Comparative study of evoked electromyography and facial nerve latency test in the prognosis of idiopathic facial nerve palsy in childhood

We report our results from the application of evoked electromyography (EEMG) and facial nerve latency testing (FNLT) in 30 children aged 4–14 years with idiopathic facial palsy. Our aim was to define the value of these tests as prognostic tools in Bell's palsy. From the EEMG results we ascertained that, when the amplitude of the compound muscle action potential varied between 51% and 95% of the normal value, the neuronal damage is slight (neurapraxia). When the percentage value of muscle response decreases, the prognosis is worse. The results of the FNLT showed that, when the latency is within normal limits, the damage to the nerve is slight (neurapraxia). If the latency is prolonged, the prognosis is worse. Evaluation of our results and comparison with the index of facial nerve functional recovery showed that those two tests have a high percentage of correctness (100% for the EEMG and 96.7% for the FNLT) and a low percentage of error. We conclude that these tests are excellent for predicting the outcome of facial nerve palsy in childhood and we suggest that young patents undergo both so that the determination of the lesion may be as correct as possible.     

Investigation of unilateral facial weakness: magnetic stimulation of the proximal facial nerve and of the face-associated motor cortex

Summary Twenty-four patients with unilateral facial weakness of various aetiologies were investigated using a magnetic stimulator to stimulate the proximal segment of the facial nerve directly (short latency response) and also to activate the facial motoneurons bilaterally via corticonuclear pathways by placing the stimulating coil over the motor cortex (long latency responses). Electromyographic recordings were taken from both mentalis muscles using concentric needle electrodes. Seventeen patients were investigated at various times after onset of idiopathic facial palsy (Bell's palsy). In the acute stage (less than 5 days after onset) short and long latency responses on the paretic side were abnormal, being absent in all but one patient, in whom the short latency response was delayed. These abnormal responses were the earliest neurographic correlate for nerve conduction block. In 4 out of 9 patients seen up to 30 days after onset of palsy, trans-synaptically evoked long latency responses were absent. In patients examined more than 2 months after onset, long latency responses could always be obtained and, in 5 of 8 patients, short latency responses could also be elicited, indicating a return of the direct excitability of the nerve. Five patients with cerebral hemisphere lesions causing mild unilateral facial weakness had absent long latency responses when stimulating over the affected hemisphere, but normal bilateral long latency responses following stimulation over the unaffected cerebral hemisphere; short latency responses were normal. Magnetic stimulation of the brain and of the facial nerve can differentiate between central and peripheral causes of unilateral facial weakness and may prove useful in the early assessment of the degree of conduction block in Bell's palsy.Supported by the Deutsche Forschungsgemeinschaft     

Bell's palsy in children: analysis of clinical findings and course

To evaluate treatment of Bell's palsy (acute idiopathic peripheral facial nerve paralysis) of children, the authors analyzed 38 cases (18 females, 20 males) of Bell's palsy in children aged below 16 years old. The mean age of all cases was 6.8 +/- 6.2 years old. All cases resulted in complete recovery within 6 months. Clinical score of facial motor functions were adapted to 17 patients who were more than 5 years old. They were divided into two groups: early recovery group (clinical symptoms recovered within 3 months; 10 cases) and later recover group (over 3 months; 7 cases). Clinical scores evaluated in the first week from the onset were not significantly different. Steroid therapy was used for 9 patients of early group and 6 patient of later group. All patients of this study were recovered, thus we could not evaluate effect of steroid therapy for Bell's palsy in children. Use of steroid therapy for Bell's palsy needs more concretely administration. We consider how the region locates near to the center is an important prognostic factor.     

Evaluation of proximal facial nerve conduction by transcranial magnetic stimulation.

