Function of semicircular canals, utricles and saccules in deaf children

Abstract

OBJECTIVE: To study vestibular function in deaf children. MATERIAL AND METHODS: In 36 deaf children the function of the semicircular canals, saccules and utricles was measured by means of caloric testing, recordings of vestibular-evoked myogenic potentials (VEMPs) and measurements of the subjective visual horizontal (SVH) at different body tilts, respectively. RESULTS: In total, 30% of subjects had caloric hypo- or areflexia and 24% had a caloric asymmetry. VEMPs were weak or absent bilaterally in 22% of cases, and asymmetric in 19%. Regarding the utricle, 17% of subjects had a pathologically reduced perception of roll tilt to both sides and 25% had an asymmetry. In total, 30% of subjects were pathologic in all 3 tests and 30% were completely normal. Semicircular canal function correlated best with the function of the saccule. If hearing was better than 90 dB (pure-tone average of 0.5, 1.0 and 2.0 kHz) vestibular function was often normal. For hearing levels of 100-120 dB, otolith function declined significantly. CONCLUSIONS: Vestibular function tends to be preserved up to a point where hearing is nearly extinct. Hearing level correlates more closely with otolith function, especially that of the utricle, than with semicircular canal function.