Study design: Radiographic and electromyographic evaluation of swallowing functions was performed for different positions with a Halo-vest brace.
Objectives: 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.
Summary of background data: 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.
Conclusion: 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.