A magnetic stimulator was used for direct transcutaneous stimulation of the intracranial portion of the facial nerve in 15 normal subjects and in patients with Bell's palsy, demyelinating neuropathy, traumatic facial palsy and pontine glioma. Compound muscle action potentials (CMAPs) thus elicited in the orbicularis oris muscle of controls were of similar amplitude but longer latency (1.3 SD 0.15 ms) compared with CMAPs produced by conventional electrical stimulation at the stylomastoid foramen. No response to magnetic stimulation could be recorded from the affected side in 15 of 16 patients with Bell's palsy. Serial studies in two patients demonstrated that the facial nerve remained inexcitable by magnetic stimulation despite marked improvement in clinical function. In the patient with a pontine glioma, the CMAP elicited by transcranial magnetic stimulation was of low amplitude but normal latency. In six of seven patients with demyelinating neuropathy, the response to intracranial magnetic stimulation was significantly delayed. Magnetic stimulation produced no response in either patient with traumatic facial palsy. Although the precise site of facial nerve stimulation is uncertain, evidence points to the labyrinthine segment of the facial canal as the most likely location.     

Lymphocyte subsets in Bell's palsy: immune pathogenesis and outcome prediction

The aim of this prospective study is to define the prognostic significance of lymphocyte subset analysis in children with Bell's palsy. Lymphocyte subgroup analysis in peripheral blood was performed in 17 children with Bell's palsy by using flow cytometry. Before a standard protocol of corticosteroid treatment, patients were categorized into two groups for facial nerve impairment on the basis of the clinical findings: Group 1 (mild to moderate impairment), 7 patients; and Group 2 (severe impairment), 10 patients. Outcome of the patients was evaluated at the end of 3 months follow-up and categorized as satisfactory recovery (n = 12) or unsatisfactory recovery (n = 5). Decreased percentages of B cells (CD19) and T helper/inducer (CD4) subsets were measured in patients with Bell's palsy compared with age-matched healthy control patients. Patients with severe impairment had significantly lower percentages of CD4 and CD19 subsets, whereas patients with mild to moderate impairment had only decreased percentage of CD19 subsets. There was no statistically significant difference in the percentage of lymphocyte subsets between the patients with satisfactory and unsatisfactory recovery. These results provide additional support for cell-mediated immunopathogenesis in patients with Bell's palsy, without any prognostic significance for the outcome.     

Prognostic value of minimal excitability of facial nerve in Bell's palsy.

Nerve excitability is useful for prognosis in Bell's palsy. Minimal excitability values (MEV) were obtained by stimulating the facial nerve and recording the effective current (mA) required to evoke a minimal visible contraction of frontalis, orbicularis oculi, orbicularis oris, and mentalis muscles respectively. Serial MEVs were performed on 100 patients with facial palsy, of whom 87 were followed for six months or to complete recovery; 61 patients were treated with steroids of whom 57 had good recovery. Serial MEVs were not only useful for prognosis, but also helpful in regulating the dosage of prednisone.     

Blink reflexes and lateral spreading in patients with synkinesia after Bell's palsy and in hemifacial spasm

We compared various electrodiagnostical tests in patients with hemifacial spasm and in patients who developed synkinesia after Bell's palsy. We examined the evoked blink reflexes in the orbicularis oculi (o. oculi) and orbicularis oris (o. oris) muscles in 23 patients with hemifacial spasm (HFS), in 10 patients with synkinesia after Bell's palsy (BPS) and in 22 control subjects. In the patient groups, we recorded synkinesia, latency and amplitude of compound muscle action potential (CMAP) in the mental muscle after stimulation of the facial nerve and we examined electromyographic activity of the o. oculi and mental muscles synchronously. Furthermore, we studied the phenomenon of lateral spreading, also known as ephaptic transmission, between the different facial nerve branches. Patients with BPS had a prolonged R1 latency on the affected side in o. oculi and smaller mental CMAP amplitude as an indication of facial nerve damage and nerve fiber loss. This was not found in patients with HFS, who showed an increased amplitude of the R1 and R2 responses in o. oris. Patients with BPS showed only an increased R1 amplitude in o. oris. All patients had signs of synkinesia. Lateral spreading with different patterns was present in all patients with HFS and in half of the patients with BPS. Latencies of early and late responses showed no differences between HFS and BPS. In addition to alterations in facial nucleus excitability in both conditions, ectopic re-excitation of facial nerve axons in HFS may explain the differences in neurophysiological findings between HFS and BPS patients. A loss of control following synaptic stripping may also be a contributing factor.     

