Evoked serial electromyography in the evaluation of the paralyzed face.

Serial evoked electromyography (EEMG) is a reliable, objective, repeatable test of facial nerve function. It is very important in the initial patient evaluation in determining percent degeneration of the facial nerve. A response of 0-20% will usually result in incomplete return of facial function while responses of 60% or better will usually result in normal function. With viral facial paralysis (Bell's palsy, herpes zoster oticus), serial EEMG after several weeks has little value in predicting the final percent recovery of facial function. If there is no EEMG response, the diagnosis of viral facial paralysis is questionable and serial tests should be done until facial function begins to return. If there is no return of facial function or EEMG responses, the diagnosis is probably a tumor and the nerve should be explored. When surgical manipulation of the facial nerve has resulted in partial facial weakness, EEMG helps predict the degree of recovery of facial function. EEMG results of 60% or better will result in normal facial function while EEMG results of 25% or less will result in incomplete return of facial function. Serial testing is not necessary in this group of patients. After transection and repair of the facial nerve, serial EEMG is of value in showing continuity of the repair. Lack of improvement in EEMG over 5-12 months and no return of facial function indicates poor prognosis.

Retrolabyrinthine vestibular neurectomy with simultaneous monitoring of eighth nerve action potentials and electrocochleography.

Since November 1978, we have used retrolabyrinthine vestibular neurectomy in 29 of 42 cases as the primary procedure to relieve vertigo in Meniere's disease. The results indicate that 67% of patients had no vertigo postoperatively, while 21% were much improved. Hearing was maintained within 20 dB of the preoperative level in 78%. Simultaneous intraoperative electrocochleography and eighth nerve action potentials were used to monitor auditory function in the last fourteen cases using an Amplaid Mark V evoked potential signal processor. It appears that the intraoperative electrocochleography after vestibular neurectomy can be used as an indicator of postoperative auditory function. The retrolabyrinthine vestibular neurectomy has replaced the middle fossa vestibular neurectomy and the endolymphatic subarachnoid shunt in our practice.

Use of streptomycin sulfate in the treatment of Meniere's disease.

Streptomycin sulfate has been known to be ototoxic since its use in the treatment of tuberculosis. This report describes 10 years of experience in the treatment of Meniere's disease with streptomycin. Streptomycin has been used in classical Schuknecht ablation of the vestibular system in bilateral Meniere's disease; classical Schuknecht ablation of the vestibular system in unilateral Meniere's disease in the only hearing ear; intratympanic streptomycin in the treatment of unilateral Meniere's disease; and low-dose intramuscular streptomycin as outpatient treatment in unilateral Meniere's disease. The results of bilateral vestibular ablation were similar to Schuknecht's and others. Patients developed profound ataxia with a wide-based gait and oscillopsia, which improved rapidly over a period of months. Approximately 30% experienced significant improvement in hearing, which usually deteriorated again after several months. All patients were relieved of vertigo. Patients with unilateral Meniere's disease in the only hearing ear responded as did the bilateral cases. Hearing in the only hearing ear was preserved in all cases. Low-dose subototoxic streptomycin as outpatient treatment offers promise in some cases for relieving attacks of Meniere's disease while improving hearing without producing the temporary disabling effects of ataxia and oscillopsia. Streptomycin and similar drugs that may reduce the production of endolymph may eventually be the treatment of choice in Meniere's disease.