Case of recurrent, reversible, sudden sensorineural hearing loss in a child.

This paper describes audiologic, electrophysiologic, and medical test results for a now 10year-old girl who has had 45 episodes of reversible, sudden sensorineural hearing loss over the last 8 years. Episodes have lasted from 6 to 72 hours and often have been accompanied by a mild illness . Acoustic immittance measures have been consistent with normal middle-ear function with the exception of absent ipsilateral and contralateral acoustic reflexes. Mechanically evoked perioral reflex activity was markedly asymmetric following lower lip stimulation . The asymmetry of R1 activation between right and left side lower lip inputs raises questions about the integrity of central connections within the brain stem, including internuncial pathways coursing between trigeminal sensory relay nuclei and the facial motor nucleus. An electrocochleographic evaluation revealed cochlear microphonic but absent or markedly abnormal whole nerve action potentials . Auditory brainstem responses (ABR) have been either absent or poorly formed and significantly delayed, regardless of hearing sensitivity . Middle and late auditory evoked potentials were essentially normal. Both transient-evoked and distortion-product otoacoustic emissions were present regardless of peripheral auditory sensitivity . All medical tests have been essentially normal. Although no definitive diagnosis has been reached, beta blockers have been used with some success. Taken together, these data document a very unusual case of fluctuating hearing loss. The electrocochleographic and otoacoustic emission data suggest that the outer hair cells are functioning normally and that the loss is not cochlear in origin. The ABR evaluation, mechanically evoked trigeminofacial cutaneous reflex, and acoustic reflex data point to a neural, perhaps brainstem origin; however, all other tests have failed to reveal any abnormality or underlying mechanism to explain the unusual pattern of hearing loss.