Lik Sprava. 2002 Jul-Sep;(5-6):49-53. Aspects of diagnosis and treatment of the facial nerve neuropathy [Article in Ukrainian] Mironenko TV, Korotnev VN. As many as 86 patients with neuropathy of the facial nerve complicated by development of postneuritic muscular contractures were examined. Based on the clinical-and-neurophysiological investigation, findings from rheoencephalography, electroencephalography, echoencephaloscopy, electrodiagnosis of the facial nerve, clinical variants of the facial nerve function return to normal were defined together with causes of development of muscular contractures. Efficiency is shown of use of acupuncture and magnetotherapy combined in treatment of the above trouble. Zh Nevropatol Psikhiatr Im S S Korsakova. 1997;97(3):32-5. Magnetic and electromagnetic stimulation in the combined treament of patients with paralysis of the mimetic musculature. [Article in Russian] Korotkikh NG, Korzh GM. The original method of treatment of patients with postoperative paresis of mimic muscles wis offered. The method included the use of two therapeutic factors: magnetotherapy and electromagnetostimulation of peripheral branches of facial nerve. The principles of combined influence of both components were described in detail. Data on functional control of treatment results confirm the reparation of peripheral branches of facial nerve. Nippon Jibiinkoka Gakkai Kaiho. 1995 Sep;98(9):1416-25.

Clinical investigation of transcranial magnetic stimulation of the facial nerve–an early prognostic diagnosis of patients with peripheral facial palsy and the facial nerve magnetic stimulation site.

[Article in Japanese]

Kohsyu H.

Department of Otolaryngology, Yamagata University School of Medicine.

To obtain an early prognostic diagnosis of patients with peripheral facial palsy, a magnetic stimulator (Dantec Mag 2) was used to directly stimulate the intracranial portion of the facial nerve in 15 normal subjects and 108 patients with peripheral facial palsy. In normal subjects and patients with facial palsy, compound muscle action potentials (CMAPs) of the orbicularis oris muscle elicited by transcranial magnetic stimulation were compared with CMAPs elicited by electrical stimulation at a peripheral site of the stylomastoid foramen. This technique is similar to electroneurography (ENoG) and is regularly used in our department. In normal subjects, the latency of magnetically evoked CMAPs was longer (1.0ms, SD 0.39ms) than that of CMAPs evoked by electrical stimulation. There were two categories of patients; the first group consisted of patients who visited our hospital within 2 weeks after palsy onset with a record of electrically evoked CMAPs (ENoG) and magnetically evoked CMAPs, the second group consisted of all others. The first group was then divided into four subgroups based on minimal ENoG values obtained within 2 weeks after the onset of palsy. In patients, ENoG values declined until the seventh day after palsy onset, and then plateaued. However, the amplitude ratio of magnetically evoked CMAPs between the affected side and normal side showed no tendency to deline until the seventh day after palsy onset. Thus, whether magnetically evoked CMAPs could be recorded must be discussed in relation to the prognosis of facial palsy. The patients in whom magnetically evoked CMAPs could be recorded within the seven days after the onset of palsy were classified into a group in which the minimal ENoG value was greater than 20%. These patients recovered almost 2 months after the onset of palsy, and were significantly better than the recovery rates of those patients in whom magnetically evoked CMAPs could not be recorded. The site at which the facial nerve is magnetically stimulated remains controversial. In patients with peripheral facial palsy, recovery of the stapedial reflex, blink reflex and magnetically evoked CMAPs were examined to investigate the site of magnetic stimulation. From the clinical perspective, the facial nerve is thought to be magnetically stimulated near the meatal foramen that Fisch reported the site of damage in Bell’s palsy. This stimulation site was almost the same point as that calculated from the mean latency difference between magnetically evoked CMAPs and ENoG in normal controls.

Eur Arch Otorhinolaryngol. 1995;252(6):344-7.

A comparison of transcranial magnetic stimulation with electroneuronography as a predictive test in patients with Bell’s palsy.

