Electroneurography in the prognostication of Bell's palsy

Factors associated with improvement in tibialis anterior weakness due to lumbar degenerative disease

BACKGROUND

The weakness of the tibialis anterior remains to be a controversial topic. There has been no study that used electrophysiological assessment of the function of the lumbar and sacral peripheral motor nerves. The aim is to evaluate surgical outcomes in patients with weakness of the tibialis anterior using neurological and electrophysiological assessments.

METHODS

We enrolled 53 patients. Tibialis anterior weakness was quantified by muscle strength, as assessed using a manual muscle test on a scale of 1 through 5, with scores <5 indicating weakness. Postoperative improvement in muscle strength was classified as excellent (5 grades recovered), good (more than one grade recovered), or fair (less than one grade recovered).

RESULTS

Surgical outcomes for tibialis anterior function were categorized as "excellent" in 31, "good" in 8, "fair" in 14 patients. Significant difference in outcomes were observed depending on diabetes mellitus status, type of surgery, and the compound muscle action potentials amplitudes of the abductor hallucis and extensor digitorum brevis (p < 0.05). Surgical outcomes were classified into two groups, patients with excellent and good outcomes (Group 1) and patients with fair outcome (Group 2). Using the forward selection stepwise method, sex and the compound muscle action potentials amplitudes of the extensor digitorum brevis were identified as significant factors for their positive association with Group 1 status. The diagnostic power of the predicted probability was as high as 0.87 in terms of area under curve of the receiver operating characteristic curve.

CONCLUSIONS

There was a significant correlation between the prognosis of tibialis anterior weakness and sex and the compound muscle action potentials amplitude of extensor digitorum brevis, suggesting that recording the compound muscle action potentials amplitude of extensor digitorum brevis will aid the outcome assessment of future surgical interventions for tibialis anterior weakness.

Association between Serum Varicella-Zoster Virus IgM and IgG and Prognosis of Ramsay Hunt Syndrome

Ramsay Hunt syndrome (RHS) has a poor prognosis because of varicella-zoster virus (VZV) infection. This is most closely related to severe inflammation in the geniculate ganglion of the facial nerve due to VZV infection or reactivation. This study investigated whether there were differences in the prognosis and accompanying symptoms of facial paralysis based on the presence or absence of VZV IgM and IgG antibodies. This study was conducted as a retrospective chart analysis of 105 patients with RHS who were admitted to our hospital between 2015 and 2021. The House-Brackmann (HB) grade and electroneurography (ENoG) was used to evaluate the degree of facial paralysis. Patients' subjective symptoms were evaluated by dividing them into dizziness, tinnitus, hyperacusis, and hearing loss. No difference was observed in the initial HB grade with or without IgM; however, the final HB grade was significantly higher in IgM-positive patients than in IgM-negative patients (p < 0.05). Further, when IgM was positive, the value of the orbicularis oculi muscle in the ENoG test results was significantly higher (p < 0.05), and symptoms of tinnitus and hyperacusis occurred more frequently (p < 0.05). The initial and final HB grades were significantly higher in IgG-positive patients than in IgG-negative patients (p < 0.05). When IgG was positive, the values of nasalis and oris muscles in the ENoG test results were significantly higher (p < 0.05), and symptoms of dizziness occurred more frequently (p < 0.05). This study confirmed that the more active the immunological action of the VZV in the body, the greater the damage to the facial and vestibulocochlear nerves, which are associated with the degree of facial paralysis and the accompanying otologic symptoms.

An electrophysiological prognostic diagnosis for facial palsy

Two electrophysiological tests for facial palsy-electroneurography (ENoG) and nerve excitability test (NET)-were reviewed. ENoG has advantages over NET in that it reflects the percentage of degenerated facial nerve fibers and can provide an accurate prognosis. However, as disadvantages, ENoG requires large, expensive equipment, and such supramaximal electrical stimulation can be quite painful for patients. NET is less painful due to weak stimulation with just enough current to meet the threshold, and the required equipment is compact and inexpensive to procure. However, it is impossible to calculate the percentage of degenerated nerve fibers, and NET is inferior to ENoG in terms of accurate prognostic prediction for facial palsy. The appropriate timing for both ENoG and NET is 7 to 10 days after the onset. While ENoG has proven more popular than NET because of its accuracy for prognostic prediction, we should not predict the prognosis of facial palsy based solely on the results of electrophyisiolgical examinations; a comprehensive evaluation including the facial muscle grading system is essential.

Presence of Varicella Zoster Virus DNA in Saliva May Be Associated with the Severity of Ramsay Hunt Syndrome

Background: The relationship between varicella zoster virus (VZV) collected from saliva and Ramsay Hunt syndrome (RHS) remains unclear. Therefore, this study aimed to investigate whether VZV DNA in saliva alters the clinical symptoms and prognosis of RHS. Methods: To measure the severity of clinical symptoms of 100 RHS patients, the initial House−Brackmann (HB) grade and associated symptoms were evaluated. The final HB grade at the end of treatment was measured to determine the prognosis. Electroneurography (ENoG) was performed on four facial muscles, including the frontalis, oculi, nasalis, and oris. Results: Salivary VZV DNA was isolated from 72 patients with RHS. The VZV DNA-positive group was 34.023 times more likely to have severe initial HB grade than the control group (95% CI, 3.21−359.68; p = 0.003). There were no significant differences in final HB grade. All ENoG values of the VZV DNA-positive group were significantly higher than those of the control group (frontalis, p = 0.003; oculi, p = 0.001; nasalis, p < 0.001; oris, p = 0.037). Conclusions: RHS patients with salivary VZV DNA have more severe clinical symptoms than the control group. There were no differences in prognosis and associated symptoms. A VZV DNA test using saliva samples of patients with RHS can evaluate the clinical symptoms and provide early confirmation of VZV infection, enabling timely treatment in a non-invasive way.

Prognosis prediction changes based on the timing of electroneurography after facial paralysis

BACKGROUND

The process of determining the prognosis and subsequent facial nerve decompression has become an important factor in determining the patient's quality of life.

AIM

In this study, the prognosis of facial paralysis was verified in detail based on the timing of electroneurography (ENOG) and nerve conduction study (NCS).

MATERIALS AND METHODS

The ENOG and NCS of 368 facial palsy patients were analyzed. House-Brackmann (HB) scale after 6 months was used as an outcome. For the ENOG, nasalis muscle/levator labii superioris alaeque nasi (NL), and orbicularis oculi (OO) muscle were used and NCS performed using temporal, zygomatic, and buccal branches.

RESULTS

ENOG at the OO performed 4-6 d after onset was ≤10% (p = .002, 10.0-fold) and showed unfavorable results (when the standard was ≥30%). In addition, the ENOG at the NL performed 13-15 d after onset was ≤10% (p = .001, 10.5-fold) and showed unfavorable results (when the standard was ≥30%).

CONCLUSIONS

The results indicated that ENOG at the OO performed 4-6 d after onset and ENOG at the NL performed 13-15 d after onset had more prognostic value for the outcomes of acute peripheral facial palsy.

Does Evoked Electromyography Detect the Injured Facial Nerve Recovery Earlier Than Clinical Assessments?

PURPOSE

The key element in managing postoperative facial nerve (FN) injuries is timely diagnosis and intervention as indicated. The purpose of this study was to measure and compare evoked electromyography (EEMG) and clinical assessment in terms of the recovery of the injured FN in operated temporomandibular joint ankylosis (TMJA) cases.

