Facial Synkinesis Research Articles

Five-year follow-up after neurosurgery complicated by facial neuropathy

Botulinum toxin A (BTA) injections are effective for facial neuropathy. However, there is insufficient number of studies devoted to long-term management of these patients. To evaluate the effectiveness and safety of BTA therapy in patients with facial neuropathy after neurosurgical interventions. The study included 86 patients with facial neuropathy after surgical treatment of posterior cranial fossa and cerebellopontine angle tumors. All ones were divided into 2 groups: group I (main) - 57 patients with BTA prescribed early after facial nerve injury, group II (control) - 29 people undergoing exercise therapy, as well as special exercises and acupressure of painful muscle cords. The Sunnybrook Facial Grading Scale (SFGS) was used to assess facial symmetry and synkinesis, the Facial Disability Index (FDI scale) - to assess the quality of life. Overall duration of the study was 5 years (control points: 6 months, 1, 2, 3 and 5 years). The SFGS scores after 1, 2, 3 and 5 years were significantly better in the main group (resting symmetry p<0.01, voluntary movement symmetry p<0.01, synkinesis p<0.01, general condition of facial muscles p<0.01). Scores of physical and social functioning were significantly higher in the main group after 1 (p<0.01), 2 (p<0.01), 3 (p<0.01) and 5 years (p<0.01) after surgery. There was no need to change BTA dosage over 5 years. Thus, this form of BTA may be the most effective for synkinesis of facial muscles. Correction of synkinesis caused by facial neuropathy requires long-term follow-up and long-term treatment. BTA is effective and may be recommended for long-term treatment of these patients.

Ocular-oral synkinesis caused by partial injury of the zygomatic and buccal branches of the facial nerve after mid-face trauma

BackgroundFacial nerve paralysis induced by acute traumatic facial nerve injuries limited to the zygomatic and buccal branches shows unique complication symptoms, such as strong co-contractions of the lower facial muscles around the lips during voluntary eye blinking (ocular-oral synkinesis). We investigated the characteristics of facial complications after facial nerve injury in the mid-face area and report the treatment results. MethodsA total of 21 patients with facial nerve injuries on the zygomatic and/or buccal branches were evaluated for the degree of facial synkinesis and mouth asymmetry. The patients with mild to moderate symptoms were treated with physical rehabilitation therapy combined with botulinum toxin (Botox) injection, and the patients with severe or uncontrolled symptoms were treated with surgical therapy. ResultsInitial/final mean synkinesis scores and mouth asymmetry degrees were 2.17/1.75 and 0.85/0.66 in the physical therapy group, and 3.11/0.78 and 2.41/-0.31 in the surgery group. Physical therapy with Botox injection alone did not result in significant improvements in synkinetic symptoms of the patients with mild to moderate synkinesis (p>0.05), whereas surgical therapy resulted in significant improvements in both synkinesis and mouth asymmetry (p<0.05). ConclusionsSurgical treatment is an effective adjustment procedure for management of facial complications of severe or uncontrolled synkinesis after facial nerve injury in the mid-face area.

The Impact of Surgical and Nonsurgical Interventions on Overall Oral, Palpebral Fissure, and Brow Height Symmetry in a Patient with Facial Synkinesis

The Impact of Surgical and Nonsurgical Interventions on Overall Oral, Palpebral Fissure, and Brow Height Symmetry in a Patient with Facial Synkinesis

Efficacy of adding selective electrical muscle stimulation to usual physical therapy for Bell's palsy: immediate and six-month outcomes.

Bell's palsy is the most common cause of facial paralysis, affecting one in every 60 people in their lifetime. Transcutaneously applied selective electrical muscle stimulation could potentially accelerate recovery from Bell's palsy but this intervention remains controversial. Studies have shown benefit, but concerns for lack of efficacy and potential for worsening synkinesis remain. We performed a prospective controlled trial comparing outcomes at initial recovery and six months later with selective electrical muscle stimulation and usual physical therapy versus usual physical therapy alone in adults with acute Bell's palsy. Outcomes were facial function assessed with the House Brackman and eFACE scales. Outcomes were evaluated at discharge and six months after discharge. Discharge occurred when participants were judged to be fully recovered by their treating therapist and supervisor. 38 adults participated in the study. Participants in the electrical stimulation group achieved maximal recovery twice as fast as the control group (2.5 weeks versus 5.2 weeks) with no significant differences in facial function or synkinesis between groups at any time point. This study is the first human trial of electrical stimulation in Bell's palsy to follow patients 6 months from recovery and supports that selective electrical muscle stimulation accelerates recovery and does not increase synkinesis.