Laranne J, Rimpilainen I, Karma P, Eskola H, Hakkinen V, Laippala P.

Department of Otorhinolaryngology, School of Medicine, University of Tampere, Finland.

The aim of this study was to examine the neuronographic findings of electrical and transcranial magnetic stimulation of the facial nerve and to compare their ability to predict clinical recovery from idiopathic facial nerve palsy (Bell’s palsy). Eighty-six patients were examined clinically and neurophysiologically immediately on presentation to Tampere University Hospital. Electroneuronography (ENoG) and transcranial magnetic stimulation (TMS) were performed 1-6 times for each patient. The time interval between each examination varied from 2 to 7 days. Seventy-eight patients were followed for a median period of 13 months after the onset of palsy. Facial nerve function was graded according to the House-Brackmann grading system. Relative amplitude differences of ENoG and TMS during the acute phase were then correlated with clinical outcome. Statistical analysis of the results showed that a TMS response elicitable during the first 5 days of the palsy was correlatable with a good prognosis. ENoG results correlated with clinical outcome at a later time from onset of symptoms. TMS was well tolerated and no adverse effects were seen. These results indicate that TMS is a useful method for the early prediction of outcome in patients with Bell’s palsy.

HNO. 1994 Sep;42(9):559-64.

Does transcranial magnetic stimulation provide improved assessment of “idiopathic” facial paralysis?  Initial results.

[Article in German]

Wolf SR, Schneider W.

Klinik und Poliklinik fur Hals-Nasen- und Ohrenkranke, Universitat Erlangen-Nurnberg.

To evaluate transcranial magnetic stimulation (TMS) in patients suffering from idiopathic facial palsy, results from 31 patients were reviewed. TMS was applied to the facial nerve by parieto-occipital, ipsilateral coil placement. At the time of the first examination (2-25 days after the onset of palsy), 11 of 31 nerves on the affected side were excitably by TMS. Patients were classified according to whether magnetic excitability of the facial nerve was possible (group I) or not possible (group II). In general, the percentage of patients with complete or nearly complete recovery of facial function was 97% following either a standard infusion therapy (corticosteroids, hydroxyethylstarch and pentoxifyllin) or orally administered corticoids (equal percentages in each group, respectively). In the first group of patients, 11 had facial nerves that were excitable with TMS and showed complete recovery of motor function within a median period of 7 weeks. In those patients with successful TMS only one experienced “crocodile tears” syndrome one year after Bell’s palsy but without any further motor deficit of facial function. In patients with unresponsive nerve function following TMS 17 recovered without sequelae (median, 11 weeks), whereas 3 of 20 (15%) developed deficits of motor function. Two of these latter cases suffered from synkinesias (one that was slight after surgical decompression of the facial nerve and one severe) while one had facial contractures but without motor deficits.(ABSTRACT

Electroencephalogr Clin Neurophysiol. 1994 Apr;93(2):113-20.

Magnetic transcranial and electrical stylomastoidal stimulation of the facial motor pathways in Bell’s palsy: time course and relevance of electrophysiological parameters.

Glocker FX, Magistris MR, Rosler KM, Hess CW.

Department of Neurology, University of Berne, Switzerland.

Facial nerve motor neurography was performed at various times after the onset of Bell’s palsy in 97 patients. Stimulation of the facial nerve was performed (1) electrically in the fossa stylomastoidea (ElStim), and (2) magnetically in the labryinthine segment of the facial canal (MagStim), evaluating different coil positions over the skull. Additionally, the face-associated motor cortex was stimulated magnetically in 47 patients (CxStim). A marked reduction of the amplitudes of the compound muscle action potentials (CMAP) evoked by MagStim on either m. nasalis or mentalis, or both, was observed which was clearly more pronounced than the amplitude reduction to ElStim. This discrepancy occurred very early during the disease, the mean amplitude (expressed in percent of the amplitude on the unaffected side) being 82% (S.D. 9.1) for ElStim and 1% (2.7) for MagStim at days 0-4. It persisted for several months, often when facial nerve function had recovered to normal, as assessed by clinical observation, ElStim, and CxStim. This amplitude decrease to MagStim, which appears to be related to a locally enhanced stimulation threshold of the facial nerve, is a very sensitive and reproducible finding in Bell’s palsy. It may prove specific of the disorder, of diagnostic value, and of interest in the follow-up of patients during treatment trials.

