A comparison of electroneuronography with facial nerve latency testing for prognostic accuracy in patients with Bell's palsy

Abstract

The purpose of this study was to evaluate the ability of electroneuronography (ENOG), also called evoked electromyography (EEMG), and facial nerve latency testing (FNLT) to assess the prognosis of facial nerve palsy, using the House-Brackmann facial nerve grading system as criterion. From 1988 to 1994 these tests were employed at the ORL Clinic of the University of Ioannina in 250 patients with idiopathic facial nerve palsy. The ENOG test results indicated that when the amplitude of the compound muscle action potentials ranged from 51% to 95% of the normal value, 97% of the patients achieved complete functional recovery (grade I) within at least 2 months. When the muscle action potential decreased to a value below 51% of normal values, prognosis for recovery was considerably worse. FNLT test results indicated that as the latency time extended, the recovery grade of the facial nerve worsened. When latency time was within the normal range (group A patients), about 92% of patients had complete functional recovery. In contrast all patients having either a very extended latency time or unable to be monitored (groups C and D) demonstrated incomplete functional recoveries that ranged from grade II to grade VI. Comparing each test with the House-Brackmann facial nerve grading system, we ascertained that the percent accuracy for ENOG was 97.6%, and that for FNLT was 94.4%.

A comparative study of age and degree of facial nerve recovery in patients with Bell's palsy

“…The neurophysiological status of the facial nerve and the degree of nerve injury were determined by two quantitative electrodiagnostic tests (electroneuronography [2,4,5] and the facial nerve latency test [2,8,10]) and one qualitative test (the maximum nerve stimulation test [1,9]). …”

Clinical and electromyographic assessment of facial nerve function after temporomandibular joint surgery

“…Similar analyses were performed using the FNLT and MUAP groupings of Danielides et al 14,15 The results are shown in Table 4. There were no significant differences between surgical approaches in FNLT groupings for any of the four time periods (P > 0.05 for each).…”

“…This finding is supported by the studies reported by Danielides et al, in which the authors showed a correlation between the latency time and MUAP and the prognosis of the facial nerve disorder. 14,15 Based on the results of the present study, postoperative facial nerve injury is a multifactorial complication that is transient in nature and does not depend on the surgical approach alone. Other contributing factors include the type of surgery, the surgical difficulties encountered, the duration of surgery, and previous surgery to the joint.…”

“…With regard to MUAP, all patients were classified into one of three groups in accordance with Danielides et al 14 : (1) group A were those in whom the muscle response was 51-95% of the response of the healthy muscle; (2) group B were those in whom the muscle response was 25-50% of the healthy muscle; (3) group C were those in whom the muscle response was <24% of the healthy muscle. For FNLT, all patients was classified into one of three groups in accordance with Danielides et al 15 : (1) group 1 were those in whom latency varied from 2.4 to 4 ms; (2) group 2 were those in whom latency varied from 4 to 6 ms; (3) group 3 were those in whom there was an absence of action potential (no response).…”

The Spectrum of Electrophysiological Abnormalities in Bell's Palsy

“…In the past, results were used to decide who might be a candidate for controversial and now out-of-vogue procedures such as intracanicular decompression. [1][2][3][4][5] The natural history of Bell's palsy is that 50-60% of patients will recover in three weeks 1 and 80-90% have normal or near-normal recovery by six months. 6 If the maximal deficit is paresis rather than palsy, nearly all (>95%) patients will achieve a full recovery three to eight weeks after onset.…”