METHODS

The investigators designed a prospective cohort study in the primary operated TMJA patients. The primary predictor variable was the technique used to assess FN function, House-Brackmann Facial Nerve Grading System (HBFNGS) or EEMG. The primary outcome variable was time to FN recovery. The FN recovery was assessed in different time points (1 week, 1 month, 3 months, and 6 months). Age, gender, side (unilateral/bilateral), type of ankylosis (Sawhney's classification), and operating time were kept as covariates. Categorical variables were analyzed using Fisher's exact test. Multilevel survival analysis was performed considering the subject as cluster to perform Kaplan-Meier analysis and compute the hazards ratio using the Cox-regression method with adjustment for covariates. P <0.05 was set as statistically significant.

RESULTS

The study sample composed of 43 (69 sides) TMJA cases who underwent surgery developed iatrogenic FN injury in 10 cases (14 sides [9 right; 5 left]). The incidence of FN injury was 20.3% (14/69). Sawhey's type III/type IV ankylosis and the operating time for more than 2 hours showed a statistically significant (p<0.05) increase in FN injury. The mean duration to detect FN recovery by EEMG was 9 days (95% confidence interval, 5 to 12 days), but the HBFNGS took 161 days (95% confidence interval, 141 to 181 days). The chance of early detection by EEMG was 18.6 times more than the chance by the HBFNGS (Cox-hazard ratio, 18.6).

CONCLUSIONS

To conclude, EEMG is a noninvasive and reliable tool that detects FN recovery much earlier than the HBFNGS in the postoperative TMJA cases.

Bell’s palsy: clinical and neurophysiologic predictors of recovery

Background

The annual incidence of Bell’s palsy (BP) is 15 to 20 per 100,000 with 40,000 new cases each year, and the lifetime risk is 1 in 60. For decades, clinicians have searched the prognostic tests of sufficient accuracy for acute facial paralysis.

Objective

The present study was designed to verify in BP which clinical or electrophysiological parameters could be considered as predictive of the degree of recovery of normal facial muscle function.

Methods

Sixty-three patients with BP were initially assessed according to the House and Brackmann facial function scoring system “HB system”. All patients were followed for 3 months, the functional recovery then reassessed according to HB system. Nerve conduction studies were measured on the affected side via a bipolar surface stimulator placed over the stylomastoid foramen.

Results

We could not find statistically significant differences between BP with good and poor prognosis as regard age, sex, onset, diabetes, hypertension, dyslipidemia, or the initial HB Score. Compound motor action potential amplitude (CMAP) detected during the initial electroneurography (ENoG) was statistically significant between BP with good and poor prognosis.

Conclusions

The initial ENoG is more predictive of recovery of Bell’s palsy than the initial clinical grading using the HB system. Age, sex, hypertension, diabetes, and dyslipidemia do not seem to correlate with the degree of recovery in Bell’s palsy.

Optimal current intensity for supramaximal stimulation during electroneurography for facial palsy

OBJECTIVE

To determine the optimal current intensity for supramaximal stimulation during electroneurography (ENoG) for facial palsy.

METHODS

Forty patients with unilateral facial palsy (32 Bell's palsy, 7 Ramsay Hunt syndrome, and 1 temporal bone fracture) were enrolled. All patients were initially treated with intravenous steroid injections and examined using ENoG. Compound muscle action potentials (CMAPs) of the orbicularis oris muscle were measured on the paralyzed and healthy sides. Stimulation current intensity was varied every 5 mA from 20 mA to 50 mA using two recording methods (the midline and standard methods). The CMAPs of both sides were monitored to see whether they would saturate under the high current intensity stimulation or not.

RESULTS

No obvious saturation of CMAPs was observed in either side with the midline or standard methods. Statistically, a current of 35 mA and above in the healthy side, and 30 mA and above in the paralytic side, resulted in no difference to each side when using the midline recording method. On the other hand, a current of 35 mA and above in the healthy side, and 25 mA and above in the paralytic side, resulted in no difference to each side when using the standard recording method.

CONCLUSIONS

These results indicate that a current intensity of at least 35 mA is required to achieve supramaximal stimulation on the healthy side in a patient with unilateral facial nerve palsy. Clinically, for simplicity or standardization purposes, if the same current intensity is introduced bilaterally for ENoG measurements, adopting 40 mA (35 mA plus 10-20%) stimulation would be appropriate for supramaximal stimulation, while being cognizant of the potential effects of artifacts from other muscles.

Electrodiagnostic testing in acute facial palsy: Outcomes and comparison of methods

OBJECTIVE

To study the relationship between various electrodiagnostic modalities in acute facial palsy.

SETTING

Academic tertiary care center.

PATIENTS

One-hundred and six patients who presented with traumatic or non-traumatic acute facial paralysis (House-Brackmann, HB, grade 6/6) between 2008 and 2017 and underwent acute electrodiagnostic testing.

INTERVENTION

Electroneurography (ENoG) using nasolabial fold (NLF) or nasalis muscle (NM) methods, and volitional electromyography (EMG) in all patients.

MAIN OUTCOME MEASURES

Percent degeneration of ipsilateral facial nerve compound muscle action potentials (CMAP) on NLF- and NM-ENoG, presence or absence of muscle unit potentials (MUPs) on EMG.

RESULTS

Extent of facial nerve degeneration measured by NLF- and NM-ENoG were highly correlated (r = 0.85, P < .01) on each test and on serial testing. NLF- and NM-ENoG concordantly diagnosed ≥90% degeneration in 44 patients (80%), of whom 32 patients were diagnosed to have 100% degeneration by both methodologies. Absence of MUPs on EMG was 63% sensitive and 92% specific for ≥90% degeneration on ENoG, with a positive predictive value of 90%. For patients with Bell's palsy, percent degeneration on ENoG was also correlated to HB score at 1 year. Surgical decompression resulted in mean HB scores of 2.2 and 3.0 for patients with Bell's palsy and trauma, respectively.

CONCLUSIONS

NM-ENoG may be a valid and comparable method to NLF-ENoG for predicting the recovery of facial nerve function in acute paralysis. Absence of MUPs on EMG is a specific measure of severe degeneration and highly predictive of candidacy for surgical decompression.

LEVEL OF EVIDENCE

Level 3.

Facial Palsy: A Retrospective Study of 416 Cases Based on Electrodiagnostic Consultation

Background:

Facial nerve palsy (FP) is a frequent neurological condition caused mostly by Bell´s Palsy (BP).

Objectives:

The main objective of this study is to describe electrophysiological parameters in a retrospective 28-year review of 416 cases of FP based on electrodiagnostic consultation.

Methods:

In total, 520 exams from 416 patients over a 28-year period were reviewed. Sex, age, etiology, comorbidities, and variables from electroneurography and needle electromyography were analyzed. Cases were grouped as BP (70.7%), injury (16.4%), iatrogenic (10.3%) and Ramsay Hunt syndrome (RHS) (2.6%).

Results:

The mean age was 41 years (3-82), 53.4% female. Diabetes was the most frequent comorbidity. Estimated Axon Loss (EAL), >90%, was found in 50% of the cases, mainly in the iatrogenic group. The amplitude drop of the Compound Muscle Action Potentials (CMAPs) was proportional in the Orbicularis Oculi, Orbicularis Oris and Nasalis muscles. The absence of CMAPs was more frequent in the iatrogenic group and less frequent in the BP one. Bell´s palsy associated with diabetes was more severe. The R1 latency (blink reflex) was significantly longer in the BP group (P>0.001). Synkinesis due to the misdirection of regenerating axons was much more frequent in the BP and RHS groups.

