of a sleep disorder which occurs in addition to, and may be a determinant of, the kindled seizure disorder.

Baseline studies and anticonvulsant drug effects on the sleep EEG power spectral profile.

This study explored a new approach to the application of electroencephalogram (EEG) power spectral analysis in the search for an objective, quantitative evaluation of anticonvulsant drug effects on the primate central nervous system. Standardized EEG samples were drawn from the slow wave sleep state. Four rhesus monkeys were adapted to restraining chairs and to prolonged recording in an isolation cubicle. Surgically placed, permanent electrodes provided for the monitoring of sleep-waking states and of bipolar frontal, central and occipital EEG traces. Baseline spectral density data were drawn from standard successive and spaced recording nights, and from post-intramuscular saline injection recording nights. These were compared with identical data drawn 1.5-2.5 h after a single, acute intramuscular administration of 5 compounds, including: diazepam, carbamazepine, valproic acid, phenobarbital and pentobarbital, the latter providing a non-anticonvulsant control. All dose values were low relative to clinical norms, as confirmed by serum samples drawn after EEG samples. Baseline measures showed stability across all non-drug test conditions, particularly those derived from somatosensory cortex. Identical post-drug power spectral changes indicated a unique and significant attenuation of 4-7 c/sec activity bilaterally in somatosensory cortex for all test compounds except pentobarbital, when compared to saline values. Since pentobarbital has only weak anticonvulsant actions, these data suggest a common effect of anticonvulsant drugs on central cortical EEG substrates. Other neurophysiological findings are reviewed which suggest that this effect may stem from an altered cortical response to intrinsic somatosensory thalamo-cortical afferent discharge in sleep, resulting from reduced neuronal excitability.