Facial Nerve Conduction Studies Research Articles

Predicting value for incomplete recovery in Bell's palsy of facial nerve ultrasound versus nerve conduction study

ObjectiveThis longitudinal study aims at assessing the predictive value of facial nerve high-resolution ultrasound (HRUS) for incomplete clinical recovery in patients with Bell’s palsy, the most common facial nerve disease. MethodsWe prospectively enrolled 34 consecutive patients with Bell’s palsy. All patients underwent neurophysiological testing (including facial nerve conduction study) and HRUS evaluations 10–15 days (T1), one month (T2), and three months (T3) after the onset of Bell’s palsy. Patients who did not experience complete recovery within three months were also evaluated after six months (T4). We have then compared the accuracy of HRUS with that of the facial nerve conduction study in predicting incomplete clinical recovery at three and six months. ResultsAt T1, the facial nerve diameter, as assessed with HRUS, was larger on the affected side than on the normal side, particularly in patients with incomplete recovery at T2, T3 and T4. ROC curve analysis, however, showed that the facial nerve diameter at T1 had a lower predictive value than the facial nerve conduction study for an incomplete clinical recovery at three (T3) and six (T4) months. Still, the facial nerve diameter asymmetry, as assessed with HRUS, had a relatively high negative predictive value (thus indicating a strong association between normal HRUS examination and a good prognosis). ConclusionsAlthough HRUS shows abnormally increased facial nerve diameter in patients in the acute phase of Bell’s palsy, the predictive value of this technique for incomplete clinical recovery at three and six months is lower than that of the nerve conduction study. SignificanceNerve ultrasound has a low predictive value for incomplete clinical recovery in patients with Bell’s Palsy.

Comparison of 3 Grading Systems (House-Brackmann, Sunnybrook, Sydney) for the Assessment of Facial Nerve Paralysis and Prediction of Neural Recovery.

Currently, multiple classification systems exist for the assessment of facial nerve paralysis. This study was designed to choose the most practical system for use in a clinical setting depending on the clinician need. We compared the responsiveness of the 3 facial nerve grading systems, i.e., House-Brackmann, Sydney, and Sunnybrook, as the subjective method and compared the outcomes with the objective method, i.e., the nerve conduction study. The correlation between the subjective and objective assessments was determined. A total of 22 consented participants with facial palsy was assessed with photos and videography recordings where they performed 10 standard facial expressions. The severity of facial paralysis was evaluated with the House-Brackmann, Sydney, and Sunnybrook grading scales subjectively and with the facial nerve conduction study objectively. The assessments were repeated after 3 months. A Wilcoxon signed-rank test showed that there were statistically significant change in all three gradings after 3-month of assessment. The responsiveness of the nerve conduction study was significant for the nasalis and orbicularis oris muscles. It was not significant for the orbicularis oculi muscle. The nasalis and orbicularis oculi showed statistically significant correlation with the three classification systems except for the orbicularis oculi muscle. All three grading systems, House-Brackmann, Sydney, and Sunnybrook, showed statistically significant responsiveness after 3 months of evaluation. The nasalis and orbicularis oculi muscle can be used to predict facial palsy recovery because they showed strong positive and negative correlations with the extent of facial nerve degeneration from the nerve conduction study.

Patterns of facial and blink reflex abnormalities in type 2 diabetes mellitus patients with short disease duration: a clue to subclinical cranial neuropathy

