Prognostication of Bell's palsy using transcranial magnetic stimulation

Efficacy of repetitive transcranial magnetic stimulation at different sites for peripheral facial paralysis: a prospective cohort study

Background

There are very few studies on transcranial magnetic stimulation (TMS) therapy for facial paralysis and no studies comparing the efficacy of central and peripheral TMS in the treatment of peripheral facial paralysis (PFP).

Purpose

To observe the therapeutic effect and security of central and peripheral repetitive transcranial magnetic stimulation (rTMS) on PFP.

Methods

Patients with unilateral onset of peripheral facial paralysis within 1 month were prospectively recruited, 97 patients with PFP were divided into the peripheral group, central group, and control group. The control group was given common treatment (drug therapy and acupuncture), and the peripheral and central groups received rTMS in addition to conventional treatment. After 2 weeks of treatment, the House-Brackmann (HB) grading scale, Sunnybrook facial grading system (SFGS), and modified Portmann scale (MPS) were used to evaluate the facial muscle function of patients in the three groups.

Result

After 2 weeks of rTMS treatment, the HBGS/SFGS/MPS scores of the three groups were significantly better than before (p < 0.05), and the mean change values of HBGS, SFGS, and MPS scores were significantly higher in participants in Peripheral Group (p < 0.001; p < 0.001; p = 0.003; respectively) and Central Group (p = 0.004; p = 0.003; p = 0.009; respectively) than in Control Group. But the mean change values of HBGS, SFGS, and MPS scores showed no significant differences in participants in the Peripheral Group than in the Central Group (p = 0.254; p = 0.139; p = 0.736; respectively) after 2 weeks of treatment (p > 0.05).

Conclusion

Our study shows that rTMS can be a safe and effective adjuvant therapy for patients with PFP. Preliminary studies have shown that both peripheral and central stimulation can effectively improve facial nerve function, but there is no significant difference in the efficacy of the two sites.

Peripheral Repetitive Transcranial Magnetic Stimulation(rTMS) for Idiopathic Facial Nerve Palsy: A Prospective, Randomized Controlled Trial

Purpose

The purpose of this study was to evaluate the clinical efficacy of peripheral repetitive transcranial magnetic stimulation (rTMS) in the treatment of idiopathic facial paralysis, to explore an ideal treatment scheme for idiopathic facial paralysis, and to provide evidence for clinical rehabilitation.

Methods

65 patients with idiopathic facial nerve palsy with the first onset were recruited and randomly divided into rTMS group and control group. Both groups received conventional treatment, rTMS group received additional repetitive transcranial magnetic stimulation to the affected side once a day, 5 times a week for 2 weeks. House-Brackmann (HB) grading scale, Sunnybrook facial grading system (SFGS), and modified Portmann scale (MPS) were used to assess facial nerve function before and after treatment, and the time for patients to return to normal facial nerve function and adverse reaction (AR) was also the main observation index.

Results

After a 2-week intervention, HB, SFGS, and MPS increased in both groups (P < 0.01); the improvement of HB, SFGS, and MPS in rTMS group was significantly higher than that in control group (P < 0.01). The effective improvement rate of the TMS group after 2 weeks was 90.0%, and that of the control group was 53.3%, and the difference was statistically significant (P < 0.01).

Conclusions

Repetitive transcranial magnetic stimulation is a safe and effective noninvasive method for the treatment of idiopathic facial paralysis, which can significantly accelerate the recovery of facial nerve function and provide a new treatment idea for further improving the prognosis of patients with idiopathic facial paralysis.

Visual Attention Affects the Amplitude of the Transcranial Magnetic Stimulation-associated Motor-evoked Potential: A Preliminary Study With Clinical Utility

BACKGROUND

The transcranial magnetic stimulation (TMS)-elicited motor-evoked potential (MEP) is a valuable measure for clinical evaluations of various neurological disorders and is used to determine resting motor threshold for repetitive TMS dosing. Although MEP amplitude is primarily associated with motor system function, there is evidence that nonmotor factors may also influence amplitude. This experiment tested the hypotheses that manipulation of 2 factors (visual attention, cognitive regulation) in human participants would significantly affect MEP amplitude.

METHODS

Blocks of MEPs were recorded from the dominant right hand as participants (N=20) were instructed to shift their visual attention (toward and away from the hand) and cognitively regulate the MEPs (rest, attenuate MEP amplitude, potentiate MEP amplitude) using their thoughts (6 blocks, 20 pulses/block, randomized, 110% resting motor threshold).

