Objective: To report a case of idiopathic oculostapedial synkinesis without facial nerve disorder.
Patient: A 30-year-old woman with tinnitus synchronous with eye closure is presented. The patient had no history of facial nerve disorder.
Result: An impedance audiometer, in the absence of an auditory stimulus, was used to record tympanic membrane compliance without sound stimulation, revealing decreased compliance in the concomitant with eye blinking. Her symptoms disappeared spontaneously, so no intervention was undertaken.
Conclusion: Although oculostapedial synkinesis is often observed as one of the sequelae of facial nerve palsy, idiopathic oculostapedial synkinesis is very rare. The use of an impedance audiometer in the absence of an auditory stimulus is very useful for demonstrating objective changes in the compliance of the tympanic membrane. It is assumed that the cause of the synkinesis in our case was abnormal transmission of signals for orbicularis oculi muscle to the stapedial and orbicularis oris muscles rather than misdirected regenerating fibers. Resection of the stapedial muscle tendon should be considered if her symptoms recur.