Abstract Background Cranial neuropathies occur in 3 to 14% of diabetic patients. Motor conduction study of the facial nerve and blink reflex study are electrophysiologic techniques used to assess the facio-trigeminal pathway in diabetic patients. The patterns of facial and blink reflex abnormalities are inconsistent among studies. This study aimed to assess the subclinical facial nerve and blink reflex abnormalities patterns in short-duration type 2 diabetes mellitus patients. This cross-sectional study included 30 type 2 diabetic patients with disease duration ≤ 5 years. We included only patients with the Toronto clinical neuropathy score ≤ 5. We enrolled 30 age- and sex-matched healthy subjects as a control group. We performed facial nerve motor conduction and blink reflex studies. Patients with prior history of cranial nerve lesions, stroke, or any other disease-causing polyneuropathy or drug-induced neuropathy were excluded from the study. Results Thirty diabetic patients were included, 20 females (66.7%) and ten males (33.3%). Their mean age was 52.63 ± 8.94 years. None of the patients had clinical evidence of neuropathy. There were significant differences between patients and controls in the distal latencies and amplitudes of facial nerve compound muscle action potentials and contralateral R2 late response latencies of the blink reflex. We detected subclinical cranial abnormalities in 6 diabetic patients (20%). One of them (3.3%) had facial nerve conduction abnormalities, four of them (13.4%) had blink reflex abnormalities, and one of them (3.3%) had both facial nerve and blink reflex abnormalities. Conclusion Subclinical cranial neuropathy can occur in short-duration type 2 diabetes mellitus patients. We detected different blink reflex patterns and facial conduction study abnormalities. We recommend blink reflex and facial nerve conduction studies as simple tests for the early evaluation of neurological subclinical affection in patients with short disease duration of T2DM as they may appear in the absence of peripheral neuropathy.

Comparison of nerve conduction study and transcranial magnetic stimulation for early diagnosis and prognosis prediction of idiopathic facial palsy.

Multiple electrophysiologic studies have been conducted in the evaluation of facial neuropathy. In our study, the diagnostic and prognostic values of nerve conduction studies (NCSs) and transcranial magnetic stimulation (TMS) were compared for idiopathic unilateral facial neuropathy. We recruited patients with newly diagnosed idiopathic unilateral facial neuropathy and performed a blink reflex test, facial NCSs, and TMS. The amplitude of facial compound muscle action potential (CMAP) and motor evoked potential (MEP) between the affected and unaffected sides of the face was compared. A total of 30 patients were enrolled in the final analysis. TMS yielded a better detection rate, and MEP reduction rate was significantly higher than CMAP reduction rate, early in the course of the disease. Poor prognosis was positively associated with the CMAP reduction rate. The cutoff value of the CMAP reduction rate in the prediction of poor prognosis was established as 0.42. Facial TMS could detect idiopathic unilateral facial neuropathy with a high sensitivity when used as an early diagnostic tool. Facial NCS could predict prognosis, and the CMAP reduction rate was significantly associated with poor short-term prognosis.

Comparative Analysis of CMAP Amplitudes of Electro-physiologically Evaluated Facial Muscles in Facial Palsy Patients


 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Background
 The study describes the retrospective analysis of compound motor action potential (CMAP) amplitudes in 50 cases (25 males & 25 females) of facial nerve palsy seen in our neurophysiology Laboratory during last two years.
 Methodology
 Clinically diagnosed cases of facial nerve palsy encountered at neurophysiology laboratory went under facial nerve conduction studies. Patients evaluated for CMAPs of orbicularis occli, Nasalis and Orbicularis oris muscles were analyzed
 Results
 Study included 50 male and female (n=25 each) patients of unilateral facial palsy with the mean age of 33.98 ± 14.13 yr. CMAP amplitudes of all the three muscles on affected side were significantly (p value <0.0001) lower compared to that of normal side. CMAP amplitudes in males and females were not significantly different over both affected and normal side muscles. ANOVA of affected and normal side muscles of all the patients showed significantly (p value <0.05) different CMAP amplitudes among both affected side and normal side muscles.
 Conclusion
 It was concluded that CMAP amplitudes are significantly reduced on the affected side in facial palsy patients and they do not reflect any gender differences. CMAP amplitudes show an increasing trend from orbicularis occuli, nasalis to orbicularis oris muscle.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

P08-T Ultrasound evaluation of facial nerve diameter for prognosis in patients with Bell’s palsy