RESULTS

MEP amplitude was significantly affected by the direction of visual attention; looking away from the hand led to higher amplitudes (P=0.003). The relationship with cognitive regulation was nonsignificant.

CONCLUSIONS

The significant effect of visual attention on MEP suggests that this should be a standardized parameter in clinical and research studies. These data underscore the importance of rigorous reporting of methods and use of standardized practices for MEP acquisition and TMS dosing to ensure consistent clinical measurement and treatment.

Canalicular magnetic stimulation lacks specificity to differentiate idiopathic facial palsy from borreliosis in children

OBJECTIVE

To investigate the role of transcranial magnetic stimulation (TMS) to differentiate between idiopathic facial nerve palsy (iFNP) and facial nerve palsy due to borreliosis (bFNP).

PATIENTS AND METHODS

Transcranial and intracanalicular magnetic and peripheral electrical stimulation of the facial nerve together with clinical grading according to the House and Brackmann scale were performed in 14 children and adolescents with facial palsy (median age 11.5 yr, range 4.6-16.5 yr). Serum and cerebrospinal fluid (CSF) were evaluated for antibodies against Borrelia burgdorferi and CSF cell count, glucose and protein content were screened with methods of routine laboratory testing. Data of patients were compared with normal values established in 10 healthy subjects (median age 10.2 yr, range 5.1-15.3 yr).

RESULTS

Patients with iFNP showed a significant decrease in MEP amplitude to canalicular magnetic stimulation compared with healthy controls (p=0.03). However, MEP amplitude did not discriminate sufficiently between the two groups, because the ranges of dispersion of MEP amplitudes overlapped. Patients with bFNP had normal MEP amplitudes to canalicular magnetic stimulation compared with normal subjects.

CONCLUSION

Diagnostic assessment by TMS failed to provide a reliable diagnostic criterion for distinguishing between iFNP and bFNP in children and adolescents.

Management of peripheral facial nerve palsy

Peripheral facial nerve palsy (FNP) may (secondary FNP) or may not have a detectable cause (Bell's palsy). Three quarters of peripheral FNP are primary and one quarter secondary. The most prevalent causes of secondary FNP are systemic viral infections, trauma, surgery, diabetes, local infections, tumor, immunological disorders, or drugs. The diagnosis of FNP relies upon the presence of typical symptoms and signs, blood chemical investigations, cerebro-spinal-fluid-investigations, X-ray of the scull and mastoid, cerebral MRI, or nerve conduction studies. Bell's palsy may be diagnosed after exclusion of all secondary causes, but causes of secondary FNP and Bell's palsy may coexist. Treatment of secondary FNP is based on the therapy of the underlying disorder. Treatment of Bell's palsy is controversial due to the lack of large, randomized, controlled, prospective studies. There are indications that steroids or antiviral agents are beneficial but also studies, which show no beneficial effect. Additional measures include eye protection, physiotherapy, acupuncture, botulinum toxin, or possibly surgery. Prognosis of Bell's palsy is fair with complete recovery in about 80% of the cases, 15% experience some kind of permanent nerve damage and 5% remain with severe sequelae.

Intraoperative facial motor evoked potential monitoring with transcranial electrical stimulation during skull base surgery

OBJECTIVE

To address the limitations of standard electromyography (EMG) facial nerve monitoring techniques by exploring the novel application of multi-pulse transcranial electrical stimulation (mpTES) to myogenic facial motor evoked potential (MEP) monitoring.

METHODS

In 76 patients undergoing skull base surgery, mpTES was delivered through electrodes 1cm anterior to C1 and C2 (M1-M2), C3 and C4 (M3-M4) or C3 or C4 and Cz (M3/M4-Mz), with the anode contralateral to the operative side. Facial MEPs were monitored from the orbicularis oris muscle on the operative side. Distal facial nerve excitation was excluded by the absence of single pulse responses and by onset latency consistent with a central origin.

RESULTS

M3/M4-Mz mpTES (n=50) reliably produced facial MEPs while M1-M2 (n=18) or M3-M4 (n=8) stimulation produced 6 technical failures. Facial MEPs could be successfully monitored in 21 of 22 patients whose proximal facial nerves were inaccessible to direct stimulation. Using 50, 35 and 0% of baseline amplitude criteria, significant facial deficits were predicted with a sensitivity/specificity of 1.00/0.88, 0.91/0.97 and 0.64/1.00, respectively.

