1995 Volume 38 Issue 1 Pages 44-48
A study of tinnitus due to abnormal contraction of the stapedial muscle in eight patients with hemifacial spasm was done. The electromyographic response of the orbicularis oculi and the orbicularis oris muscles and the non-acoustic stapedial reflex were simultaneously recorded during hemifacial spasm before microvascular decompression. During hemifacial spasm, the electromyographic response revealed the recurrence of action potentials and the non-acoustic stapedial reflex showed the decrease of compliance. The decrease of compliance was found to be 0.54±0.36cc (n=8). The microvascular decompression was performed in 6 of 8 patients. In all the patients, the tinnitus disappeared without any complication after operation. The seventh cranial nerve was compressed by a loop of the anterior inferior cerebellar artery in 4 of 6 patients and by a loop of the posterior inferior cerebellar artery in 2 of 6. There findings suggested that the non-acoustic stapedial reflex could be a useful tool for evaluation of tinnitus due to abnormal contraction of the stapedial muscle in the patients with hemifacial spasm and the microvascular decompression could be effective treatment.