Exploration of rich-club reorganization in facial synkinesis: insights from structural and functional brain network analysis.

Facial palsy therapies based on cortical plasticity are in development, but facial synkinesis progress is limited. Studying neural plasticity characteristics, especially network organization and its constitutive elements (nodes/edges), is the key to overcome the bottleneck. We studied 55 participants (33 facial synkinesis patients, 22 healthy controls) with clinical assessments, functional magnetic resonance imaging (fMRI), and diffusion tensor imaging (DTI). We analyzed rich-club organization and metrics of structural brain networks (rich-club coefficients, strength, degree, density, and efficiency). Functional brain network metrics, including functional connectivity and its coupling with the structural network, were also computed. Patients displayed reduced strength and density of rich-club nodes and edges, as well as decreased global efficiency. All nodes exhibited decreased nodal efficiency in patients. Patients had significantly increased functional connectivity and decreased structural-functional coupling strength in rich-club nodes, rich-club edges, and feeder edges. Our study indicates that facial synkinesis patients have weakened structural connections but enhanced functional transmission from rich-club nodes. The loss of connections and efficiency in structural network may trigger compensatory increases in functional connectivity of rich-club nodes. Two potential biomarkers, rich-club edge density and structural-functional coupling strength, may serve as indicators of disease outcome. These findings provide valuable insights into synkinesis mechanisms and offer potential targets for cortical intervention.

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

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

How to Enhance the Success of Selective Neurectomy for Facial Synkinesis by Considering the Patient's Preferences: Lesson Learned from a Retrospective Analysis of 122 Cases.

Facial synkinesis can result in facial tightness, smile dysfunction, and eyelid aperture narrowing due to overactive and uncoordinated muscle activity. We hypothesized that the outcome of a selective neurectomy could rely on the patient's chief complaints. We retrospectively reviewed 122 patients who underwent selective neurectomy at our hospital. Preoperatively, the patients were asked nine questionnaires to identify their two major chief complaints (treatment priorities). Postoperatively, facial tightness, limited mouth movement, and eyelid aperture narrowing were measured. The most common chief complaints in our series were facial tightness (n=38), eyelid narrowing (n=32), and limited mouth movement (n=28); the second most common chief complaints (second priority) were limited mouth movement (n=47), facial tightness (n=21), and eyelid narrowing (n=20). The mean score for facial tightness significantly improved from 4.3 to 1.1 in the first priority group. Among the 28 patients whose corners of the mouth constituted the top priority of surgical correction, the vertical inclination on the affected side significantly improved from 74.1 ± 7.6° to 55.5 ± 6.0°, and the horizontal angles were changed from 4.2 ± 2.7° to 2.0 ± 1.3° after selective neurectomy without statistically significant. Among the 32 patients for whom eyelid narrowing constituted the top priority, the mean eyelid narrowing score improved from 4.5 ± 1.1 to 1.5 ± 1.2. Selective neurectomy can provide a significantly satisfactory outcome regarding facial tightness and eyelid aperture narrowing. The vertical inclination of the mouth corner can be significantly improved, while the improvement of horizontal angles can be suboptimal. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Predicting synkinesis caused by Bell's palsy or Ramsay Hunt syndrome using machine learning-based logistic regression.

To investigate whether machine learning (ML)-based algorithms, namely logistic regression (LR), random forest (RF), k-nearest neighbor (k-NN), and gradient-boosting decision tree (GBDT), utilizing early post-onset parameters can predict facial synkinesis resulting from Bell's palsy or Ramsay Hunt syndrome more accurately than the conventional statistics-based LR. This retrospective study included 362 patients who presented to a facial palsy outpatient clinic. Median follow-up of synkinesis-positive and -negative patients was 388 (range, 177-1922) and 198 (range, 190-3021) days, respectively. Electrophysiological examinations were performed, and the rate of synkinesis in Bell's palsy and Ramsay Hunt syndrome was evaluated. Sensitivity and specificity were assessed using statistics-based LR; and electroneurography (ENoG) value, the difference in the nerve excitability test (NET), and scores of the subjective Yanagihara scaling system were evaluated using early post-onset parameters with ML-based LR, RF, k-NN, and GBDT. Synkinesis rate in Bell's palsy and Ramsay Hunt syndrome was 20.2% (53/262) and 40.0% (40/100), respectively. Sensitivity and specificity obtained with statistics-based LR were 0.796 and 0.806, respectively, and the area under the receiver operating characteristic curve (AUC) was 0.87. AUCs measured using ML-based LR of "ENoG," "difference in NET," "Yanagihara," and all three components ("all") were 0.910, 0.834, 0.711, and 0.901, respectively. ML-based LR model shows potential in predicting facial synkinesis probability resulting from Bell's palsy or Ramsay Hunt syndrome and has comparable reliability to the conventional statistics-based LR. 3.

