Effect of an Intensified Combined Electromyography and Visual Feedback Training on Facial Grading in Patients With Post-paralytic Facial Synkinesis

Synchronous surface electromyography as objective method to evaluate the outcome of a biofeedback training in patients with facial synkinesis

Facial aberrant reinnervation after unilateral facial paralysis is characterized by facial synkinesis and global facial muscle hypertonicity. Therefore, therapy effort is directed on improved facial symmetry by reducing facial synkinesis and the elevated muscle tone. There are no established methods to confirm these aims objectively. Therefore the aim of the present study was to verify if high-resolution surface electromyography (HR-sEMG) mapping of the entire face during standardized facial movements is one such sought-after method. Bilateral HR-sEMG facial mapping was performed in 36 patients (81% women; age range: 24-70 years) with a postparalytic facial nerve syndrome. Participants performed a standard set of standardized facial movement tasks before start (T0) and after nine days of training (T9). A linear mixed-effects model was used to evaluate differences between the facial movement tasks in-between the synkinetic side and the contralateral side at T0 and T9. The overall facial muscle activity was higher on the synkinetic side compared to the contralateral side at T0 (p < 0.001) and also at T9, but with reduced difference between sides (p ≤ 0.002). The overall muscle activity decreased on the synkinetic side and on the contralateral side (both p < 0.001). These effects were also verifiable for almost every investigated muscle. HR-sEMG facial mapping proved its suitability as an objective method to confirm facial feedback training effects: A combined visual and EMG-based facial biofeedback training seemed to reduce the facial muscle activity on both facial sides, but markedly more effective on the synkinetic side.

Surface Electromyographic Features for Severity Classification in Facial Palsy: Insights from a German Cohort and Implications for Future Biofeedback Use

Facial palsy (FP) significantly impacts patients' quality of life. The accurate classification of FP severity is crucial for personalized treatment planning. Additionally, electromyographic (EMG)-based biofeedback shows promising results in improving recovery outcomes. This prospective study aims to identify EMG time series features that can both classify FP and facilitate biofeedback. Therefore, it investigated surface EMG in FP patients and healthy controls during three different facial movements. Repeated-measures ANOVAs (rmANOVA) were conducted to examine the effects of MOTION (move/rest), SIDE (healthy/lesioned) and the House-Brackmann score (HB), across 20 distinct EMG parameters. Correlation analysis was performed between HB and the asymmetry index of EMG parameters, complemented by Fisher score calculations to assess feature relevance in distinguishing between HB levels. Overall, 55 subjects (51.2 ± 14.73 years, 35 female) were included in the study. RmANOVAs revealed a highly significant effect of MOTION across almost all movement types (p < 0.001). Integrating the findings from rmANOVA, the correlation analysis and Fisher score analysis, at least 5/20 EMG parameters were determined to be robust indicators for assessing the degree of paresis and guiding biofeedback. This study demonstrates that EMG can reliably determine severity and guide effective biofeedback in FP, and in severe cases. Our findings support the integration of EMG into personalized rehabilitation strategies. However, further studies are mandatory to improve recovery outcomes.

Electromyography as an Objective Outcome Measure for the Therapeutic Effect of Biofeedback Training to Reduce Post-Paralytic Facial Synkinesis

Biofeedback rehabilitation for facial palsy is not yet routinely available for patients. Methods: To improve evidence, the effect of an intensive two-week facial training combining electromyography (EMG) and visual biofeedback training of 30 patients (76.7% female; median age: 48.6 years) with post-paralytic facial synkinesis was objectively evaluated. At the beginning of each training day, EMG amplitudes of both halves of the face were recorded during relaxation using the EMG system that was synchronously used for the EMG biofeedback training. A single-factor analysis of variance was performed for the change over time, and a t-test was used to evaluate the side differences. Results: At the end of the training program, there was a significant decrease in the EMG amplitudes of both halves of the face (synkinetic side: p < 0.001; contralateral side p = 0.003), indicating an improved voluntary muscle relaxation. There was also a significant improvement in Sunnybrook Facial Grading System, Facial Disability Index and Facial Clinimetric Evaluation scores, which were assessed before the start of training and at the end (p < 0.001). Conclusion: Electrophysiological improvements can be objectively measured using surface EMG.

Treatment of acute and chronic facial palsy in children and adolescents: Prognostic factors for the outcomes

INTRODUCTION

Pediatric facial palsy is a rare disease. There is a lack of data on the outcome of peripheral acute facial palsy (AFP) or chronic facial palsy (CFP) in children and adolescents after treatment and on the prognostic factors.