Conclusion:

Bell´s palsy was the most common cause. The EAL was equal in all facial branches. Facial nerve inexcitability was more frequent in the iatrogenic/injury groups. The R1 latency was found to be prolonged in the BP group and the only good prognosis indicator in a few cases. Misdirection reinnervation was more frequent in BP and RHS groups. There was no sex or side predominance.

Recurrent facial palsy: The prognostic value of electrophysiological tests according to recurrence interval

OBJECTIVE

The prognostic value of nerve excitability tests (NET) and electroneurography (ENoG) for recurrent peripheral facial palsy is poorly understood. This study aimed to evaluate the association between NET/ENoG results for the current palsy and recovery.

METHODS

We extracted data on patients who were referred to our hospital (2005-2017). Adult patients with recurrent peripheral facial palsy who underwent NET and ENoG within 3 weeks of onset were retrospectively analyzed (n = 26). Favorable recovery was defined as the achievement of either House-Brackmann grade I/II or the same level of facial movement as before the current palsy. We evaluated the predictive NET/ENoG results by making comparison between the favorable recovery group and the unfavorable recovery group, which were subdivided based on the length of time after the previous palsy.

RESULTS

In terms of patients with a >4-year recurrent interval, 8 out of 12 patients achieved favorable recovery. Compared to the favorable recovery group, the unfavorable recovery group had significantly higher NET results (9.03 mA vs. -1.08 mA, p = 0.017). Also, the unfavorable recovery group had significantly higher NET results in patients with a >2-year recurrent interval (9.03 mA vs. 1.06 mA, p = 0.036). However, other test results (NET in ≤4-year recurrent interval/all 26 patients, and ENoG in >4-year recurrent interval/≤4-year recurrent interval/all 26 patients) did not differ significantly between patients with favorable and unfavorable recovery.

CONCLUSION

NET might be a useful prediction method in patients with at least a few years interval between the previous and the current palsy.

Prognostic role of neurophysiological testing 3-7 days after onset of acute unilateral Bell's palsy

OBJECTIVE

Recovery from acute Bell's palsy (BP) is variable and there are few predictors of response. We evaluated the usefulness of a range of neurophysiological parameters to predict outcome in BP.

METHODS

Fifty-nine patients (age: 33.7±15.4 years) with acute unilateral BP were recruited within 3-7 days of onset. They were evaluated with electroneurography, facial nerve excitability, and the blink reflex. House-Brackmann (HB) clinical scores were obtained at the same time and three months later. All patients received prednisolone treatment and regular rehabilitation.

RESULTS

At three months, 41 patients (69.5%) had good recovery, while 18 patients (30.5%) had poor recovery according to the HB scale. The facial nerve excitability threshold and threshold difference between sides were significantly lower in patients with good recovery than those with poor recovery (P values=0.022 and 0.006 respectively). Facial nerve degeneration rate (1 - affected/unaffected amplitude of CMAP of muscle ×100%) recorded in frontalis (P=0.002) and orbicularis oris (P=0.038) were also smaller in good recovery than poor recovery patients. There were no differences in latency and amplitude of CMAPs recorded from frontalis or orbicularis oris muscle, nor in latencies of the components of the blink reflex. ROC analysis showed that patients who had a threshold side difference <13mA (35 cases), had a higher chance of good recovery (85.7% versus 14.3% poor recovery). Patients who had a degeneration rate<50% (38 cases) also had a higher chance of good recovery (78.9%) versus 21.1% who had poor recovery, while patients with a degeneration rate>50% (21 cases) had a 47.8% chance of good recovery versus 52.2% poor recovery (P=0.004). Logistic regression analysis showed that the most significant predictive indicator of BP recovery was the facial nerve degeneration rate of frontalis muscle (P=0.011).

CONCLUSION

Facial nerve degeneration rate of frontalis muscle provides the most sensitive prognostic indicator of recovery from acute BP and may provide useful management strategies.

Ocular vestibular evoked myogenic potential testing for the prognosis of Bell's palsy

CONCLUSION

oVEMP could be a useful tool for predicting the prognosis of Bell's palsy comparable to ENoG and H-B grade.

OBJECTIVES

Several previous studies have reported cases of Bell's palsy with vestibular function disorder. The basic hypothesis behind this effect lies in the close proximity of the vestibular and facial nerves in the internal auditory canal (IAC). Therefore, the aim of this study was to investigate the correlation between Bell's palsy prognosis and ocular vestibular evoked myogenic potentials (oVEMPs).

METHODS

Total 104 consecutive patients who were diagnosed with Bell?s palsy from January 2012 to December 2014 were enrolled. Patients were divided into complete recovery group and incomplete recovery group. All of patients underwent oVEMP recordings within 1 week after disease onset. For the evaluation of correlation between H-B grades, ENoG, oVEMP and Recovery of Bell?s palsy, logistic regression analysis was performed.

RESULTS

The mean value of ocular vemp asymmetry was significantly higher in the incomplete recovery group than the complete recovery group (p < 0.05). No association was found between the ipsilesional PTA threshold, caloric test, and rate of abnormal EMG and recovery state. However, the initial state of ENoG, initial H-B grade, and oVEMP abnormal findings (Latency & Amplitude symmetry ratio) were significantly correlated with the rate of recovery (p = 0.025, p = 0.013, and p < 0.005, respectively).

Focal and entrapment neuropathies

Of the many patterns of peripheral nerve disorders in diabetes mellitus (DM), isolated clinical involvement of single nerves, though less common than distal symmetric polyneuropathy and perhaps polyradiculoneuropathy, constitute an important collection of characteristic syndromes. These fall into four anatomical regions of the body: cranial, upper limb, truncal, and lower limb territories. Each of these groups of mononeuropathies has its own ensemble of epidemiologic patterns, clinical presentations, laboratory and radiologic findings, differential diagnosis, management principles and prognosis.

Clinical Efficacy of Electroneurography in Acute Facial Paralysis

The estimated incidence of acute facial paralysis is approximately 30 patients per 100000 populations annually. Facial paralysis is an extremely frightening situation and gives extreme stress to patients because obvious disfiguring face may cause significant functional, aesthetic, and psychological disturbances. For stressful patients with acute facial paralysis, it is very important for clinicians to answer the questions like whether or not their facial function will return to normal, how much of their facial function will be recovered, and how long this is going to take. It is also important for clinicians to treat the psychological aspects by adequately explaining the prognosis, in addition to providing the appropriate medical treatment. For decades, clinicians have used various electrophysiologic tests, including the nerve excitability test, the maximal stimulation test, electroneurography, and electromyography. In particular, electroneurography is the only objective measure that is useful in early stage of acute facial paralysis. In this review article, we first discuss the pathophysiology of injured peripheral nerve. And then, we describe about various electrophysiologic tests and discuss the electroneurography extensively.

Antiviral agents convey added benefit over steroids alone in Bell's palsy; decompression should be considered in patients who are not recovering

BACKGROUND

The management of Bell's palsy has been the subject of much debate, with corticosteroids being the preferred medication. However, evidence also supports the use of antiviral drugs for severe cases and even decompression surgery in patients who, despite medical treatment, are not recovering.

METHOD

A literature review was conducted on the management of Bell's palsy.

RESULTS

This paper describes the background, statistical evidence, study results and pathophysiological theories that support more aggressive treatment for patients with severe palsy and those who have inadequate recovery.

CONCLUSION

Combination therapy including antiviral medication significantly improves outcomes in patients with severe Bell's palsy. Decompression should be considered in patients who have not recovered with drug treatment.

The prognostic value of electroneurography of Bell's palsy at the orbicularis oculi versus nasolabial fold

OBJECTIVES/HYPOTHESIS

We compared the prognostic value of different placements measured by electroneurography (ENoG) in Bell's palsy, especially among patients with poor results on ENoG.