Otolaryngol Pol. 1994;48(1):33-6.

Magnetic stimulation of the facial nerve: a new testing method

[Article in Polish]

Pietruski J.

Abstract

Magnetic stimulation (MST) is the new method electrodiagnostic testing. The motor nerves are contrally stimulated proximally to the pathology. This technique enables to evaluate the function of the facial nerve immediately after onset. It can also be used to evaluate the function of the facial nerve in Bell’s palsy. The technique is absolutely painless. The results suggest that MST provides a sensitive data of evaluation of facial palsy and will be a very valuable prognostical test.

Nippon Jibiinkoka Gakkai Kaiho. 1993 Sep;96(9):1410-6.

Magnetic stimulation of the facial nerve.

[Article in Japanese]

Yamakawa T, Yoshikawa H, Sakurai A, Ichikawa G.

Department of Otorhinolaryngology, Juntendo University, School of Medicine, Tokyo.

Intracranial activation of the facial nerve and the face-associated motor cortex are now possible with noninvasive magnetic stimulation techniques. Compound muscle action potentials (CMAPs) and the Blink reflex, in response to magnetic stimulation, were investigated. Subjects were 10 normal controls and 2 Bell’s palsy patients. CMAPs were elicited in the orbicularis oris muscle by magnetic stimulation at the parieto-occipital skull and stylomastoid foramen. Furthermore, CMAPs were evoked by a magnetic coil oriented over the cortex. CMAP recording was possible with magnetic stimulation and the latencies of CMAPs at the parieto-occipital skull were slightly greater than those at the stylomastoid foramen. In 10 normal subjects, the mean onset latency following transcranial magnetic stimulation of the facial nerve at the parieto-occipital skull was 5.07 msec (SD = 0.40), while transcutaneous latency at the stylomastoid foramen was 2.77msec (SD = 0.539). In the blink reflex, R1 latency was 10.99 msec (SD = 1.27), ipsilateral-R2 latency was 37.46 msec (SD = 2.57), and contralateral-R2 latency was 38.925 msec (SD = 3.20). The blink reflex thus had a configuration similar to that evoked by conventional electrical stimulation. In the patients with Bell’s palsy, CMAPs elicited by magnetic stimulation were of low amplitude with normal latency. However, in the blink reflex, only a contralateral R2 response could be recorded, and R1 and ipsilateral-R2 showed no response to stimulation at the affected side. Investigation of patients with Bell’s palsy using this technique may therefore prove useful in the evaluation of peripheral facial nerve disorders.

Acta Otolaryngol. 1992;112(2):311-6.

Magnetic facial nerve stimulation in Bell’s palsy.

Rimpiläinen I, Karma P, Laranne J, Eskola H, Häkkinen V.

Department of Clinical Neurophysiology, Tampere University Central Hospital, Finland.

Abstract

The transcranial magnetic stimulation (TMS) technique makes it possible to stimulate the intracranial part of the facial nerve. In a total of 51 patients with acute Bell’s palsy, TMS was performed, and the responses were compared with those elicited by conventional extracranial electric stimulation (EES). Clinical recovery was evaluated at 258-539, mean 410, days from the beginning of the palsy. With both techniques the motor evoked potentials (MEPs) could always be elicited on the healthy side, the mean latency being 4.7 ms with TMS and 3.7 ms with EES. In the acute phase, TMS elicited MEPs on the paralyzed side in 47% of the patients, and EES in 98%. The patients with TMS elicitable MEPs during the first 4 days of the palsy had significantly better recovery than those without response (p less than 0.05). The difference in recovery between patients with or without elicitable TMS responses on days 5-8 and 9-14 was not significant. In EES, the amplitude difference between the two sides within the first 4 days was not significantly (p greater than 0.05) different. On days 9-14 the patients with a less than 80% difference between the two sides recovered significantly (p less than 0.05) better than those with a difference of greater than or equal to 80%, So, TMS may be of help in the early prognosis of Bell’s palsy.

