title: Relationship between changes in EMG and respiratory sinus arrhythmia in a study of relaxation therapy for asthma.
abstract: This paper reports the relationships among changes in cardiovagal activity, surface EMG, and measures of pulmonary function in a study of relaxation therapy for asthma. Changes in FEV1/FVC were negatively correlated with those in cardiac interbeat interval, consistent with the hypothesis that relaxation-induced changes in airway function are mediated autonomically, with increased vagal tone and/or decreased sympathetic arousal producing bronchoconstriction. Contrary to Kotses's theory of a vagal-trigeminal reflex as mediator for relaxation-induced improvement in asthma, decreases in pulmonary function occurred during relaxation sessions, accompanied by increases in cardiovagal activity, and within-session changes in frontal EMG in the first session of training were positively associated with changes in a measure of pulmonary function (FEV1/FVC). However, consistent with this hypothesis, first-session frontalis EMG changes were positively associated with changes in respiratory sinus arrhythmia, and last-session changes in cardiac interbeat interval were positively associated with changes in FEV1/FVC. The results suggest that the immediate effects of generalized relaxation instruction can be associated with a parasympathetic rebound, which, in tum, may induce countertherapeutic changes in asthma. However, the effects of specific facial muscle relaxation remain unclear.
authors.affiliation: UMDNJ-Robert Wood Johnson Medical School, Piscataway 08854-5635, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Lehrer
authors.forename: S M
authors.initials: SM
authors.lastname: Hochron
authors.forename: T M
authors.initials: TM
authors.lastname: Mayne
authors.forename: S
authors.initials: S
authors.lastname: Isenberg
authors.forename: A M
authors.initials: AM
authors.lastname: Lasoski
authors.forename: V
authors.initials: V
authors.lastname: Carlson
authors.forename: J
authors.initials: J
authors.lastname: Gilchrist
authors.forename: S
authors.initials: S
authors.lastname: Porges
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000628:therapy*; D004562:Electrocardiography; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012064:Relaxation Therapy; D012129:Respiratory Function Tests