Contralateral early blink reflex in patients with facial nerve palsy: indication for synaptic reorganization in the facial nucleus during regeneration.

Fifty patients with Bell's palsy and 30 patients with etiologically different symptomatic peripheral facial nerve palsy were studied by means of electrically evoked blink reflexes 1-23 days after onset of paresis. Their results were compared with a normal control group of 30 healthy subjects. In a significant number of patients (64% in Bell's palsy and 53% in symptomatic facial nerve palsy) a contralateral early blink reflex response (R1) could be elicited upon stimulation of the normal side as compared to 13% in the control group. It is suggested that this result may be explained by synaptic reorganization of the facial nucleus leading to functional unmasking of pre-existing crossed trigemino-facial reflex pathways during regeneration. This view is in line with previous experimental data in animals on the time course of structural changes in the facial nucleus after lesioning of the ipsilateral facial nerve.     

Myokymic discharges and enhanced facial nerve reflex responses after recovery from idiopathic facial palsy.

A functional disorder of facial muscle activity commonly occurs in patients after recovery from Bell's palsy with axonal degeneration. The postparalytic facial dysfunction is probably related to the aberrant growing of regenerating axons, although other theories such as ephaptic transmission, spontaneous generation of impulses, and enhancement of motoneuron excitability should also be considered. In this work, we have carried out a comparative electrophysiological study of both sides of the face in 23 patients who had recovered from a unilateral Bell's palsy with axonal degeneration. At rest, spontaneous firing of motor units was observed in muscles of the previously paralyzed side. Direct motor responses to facial nerve stimulation were smaller in the muscles of the previously paralyzed side, but reflex responses obtained in the same muscles by stimulation of either the facial or trigeminal nerve were larger when compared with those of the contralateral side. These data indicate that patients with "postparalytic facial dysfunction" may have an increased background muscle activity, as well as an enhanced recruitment of facial motoneurons to reflex activation in the side of the previous paralysis. These findings are compatible with an enhanced level of motoneuron excitability in the facial nucleus.     

Unmasking of the trigemino-accessory reflex in accessory facial anastomosis

OBJECTIVE: To evaluate the possible blink reflex responses in facial muscles reinnervated by the accessory nerve. METHOD: Eleven patients with a complete facial palsy were submitted to a surgical repair by an accessory facial nerve anastomosis (AFA). In this pathological group, blink reflex was studied by means of percutaneous electrical stimulation of the supraorbital nerve and recording from the orbicularis oculi muscle. A control group comprised seven normal people and seven patients with a complete Bell's facial palsy; in this group, responses on the sternocleidomastoideus (SCM) muscles were studied after supraorbital nerve stimulation. RESULTS: All the patients with AFA showed a consistent degree of facial reinnervation. Ten out of the 11 patients with AFA showed reflex responses; in six, responses were configured by a double component pattern, resembling the R1 and R2 components of the blink reflex; three patients had an R1-like response and one patient showed a unique R2 component. Mean values of latencies were 15.2 (SD 4.6) ms for the R1 and 85.3 (SD 9.6) ms for the R2. In the control group, eight out of 14 people had evidence of reflex responses in the SCM muscles; these were almost exclusively configured by a bilateral late component (mean latency 63.5 (SD15.9) ms) and only one of the subjects showed an early response at 11 ms. CONCLUSION: The trigemino-accessory reflex response in the pathological group was more complex and of a significantly higher incidence than in the control group. These differences could be tentatively explained by a mechanism of synaptic plasticity induced by the impairment of the efferent portion of the reflex. This could unmask the central linking between the trigeminal and the accessory limbs of the reflex. The findings described could be a demonstration of neurobionomic function in the repairing process of the nervous system.     

