title: The Autonomic System Functional State Predicts Responsiveness in Disorder of Consciousness.
abstract: Diagnosis and early prognosis of the vegetative state/unresponsive wakefulness syndrome (VS/UWS) and its differentiation from the minimally-conscious state still rest on the clinical observation of responsiveness. The incidence of established clinical indicators of responsiveness also has proven variable in the single subject and is correlated to measures of heart rate variability (HRV) describing the sympathetic/parasympathetic balance. We tested responsiveness when the HRV descriptors nuLF and peakLF were or were not in the ranges with highest incidence of response based on findings from previous studies (10.0-70.0 and 0.05-0.11 Hz, respectively). Testing was blind by The Coma Recovery Scale-revised in the two conditions and in two experimental sessions with a one-week interval. The incidence of responses was not randomly distributed in the "response" and "no-response" conditions (McNemar test; p < 0.0001). The observed incidence in the "response" condition (visual: 55.1%; auditory: 51.5%) was higher than predicted statistically (32.1%) or described in previous clinical studies; responses were only occasional in the "no-response" condition (visual, 15.9%; auditory, 13.4%). Models validated the predictability with high accuracy. The current clinical criteria for diagnosis and prognosis based on neurological signs should be reconsidered, including variability over time and the autonomic system functional state, which could also qualify per se as an independent indicator for diagnosis and prognosis.
authors.affiliation: 1 Institute S. Anna and RAN-Research in Advanced Rehabilitation , Crotone, Italy .
authors.forename: Francesco
authors.initials: F
authors.lastname: Riganello
authors.affiliation: 1 Institute S. Anna and RAN-Research in Advanced Rehabilitation , Crotone, Italy .
authors.forename: Maria D
authors.initials: MD
authors.lastname: Cortese
authors.affiliation: 1 Institute S. Anna and RAN-Research in Advanced Rehabilitation , Crotone, Italy .
authors.forename: Giuliano
authors.initials: G
authors.lastname: Dolce
authors.affiliation: 1 Institute S. Anna and RAN-Research in Advanced Rehabilitation , Crotone, Italy .
authors.forename: Lucia F
authors.initials: LF
authors.lastname: Lucca
authors.affiliation: 2 Department of Neuroscience, Ophthalmology, and Genetics, University of Genova , Genova, Italy .|3 Department of Psychiatry, State University of New York , Stony Brook, New York.
authors.forename: Walter G
authors.initials: WG
authors.lastname: Sannita
mesh_terms: D000293:Adolescent; D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology*; D003243:Consciousness / Q000502:physiology*; D003244:Consciousness Disorders / Q000175:diagnosis* / Q000503:physiopathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018458:Persistent Vegetative State / Q000175:diagnosis* / Q000503:physiopathology; D011379:Prognosis; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult
keywords: HRV; auditory response; central autonomic system; disorder of consciousness; hear rate variability; minimally-conscious state; vegetative state; visual pursuit response