Facial nerve conduction study in the prognosis of Bell’s palsy outcomes by using Facial Nerve Grading System 2.0

Journal of military pharmaco-medicine no5-2018<br /> <br /> FACIAL NERVE CONDUCTION STUDY IN THE PROGNOSIS OF<br /> BELL’S PALSY OUTCOME BY USING FNGS 2.0<br /> Le Trung Duc*; Nguyen Duc Thuan*; Nguyen Tien Son*<br /> SUMMARY<br /> Objectives: To evaluate the prognosis value of facial nerve conduction study in Bell’s palsy<br /> outcome. Subjects and methods: A descriptive and cross-sectional study using electro<br /> diagnostic data and medical chart review on 29 patients diagnosed with Bell’s palsy in<br /> Department of Neurology, Military Hospital 103 from January 2017 to December 2017, were<br /> evaluated using the facial nerve grading system 2.0 (FNGS) during their initial visit and on day<br /> 20 and day 40. We performed facial nerve conduction studies (NCS) in the first 5 days and on<br /> th<br /> the 20 day. Facial NCS results were classified into amplitude loss less than 75% and<br /> amplitude loss 75% or greater to stratify into good or poor prognosis. Results: In the first 5 days,<br /> the amplitude loss was less than 75% in 13 patients (44.8%) and 75% or greater in 16 patients<br /> th<br /> (55.2%). On the 20 day, the amplitude loss was less than 75% in 8 patients (27.6%) and 75%<br /> or greater in 21 patients (72.4%). There was a statistically significant correlation between<br /> patients with compound muscle action potential (CMAP) amplitude difference 75% or higher in<br /> the first 5 days and those with FNGS 2.0 equal to grade 3 or above (Chi Square = 9.311, p =<br /> 0.004). There was a statistically significant correlation between patients with CMAP amplitude<br /> th<br /> difference 75% or higher on 20 day and those with FNGS 2.0 equal to grade 3 or above (Chi<br /> square = 19.859, p < 0.001). Conclusion: The facial nerve conduction study is a valuable tool for<br /> follow-up and recovery prognosis of the Bell’palsy, especially in the subacute phase. Based on<br /> our data, poor prognosis is predicted in patients with more than 75% amplitude loss at both the<br /> initial and the follow-up facial NCS.<br /> * Key words: Bell’s palsy; Facial nerve; Nerve conduction study.<br /> <br /> <br /> INTRODUCTION Electrophysiological methods have been<br /> used to determine the severity of nerve<br /> Bell’s palsy, defined as an acute degeneration and prognosis in IPFP since<br /> unilateral peripheral facial nerve palsy the 1960s. Currently, the nerve excitability<br /> without detectable cause, is the most test, NCS, blink reflex test and needle<br /> common cause of facial nerve palsy. electromyography are used to determine<br /> the prognosis.<br /> FNGS 2.0, first introduced in 2009,<br /> The purpose of our study was: To<br /> was designed to overcome the limitations<br /> evaluate the prognosis value of facial<br /> of existing grading systems like House nerve conduction study in Bell’s palsy<br /> Brackmann, Sunnybrook. outcome by using FNGS 2.0.<br /> <br /> *<br /> Corresponding author: Nguyen Duc Thuan (thuanneuro82@gmail.com)<br /> Date received: 29/03/2018<br /> Date accepted: 21/03/2018<br /> <br /> 188<br />  Journal of military pharmaco-medicine no5-2018<br /> <br /> SUBJECTS AND METHODS facial paralysis, diabetes and other peripheral<br /> This is a prospective study on the patients neuropathies. All patients were treated<br /> with Bell’s palsy between the period of with methylprednisolon 80 mg/day IV<br /> January 2017 to December 2017 in Neurology within 7 days and neurotrophic drugs after<br /> Department of Military Hospital 103. The the onset of disease. The initial dose of<br /> study included 29 patients diagnosed with methylprednisolon was administered for a<br /> idiopathic peripheral facial paresis. Patients week and then tapered gradually over the<br /> who were characterized by acute onset, following week. Clinical evaluation<br /> isolated, unilateral, peripheral facial nerve comprised the FNGS and facial NCS was<br /> paralysis without detectable cause were conducted in the first 5 days and 20th and<br /> included. The clinical diagnosis of idiopathic 40th days after paralysis onset. We<br /> peripheral facial paresis was based on the defined a good outcome as the FNGS<br /> ICD-X criteria. Exclusion criteria were grade I or grade II and a poor outcome as<br /> previous history of peripheral or central FNGS grade 3 or higher.