Orbicularis oculi-Reflexe und Summenpotentiale des Orbicularis oris bei idiopathischer Facialislähmung

In 84 patients with idiopathic, clinically complete Bell's palsy the electrically induced blink reflexes with their two components (OOR I and II) were electromyographically recorded on both sides using skin electrodes. In 67 of these patients the evoked responses of the orbicularis oris muscle were also studied. The latencies and amplitudes were measured and related to the clinical outcome of the facial paralysis. The patients were divided into two groups, one with good recovery of the palsy (46 patients), the other with significant residual paresis and/or strong associated movements of the facial musculature (38 patients). In the group with good recovery the following results were obtained: 1. the OOR I remained elicitable or reappeated during the first 12 days after the onset of palsy; 2. the OOR II began to rise during the first 10 days of palsy; 3. the amplitude of the orbicularis oris response did not decrease to below 10%. In the group with poor recovery: 1. both components of the OOR were absent or diminished to below 4% for more than 12 days after the onset of palsy; 2. the latency difference of the OOR I exceeded 8 msec; 3. the amplitude of the orbicularis oris responses decreased to below 10%. Using these criteria it appears to be possible in about 85% of patients to make a prognosis between the 3rd to 5th and the 10th to 12th day after the onset of Bell's palsy.     

Practice parameter: Steroids, acyclovir, and surgery for Bell's palsy (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology

OBJECTIVE: To determine the effectiveness of steroids, acyclovir, and surgical facial nerve decompression in Bell's palsy. METHODS: The authors identified articles by searching MEDLINE and selected those that prospectively compared outcomes in patients treated with steroids, acyclovir, or surgery with patients not receiving these modalities. The authors graded the quality of each study (class I to IV) using a standard classification-of-evidence scheme. They compared the proportion of patients recovering facial function in the treated group to the proportion of patients recovering facial function in the control group. RESULTS: The authors identified no adequately powered class I studies for any treatment modality. The pooled results of two class I and two class II studies showed significantly better facial outcomes in steroid-treated patients compared with non-steroid-treated patients (relative rate good outcome 1.16, 95% CI 1.05 to 1.29). One class II study demonstrated a significant benefit from acyclovir in combination with prednisone compared with prednisone alone (relative rate good outcome 1.22, 95% CI 1.02 to 1.45). All studies describing outcomes in patients treated with facial nerve decompression were graded as class IV. CONCLUSION: For patients with Bell's palsy, a benefit from steroids, acyclovir, or facial nerve decompression has not been definitively established. However, available evidence suggests that steroids are probably effective and acyclovir (combined with prednisone) is possibly effective in improving facial functional outcomes. There is insufficient evidence to make recommendations regarding surgical facial nerve decompression for Bell's palsy. Well-designed studies of the effectiveness of treatments for Bell's palsy are still needed.     

Annualized incidence and spectrum of illness from an outbreak investigation of Bell's palsy

BACKGROUND: There are limited clinical and epidemiological data on patients diagnosed with Bell's palsy. While investigating an apparent clustering of Bell's palsy, we sought to characterize the spectrum of illness in patients with this diagnosis. METHODS: A telephone survey of persons with idiopathic facial (Bell's) palsy in the Greater Toronto Area (GTA, population = 4.99 million) and Nova Scotia (population = 0.93 million) from August 1 to November 15, 1997 collected information on subject demographics, neurological symptoms, constitutional symptoms, medical investigation and management. Information regarding potential risks for exposure to infectious agents, past medical history, and family history of Bell's palsy was also collected. Subjects with other secondary causes of facial palsy were excluded. RESULTS: In the GTA and Nova Scotia, 222 and 36 patients were diagnosed with idiopathic facial (Bell's) palsy, respectively. The crude annualized incidence of Bell's palsy was 15.2 and 13.1 per 100,000 population in the GTA and Nova Scotia, respectively. There was no temporal or geographical clustering, and symptomatology did not differ significantly between the two samples. The mean age was 45 years, with 55% of subjects being female. The most common symptoms accompanying Bell's palsy were increased tearing (63%), pain in or around the ear (63%), and taste abnormalities (52%). A significant number of patients reported neurological symptoms not attributable to the facial nerve. CONCLUSION: No clustering of cases of Bell's palsy was observed to support an infectious etiology for the condition. Misdiagnosis of the etiology of facial weakness is common. Patients diagnosed with Bell's palsy have a variety of neurological symptoms, many of which cannot be attributed to a facial nerve disorder.     