CONCLUSIONS

Facial MEPs can provide an ongoing surgeon-independent assessment of facial nerve function and predict facial nerve outcome with sufficiently useful accuracy.

SIGNIFICANCE

This method substantially improves facial nerve monitoring during skull base surgery.

Electrodiagnostic studies in the management and prognosis of neuromuscular disorders

Prognosis remains a neglected aspect of modern medical care and research, behind diagnosis and treatment. The very term "electrodiagnosis" implies as much. Despite this, much has been published regarding the use and benefit of electrodiagnostic techniques in assessing prognosis and assisting in management of patients after the diagnosis has been established. This information is often hidden or otherwise not emphasized. This review summarizes the literature regarding the use of such techniques for prognosis and management of disorders of lower motor neurons, peripheral nerves, neuromuscular transmission, and muscle.

Transcranial magnetic stimulation in neurology

Transcranial magnetic stimulation (TMS) is a non-invasive tool for the electrical stimulation of neural tissue, including cerebral cortex, spinal roots, and cranial and peripheral nerves. TMS can be applied as single pulses of stimulation, pairs of stimuli separated by variable intervals to the same or different brain areas, or as trains of repetitive stimuli at various frequencies. Single stimuli can depolarise neurons and evoke measurable effects. Trains of stimuli (repetitive TMS) can modify excitability of the cerebral cortex at the stimulated site and also at remote areas along functional anatomical connections. TMS might provide novel insights into the pathophysiology of the neural circuitry underlying neurological and psychiatric disorders, be developed into clinically useful diagnostic and prognostic tests, and have therapeutic uses in various diseases. This potential is supported by the available studies, but more work is needed to establish the role of TMS in clinical neurology.

Bell's Palsy and Herpes Zoster Oticus

Normal facial movement is required for chewing, swallowing, speaking, and protecting the eye. Bell's palsy causes most cases of acute, unilateral facial palsy; infection with herpes simplex virus (HSV) type 1 may be its major cause. Varicella zoster virus (VZV) reactivation (Ramsay Hunt syndrome) is less common, but may appear without skin lesions in a form indistinguishable from Bell's palsy. Symptoms improve in nearly all patients with Bell's palsy, and most patients with Ramsay Hunt syndrome, but many are left with functional and cosmetic deficits. Steroids are frequently used to optimize outcomes in Bell's palsy, but proof of their effectiveness is marginal. Oral prednisone has been studied extensively, although some reports have suggested a higher recovery rate with intravenous steroids. Given the existing data, we support the use of oral prednisone in those patients with complete facial palsy, and no contraindications to their use (Fig. 1). In this author's opinion, the greatly increased cost and inconvenience of intravenous steroids cannot be justified by the data available. Antiviral agents may also be effective in treatment of Bell's palsy; HSV is susceptible to acyclovir and related agents. There have been few investigations of acyclovir treatment in Bell's palsy, but one controlled study showed added benefit when the drug was used with prednisone. The risk and cost of acyclovir is low enough that we support its use, with oral steroids, in those patients with complete facial paralysis. Several small studies have implied that oral acyclovir improves the outcome of facial palsy for patients with Ramsay Hunt syndrome. Although these studies do not prove efficacy, evidence for the benefits of antiviral agents in other forms of zoster is strong enough to recommend their use when the facial nerve is involved. VZV is less sensitive to acyclovir than HSV, so higher doses are recommended to treat Ramsay Hunt syndrome. Because some Ramsay Hunt syndrome patients with partial facial palsy do not fully recover, we recommend oral antiviral agents in all patients suspected of having zoster. There is weak evidence to suggest additional benefit of oral steroids in facial zoster, and their use can be supported in immunocompetent individuals. Facial nerve decompression surgery for Bell's palsy and herpes zoster oticus has experienced varying levels of enthusiasm over the years. Recent work implies that early, extensive decompression of the nerve through a middle fossa craniotomy may benefit patients at high risk for persistent deficits. However, until this procedure is subjected to a rigorous, controlled trial comparing it with maximal medical therapy, it is difficult to justify the very high costs and risk.

Paediatric facial paralysis. Current opinion in evaluation and management

Facial palsy in the paediatric age group is less common than in adults, but poses its own problems because clinical diagnosis and investigations are more difficul. i' perform. In recent years, electroneuronography (EnoG) has proved to be useful for prognosis, and in many endemic areas, neuroborreliosis (Lyme'sDisease) has proved to be the commonest cause of this condition in children. Fortunately the prognosis in children appears to be better than in adults.