Functional Dysphonia During Mental Imagery: Testing the Trait Theory of Voice Disorders

Abstract

Previous research has proposed that persons with functional dysphonia (FD) present with temperamental traits that predispose them to their voice disorder. We investigated this theory in a controlled experiment and compared them with social anxiety (SA) and healthy control (HC) groups. Twelve participants with FD, 19 participants with SA, and 23 HC participants were studied before, during, and after mental imagery of positive, neutral, and aversive scripts in a within-subject reversal paradigm with multiple experimental conditions using psychometric, self-report, and psychophysiological measures. In psychometric tests, those with FD demonstrated increased fear in social situations but not increased avoidance. On measures of mood, all groups responded with predicted increases in pleasant mood for positive scripts and unpleasant mood for aversive scripts; on vocal effort ratings, those with FD reported greater effort for all scripts following imagery. Under experimentally controlled conditions, the SA and HC groups demonstrated predicted activation of EMG measures of mood, whereas the FD group demonstrated overall reduced activation of EMG measures. Results may suggest that those with FD respond to emotional stimuli with reduced behavioral expression, compared with SA and HC groups, consistent with the temperamental trait of behavioral constraint.