STUDY DESIGN

Retrospective study using electrodiagnostic data and medical chart review from August 2006 to June 2013 was performed of patients who were diagnosed with Bell's palsy.

METHODS

We included 81 patients treated from August 2006 to June 2013. Initial and final facial function was established clinically by the House-Brackmann scale. Final state of facial palsy was estimated after 6 months from onset of facial palsy. Patients with less than 10% of ENoG response (more than 90% degeneration) were divided into three groups according to ENoG response by electrode placement as follows: group A, ENoG for orbicularis oculi (oculi) ≥ 10% and ENoG for nasolabial fold (NLF) < 10%; group B, ENoG (oculi) < 10% and ENoG (NLF) ≥ 10%; and group C, ENoG (oculi) < 10% and ENoG (NLF) < 10%.

RESULTS

There were no differences in demographic data among the three groups in terms of age, gender, initial paralysis, and days from the onset to ENoG. The complete/nearly complete recovery rates were the following: group A, 49.9%; group B, 75%; group C, 32%. The overall incomplete recovery rate in groups A and C was significantly worse than group B, and group C was the worst (P < 0.05).

CONCLUSION

The results suggest that ENoG of the NLF has more prognostic value in the outcomes of Bell's palsy than ENoG of the oculi, with poorest results in patients with the NLF < 10%.

LEVEL OF EVIDENCE

4. Laryngoscope, 126:1644-1648, 2016.

A novel muscle for electroneurography in peripheral facial palsy: occipitalis

Electroneurography (ENoG) is one of the most objective tests in grading the damage and prediction of prognosis in peripheral facial palsy (PFP). We aimed to determine temporal changes of ENoG recorded over occipitalis muscle in acute idiopathic PFP. Consecutive 21 patients with unilateral acute idiopathic PFP and age- and sex-matched 15 healthy volunteers were included in the study. Nasal and occipital ENoG values were recorded once in the control group and the same procedure was repeated daily between the second and eight days of the disorder in the PFP group. Occipital ENoG value began to increase on the third day while nasal ENoG value was still within the normal range (27.04 vs 7.69 %, p = 0.0001). In the fourth, fifth and sixth days, occipital ENoG value was significantly high compared to nasal ENoG value (p = 0.0001 for each day) whereas nasal and occipital ENoG values were very similar in the seventh and eighth days (p = 0.181 and p = 0.584, respectively). Our study presents further support for technical possibility of occipital ENoG which may reflect the degree of fiber degeneration earlier than the nasalis muscle in PFP.

Idiopathic oculostapedial synkinesis without history of facial nerve palsy

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.

Correlations between the clinical, histological and neurophysiological examinations in patients before and after parotid gland tumor surgery: verification of facial nerve transmission

Parotid gland tumor surgery sometimes leads to facial nerve paralysis. Malignant more than benign tumors determine nerve function preoperatively, while postoperative observations based on clinical, histological and neurophysiological studies have not been reported in detail. The aims of this pilot study were evaluation and correlations of histological properties of tumor (its size and location) and clinical and neurophysiological assessment of facial nerve function pre- and post-operatively (1 and 6 months). Comparative studies included 17 patients with benign (n = 13) and malignant (n = 4) tumors. Clinical assessment was based on House-Brackmann scale (H-B), neurophysiological diagnostics included facial electroneurography [ENG, compound muscle action potential (CMAP)], mimetic muscle electromyography (EMG) and blink-reflex examinations (BR). Mainly grade I of H-B was recorded both pre- (n = 13) and post-operatively (n = 12) in patients with small (1.5-2.4 cm) benign tumors located in superficial lobes. Patients with medium size (2.5-3.4 cm) malignant tumors in both lobes were scored at grade I (n = 2) and III (n = 2) pre- and mainly VI (n = 4) post-operatively. CMAP amplitudes after stimulation of mandibular marginal branch were reduced at about 25 % in patients with benign tumors after surgery. In the cases of malignant tumors CMAPs were not recorded following stimulation of any branch. A similar trend was found for BR results. H-B and ENG results revealed positive correlations between the type of tumor and surgery with facial nerve function. Neurophysiological studies detected clinically silent facial nerve neuropathy of mandibular marginal branch in postoperative period. Needle EMG, ENG and BR examinations allow for the evaluation of face muscles reinnervation and facial nerve regeneration.

Comparison of Transcranial Magnetic Stimulation and Electroneuronography Between Bell's Palsy and Ramsay Hunt Syndrome in Their Acute Stages

Objective

To examine the neurophysiologic status in patients with idiopathic facial nerve palsy (Bell's palsy) and Ramsay Hunt syndrome (herpes zoster oticus) within 7 days from onset of symptoms, by comparing the amplitude of compound muscle action potentials (CMAP) of facial muscles in electroneuronography (ENoG) and transcranial magnetic stimulation (TMS).

Methods

The facial nerve conduction study using ENoG and TMS was performed in 42 patients with Bell's palsy and 14 patients with Ramsay Hunt syndrome within 7 days from onset of symptoms. Denervation ratio was calculated as CMAP amplitude evoked by ENoG or TMS on the affected side as percentage of the amplitudes on the healthy side. The severity of the facial palsy was graded according to House-Brackmann facial grading scale (H-B FGS).

Results

In all subjects, the denervation ratio in TMS (71.53±18.38%) was significantly greater than the denervation ratio in ENoG (41.95±21.59%). The difference of denervation ratio between ENoG and TMS was significantly smaller in patients with Ramsay Hunt syndrome than in patients with Bell's palsy. The denervation ratio of ENoG or TMS did not correlated significantly with the H-B FGS.

Conclusion

In the electrophysiologic study for evaluation in patients with facial palsy within 7 days from onset of symptoms, ENoG and TMS are useful in gaining additional information about the neurophysiologic status of the facial nerve and may help to evaluate prognosis and set management plan.

Bell's palsy in children: relationship between electroneurography findings and prognosis in comparison with adults

OBJECTIVES

To investigate the correlation between electroneurography (ENoG) findings and the prognosis of Bell's palsy in children compared with adults.

METHODS

Twenty-two children and 92 adults with Bell's palsy who underwent ENoG between 8 days and 4 weeks from the onset of symptoms were retrospectively enrolled. The time to maximal recovery and rate of favorable recovery (House-Brackmann grade I or II) was assessed. Children (C) and adults (A) were further subdivided into low (<10%) or high (≧10%) subgroups according to their ENoG values (affected versus unaffected side) at initial evaluation. The numbers in each subgroup were as follows: C-low (n = 8), A-low (n = 21), C-high (n = 14), and A-high (n = 71).

RESULTS

Of the 22 children assessed, 2 of the 4 patients who showed a total loss of evoked potentials on the affected side (0% ENoG value) exhibited an unfavorable recovery. The remaining 20 patients achieved a favorable recovery eventually. Patients in group C-low reached a maximal recovery of facial movement significantly later than those in group C-high (p < 0.001). Time to maximal recovery of facial movement in group A-low was later than that in group C-low, although the difference was not statistically significant (p = 0.15). The patients in group A-high reached a maximal recovery significantly later than those in group C-high (p < 0.05).

CONCLUSION

Bell's palsy seems to recover earlier in children than adults when matched for severity. The presence of an identifiable response in ENoG, irrespective of its amplitude, may indicate a favorable recovery of facial movement in children.

Clinical manifestations and prognosis of patients with Ramsay Hunt syndrome

PURPOSE

Patients with Ramsay Hunt syndrome have a poorer prognosis than those with Bell palsy despite the use of various treatment modalities. We compared the clinical characteristics, treatment methods, and outcomes in patients with Ramsay Hunt syndrome and Bell palsy.