J Neurol. 1989 Feb;236(2):102-7.

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

Meyer BU, Britton TC, Benecke R.

Neurologische Klinik, Universität Düsseldorf, Federal Republic of Germany.

Abstract

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.

Ann Otolaryngol Chir Cervicofac. 1988;105(5):397-402.

On the contribution of magnets in sequelae of facial paralysis.  Preliminary clinical study.

[Article in French]

Fombeur JP, Koubbi G, Chevalier AM, Mousset C.

Service d’Oto-Rhino-Laryngologie, Hopital Saint-Michel, Paris.

This trial was designed to evaluate the efficacy of EPOREC 1 500 magnets as an adjuvant to rehabilitation following peripheral facial paralysis. Magnetotherapy is used in many other specialties, and in particular in rheumatology. The properties of repulsion between identical poles were used to decrease the effect of sequelae in the form of contractures on the facial muscles. There were two groups of 20 patients: one group with physiotherapy only and the other with standard rehabilitation together with the use of magnets. These 40 patients had facial paralysis of various origins (trauma, excision of acoustic neuroma, Bell’s palsy etc). Obviously all patients had an intact nerve. It was at the time of the development of contractures that magnets could be used in terms of evaluation of their efficacy of action on syncinesiae, contractures and spasticity. Magnets were worn at night for a mean period of six months and results were assessed in terms of disappearance of eye-mouth syncinesiae, and in terms of normality of facial tone. Improvement and total recovery without sequelae were obtained far more frequently in the group which wore magnets, encouraging us to continue along these lines.

Arch Ophtalmol (Paris). 1976 Aug-Sep;36(8-9):549-54.

Eyelid magnets for facial paralysis.

[Article in French]

Marchac D.

The author presents his experience in the use of lid magnets. The positioning is delicate but tolerance is good and the aesthetic and functional result satisfactory. The essential indication is the development of corneal problems overnight from defective occlusion.

Klin Monatsbl Augenheilkd. 1976 Oct;169(4):529-33.

A simple method of restoring lidfunction in facial nerve paralysis with permanent magnets (author’s transl).

[Article in German]

Momma WG, Biermann B.

This is a report on 8 cases of lagophthalmos due to paralysis of the facial nerve. The in-ability to close the eyelid may bring about severe diseases of the eyes. By implantation of permanent magnets in the rims of the eyelids the dynamic lidfunction can be restored. We developed a very easy method implanting the magnets. The operation can now be done on out-patients. The results after 2 1/2 years’ follow-up are presented

Clin Neurophysiol. 2005 Sep;116(9):2051-7.

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

Nowak DA, Linder S, Topka H.

Department of Psychiatry III, University of Ulm, Germany.dr.dennis.nowak@gmx.de

Abstract

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.

Laryngoscope. 1999 Mar;109(3):492-7.

A clinical study on the magnetic stimulation of the facial nerve.

Yamakawa T, Yoshikawa H, Arai A, Miyazaki T, Ichikawa G.

Department of Otorhinolaryngology, Juntendo University, School of Medicine,

Abstract

OBJECTIVES: A clinical study on the usefulness of magnetic stimulation of the Tokyo, Japan.facial nerve, with special attention paid to the selection of the coil shape and stimulation procedures.

STUDY DESIGN: The subjects consisted of 55 patients with Bell’s palsy, 1 patient with a cerebellopontine angle (CPA) tumor, 1 patient with multiple sclerosis (MS), and 30 normal subjects. Three types of coils were used in this study; a 90-mm large single coil, a 40-mm small single coil, and a 20-mm small double coil.