Peripheral facial nerve paralysis in children: the value of routine diagnostic work-up studies

Acute facial nerve paralysis is a relatively common pediatric disorder. Idiopathic facial nerve palsy (Bell's palsy) has to be distinguished from other etiologies. Retrospective review of the results of routine diagnostic work-up studies of our patients, failed to reveal any clinically significant abnormalities and did not provide more data as far as etiology or indication for management. Significant history and positive findings on physical examination should direct the physician towards specific diagnostic procedures.     

Successful response of non-recovering Ramsay Hunt syndrome to intravenous high dose methylprednisolone

Ramsay Hunt syndrome (RHS) is a frequent cause of facial palsy. It is a consequence of the infection of geniculate ganglion by herpes zoster or herpes simplex virus. In the lack of randomized controlled trials, RHS is empirically treated by a combination therapy of antiviral agents and steroids given orally. However, RHS has, per se, a poorer prognosis than idiopathic facial palsy (Bell's palsy). We describe a case series of two patients with RHS unsuccessfully treated with antiviral drugs and oral corticosteroids, showing an almost complete recovery after late administration of intravenous (i.v.) high dose methylprednisolone. Both patients had all recognized negative prognostic factors including age of onset, a high grade facial weakness, absence of R1 and R2 response at blink reflex test, and in the first case, the involvement of greater superficial petrosal nerve. We propose that i.v. high dose methylprednisolone should be considered, even as a late treatment option, in patients with RHS non recovering after standard antiviral and oral steroid therapy as well as presenting clinical features suggestive of a poor prognosis.     

Diagnostic relevance of transcranial magnetic and electric stimulation of the facial nerve in the management of facial palsy.

OBJECTIVE: Earlier investigations have suggested that isolated conduction block of the facial nerve to transcranial magnetic stimulation early in the disorder represents a very sensitive and potentially specific finding in Bell's palsy differentiating the disease from other etiologies. METHODS: Stimulation of the facial nerve was performed electrically at the stylomastoid foramen and magnetically at the labyrinthine segment of the Fallopian channel within 3 days from symptom onset in 65 patients with Bell's palsy, five patients with Zoster oticus, one patient with neuroborreliosis and one patient with nuclear facial nerve palsy due to multiple sclerosis. RESULTS: Absence or decreased amplitudes of muscle responses to early transcranial magnetic stimulation was not specific for Bell's palsy, but also evident in all cases of Zoster oticus and in the case of neuroborreliosis. Amplitudes of electrically evoked muscle responses were more markedly reduced in Zoster oticus as compared to Bell's palsy, most likely due to a more severe degree of axonal degeneration. The degree of amplitude reduction of the muscle response to electrical stimulation reliably correlated with the severity of facial palsy. CONCLUSIONS: Transcranial magnetic stimulation in the early diagnosis of Bell's palsy is less specific than previously thought. While not specific with respect to the etiology of facial palsy, transcranial magnetic stimulation seems capable of localizing the site of lesion within the Fallopian channel. SIGNIFICANCE: Combined with transcranial magnetic stimulation, early electrical stimulation of the facial nerve at the stylomastoid foramen may help to establish correct diagnosis and prognosis.     

Magnetic resonance imaging findings in bilateral Bell's palsy.