MATERIALS AND METHODS

Patients with Ramsay Hunt syndrome were compared with patients with Bell palsy treated using oral steroids and with those treated with both steroids and an antiviral agent. Functional recovery of the facial nerve was scored according to the House-Brackmann grading system. Patients were followed up until recovery or for 3 months. Recovery rates in each group were assessed by age, sex, and initial and last House-Brackmann grade.

RESULTS

Compared with patients with Bell palsy, those with Ramsay Hunt syndrome were generally younger, had initially more severe facial palsy, and a lower recovery rate. Various factors including initial House-Brackmann grade, starting time to treatment, age, comorbid disease, electroneurography, and electromyography showed some correlations with prognosis in all groups. The addition of antiviral agents to an oral steroid regimen did not improve the recovery rate of patients with Bell palsy.

CONCLUSION

Patients with Ramsay Hunt syndrome have a poorer prognosis than do those with Bell palsy.

Role of Kabat physical rehabilitation in Bell's palsy: a randomized trial

CONCLUSION

When applied at an early stage, Kabat's rehabilitation was shown to provide a better and faster recovery rate in comparison with non-rehabilitated patients.

OBJECTIVE

To assess the validity of an early rehabilitative approach to Bell's palsy patients.

PATIENTS AND METHODS

A randomized study involved 20 consecutive patients (10 males, 10 females; aged 35-42 years) affected by Bell's palsy, classified according to the House-Brackmann (HB) grading system and grouped on the basis of undergoing or not early physical rehabilitation according to Kabat, i.e. a proprioceptive neuromuscular rehabilitation. The evaluation was carried out by measuring the amplitude of the compound motor action potential (CMAP), as well as by observing the initial and final HB grade, at days 4, 7 and 15 after onset of facial palsy.

RESULTS

Patients belonging to the rehabilitation group clearly showed an overall improvement of clinical stage at the planned final observation, i.e. 15 days after onset of facial palsy, without presenting greater values of CMAP.

Recovery of facial movement and facial synkinesis in Bell's palsy patients

OBJECTIVE

We examined the relationship between the time course of development of facial synkinesis in patients with Bell's palsy and the severity of facial nerve damage.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary referral center.

PATIENTS

Thirty-nine consecutive patients with Bell's palsy who developed synkinesis.

INTERVENTION

Diagnostic.

MAIN OUTCOME MEASURES

Subjects were divided into groups A (electroneurographic [ENoG] value, <10%; n = 31) and B (ENoG value, > or =10%; n = 8). Development of facial synkinesis was assessed based on the appearance of synkinetic potentials from the orbicularis oris muscle on the blink reflex test. Times to appearance of facial synkinesis in groups A and B were compared. The proportion of patients who developed facial synkinesis after complete recovery of facial movement was also assessed in 14 patients whose facial movement recovered completely.

RESULTS

The mean time to maximal recovery of facial movement was significantly longer in group A than in group B (p < 0.001), whereas the duration between the appearance of facial synkinesis and the onset of facial paralysis did not differ significantly between the 2 groups (p = 0.72). The proportion of patients who developed facial synkinesis after complete recovery of facial movement was significantly greater in group B than in group A (p = 0.015).

CONCLUSION

During the course of recovery from Bell's palsy, the patients with an ENoG value of 10% or greater have a higher risk of developing facial synkinesis after complete recovery of facial movement.

Prognostic value of electroneurography in Bell's palsy and Ramsay-Hunt's syndrome

OBJECTIVES

This study evaluated the accuracy of electroneurography to predict the prognosis of Bell's palsy and Ramsay-Hunt's syndrome.

DESIGN

A retrospective, institutional review board-approved study.

SETTING

A secondary referral and a university-based centre.

PARTICIPANTS

The patients had been treated for a sudden onset unilateral facial paralysis over the past 10 years (1994-2004). This retrospective study included only those patients who had been followed up for at least 3 months or if they had reached a complete recovery before then.

MAIN OUTCOMES MEASURES

House-Backmann grade versus electroneurography value.

RESULTS

The recovery rates to House-Brackmann grade II or better were 95% in those with Bell's palsy and 84% in those with herpes zoster oticus. The electroneurography value of the recovery and non-recovery groups from those with either Bell's palsy or herpes zoster oticus was similar. The logistic regression model between the electroneurography values and the probability of recovery showed no correlation in those with Bell's palsy or with herpes zoster oticus. This study did not identify the proper electroneurography value that had enough appropriate sensitivity and specificity to predict the prognosis of paralysis accurately in Bell's palsy or in herpes zoster oticus patients.

CONCLUSION

Electroneurography performed between day 7 and 10 for Bell's palsy or day 10 and 14 for herpes zoster oticus does not provide accurate information on the prognosis or recovery rate of the facial paralysis.

+ - Reconstruction of the intratemporal facial nerve using interposition nerve graft: time course of recovery in facial movement and electrophysiological findings

CONCLUSIONS

Data about the recovery course of facial function after intratemporal facial nerve reconstruction using interposition nerve graft would provide useful information for clinicians to understand the regenerative process of the facial nerve after this type of surgery. It would also enable them to obtain informed consent from the patients by preoperatively explaining the predicted outcome of the postoperative facial paralysis.

OBJECTIVE

The purpose of this study was to describe the recovery course of facial movement and electrophysiological findings after intratemporal facial nerve reconstruction using interposition graft.

PATIENTS AND METHODS

Five patients who underwent reconstruction of the facial nerve using interposition nerve graft immediately after facial nerve excision during surgery for temporal bone lesions were included in this study. Each patient was evaluated for facial movement (Yanagihara score), blink reflex (BR), and electroneurography (ENoG) preoperatively and postoperatively.

RESULTS

Improvement in facial movement began 8-10 months postoperatively. The score then gradually increased, and reached a plateau level by 2 years following surgery. The final score in four of the five patients ranged from 20 to 24 points, while the facial score of one patient only reached 12 points even at 3 years after surgery. All patients demonstrated moderate to severe synkinesis. The reappearance of R1 in BR occurred 7-10 months postoperatively, almost simultaneously with the beginning of recovery of facial movement. The latency of R1 on the operated side became shortened with increasing postoperative time, although it remained considerably longer than that on the unoperated side, even after 2 postoperative years. The onset of recovery of ENoG value (10-12 months postoperatively) was always delayed compared with the actual facial movement recovery and never returned to the level in the unoperated side.

Analysis of prognostic factors in Bell's palsy and Ramsay Hunt syndrome

OBJECTIVE

This study evaluated the prognostic factors in Bell's palsy and Ramsay Hunt syndrome (HZO).

METHODS

A retrospective, institutional review board-approved study at a university-based hospital. A total of 81 patients consisting of 55 Bell's palsy patients and 26 HZO patients were enrolled in this study. The treatment consisted uniformly in all cases, and acyclovir was administered in the case of Ramsay Hunt syndrome. All patients were followed up until they recovered or for least up 6 months.

RESULTS

The recovery rates to House-Brackmann grade II or better were 96.3% in those with Bell's palsy and 84.6% in those with HZO. In the HZO cases, older patients had a poorer initial and final status, and less chance of making a complete recovery than the younger patients. The HZO patients without diabetes mellitus had a higher chance of recovery, a higher chance of complete recovery, and a better final status. In addition, HZO patients without essential hypertension had a higher degree of recovery. HZO patients not suffering from vertigo had a higher chance of recovery.

