Stapedial synkinesis causing change in hearing threshold with facial motion

Objective: Synkinetic facial movement after facial nerve regeneration is a well-documented phenomenon. Rarely, patients recovering from facial nerve injury report feelings of auditory ringing, fullness, and a sensation of ear tightness as a result of stapedial muscle involvement. It is exceedingly rare for such synkinesis to produce perceivable changes in hearing threshold. We report a unique case of stapedial synkinesis causing pure-tone changes in hearing threshold with activation of the facial musculature. Patient: A single patient is presented who developed stapedial synkinesis after suboccipital resection of a unilateral acoustic neuroma. Results: Despite facial nerve sparing, surgery resulted in House- Brackmann grade V/VI right facial nerve paralysis that improved to Grade III/VI after 7 months. Synkinesis developed that caused eye closure with puckering of the lips. Puckering of the lips likewise caused decreased hearing in the right ear, corresponding to a measured decrease of 10 dB in the PTA. Over the next several months, facial motion continued to improve, and hearing changes became less bothersome, so no intervention was undertaken. Conclusion: The changes presented in the hearing threshold fit within the classically described 15-dB attenuation provided by the stapedial reflex. Although no intervention was undertaken in this particular case, some patients with unremitting stapedial synkinesis might benefit from sectioning of the stapedial muscle. Thus, consideration should be made for audiometric evaluation with and without facial muscle contraction in the evaluation of individuals with synkinetic facial movement.