METHODS

A retrospective study was conducted in a university facial nerve center. Clinical data was analyzed for their impact on probability of recovery or functional improvement using univariable and multivariable statistics.

RESULTS

84 F P patients (range: 0-18 years, 35 % AFP, 17.9 % flaccid CFP; 29.8 % synkinetic CFP) treated 2003-2021 were included. All AFP received intravenous prednisolone therapy (PT). 56 % of patients with synkinetic CFP were treated with electromyography biofeedback facial training (EBFT). Facial nerve reconstruction (FNR) was the most common treatment (40 %) for flaccid CFP. 82.8 % of AFP fully recovered. Synkinetic CFP showed improvement in 60 %. 26.7 % of flaccid CFP patients showed improved facial mobility. AFP patients with a Stennert Index (SI) > 6 (p = 0.024), House Brackmann scale (HB) > III (p = 0.034), or PT started more than 96 h after onset had worse outcomes. CFP patients with SI motor function >4 (p = 0.002), total SI > 6 (p = 0.015), HB > III (p = 0.002), or ipsilateral loss of the stapedius reflex (p = 0.021) had a lower probability of improvement.

CONCLUSIONS

PT should ideally begin within 96 h after the onset of AFP in children to maximize recovery chances. The severity of FP is a key prognostic factor for recovery. Like adults, children with synkinetic CFP benefit from EBFT. Guideline-based therapies for adults seem to be also effective for children and adolescents.

Clinical Perspectives on the Pathophysiology of Facial Synkinesis: A Narrative Review

Importance

Facial synkinesis refers to pathologic cocontraction and baseline hypertonicity of muscles innervated by the facial nerve, commonly attributed to the aberrant regeneration of nerve fibers following injury. The pathomechanism and optimal treatment of facial synkinesis remain unclear. The goal of this review is to highlight current understanding of the epidemiology, pathophysiology, clinical presentation, assessment, and treatment of facial synkinesis.

Observations

Research into the epidemiology and risk factors of facial synkinesis is limited due to a lack of large databases tracking patients with facial palsy, inherent selection bias, and the wide range of symptom severity. Misguided nerve regeneration, polyneuronal innervation, and cortical changes are implicated in the development of synkinesis, and a better understanding of these mechanisms is required to develop new treatments. The clinical presentation of facial synkinesis varies considerably among patients, and important prognostic questions regarding timing of onset and progression of symptoms remain incompletely answered. Current management options for facial synkinesis include noninvasive modalities, chemodenervation, myectomy, and selective neurectomy. Potential new treatments for facial synkinesis are being investigated in animal models, but few have been tested in humans.

Conclusions and Relevance

The treatment of facial synkinesis is currently hindered by limitations in clinical research and understanding of pathomechanism. Current studies predominantly yield level 4 evidence or lower. The development of large datasets of patients with facial palsy and the translation of basic science evidence to humans will facilitate the advancement of new treatments.

[Telemedicine for patients with facial palsy : Current developments and options in otorhinolaryngologic treatment]

Digitalization is also becoming increasingly important in medicine. The COVID-19 pandemic has further accelerated this process and politicians are trying to create a framework for successful knowledge transfer and better digital medical care. This article describes the role of telemedicine in the treatment of patients suffering from facial nerve palsy. Facial nerve palsy has a wide range of effects, from limitations in facial mobility to psychological sequelae. While many of the acute, idiopathic facial nerve palsies improve after a few weeks, around a third of those affected develop synkinesis, involuntary movements that have lifelong functional and psychological consequences. Treatment includes various modalities, from medication and surgery to movement training. Telemedicine offers innovative solutions in cases of regional underuse, but also in the treatment of chronic facial nerve palsies. The article defines the term "telemedicine" in the current context and presents different types of application. A detailed analysis of the application scenarios of telemedicine in facial nerve palsy patients shows that despite a lack of evidence, many potentially useful concepts exist.

Facial nerve function training in patients with peripheral facial paralysis: an expert consensus

Facial nerve training can prevent facial expression muscle atrophy and promote the recovery of facial para-lysis in patients with peripheral facial paralysis. However, there is still a lack of specific and unified technical standards for facial nerve training, which results in a variety of clinical training methods and uneven levels. In order to standardize the application of facial nerve function training technology for nursing staff, the study convened relevant domestic experts, based on evidence-based combination with the disease characteristics of peripheral facial paralysis and expert clinical experience, conducted in-depth interviews with experts, expert correspondence and expert meetings, and finally formulated the expert consensus on facial nerve function training in patients with peripheral facial paralysis. Overall, suggestions for standardizing the timing, training methods, evaluation methods, health education and other aspects were provided for clinical reference.