CONCLUSION

There was no prognostic factor found in the Bell's palsy patients in this study. The prognostic factors of HZO were age, diabetus mellitus, essential hypertension and vertigo.

Prognoseabschätzung der peripheren Fazialisparese

BACKGROUND

In this retrospective study, we assessed the long-term prognostic value of the minimal nerve excitability test (NET) by comparing the results it yielded with the House-Brackmann (HB) index in patients with the most common types of facial paralysis, Bell's palsy and traumatic facial palsy.

PATIENTS AND METHODS

Three hundred and fifty patients aged 9-85 years (mean age 42.4 years; 156 male and 194 female), all of whom were treated initially with the same steroid therapy, entered on study. Patients in whom decompression surgery had been performed were excluded so as to avoid falsely optimistic prognoses. The 350 study patients were divided into two groups: group 1 was made up of 250 with Bell's palsy and group 2, of 100 with nonpenetrating traumatic facial palsy following temporal bone fracture. The NET was conducted repeatedly in all patients for 3 weeks from the start of day 3 of treatment, the value recorded on day 14 being used in the evaluation. For each patient, the result of the NET was recorded as 'normal', 'diminished' or 'without response' according to the difference between the two sides of the face. The final HB grading was determined after 1 year to check for the agreement between the electrical prognosis and the clinical outcome and thus the reliability of the prognosis indicated by the NET.

RESULTS

The results indicate that a normal NET forecast a satisfactory outcome that could be classed as HB I-II in almost all the patients in both groups. Among patients who had no response on NET, 85% of those with Bell's palsy and 90% of those with traumatic facial palsy failed to recover nerve function. Diminished nerve excitability proved to be a sign of a relatively favourable prognosis: 74% of patients in each group recovered normal facial function.

CONCLUSION

The NET is a method of investigation that is easily applied and can make a positive contribution to the assessment of prognosis in Bell's palsy and in traumatic facial palsy, reflecting the functional state of the facial nerve reliably in most of cases.

Diabetic Neuropathies

Diabetes mellitus is associated with a wide spectrum of neuropathy syndromes, ranging from a mild asymptomatic distal sensory neuropathy to a severe disabling radiculoplexus neuropathy. As the pathophysiology of these separate conditions is better understood, classification of the various phenotypes becomes important because of treatment implications. Here we provide a short summary of the history of the classification of diabetic neuropathies and try to describe the most common forms classified according to their presumed pathophysiology. We have tried to include epidemiological data where available, as well as histopathology of nerve in several diabetic neuropathies.

[Evaluation of electroneurography as a prognostic method in the development of peripheral facial paralysis]

Electroneurography (EnoG) is a prognostic test used in the assessment of the peripheral facial nerve paralysis. We believe that when performed in standard conditions and together with the clinical evolutive parameters, it is very useful to reveal the critical time for a more radical treatment. We studied 44 patients; 13 patients had greater than 90% neural degeneration on EnoG. 5 of them underwent facial nerve surgical decompression due to a poor clinical outcome and up to three of these patients had a normal facial function after this.

Electrophysiologic assessment of shoulder girdle weakness in patients with cervical spondylosis: prognostic value of supraclavicular stimulation

OBJECTIVES

We tested the use of supraclavicular stimulation as a prognostic measure of deltoid function after cervical spondylotic radiculopathy.

METHODS

Electrophysiological study consisted of supramaximally stimulating the brachial plexus and recording compound muscle action potentials (CMAPs) from the deltoid in 32 patients with unilateral weakness of 3 months or shorter duration as compared with 69 healthy subjects.

RESULTS

Despite considerable individual variability and age-related reduction in amplitude and area of deltoid CMAPs, the side-to-side ratios yielded useful, reproducible values. The measures recorded initially correlated significantly with the eventual recovery of deltoid strength but, interestingly, not with the initial degree of weakness. In particular, the CMAPs greater than 50%, even in the face of severe weakness, predicted a nearly complete return of function.

CONCLUSIONS

Supraclavicular stimulation provides a useful measure in monitoring deltoid weakness and predicting its recovery in patients with cervical spondylosis.

Pathophysiology of facial nerve paralysis induced by herpes simplex virus type 1 infection

Herpes simplex virus type 1 (HSV-1) has been proven to be a cause of Bell's palsy; however, the underlying pathophysiology of the facial nerve paralysis is not fully understood. We established a mouse model with facial nerve paralysis induced by HSV-1 infection simulating Bell's palsy and investigated the pathophysiology of the facial nerve paralysis. The time course of the R1 latency in the blink reflex tests paralleled the recovery of the facial nerve paralysis well, whereas electroneurographic recovery tended to be delayed, compared to that of the paralysis; these responses are usually seen in Bell's palsy. On histopathologic analysis, intact, demyelinated, and degenerated nerves were intermingled in the facial nerve in the model. The similarity of the time course of facial nerve paralysis and the electrophysiological results in Bell's palsy and the model strongly suggest that the pathophysiological basis of Bell's palsy is a mixed lesion of various nerve injuries.

Use of electroneurography as a prognostic indicator of Bell's palsy in Chinese patients

OBJECTIVE

To evaluate the use of electroneurography (ENOG) as a prognostic indicator in Bell's Palsy for Chinese patients in Hong Kong.

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral outpatient center.

PATIENTS

Sixty-three consecutive patients with a diagnosis of Bell's Palsy in Tuen Mun Hospital, Hong Kong, from January 1995 to January 1998.

INTERVENTIONS

ENOG, protective eye care, and exercise of the facial muscles.

MAIN OUTCOME MEASURES

ENOG was performed 5 to 14 days after the onset of facial palsy. The recovery of facial nerve function was documented by House and Brackmann grading. All the patients were followed up monthly until recovery or up to 6 months.

RESULTS

Sixty-three patients were randomly divided into two groups of 32 and 31 patients. The first part of the study was to analyze the correlation between ENOG values and the chance of recovery in Group 1 patients (n = 32) by means of a logistic regression model. The result showed that patients with ENOG values less than 72.63% had a greater than 90% chance of recovery to House Grade II or better within 2 months (Wald = 6.19, p < 0.05). The second part of the study was to assess the capability of this ENOG value to accurately predict the prognosis of Bell's Palsy in Group 2 patients (n = 31) using Fisher's exact test (p < 0.0001). The sensitivity and specificity of ENOG in predicting a good prognosis (recovery to House Grade III or better after 2 months) in patients with Bell's Palsy were 82% and 100%, respectively.

CONCLUSION

The ENOG value as a useful prognostic indicator in Chinese patients with Bell's Palsy in Hong Kong was confirmed.

Prognostic value of electromyography in acute peripheral facial nerve palsy

OBJECTIVE

To analyze the value of electromyography in predicting recovery from acute idiopathic facial nerve paralysis.

STUDY DESIGN

Retrospective case-series review.

SETTING

University-based hospital department of otorhinolaryngology/head neck surgery.

PATIENTS

Three hundred fifty-five patients with sudden facial paralysis of unknown cause (Bell's palsy).

INTERVENTION

Treatment consisted uniformly of high-dose prednisolone, dextran, and pentoxifylline. Prognostication was based on electromyography performed not earlier than 10 to 14 days after the onset of palsy. The findings were classified according to Seddon into neurapraxia and axonotmesis/ neurotmesis. There is an inherent statement on prognosis in this classification because neurapraxia is presumed to recover completely within 8 to 12 weeks, whereas axonotmesis is most likely to be followed by sequelae.

MAIN OUTCOME MEASURES

Facial nerve function after 6 months.

RESULTS

Complete recovery was predicted correctly in 92.4% of cases. For the relatively rare and therefore principally more difficult predictable event defective recovery prognosis was still accurate in 80.8%.