METHODS: The compound muscle action potentials (CMAPs) and long latency response were evoked by transcranial magnetic stimulation (TMS) with a 90-mm large single coil. The 40-mm small single coil was used to test blink reflex by aiming it at the supraorbital nerve as the target site. The subcutaneous activation of the infra-auricular facial nerve was performed with the 20-mm double coil.

RESULTS: The reproducible CMAP and long latency responses were obtained from normal subjects with TMS. However, responses were observed only in patients with relatively mild Bell’s palsy. The magnetic stimulation-evoked responses reflected the brainstem function in the patients with a CPA tumor and MS.

CONCLUSION: Although magnetic stimulation remains inferior to conventional electric stimulation in some sense and requires further study, this method is potentially useful because it can stimulate the facial nerve continuously from the cortex to the periphery and can effectively evoke responses reflecting the brainstem function.

Neurosci Behav Physiol. 1998 Sep-Oct;28(5):594-7.

Magnetic and electrical stimulation in the rehabilitative treatment of patients with organic lesions of the nervous system.

Tyshkevich TG, Nikitina VV.

A. L. Polenov Russian Science Research Neurosurgical Institute, St. Petersburg.

Abstract

Studies were performed on 89 patients with organic lesions of the nervous system in which the leading clinical symptoms consisted of paralysis and pareses. Patients received complex treatment, including pulsed magnetic fields and an electrical stimulation regime producing multilevel stimulation. A control group of 49 patients with similar conditions was included, and these patients received only sinusoidal currents. Combined treatment with magnetic and electrical stimulation was more effective, as indicated by radiographic and electromyographic investigations.

Arch Otolaryngol Head Neck Surg. 1998 Apr;124(4):383-9.

Effect of pulsed electromagnetic stimulation on facial nerve regeneration.

Byers JM, Clark KF, Thompson GC.

Department of Otorhinolaryngology, University of Oklahoma Health Sciences Center, Oklahoma City, USA.

OBJECTIVE: To determine if exposure to electromagnetic fields influences regeneration of the transected facial nerve in the rat.

DESIGN AND METHODS: The left facial nerve was transected in the tympanic section of the fallopian canal in 24 rats randomly assigned to 2 groups. The cut ends of the facial nerve were reapproximated without sutures within the fallopian canal to maximize the potential for regeneration. Rats in the experimental group (n= 12) were then exposed to pulsed electromagnetic stimulation (0.4 millitesla at 120 Hz) for 4 hours per day, 5 days per week, for 8 weeks. Rats in the control group (n=12) were handled in an identical manner without pulsed electromagnetic stimulation. Four other rats were given sham operations in which all surgical procedures were carried out except for the actual nerve transection. Two of these rats were placed in each group. Nerve regeneration was evaluated using electroneurography (compound action potentials), force of whisker and eyelid movements, and voluntary facial movements before and at 2-week intervals after transection. Histological evaluation was performed at 10 weeks after transection. Each dependent variable was analyzed using a 2-way analysis of variance with 1 between variable (groups) and 1 within repeated measures variable (days after transection).

RESULTS: Statistical analysis indicated that N1 (the negative deflection of depolarization phase of the muscle and/or nerve fibers) area, N1 amplitude, and N1 duration, as well as absolute amplitude of the compound action potentials, were all significantly greater 2 weeks after transection in the experimental than in the control group of rats. The force of eye and whisker movements after electrical stimulation was statistically greater in the experimental group of rats 4 weeks after transection. Voluntary eye movements in the experimental group were significantly better at 5 and 10 weeks, while whisker movements were better at 3 and 10 weeks. There was no statistical difference between the 2 groups for any histological variable.

CONCLUSION: Results of this study indicate that pulsed electromagnetic stimulation enhances early regeneration of the transected facial nerve in rats.

Nippon Jibiinkoka Gakkai Kaiho. 1995 Sep;98(9):1416-25.

