title: Sluggish vagal brake reactivity to physical exercise challenge in children with selective mutism.
abstract: Cardiovascular response patterns to laboratory-based social and physical exercise challenges were evaluated in 69 children and adolescents, 20 with selective mutism (SM), to identify possible neurophysiological mechanisms that may mediate the behavioral features of SM. Results suggest that SM is associated with a dampened response of the vagal brake to physical exercise that is manifested as reduced reactivity in heart rate and respiration. Polyvagal theory proposes that the regulation of the vagal brake is a neurophysiological component of an integrated social engagement system that includes the neural regulation of the laryngeal and pharyngeal muscles. Within this theoretical framework, sluggish vagal brake reactivity may parallel an inability to recruit efficiently the structures involved in speech. Thus, the findings suggest that dampened autonomic reactivity during mobilization behaviors may be a biomarker of SM that can be assessed independent of the social stimuli that elicit mutism.
authors.affiliation: Department of Psychiatry, University of Illinois at Chicago, 1747 West Roosevelt Road, Chicago, IL 60608, USA. kheilman@psych.uic.edu
authors.forename: Keri J
authors.initials: KJ
authors.lastname: Heilman
authors.forename: Sucheta D
authors.initials: SD
authors.lastname: Connolly
authors.forename: Wendy O
authors.initials: WO
authors.lastname: Padilla
authors.forename: Marika I
authors.initials: MI
authors.lastname: Wrzosek
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Graczyk
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Porges
mesh_terms: D000293:Adolescent; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D015444:Exercise / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D009155:Mutism / Q000503:physiopathology*; D012119:Respiration; D014630:Vagus Nerve / Q000503:physiopathology*