CONCLUSION

The detection of spontaneous fibrillation in needle electromyography is a reliable sign predicting unfavorable outcome. An accuracy of 80.8% for predicting unfavorable outcome may be sufficient to advise patients what to expect in the course of their facial nerve disorder. However, it seems dubious to build a decision about surgical intervention on such a test, because in the process, unnecessary surgery would be accepted for as much as one fifth of the patient population.

Electroneurographic facial muscle pattern in Bell's palsy

To study the electroneurographic facial muscle pattern in Bell's palsy over time, electroneurographic recordings in the frontalis, orbicularis oculi, nasalis, and mentalis muscle regions were performed early (mean, day 11) and 1 and 3 months after the onset of the condition in 30 consecutive patients. The correlation between facial muscle electroneurographic recordings over time was also calculated. An additional aim was to assess whether further prognostic information could be obtained by electroneurographic recordings in more than one facial region. The recovery pattern was similar in all 4 facial regions. Initially, the correlation between the facial recordings was weak (r = 0.20-0.27), but it was improved at follow-up examinations (r = 0.33-0.65). Favorable outcome in 23 of 24 patients (96%) could have been predicted by the initial nasalis and/or mentalis recordings. The gap between patients with favorable outcome and patients with unfavorable outcome increased when the average electroneurography values were calculated from 1, 2, and 4 muscle recordings (4%, 8%, and 15%, respectively). Our results indicate that in Bell's palsy, electroneurographic examination of more than one facial muscle region may add prognostic information and that the degree of degeneration is initially different in the nerve branches.

Surgical management of Bell's palsy

OBJECTIVES

Incomplete return of facial motor function and synkinesis continue to be long-term sequelae in some patients with Bell's palsy. The aim of this report is to describe a prospective study in which a well-defined surgical decompression of the facial nerve was performed in a population of patients with Bell's palsy who exhibit the electrophysiologic features associated with poor outcomes. In addition, management issues related to Bell's palsy including herpes simplex virus typel etiology, the natural history, electrodiagnostic testing, and efficacy of surgical strategies are reviewed.

STUDY DESIGN AND METHODS

A multicenter prospective clinical trial was designed utilizing electroneurography (ENOG) and voluntary electromyography (EMG) to identify patients with Bell's palsy who would most likely develop poor return of facial function, as suggested by Fisch and Esslen. Patients who displayed electrodiagnostic features of poor outcome, >90% degeneration on ENOG testing and no voluntary motor unit EMG potentials within 14 days of onset of total paralysis, were offered a surgical decompression of the facial nerve through a middle cranial fossa surgical exposure, including the tympanic segment, geniculate ganglion, labyrinthine segment, and meatal foramen. Control subjects were those who displayed similar electrodiagnostic features and time course.

RESULTS

Subjects who did not reach 90% degeneration on ENOG within 14 days of paralysis all returned to House-Brackmann grade I (n = 48) or II (n = 6) at 7 months after onset of the paralysis. Control subjects self-selecting not to undergo surgical decompression when >90% degeneration on ENOG and no motor unit potentials on EMG were identified had a 58% chance of developing a poor outcome at 7 months after onset of paralysis (House-Brackmann grade III or IV [n = 19]). A group with similar ENOG and EMG findings undergoing middle fossa facial nerve decompression exhibited House-Brackmann grade I (n = 14) or II (n = 17) in 91% of the cases. An exact permutation test confirmed that the surgical group had a significantly higher proportion of patients with a good outcome (House-Brackmann grade I or II) (P = .0002).

CONCLUSION

Electroneurography in combination with voluntary EMG successfully identified patients who will most likely return to normal from those who had a greater chance of long-term sequelae from Bell's palsy. Surgical decompression medial to the geniculate ganglion significantly improves the chances of normal or near-normal return of facial function in the group that has a high probability of a poor result. Surgical decompression must be performed within 2 weeks of onset of total paralysis for it to be effective.

Twenty-four-hour oscillations of facial electroneurography parameters and their relationship to body temperature

The purpose of the present study was to assess the temporal variation of the facial electroneurography (ENoG) parameters recorded from the nasolabial crease and to compare it to the temporal oscillations of oral and facial cutaneous temperatures. Twelve healthy individuals were examined at 4-hour intervals for 2 consecutive days. Twenty-four-hour rhythms of oral and facial cutaneous temperatures were found in all subjects (troughs on average at 4:20 and 4:00 AM, respectively). Significant 24-hour oscillations of ENoG amplitude were found in all subjects, which were positively correlated to the oscillations of oral and facial cutaneous temperatures (trough on average at 2:40 AM). The compound action potential (CAP) latency fluctuated during the day and was negatively correlated with local temperatures. However, these fluctuations and correlations did not reach statistical significance. We also found a significant reduction of ENoG amplitude in 5 patients with artificial cooling of the face near the facial nerve. Also, there was a small increase in CAP latency with facial cooling. Interpreting ENoG recordings in accordance with oral temperature and recording time of day reduce the intertest variation.

Electroneurography during facial nerve expansion

With the use of tissue-expansion techniques, it is possible to elongate the facial nerve without impairing its function. The rate of expansion is limited by ischemic events imposed by stretching of the nerve and by anatomic characteristics of the nerve segment. In this study, we used various electroneurography techniques to determine the first sign of facial dysfunction during expansion. The main objective of the study was to ascertain test-retest variability of electroneurography techniques. Facial nerves were expanded in 16 cats with the use of a tissue expander secured more deeply to the main trunk. We conducted electroneurography measurements with the use of surface electrodes, temporary needle electrodes, and permanently implanted electrodes. Technique-dependent variations encountered with the surface electrodes made this method unreliable. Using implanted electrodes, we noted gradual worsening of the compound-action potential amplitude with increasing expansion. During acute expansion, reduction in compound-action potential amplitude was correlated with clinically observed deterioration of facial-nerve function. In this study, electroneurography with implanted electrodes was found to be the most reliable predictor of the rate of successful facial nerve expansion.

House-Brackmann and Yanagihara grading scores in relation to electroneurographic results in the time course of Bell's palsy

The results of House Brackmann and Yanagihara grading were compared with electroneurographic (ENoG) data in 30 consecutive patients with Bell's palsy. The examinations were made on mean days 11, 36 and 99. Twenty-four patients had a favourable outcome (Yanagihara > or = 36 at three months). Based on our observations, 23 (96%) of these could have been predicted by ENoG, 18 (75%) by Yanagihara grading and 6 (25%) by House Brackmann grading. Initially, the relative House Brackmann scores showed a slightly milder palsy than the Yanagihara scores, but in the follow-up period the gradings were almost identical. The mild palsies, defined on the initial ENoG results, initially demonstrated relatively less nerve dysfunction on ENoG than the clinical grading; by the first follow-up, the ENoG and clinical grading had both returned to normal. The intermediate palsies had almost the same initial relative clinical and ENoG values, but at the first follow-up (mean day 36), the facial function had returned to normal despite abnormally reduced, but improved, ENoG values. In the severely affected patients, the follow-up studies showed an improved clinical function but ENoG values still demonstrated a high degree of degeneration (slightly improved at second follow-up). In this study, patients with a favourable outcome were best predicted with ENoG. Clinical identification of these patients was more accurate with Yanagihara than with House Brackmann. Furthermore, in all three groups a clinical improvement, due to the release of neurapraxia, was noted at the first follow-up. The slow ENoG improvement noted at follow-up was probably due to nerve regeneration by collateral sprouting. Based on the time course of our ENoG findings, it appears that patients with a high degree of degeneration at both the initial examination and first follow-up have a poorer prognosis.