Clinical investigation of transcranial magnetic stimulation of the facial nerve–an early prognostic diagnosis of patients with peripheral facial palsy and the facial nerve magnetic stimulation site.

[Article in Japanese]

Kohsyu H.

Department of Otolaryngology, Yamagata University School of Medicine.

To obtain an early prognostic diagnosis of patients with peripheral facial palsy, a magnetic stimulator (Dantec Mag 2) was used to directly stimulate the intracranial portion of the facial nerve in 15 normal subjects and 108 patients with peripheral facial palsy. In normal subjects and patients with facial palsy, compound muscle action potentials (CMAPs) of the orbicularis oris muscle elicited by transcranial magnetic stimulation were compared with CMAPs elicited by electrical stimulation at a peripheral site of the stylomastoid foramen. This technique is similar to electroneurography (ENoG) and is regularly used in our department. In normal subjects, the latency of magnetically evoked CMAPs was longer (1.0ms, SD 0.39ms) than that of CMAPs evoked by electrical stimulation. There were two categories of patients; the first group consisted of patients who visited our hospital within 2 weeks after palsy onset with a record of electrically evoked CMAPs (ENoG) and magnetically evoked CMAPs, the second group consisted of all others. The first group was then divided into four subgroups based on minimal ENoG values obtained within 2 weeks after the onset of palsy. In patients, ENoG values declined until the seventh day after palsy onset, and then plateaued. However, the amplitude ratio of magnetically evoked CMAPs between the affected side and normal side showed no tendency to deline until the seventh day after palsy onset. Thus, whether magnetically evoked CMAPs could be recorded must be discussed in relation to the prognosis of facial palsy. The patients in whom magnetically evoked CMAPs could be recorded within the seven days after the onset of palsy were classified into a group in which the minimal ENoG value was greater than 20%. These patients recovered almost 2 months after the onset of palsy, and were significantly better than the recovery rates of those patients in whom magnetically evoked CMAPs could not be recorded. The site at which the facial nerve is magnetically stimulated remains controversial. In patients with peripheral facial palsy, recovery of the stapedial reflex, blink reflex and magnetically evoked CMAPs were examined to investigate the site of magnetic stimulation. From the clinical perspective, the facial nerve is thought to be magnetically stimulated near the meatal foramen that Fisch reported the site of damage in Bell’s palsy. This stimulation site was almost the same point as that calculated from the mean latency difference between magnetically evoked CMAPs and ENoG in normal controls.

Electroencephalogr Clin Neurophysiol. 1994 Apr;93(2):113-20.

Magnetic transcranial and electrical stylomastoidal stimulation of the facial motor pathways in Bell’s palsy: time course and relevance of electrophysiological parameters.

Glocker FX, Magistris MR, Rosler KM, Hess CW.

Department of Neurology, University of Berne, Switzerland.

Facial nerve motor neurography was performed at various times after the onset of Bell’s palsy in 97 patients. Stimulation of the facial nerve was performed (1) electrically in the fossa stylomastoidea (ElStim), and (2) magnetically in the labryinthine segment of the facial canal (MagStim), evaluating different coil positions over the skull. Additionally, the face-associated motor cortex was stimulated magnetically in 47 patients (CxStim). A marked reduction of the amplitudes of the compound muscle action potentials (CMAP) evoked by MagStim on either m. nasalis or mentalis, or both, was observed which was clearly more pronounced than the amplitude reduction to ElStim. This discrepancy occurred very early during the disease, the mean amplitude (expressed in percent of the amplitude on the unaffected side) being 82% (S.D. 9.1) for ElStim and 1% (2.7) for MagStim at days 0-4. It persisted for several months, often when facial nerve function had recovered to normal, as assessed by clinical observation, ElStim, and CxStim. This amplitude decrease to MagStim, which appears to be related to a locally enhanced stimulation threshold of the facial nerve, is a very sensitive and reproducible finding in Bell’s palsy. It may prove specific of the disorder, of diagnostic value, and of interest in the follow-up of patients during treatment trials.