Objective Prognosis for Bell’s palsy is good, but the proportion of patients with poor outcomes may reach 30%. Ultrasound (US) may provide a tool to assess the anatomical aspects of the nerve, complementary to the functional aspects assessed by electrodiagnostic studies. The aim of this study was to evaluate the prognostic role of neuromuscular ultrasound in Bell’s palsy. Method A total of 45 patients with acute onset of Bell’s palsy were included in the study. We measured the bilateral diameter of the distal facial nerve using US along with calculation of side to side differences in each patient. Direct facial nerve conduction studies recording compound muscle action potentials of 4 facial muscles were determined bilaterally and the percent amplitude reduction was calculated by comparing each side. If the percent amplitude reduction of any facial muscle satisfy the condition of more than 90% was assigned to the unfavorable prognosis group, and the remainder to the favorable prognosis group. Bilateral facial nerve diameters and side to side differences were compared between the two groups. Results In affected side, the facial nerve diameter was significantly larger in the unfavorable prognosis group than favorable prognosis group (p = 0.036, 95% CI = 0.008–0.236), with a significant side-to-side difference in the unfavorable prognosis group as well (p = 0.017, 95% CI = 0.026–0.248). Conclusion The significant difference in facial nerve diameter and the side-to-side difference in diameter between the two groups denotes the ability of ultrasound to detect facial nerve enlargement which may be useful to predict prognosis in patients with Bell’s palsy.

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

ObjectiveTo 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).MethodsThe 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).ResultsIn 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.ConclusionIn 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.

Cellular immune response in prognosis of Bell's palsy and its relation to clinical and electrophysiological findings

ObjectiveTo determine the cellular immune response in Bell's palsy (BP) and its prognostic value in relation to clinical and electrophysiological findings. MethodsTwenty patients with BP were subjected to: Facial nerve paralysis assessment according to House–Brackmann (H&B) grading system, bilateral facial nerve conduction study with electroneurography (ENoG) quotient calculation, blink reflex, and needle electromyography (EMG) for the affected side; one week from the onset. Before the start of medical treatment, peripheral blood mononuclear cell subsets were analyzed to reveal the percentage of total T cells (CD3+), T helper/inducer cells (CD4+), T cytotoxic (CD8+) and B cells (CD19+). Patients were followed up by H&B, ENoG and needle EMG up to 3months from the onset (end point). Fifteen age and sex matched healthy control subjects for the electrophysiological study and laboratory tests were included. ResultsThe percentages of CD3+, CD4+ & CD8+ were significantly depressed in BP patients than in control. CD19+ percentage did not show significant difference between them. On follow up, H&B revealed significant improvement. Neither electrophysiological parameters nor ENoG showed significant difference between initial and follow up assessments. Initial CD4+ percentage correlated negatively with disease duration. While Initial CD8+ percentage correlated positively with follow up compound muscle action potential (CMAP) amplitude of orbicularis oris muscle and ENoG of orbicularis oculi and nasalis muscles. Initial CD19+ percentage correlated negatively with follow up H&B and R1 & R2 responses of follow up blink reflex. Initial CD3+ percentage did not correlate with any of the follow up measures. ConclusionDecreased percentage of peripheral blood CD3+, CD4+ & CD8+ in BP patients emphasizes the role of cell mediated autoimmune pathogenesis in the acute stage of the disease. These cells have a prognostic significance for prediction of the disease duration and outcome. Analysis of T lymphocytes subsets may provide an additional parameter to differentiate patients with favorable from those with poor prognosis.

Facial Nerve Conduction after Sclerotherapy in Children with Facial Lymphatic Malformations: Report of Two Cases

Surgical excision is thought to be the standard treatment of choice for lymphatic malformations. However, when the lesions are limited to the face only, surgical scar and facial nerve injury may impair cosmetics and facial expression. Sclerotherapy, an injection of a sclerosing agent directly through the skin into a lesion, is an alternative method. By evaluating facial nerve conduction, we observed the long-term effect of facial lymphatic malformations after intralesional injection of OK-432 and correlated the findings with anatomic outcomes. One 12-year-old boy with a lesion over the right-side preauricular area adjacent to the main trunk of facial nerve and the other 5-year-old boy with a lesion in the left-sided cheek involving the buccinator muscle were enrolled. The follow-up data of more than one year, including clinical appearance, computed tomography (CT) scan and facial nerve evaluation were collected. The facial nerve conduction study was normal in both cases. Blink reflex in both children revealed normal results as well. Complete resolution was noted on outward appearance and CT scan. The neurophysiologic data were compatible with good anatomic and functional outcomes. Our report suggests that the inflammatory reaction of OK-432 did not interfere with adjacent facial nerve conduction.