Variability of repeated facial nerve electroneurography in healthy subjects

BACKGROUND

Facial electroneurography is an objective measurement of a muscle compound action potential. The amplitude ratio between the paretic and the normal side is used as a basis for estimating the prognosis of facial palsy. According to Esslen, the difference of amplitudes in healthy subjects is only 3%. Twenty healthy test persons were investigated with the aim of 1. reproducing the published data on the left-right difference in normal test subjects and 2. determining whether the amplitude ratio is constant over time after repeated measurements.

STUDY DESIGN

Bilateral electroneurography was conducted on 20 healthy volunteers (age range, 23-36 y; 12 men, eight women). Two investigators performed four measurements at 1-week intervals on every subject.

RESULTS

Mean amplitude ratio was 32.5%. Repeated measurements on the same individual differed considerably-- from 0% to 80%. The 99% confidence interval computed from the data ranged from 26% to 39% amplitude ratio.

CONCLUSION

The symmetry of facial evoked compound potentials postulated by Esslen and Fisch is not supported by these data. As have other investigators, the authors found significant left-right differences in healthy subjects. Furthermore, they showed for the first time that the amplitude ratio is not constant in every individual at repeated measurements. In light of these data, prognosis of facial palsy based on electroneurographic data alone seems doubtful.

Serial Gadolinium-Enhanced Magnetic Resonance Imaging and Assessment of Facial Nerve Function in Bell's Palsy

Eleven patients with mild or moderate acute idiopathic peripheral facial palsy, so-called Bell's palsy, were serially examined by gadolinium-DTPA-enhanced MRI on mean days 11, 40, and 97 (third examination, n = 10) after the onset of palsy. Results of the clinical and neurophysiologic assessment of facial nerve function were compared with the gadolinium-enhanced MRI findings. Eight of the 11 patients demonstrated contrast enhancement of the facial nerve at the initial examination, but in 7 of them, the enhancement had disappeared by the time of the serial follow-up gadolinium-enhanced MRI scans. The disappearance of facial nerve enhancement was found to be related to clinical and neurophysiologic improvements in facial nerve function during recovery from Bell's palsy. The three patients whose scans were negative at the initial gadolinium-enhanced MRI examination had the same clinical severity of palsy, but initially they had milder neurophysiologic involvement than those who demonstrated enhancement; these three patients did not exhibit enhancement at serial follow-up scans. These findings indicate that the presence of enhancement at the initial MRI scan is not necessarily indicative of a poor prognosis for recovery.

Electroneurography in the late period of Bell's palsy

Our purpose is to investigate the electrophysiological characteristics of Bell's palsy and to obtain clues for estimating prognosis in the late period by using electroneurography. Thirty-three patients were followed by electroneurography over a period of 12 months. They were classified according to House-Brackman system. At the end of the follow-up, 100% of grade II-III patients, and 61% of grade IV patients recovered completely. Thirty per cent of grade IV patients recovered as grade II, and one grade IV (8%) and one grade V (100%) patient had bad prognoses (grade IV). There were significant differences between each group in the time course between the first and third months of onset. We concluded that the amount of non-degenerated synchronous fibres can allow us to estimate prognosis of Bell's palsy, especially between the first and third month of onset, if we make serial tests.

Neurophysiological evaluation of acute facial paralysis in children

Objective evaluation of facial nerve paralysis represents a unique challenge to the clinician. Electroneurography (ENoG) and the acoustic reflex (AR) have been widely used as neurophysiological tests in an assessment of facial nerve function. However, ENoG or AR alone does not suffice diagnostic and prognostic purposes of facial function evaluation in children. To further investigate the diagnostic aspects of facial nerve paralysis, the prognostic value of AR and ENoG, and the time course of the disease in pediatric population, a series of 30 children with acute facial paralysis were investigated by correlation of findings from video-taped House-Brackmann facial grading system. AR and ENoG. The results showed that AR was absent or abnormal for thresholds in 68.2% of patients with Bell's palsy and normal middle ear function. Shorter duration and higher percentage of recovery were found in the children with a normal AR than those with an abnormal AR. Three children showed an abnormal tympanogram and hearing loss associated with acute facial paralysis. These findings should alert the clinician to the presence of a specific, treatable disease in the evaluation of Bell's palsy. The percentage of electroneurographic response varied with different days after onset. ENoG showed minimal responses at weeks 1 3 after onset of Bell's palsy in most patients. The study of the time-course in the children with Bell's palsy demonstrated a functional gap in the early (< 1 week) and late clinical stage (after 6 weeks) of the disease, suggesting that ENoG predicted well only during weeks 1-4 after onset. In general, ENoG showed a good recovery in children, however, recurrent Bell's palsy becomes a concern. The need for neurophysiological follow-up for possible incomplete recovery of the facial nerve is emphasized. It is recommended that AR and ENoG should be included in the diagnostic workup when evaluating pediatric facial function.

Prognostication of Bell's palsy using transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) provides a method to noninvasive excitation of the facial nerve in its intracranial segment close to the internal acoustic meatus. Thus, the site of facial nerve activation with TMS is proximal to or within the site of the lesion in Bell's palsy. To evaluate the prognostic capability of TMS in unilateral Bell's palsy we examined 137 patients with this method, and compared the results with electroneuronography (ENoG). Within 0-4 days from the onset of palsy, the patients with elicitable TMS responses recovered better than those in whom TMS responses were not elicitable. If TMS was performed 5-9 days or 10-28 days after the onset of palsy, it did not provide any prognostic information. Based on amplitude side-to-side differences, ENoG did not contribute prognostic information during the first 9 days from the onset of palsy. Later on, 10-28 days after the onset of palsy, ENoG showed an increased capability to discriminate the patients with poor prognosis. Thus, elicitable facial motor response with TMS predicts good prognosis of Bell's palsy at an early stage whereas poor response with ENoG predicts less favorable prognosis at a later stage.

Facial electroneurography in Bell's palsy. Variability in the early stage and comparison between interpretation methods

To determine the variability of the abnormalities found in the electroneurography (ENG) of the facial nerve in cases of Bell's palsy during the initial two week period was one of the objectives of the authors. A second one was to investigate the value of ENG as a tool to determine an early prognosis of recovery utilizing two different methods. In the first one the amplitude of the compound muscular action potential (CMAP) obtained on the paralyzed side was compared to this potential on the opposite (normal) side. The second method compared the CMAP on the paralyzed side to normal standardized data from normal individuals. A group of 33 patients with Bell's palsy was followed until total recovery of for at least 4 months, if the recovery was not achieved earlier. It was observed that amplitude of the CMAP become stable towards the sixth day of palsy and this is a good time to establish the prognosis. Another conclusion is that both methods were equivalent to determine the prognosis in Bell's palsy.

Facial nerve electroneurography. Variability in normal subjects

Twenty normal individuals were submitted to facial nerve electroneurography using different techniques in order to determine the most accurate to obtain the latencies and amplitudes of the compound muscle action potentials (CMAP) of the facial muscles. First of all it was determined in which muscle or muscle group highest amplitude CMAP could be recorded with the lowest variability between sides and in test-retest. Different techniques were studied in order to determine which could give the best results. This was shown to be an arrangement of bipolar surface electrodes fixed to a plastic bar. The records with higher amplitude where obtained from the nasolabial fold muscles. Therefore 65 normal volunteers were examined using this technique and recording the potentials obtained over the nasolabial fold muscles. Normal values were determined (latency lower than 4.5 ms and amplitude larger than 2 mV--95% confidence limits).