Positional stability of five insert-type hearing protectors as a function of controlled jaw movement

Five insert-type hearing protectors (three viscose foam, one multiflanged, and one glass fiber) were evaluated for lateral drift in the ear canal as a result of 30 min of controlled jaw movement. The lateral drift was compared to changes in attenuation for the same protectors over the same duration of jaw movement. The ranked correlation of positional and attenuation stability was very low (Spearman Rho = 0.3). Possible explanations for this observation are discussed.