<br /> <br /> Table 1:<br /> <br /> FNGS 2.0<br /> <br /> Degree of<br /> Score Brow Eye NLF Oral secondary<br /> movement<br /> <br /> 1 Normal Normal Normal Normal None<br /> <br /> 2 Slight weakness Slight weakness > Slight Slight Slight synkinesis,<br /> > 75% of normal 75% of normal weakness > weakness > minimal<br /> Complete closure 75% of normal 75% of normal contracture<br /> with mild effort<br /> <br /> 3 Obvious Slight weakness > Slight Slight Obvious<br /> weakness > 75% of normal weakness > weakness > synkinesis, mild<br /> 50% of normal Complete closure 75% of normal 75% of normal to moderate<br /> Resting with maximal effort Resting Resting contracture<br /> symmetry symmetry symmetry<br /> <br /> 4 Asymmetry at Asymmetry at rest Asymmetry at Asymmetry at Disfiguring<br /> rest < 50% of < 50% of normal rest < 50% of rest < 50% of synkinesis,<br /> normal normal normal severe<br /> Cannot close contracture<br /> completely<br /> <br /> 5 Trace Trace movement Trace Trace<br /> movement movement movement<br /> <br /> 6 No movement No movement No movement No movement<br /> <br /> <br /> <br /> 189<br /> Journal of military pharmaco-medicine no5-2018<br /> <br /> Grade Total score<br /> I 4<br /> II 5-9<br /> III 10 - 14<br /> IV 15 - 19<br /> V 20 - 23<br /> VI 24<br /> <br /> <br /> * Electrophysiological assessment: days with those on the 20th day. The<br /> All patients underwent facial NCS on significance level was set at p < 0.05.<br /> admission using Natus VikingQuest.<br /> RESULTS<br /> Facial NCS was performed first on the<br /> intact side and then repeated on the 1. Clinical evaluation.<br /> affected side. Potentials were recorded Twenty nine patients (19 males and 10<br /> from each of the frontal, orbicularis oris females; mean age 44.3 years, range:<br /> and orbicularis oculi muscles. The stimulation 20 - 79 years) diagnosed with Bell’s palsy<br /> intensity ranged from 30 to 45 mA. The were studied. In the first 5 days, the clinical<br /> current intensity was increased stepwise evaluation according to the FNGS revealed<br /> until there was no further incrase in the that 4 patients (13.8%) was in grade III, 6<br /> amplitude of the diphasic myogenic CAP. patients (20.7%) in grade IV, 18 (62%) in<br /> An additional 10% of current was added grade V and 1 patien (3.5%) in grade VI.<br /> to ensure supramaximal stimulation. The On the 40th day, the final outcome based<br /> amplitude of the CMAP in the affected on FNGS was grade I in 17 patients<br /> side and the intact side were compared. (58.6%), grade II in 6 patients (20.7%)<br /> The value of 75% or less versus more and grade III in 6 patients (20.7%).<br /> than 75% amplitude loss was considered<br /> 12 out of 19 patients (63.1%) with<br /> a cut-off point for prognosis.<br /> complete facial nerve paralysis returned<br /> *Statistical analysis:<br /> to normal function. All patients with<br /> Statistical analysis of the data was incomplete lesions had normal facial<br /> performed using Statistical Package for nerve function in the 40th day.<br /> Social Sciences software package.<br /> Sensitivity, specificity, positive predictive 2. NCS.<br /> value and negative predictive value were On the first 5 days, the amplitude loss<br /> caculated to determine the prognostic was less than 75% in 13 patients (44.8%)<br /> value of facial NCS. The Mann-Whitney and 75% or greater in 16 patients<br /> test was used to compare the facial NCS (55,2%). On the 20th day, the amplitude<br /> result with clinical improvement. The Mc loss was less than 75% in 8 patients<br /> Nemar test was used to compare the (27.6%) and 75% or greater in 21 patients<br /> performances of facial NCS in the first 5 (72.4%).<br /> <br /> 190<br />  Journal of military pharmaco-medicine no5-2018<br /> <br /> <br /> 25<br /> 21<br /> 20<br /> <br /> 15<br /> <br /> 10<br /> 6<br /> 5<br /> 2<br /> 0<br /> 0<br /> Amplitude difference < 75% Amplitude difference >= 75%<br /> Figure 1: Relationship between FNGS 2.0 grade on the day 40 and CMAP amplitude<br /> difference on the day 20.<br /> FNGS 2.0 grade I, II FNGS 2.0 grade 3 or higher<br /> Sensitivity, specificity, PPV and NPV of NCS results are presented in table I. Poor<br /> prognosis was defined as a positive test result, good prognosis was defined as a<br /> negative test result. For initial NCS, we found a PPV and NPV of 46% and 93.8%,<br /> respectively. After a period of 15 days, PPV and NPV of follow-up NCS increased to<br /> 75% and 95.2%.<br /> Table 2: Predictive value of facial NCS.