Selective zygomaticus muscle activation by ball electrodes in synkinetically reinnervated patients after facial paralysis

Introduction

Although many different treatments were developed for facial palsy, only a few therapeutic options are available for facial synkinesis. Electrical stimulation of specific muscles via implants could be useful in restoring facial symmetry in synkinetic patients. A challenge in developing stimulation devices is finding the right stimulation location, type, and amplitude. This work assesses the ability to selectively stimulate the zygomaticus muscle (ZYG) in patients with oral-ocular synkinesis to elicit a visually detectable response of the ipsilateral corner of the mouth (COM), without causing a reaction of the orbicularis oculi muscle (OOM). We aimed to assess how close to the COM the stimulation should be delivered in order to be selective.

Methods

A total of 10 patients (eight females, two males) were enrolled. Facial function was graded according to the Sunnybrook facial grading system. Needle EMG was used to test the activities of the muscles, during volitional and "unintended" movements, and the degree of synkinesis of the ZYG and OOM. Two ball electrodes connected to an external stimulator were placed on the paretic ZYG, as close as possible to the COM.

Results

Independent of the waveform with which the stimulation was presented, a selective ZYG response was observed within 4.5 cm of the horizontal plane and 3 cm of the vertical plane of the COM. When the distance between the electrodes was kept to ≤2 cm, the amplitude necessary to trigger a response ranged between 3 and 6 mA when the stimulation was delivered with triangular pulses and between 2.5 and 3.5 mA for rectangular pulses. The required amplitude did not seem to be dependent on the applied phase duration (PD), as long as the PD was ≥5 ms.

Conclusion

Our results show that selective stimulation of the ZYG presenting synkinetic ZYG-OOM reinnervation can be achieved using a broad PD range (25-1,000 ms) and an average amplitude ≤6 mA, which may be further decreased to 3.5 mA if the stimulation is delivered via rectangular rather than triangular waves. The most comfortable and effective results were observed with PDs between 50 and 250 ms, suggesting that this range should be selected in future studies.

Clinical Trial Registration

[https://drks.de/search/de/trial/DRKS00019992], identifier (DRKS00019992).

Minimization of facial synkinesis

PURPOSE OF REVIEW

To summarize the treatment options available for the management of postparalytic facial synkinesis which include facial rehabilitation, chemodenervation, and a spectrum of surgical interventions.

RECENT FINDINGS

Facial rehabilitation and botulinum toxin chemodenervation represent the foundation of facial synkinesis management, with specific treatment paradigms directed by individual patient needs. Evolving surgical approaches range from isolated selective myectomies or neurectomies to combination approaches which may incorporate various types of nerve transfer with gracilis free muscle transplantation.

SUMMARY

Postparalytic facial synkinesis bears significant patient morbidity due to aesthetic and functional implications. Management strategies must balance patient goals with treatment risks and typically progress stepwise from the least to most invasive interventions. Emerging techniques reveal a convergence in approaches to facial reanimation and synkinesis mitigation.

Pathogenesis, diagnosis and therapy of facial synkinesis: A systematic review and clinical practice recommendations by the international head and neck scientific group

Introduction

Post-paralytic facial synkinesis after facial nerve injury produces functional disabilities and mimetic deficits, but also cosmetic and non-motor psychosocial impairments for the patients. These patients typically have a high and continuous high motivation for rehabilitation. The aim is to inform the affected patients and their therapeutic professionals (otorhinolaryngologist - head and neck surgeons; oral-maxillofacial surgeons, plastic and reconstructive surgeons, neurosurgeons, neurologists, and mime therapists be it speech and language therapy- or physiotherapy-based) and to provide practical recommendations for diagnostics and a stepwise systematic treatment approach of facial synkinesis.

Methods

In the first phase, a systematic literature search on the topic in PubMed and ScienceDirect starting in 2008 resulted in 132 articles. These were the basis for the review and a comprehensive series of consensus statements on the most important diagnostic tests and treatment options. In the second phase, one consensus article circulated among the membership of the International Head and Neck Scientific Group until a final agreement was reached for all recommendations.

Results

Diagnostics should include a standardized assessment of the degree of synkinesis using validated clinician-graded instruments and synkinesis-specific patient-reported outcome measures. Treatments for facial synkinesis include facial training mainly based on facial biofeedback retraining, chemodenervation with botulinum toxin, selective neurectomy, myectomy, and any combination treatment of these options.

Conclusion

A basic understanding of the pathomechanisms of synkinesis is essential to understand the treatment strategies. A standardized assessment of the synkinetic symptoms and the individual synkinesis pattern is needed. The first-line treatment is facial training, followed by botulinum toxin. Surgery is reserved for individual cases with unsatisfactory first-line treatment.