New evaluation method using sound stimulation for asymptomatic vestibular dysfunction.

The currently available evaluation methods for determining appropriate treatment strategies in patients with asymptomatic inner ear dysfunction are insufficient. Recently, we demonstrated the efficacy of 100-Hz sound stimulation for treating vestibular dysfunction in Meniere's disease. This case report presents the utility of 100-Hz sound stimulation as a new method for evaluating cases with asymptomatic vestibular dysfunction and their potential for recovery with early medical intervention. We evaluated the change in cervical vestibular-evoked myogenic potential (cVEMP) amplitude before and after sound stimulation (75 dB at a frequency of 100 Hz for 5 to 10 min) in two female patients with endolymphatic hydrops (EH), comparing the change based on the presence of EH. One patient presented with hearing difficulty and the other with otalgia, and neither had hearing loss and vestibular symptoms. As a result, cVEMP amplitudes in ears without EH showed no changes after the stimulation. Conversely, cVEMP amplitudes showed significant increases in ears with vestibular EH compared with the values before stimulation. Application of a 100-Hz sound stimulus might be a new method for evaluating asymptomatic vestibular dysfunction associated with EH, and for providing information about the potential for recovery from the dysfunction, facilitating early medical intervention.