The localization of facial motor impairment in sporadic Möbius syndrome

To investigate the neurophysiologic aspects of facial motor control in patients with sporadic Möbius syndrome defined as nonprogressive congenital facial and abducens palsy. The authors assessed 24 patients with sporadic Möbius syndrome by performing a complete clinical examination and neurophysiologic tests including facial nerve conduction studies, needle electromyography examination of facial muscles, and recording of the blink reflex and of the trigeminofacial inhibitory reflex. Two distinct groups of patients were identified according to neurophysiologic testing. The first group was characterized by increased facial distal motor latencies (DMLs) and poor recruitment of small and polyphasic motor unit action potentials (MUAPs). The second group was characterized by normal facial DMLs and neuropathic MUAPs. It is hypothesized that in the first group, the disorder is due to a rhombencephalic maldevelopment with selective sparing of small-size MUs, and in the second group, the disorder is related to an acquired nervous injury during intrauterine life, with subsequent neurogenic remodeling of MUs. The trigeminofacial reflexes showed that in most subjects of both groups, the functional impairment of facial movements was caused by a nuclear or peripheral site of lesion, with little evidence of brainstem interneuronal involvement. Two different neurophysiologically defined phenotypes can be distinguished in sporadic Möbius syndrome, with different pathogenetic implications.

Proximal conduction abnormality of the facial nerve in Miller Fisher syndrome: A study using transcranial magnetic stimulation

Objective To investigate facial nerve conduction, including its proximal segment, in Miller Fisher syndrome. Methods Three patients underwent facial nerve conduction studies comprising stylomastoid electrical stimulation and transcranial magnetic stimulation at the entrance of the facial canal within the skull and of the cortical representation area. All 3 patients presented with acute bilateral complete ophthalmoplegia, areflexia, mild ataxia and varying other symptoms. One of the patients had bilateral facial palsy; the other two had normal facial innervation. Results Findings suggestive of demyelination of the proximal segment of the facial nerve were observed in each of the 3 patients with Miller Fisher syndrome. The patient with bilateral facial palsy had absent responses to canalicular stimulation on both sides, while the other two showed increased temporal dispersion and prolonged latency in the proximal nerve segments. Conclusions Our findings suggest that the primary pathology of facial nerve lesion in Miller Fisher syndrome is demyelination and that it is localized to the proximal nerve segment. This is in line with the known vulnerability of proximal nerve segments (spinal roots) in other dysimmune demyelinating polyneuropathies. Significance Facial nerve conduction study with magnetic stimulation can localize and detect even subclinical facial nerve dysfunction in patients with Miller Fisher syndrome. The technique may contribute to the diagnosis of this disease, where electrophysiologic findings are scanty.

The role of facial nerve conduction studies and electromyography in predicting the outcome of Bell's palsy

Many electrophysiological tests have been used to determine prognosis and extent of recovery in Bell's palsy but the reliability and sensitivity of the different parameters used is still controversial. We performed bilateral percutaneous facial nerve conduction studies, and volitional needle electromyography on 23 patients within 10–14 days post onset of their Bell's palsy. The following parameters were assessed: denervation and recruitment of the frontalis and orbicularis oris muscles, latency of the compound muscle action potential (CMAP), and CMAP amplitude ratio. The patients were re‐examined 6 months later and their recovery graded according to the House‐Brackman classification. The CMAP amplitude ratio and the recruitment scores of the frontalis and orbicularis oris muscles were the only parameters to reliably predict outcome (p = 0.016, 0.007 and 0.036, respectively). All patients with a CMAP amplitude ratio above 10% had a complete recovery. Since Bell's palsy is probably caused by herpes simplex virus, the active disease process is completed within 10–14 days; therefore, facial nerve conduction studies and electromyography at that time are appropriate to predict prognosis.