Bell's palsy (idiopathic facial paralysis) is the most common cause of unilateral peripheral facial neuropathy. Bilateral involvement occurs in less than 10% of cases. The authors describe a 20-year-old man with bilateral idiopathic facial weakness. Brain magnetic resonance imaging (MRI) showed abnormal bilateral enhancement of the proximal intracanalicular segments of VII/VIII nerve complexes. The enhancement was most prominent in the leptomeningeal regions. There was no facial nerve swelling. Three months later he had improving residual bifacial weakness. To the authors' knowledge, this is the first report of abnormal MRI findings in bilateral Bell's palsy.     

Paralysies faciales périphériques idiopathiques. Valeur pronostique de l''étude conjointe du réflexe de clignement et de la stimulodétection du nerf facial. À propos de 91 cas

The blink reflex and stimulodetection of the facial nerve was studied during the first ten days, the 30th and 60th day and at the end of the sixth month in 91 patients with Bell's palsy. In patients with present R1 during the first ten days, there was a remarkable tendency towards a satisfactory recovery without complications. On the contrary using this single test, it is impossible to determine with 100% accuracy, which Bell's palsy will have an unsatisfactory recovery with severe dysfunction. The blink reflex seems to be a useful test for predicting the prognosis in an early stage of the paralysis. The association of the blink reflex and stimulodetection of the facial nerve allows to evaluate the risk of sequelae by the means of different electrophysiological patterns.     

Blink reflex recovery in facial weakness: an electrophysiologic study of adaptive changes

OBJECTIVE: To study the electrophysiologic effects of unilateral facial weakness on the excitability of the neuronal circuitry underlying blink reflex, and to localize the site of changes in blink reflex excitability that occur after facial weakness. BACKGROUND: Eyelid kinematic studies suggest that adaptive modification of the blink reflex occurs after facial weakness. Such adaptations generally optimize eye closure. A report of blepharospasm following Bell's palsy suggests that dysfunctional adaptive changes can also occur. METHODS: Blink reflex recovery was evaluated with paired stimulation of the supraorbital nerve at different interstimulus intervals. Comparisons were made between normal control subjects and patients with Bell's palsy who either recovered facial strength or who had persistent weakness. RESULTS: Blink reflex recovery was enhanced in patients with residual weakness but not in patients who recovered facial strength. Facial muscles on weak and unaffected sides showed enhancement. In patients with residual weakness, earlier blink reflex recovery occurred when stimulating the supraorbital nerve on the weak side. Sensory thresholds were symmetric. CONCLUSION: Enhancement of blink reflex recovery is dependent on ongoing facial weakness. Faster recovery when stimulating the supraorbital nerve on the paretic side suggests that sensitization may be lateralized, and suggests a role for abnormal afferent input in maintaining sensitization. Interneurons in the blink reflex pathway are the best candidates for the locus of this plasticity.     

Intracranial stimulation of facial nerve in humans with the magnetic coil

Using ourselves as subjects, maximal compound motor action potentials (CMAPs) were evoked in ipsilateral nasal and orbicularis oculi muscles (onset latency 4.9-5.4 msec) by a magnetic coil (MC) tangentially oriented over parieto-occipital scalp. The facial nerve was also electrically stimulated sequentially at the posterior tragus near the stylomastoid foramen, anterior tragus and 3 cm more distally. Onset latency of the CMAP elicited at posterior tragus ranged from 1.0 to 1.3 msec less than that elicited by the MC over scalp. Because the measured distal facial nerve motor conduction velocity was 50-60 m/sec, the locus of impulse generation induced by magnetic coil stimulation was estimated to be approximately 6.5 cm proximal to the site of electrical stimulation at the posterior tragus, i.e., closer to the exit of the facial nerve from the brain-stem than to its entrance into the internal auditory meatus. This non-invasive technique should be useful in evaluating patients with peripheral facial nerve disorders including Bell's palsy.