Central hyperacusis with phonophobia in multiple sclerosis.

Hearing disorders are a well-described symptom in patients with multiple sclerosis (MS). Unilateral or bilateral hyperacusis or deafness in patients with normal sound audiometry is often attributed to demyelinating lesions in the central auditory pathway. Less known in MS is a central phonophobia, whereby acoustic stimuli provoke unpleasant and painful paresthesia and lead to the corresponding avoidance behaviour. In our comparison collective, patient 1 described acute shooting pain attacks in his right cheek each time set off by the ringing of the telephone. Patient 2 complained of intensified, unbearable noise sensations when hearing nonlanguage acoustic stimuli. Patient 3 noticed hearing unpleasant echoes and disorders of the directional hearing. All patients had a clinical brainstem syndrome. ENT inspection, sound audiometry and stapedius reflex were normal. All three patients had pathologically changed auditory evoked potentials (AEPs) with indications of a brainstem lesion, and in magnetic resonance imaging (MRI) demyelinating lesions in the ipsilateral pons and in the central auditory pathway. The origin we presume in case 1 is an abnormal impulse conduction from the leminiscus lateralis to the central trigeminus pathway and, in the other cases, a disturbance in the central sensory modulation. All patients developed in the further course a clinically definite MS. Having excluded peripheral causes for a hyperacusis, such as, e.g., an idiopathic facial nerve palsy or myasthenia gravis, one should always consider the possibility of MS in a case of central phonophobia. Therapeutic possibilities include the giving of serotonin reuptake inhibitors or acoustic lenses for clearly definable disturbing frequencies.