Effects of Middle Ear Status on Rotary Chair Outcomes in Children

Middle ear dysfunction is common in young children. There are varying reports on the effects of middle ear dysfunction on the vestibular system; however, it is unknown the extent to which abnormal middle ear function affects vestibular function tests, which could lead to misdiagnosis and improper medical management. Therefore, the purpose of this study is to evaluate how middle ear status affects rotary chair outcomes in young children (6 months to 6 years).

Twenty-one children with middle ear dysfunction (mean: 30 months, 11 males) and 36 control children with normal middle ear function (mean: 33 months, 19 males) participated. All participants completed tympanometry, wideband tympanometry, and sinusoidal harmonic acceleration rotary chair testing at 0.01, 0.04, and 0.16 Hz. The primary outcomes were rotary chair gain, phase, and symmetry.

For rotary chair gain, there was a significant frequency by group interaction. As expected, gain increased with increases in frequency; however, there were larger gain increases in the middle ear dysfunction group for 0.04 and 0.16 Hz. There was no significant effect of middle ear dysfunction on rotary chair phase or symmetry. Although 6 subjects (29%) had rotary chair phase leads that were greater than 2 SDs from the control mean, there were no significant group-level differences in phase; there was also no effect of severity of middle ear dysfunction on any rotary chair outcomes.

Rotary chair in the presence of middle ear dysfunction is valid; however, isolated phase abnormalities can be present that are not explained by severity of middle ear dysfunction. Tympanometry and/or wideband tympanometry is recommended before rotary chair. In the event phase abnormalities are present coupled with abnormal tympanometry and/or wideband tympanometry, rotary chair testing could be repeated once the middle ear normalizes to rule out contributions from middle ear dysfunction.