title: The influences of Halo-vest fixation and cervical hyperextension on swallowing in healthy volunteers.
abstract: METHODS
  Radiographic and electromyographic evaluation of swallowing functions was performed for different positions with a Halo-vest brace.
  
  
  OBJECTIVE
  The aim of this study was to clarify the mechanism of dysphagia of cervical hyperextension with a Halo-vest brace in neurologically normal adult volunteers.
  
  
  BACKGROUND
  Garfin et al reported that 3 of 179 patients had dysphagia attributable to the Halo-vest brace after cervical spinal cord injury. Readjustment of the position of the head in the Halo-vest brace was required in those cases. They concluded that the head-extended position with a Halo-vest brace made it difficult to swallow. However, the details of this dysphagia were not known.
  
  
  METHODS
  Six healthy adults volunteers between the ages of 24 and 33 participated in this study. Subjects were radiographically and electromyographically observed swallowing thin liquids at the neutral position without a Halo-vest brace (N-HV), the neutral position with a Halo-vest brace (N+HV) and at hyperextension with a Halo-vest brace (E+HV).
  
  
  RESULTS
  In the durational measurements, there were significant changes between the N-HV and E+HV in pharyngeal transit time. The motion measurements showed that the initial hyoid position placed lower from the mandibular plane, and vertical hyoid movement was prolonged in the E+HV. In the electromyographic measurements, greater activity was observed from the suprahyoid muscles in the E+HV. One subject had laryngeal penetration already in the N-HV, and the same subject exhibited aspiration in the E+HV. Another two subjects exhibited penetration in the E+HV.
  
  
  CONCLUSIONS
  The result of this study demonstrated that cervical hyperextension with the Halo-vest brace caused mechanical changes in the swallowing of normal healthy adult volunteers.
authors.affiliation: Department of Rehabilitation, Toyohashi Municipal Hospital, Aichi, Japan. mnaohito@katch.ne.jp
authors.forename: Naohito
authors.initials: N
authors.lastname: Morishima
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Ohota
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miura
mesh_terms: D000328:Adult; D001915:Braces / Q000009:adverse effects*; D002574:Cervical Vertebrae; D003679:Deglutition; D003680:Deglutition Disorders / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D006801:Humans; D007103:Immobilization; D008297:Male; D009068:Movement; D009333:Neck / Q000000981:diagnostic imaging; D009334:Neck Muscles / Q000503:physiopathology; D010614:Pharynx / Q000000981:diagnostic imaging / Q000503:physiopathology; D011859:Radiography; D012016:Reference Values