P135 Retest reliability in facial nerve conduction studies

The H-reflex on stimulation of the tibial nerve in the popliteal fossa is routinely used in the diagnosis of first sacral (S1) nerve-root radiculopathy. The H-reflex latency, however, is considered to lack sensitivity since a small change from the focal root pathology can be diluted in a relatively long reflex latency. We have studied the soleus H-reflex elicited by stimulation of the S1 nerve root at the S1 foramen. The normal values for the S1-foramen H-reflex have been reported in a previous study, but there are no definitive reports in patients with S1 radiculopathy. This study was undertaken to determine whether stimulating at the S1 nerve root can improve the utility of the H-reflex for detecting an S1-root lesion.A randomised paired-study design was utilised to evaluate two H-reflexes: one elicited with tibial nerve stimulation and one elicited with S1-root stimulation. Fifty-five patients with unilateral S1 radiculopathy, confirmed by clinical, electrodiagnostic and magnetic resonance imaging (MRI) evidences were studied. A high-voltage electrical stimulator was used to elicit H-reflexes bilaterally at the S1 foramen and L4/L5 spine level. Latencies were compared with previously generated normal values and similar responses from the asymptomatic leg, focussing on the interval between the peak of M- and H-waves (HMI).On the symptomatic side, 39 of the 55 patients had abnormal tibial H-reflex latencies and 54 patients had abnormal responses on S1-foramen stimulation (absent in 18; HMI prolonged >0.4 ms in 36). On the asymptomatic side, all 55 patients had normal tibial H-reflexes, and 52 had normal responses on S1-foramen stimulation. In three patients, the HMI was abnormal on S1-foramen stimulation. In 46 patients tested with L4/L5-level stimulation, H-reflex was present in 39 and absent in seven. The latency of the M-wave to S1 stimulation was normal.Abnormal S1-root H-reflexes reveal lesions at the S1 root in patients with normal tibial H-reflexes; therefore, enhancing diagnostic sensitivity. The appearance of the H-reflex to L4/L5-level stimulation in patient with absent H-reflex to S1-foramen stimulation further localises the site of S1 nerve-root lesion to the L5/S1 spine level. Thus, H-reflex to S1-root stimulation significantly increases the diagnostic sensitivity for S1 radiculopathy.In our study, the S1-root H-reflex with high-voltage electrical stimulation has shown greater sensitivity than the tibial H-reflex in evaluating S1 compressive radiculopathies. An abnormal S1-root H-reflex helps to localise the lesion to the S1 root in patients with concurrent abnormal tibial nerve H-reflex, which may increase diagnostic specificity.

Intertrial reliability in facial nerve conduction studies

Intertrial reliability in facial nerve conduction studies

Electromyographic Studies of the Reconstructed Lower Eyelid After a Modified Hughes Procedure

We evaluated quantitatively, with electromyography, the function of orbicularis oculi muscle flaps in modified Hughes reconstructions of the lower eyelids. A modified Hughes procedure with a bipedicle orbicularis oculi flap was used to reconstruct large left lower eyelid defects after tumor excision in six consecutive patients. Standard needle electromyography and facial nerve conduction studies were performed on each reconstructed lower eyelid, and results were compared with those of the unoperated-on right lower eyelid. Electromyographic studies were performed between 143 and 517 days after division of the tarsoconjunctival flap. Blink reflexes and results of facial nerve studies were normal and similar on both sides. All operated-on eyelids demonstrated electromyographic activity during voluntary orbicularis contraction. The functional and cosmetic results were satisfactory in all patients. No complications of reconstruction, such as eyelid retraction, ectropion, tissue necrosis, or abnormal contour or thickness, occurred. A modified Hughes procedure using a bipedicle orbicularis oculi flap provides viable, electrically active muscle to the reconstructed lower eyelid and may enhance the functional results.