[Central hyperacusis with phonophobia in multiple sclerosis]

Auditory disturbances are a well known symptom in patients with multiple sclerosis (MS). Uni- or bilateral hypacusis or deafness in patients with normal auditory testing is considered to be a result of lesions in the central auditory pathway. Only rarely described is a central phonophobia whereby acoustic stimuli induce unpleasant and painful perceptions, with consecutive avoidance of these factors. Our first patient described acute shooting pain in the right cheek, triggered only through the ringing of a telephone. The second patient had uncomfortable perception of nonverbal noise. For example the wrinkling of paper bags was unbearable for him. The third patient had difficulties localizing the source of sound and disturbing echos while listening to speech or music. Clinically, in all patients symptoms of a brainstem syndrome were found, whereas auditory testing including inspection, audiometry, and stapedius reflex was normal. We found pathological acoustic evoked potentials (AEP) in all three patients with a prolonged latency III-V and T2 lesions in the ipsilateral pons and central auditory pathway. In case one, we suppose a lateral spread between the lateral lemniscus and the central trigeminal pathway. In the other cases, a dysfunction of the central sensory modulation which controls the regulation of sensitivity of incoming acoustic stimuli seems to be the cause of hyperacusis. All our patients developed clinically confirmed MS in the further course after suffering from phonophobia as their first symptom.