Electrogastrographic and autonomic responses during oculovestibular recoupling in flight simulation.
BACKGROUND
Simulator sickness causes vestibulo-autonomic responses that increase sympathetic activity and decrease parasympathetic activity. The purpose of the study was to quantify these responses through electrogastrography and cardiac interbeat intervals during flight simulation.


METHODS
There were 29 subjects that were randomly assigned to 2 parallel arms: (1) oculovestibular recoupling, where galvanic vestibular stimulation was synchronous with the visual field; and (2) control. Electrogastrography and interbeat interval data were collected during baseline, simulation, and post-simulation periods. A simulator sickness questionnaire was administered.


RESULTS
Statistically significant differences were observed in percentage of recording time with the dominant frequency of electrogastrography in normogastric and bradygastric domains between the oculovestibular recoupling and control groups. Normogastria was dominant during simulation in the oculovestibular recoupling group. In the control group, the percentage of recording time with the dominant frequency decreased by 22% in normogastria and increased by 20% in bradygastria. The percentage change of the dominant power instability coefficient from baseline to simulation was 26% in the oculovestibular recoupling group vs. 108% in the control group. The power of high-frequency components for interbeat intervals did not change significantly in the oculovestibular recoupling group and was decreased during simulation in the control group.


CONCLUSIONS
Electrogastrography and interbeat intervals are sensitive indices of autonomic changes in subjects undergoing flight simulation. These data demonstrate the potential of oculovestibular recoupling to stabilize gastric activity and cardiac autonomic changes altered during simulator and motion sickness.
Department of Otolaryngology-Head and Neck Surgery/Audiology, Mayo Clinic, 13400 E. Shea Blvd, Scottsdale, AZ 85259, USA. mcevette@mayo.edu
Michael J
MJ
Cevette
Department of Otolaryngology-Head and Neck Surgery/Audiology, Mayo Clinic, 13400 E. Shea Blvd, Scottsdale, AZ 85259, USA.
Gaurav N
GN
Pradhan
Department of Otolaryngology-Head and Neck Surgery/Audiology, Mayo Clinic, 13400 E. Shea Blvd, Scottsdale, AZ 85259, USA.
Daniela
D
Cocco
Division of Gastroeterology, Mayo Clinic, Scottsdale, AZ, USA.
Michael D
MD
Crowell
Vivonics, Waltham, MA, USA.
Anna M
AM
Galea
Department of Otolaryngology-Head and Neck Surgery/Audiology, Mayo Clinic, 13400 E. Shea Blvd, Scottsdale, AZ 85259, USA.
Jennifer
J
Bartlett
Department of Otolaryngology-Head and Neck Surgery/Audiology, Mayo Clinic, 13400 E. Shea Blvd, Scottsdale, AZ 85259, USA.
Jan
J
Stepanek
D000293:Adolescent; D000328:Adult; D000337:Aerospace Medicine; D001341:Autonomic Nervous System / Q000503:physiopathology*; D004558:Electric Stimulation; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D009041:Motion Sickness / Q000503:physiopathology*; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D013270:Stomach / Q000294:innervation; D011795:Surveys and Questionnaires