<br /> Sensitivity Specificity PPV NPV<br /> NCS on the first 5 day 85.7 % 68.2% 46.2% 93.8%<br /> NCS on the day 20 85.7 % 90.9% 75% 95.2%<br /> <br /> <br /> There was a statistically significant on 20th day. NCS on the 20th day show<br /> relationship between patients with CMAP the best performance (p < 0.05).<br /> amplitude difference 75% or higher in the<br /> first 5 days and those with FNGS 2.0 DISCUSSION<br /> equal to grade 3 or above (Chi square = For patients with Bell’s palsy in the<br /> 9.311, p = 0.004). acute phase, the NCS showed reduced<br /> There was a statistically significant amplitudes of CMAP in the frontal,<br /> relationship between patients with CMAP orbicularis oculi muscle and orbicularis<br /> amplitude difference 75% or higher on oris muscle on the affected side and the<br /> 20th day and those with FNGS 2.0 equal normal amplitudes on the intact side.<br /> to grade 3 or above (Chi square = 19.859, Statistically, the disease course was<br /> p < 0.001). described in a study by Peitersen E [3] on<br /> Mc Nemar's test was used in order to 1.011 patients. One-third had an incomplete<br /> compare NCS in the first 5 days and NCS paralysis, two-thirds had complete paralysis.<br /> <br /> 191<br /> Journal of military pharmaco-medicine no5-2018<br /> <br /> 94% of the patients with incomplete lesions grading systems and confirmed whether<br /> returned to normal function, while only FNGS could evaluate facial nerve function<br /> 60% of those with clinically complete more detail and accuracy than House<br /> lesions returned to normal function. Beckmann scale [5, 6].<br /> Among 19 patients with complete facial<br /> nerve paralysis in the present study, 12 CONCLUSION<br /> patients (63.1%) returned to normal The facial NCS is a valuable tool for<br /> function. All of patients with incomplete follow-up and recovery prognosis of the<br /> lesions had normal facial nerve function Bell’palsy, especially in the subacute<br /> on the 40th day, which reveals that we had phase. Based on our data, poor prognosis<br /> a representative population, according to is predicted in patients with more than<br /> previous studies. 75% amplitude loss at both the initial and<br /> Jabor et al reported that prognosis is the follow-up facial NCS.<br /> favorable if some recovery is seen within<br /> the first 21 days of onset [4]. In our study, REFERRENCES<br /> we performed facial NCS in the first 5 1. Fisch U. Surgery for Bell’s palsy. Arch<br /> days and on the 20th day. There was a Otolaryngol. 1981, 107, pp.1-11.<br /> statistically significant relation between 2. Danielides V, Skevas A, Van Cauwenberge<br /> patients with CMAP amplitude difference P. A comparison of electroneuronography with<br /> 75% or higher both in the first 5 days and facial nerve latency testing for prognostic<br /> on day 20 and patients with poor recovery accuracy in patients with Bell’s palsy. Eur Arch<br /> on the 40th day after onset. However, Otorhinolaryngol. 1996, 253 (1-2), pp.35-38.<br /> NCS results on day 20 illustrate a higher 3. Peitersen E. The natural history of Bell's<br /> prognosis value than those in the first 5 palsy. Am J Otol. 1982, 4, p107.<br /> days (McNemar test, p < 0.05), which is 4. Jabor M.A, Gianoli G. Management of<br /> probably consistent with axonal recovery Bell's palsy. J La State Med Soc. 1996, 148,<br /> and collateral sprouting process of facial p.279.<br /> nerve. Our results are consistent with 5. Ho Y. Lee, Moon S. Park. Agreement<br /> those that reported CMAP amplitude between the FNGS 2.0 and the House<br /> differences of ≥ 75% indicate a poor Brackmann Grading System in patients with<br /> Bell’s palsy. Clinical and Experimental<br /> prognosis at 3 months [7]. Ozgul et al<br /> Otorhinolaryngology. 2013, Sep, Vol 6, No 3,<br /> investigated the disease 3 months after pp.135-139.<br /> the onset, which indicates similar findings.<br /> 6. Jeffrey T. Vrabec, Douglas D. Backous.<br /> Besides, some studies reported 50% and FNGS 2.0. Otolaryngology-Head and Neck<br /> 90% CMAP amplitude difference in the Surgery. 2009. 140, pp.445-450.<br /> second month and in the third week 7. Engström M, Jonsson L, Grindlund M,<br /> respectively, which indicated poor prognosis Stålberg E. House-Brackmann, Yanagihara.<br /> unlike other studies [1, 2]. In our study, Grading scores in relation to electroneurographic<br /> we utilize FNGS 2.0. Few studies have results in the time course of Bell’s palsy. Acta<br /> compared FNGS 2.0 and House Brackmann Otolaryngol. 1998, 118, pp.783-789.<br /> <br /> 192<br />