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EEG coherence (COH) is a mathematically derived measure of the time- and frequency-related similarities between a pair of EEG channels. In this report, COH was measured during an externally verified motor task in which the areas of cortical involvement are known, with special consideration given to procedural and artifactual issues. Fourteen right-handed women (ages 18-39, means = 26.7 years) were instructed to alternate continuously between fist-clenching and finger extension of the right hand, left hand, both hands, or neither hand (rest condition) in a counter-balanced sequence (4 one-minute trials for each condition; 16 total minutes). One minute each of intentional eye-movement (EOG) and intentional facial muscle tension (EMG) was recorded for artifact assessment. Eight channels of eyes-closed EEG were recorded from Fp1, Fp2, F3, F4, C3, C4, P3 and P4, each referenced to the ipsilateral earlobe. FFT spectral power analyses were conducted on 8 EEG channels and COH analyses (percentage of seconds/minute in which COH greater than or equal to 0.80) were performed on 16 pairs of leads: 4 interhemispheric, 6 intrahemispheric (left) and 6 intrahemispheric (right). COH measures increased during hand movement conditions, especially in the 9-12 Hz range, and were most apparent from prefrontal, premotor and motor areas. Parietal sources were essentially unchanged. Power measures were unchanged for virtually all leads and conditions. Increases in COH were not due to EOG or EMG artifact contamination. Evidence for lateralized increases was equivocal; significant bilateral increases were observed more often regardless of the hand clenched. Implications and suggested areas for future research are discussed.

Extensive personality, demographic, and symptom-related information from a heterogeneous group of more than 300 patients was examined for patterns that would discriminate between successful and unsuccessful outcomes in patients undergoing Quieting Response (QR) training, an 8-week program that integrated EMG and thermal biofeedback with a variety of relaxation exercises. Follow-up evaluations were at 3, 6, 12 and 24 months. Agreement between expected (from stepwise discriminant analyses) and observed outcomes was 65% (whole sample), 62% (headache only), and 70% (Raynaud's only). Unimproved patient MMPI scales D, Sc, F, Hy, and Pt were significantly elevated. A variety of additional measures used indicated elevated levels of psychological stress among unsuccessful patients. While stereotypical descriptions of successful and unsuccessful patients are proposed, patterns from outcome groups were more similar than dissimilar, and no combination of factors was identified that had sufficient predictive power for use with future patients. No statistical grounds for exclusion were found among patterns of responses to the measures employed. Factors contributing to the inaccuracy of outcome prediction are discussed.

Long-term follow-up evidence for biofeedback treatment of headaches, Raynaud's disease, essential hypertension, and the irritable bowel syndrome was reviewed. Acknowledging the difficulties with cross-study comparisons, the following general success rate were determined: primary idiopathic Raynaud's disease--70%, or better; vascular headache--70%, or better; mixed headache--about 60%; and muscle contraction headache--50%, or less. With relatively fewer patients, successful outcomes with the irritable bowel syndrome and secondary Raynaud's phenomenon were roughly 60% and 40%, respectively. Few cases of clinically significant long-term decreases in diastolic blood pressure were demonstrated; however, the need for medication was reduced or eliminated in some patients. There were indications that biofeedback combined with psychotherapy resulted in highest success rates. No differences were found in effectiveness between biofeedback, other relaxation techniques, and biofeedback in combination with relaxation techniques--all had essentially comparable rates of success. No correlations between physiological and psychological measures of condition at follow-up were reported. Implications and interpretations of these findings are discussed.