Different Cortical Activation of Facial Synkinesis Patients with Different Course of Disease: A Task fMRI Study.

Facial synkinesis is a disease characterized by unintentional activation of facial muscles, which causes that the patients cannot control their facial expressions independently. Previous studies have shown that its pathogenesis is related to the reorganization of cerebral cortex, but it remains unclear what brain changes the patients have at different stage of the disease. For this study, we recruited 30 patients with facial synkinesis and 19 healthy control subjects from Shanghai Huashan Hospital. All participants completed bilateral blinking and grinning tasks while functional magnetic resonance imaging (fMRI) data was collected. We measured the brain activation strength of each task and observed the activation similarity of the ipsilateral tasks. Then we explored the correlation between activation pattern and clinical scale. Results showed different activation pattern along the courses of disease for blinking and grinning task, which may be due to the inconsistent process of cortical reorganization. The late stage group activated more in blinking task, but the least in grinning tasks, especially on the affected side (p<0.001 at voxel level, p<0.05 at cluster level, FWE corrected). Compared with healthy controls, the activation of patients between tasks on the affected side is more similar(p<0.05). There was a negative correlation in right postcentral gyrus between activation similarity and scale scores (symmetry of voluntary movement scores: R = -0.469, p = 0.009). This could be attributed to the rearrangement of the nervous system following facial nerve injury, leading to incorrect connections between nerves and muscles. Our study may be helpful for understanding mechanism of facial synkinesis and provide basis for the stage-dependent diagnosis and treatment.

Measuring the Potential Effects of Mirror Therapy Added to the Gold Standard Facial Neuromuscular Retraining in Patients With Chronic Peripheral Facial Palsy: Protocol for a Randomized Controlled Trial.

Facial neuromuscular retraining (fNMR) is a noninvasive physical therapy widely used to treat peripheral facial palsies. It consists of different intervention methods that aim to reduce the debilitating sequelae of the disease. Recently, the use of mirror therapy in the acute facial palsy and postsurgical rehabilitation contexts has shown promising results, suggesting its use as an adjunct to fNMR in treating patients with later stages of paralysis, such as the paretic, early, or chronic synkinetic. The main aim of this study is to compare the efficacy of an added mirror therapy component with fNMR in patients with peripheral facial palsy (PFP) sequelae in 3 different stages. The specific objectives of this study are to measure the effects of combined therapy compared to fNMR alone on (1) participants' facial symmetry and synkinesis, (2) quality of life and psychological aspects of the participants, (3) motivation and treatment adherence, and (4) different stages of facial palsies. This study is a randomized controlled trial that compares the effect of fNMR combined with mirror therapy (experimental group: n=45) with fNMR alone (control group: n=45) in 90 patients with peripheral facial palsy presenting with sequelae 3-12 months after onset. Both groups will receive 6 months of rehabilitation training. Facial symmetry and synkinesis; participants' quality of life; and their psychological factors, motivation, and compliance will be assessed at baseline (T0), 3 months (T1), 6 months (T2), and 12 months (T3) postintervention. Outcome measures are (1) changes in facial symmetry and synkinesis assessed with facial grading tools, (2) quality of life changes with patient questionnaires, and (3) therapy motivation with a standardized scale, as well as adherence to treatment with metadata. Changes in facial symmetry and synkinesis will be judged by 3 assessors blinded to group assignment. Mixed models and Kruskal-Wallis, chi-square, and multilevel analyses will be conducted according to the appropriate variable type. Inclusion will start in 2024 and is anticipated to be completed in 2027. The 12-month follow-up will be completed with the last patient in 2028. We expect patients included in this study to experience improvement in facial symmetry, synkinesis, and quality of life, regardless of group assignments. A potential benefit of mirror therapy for facial symmetry and synkinesis could be noted for patients in the paretic phase. We hypothesize better motivation and adherence to treatment for the mirror therapy group. The results of this trial may provide new guidelines for PFP rehabilitation with patients dealing with long-term sequelae. It also fills the need for robust evidence-based data in behavioral facial rehabilitation. PRR1-10.2196/47709.

The Facial Clinimetric Evaluation scale underestimates social well-being and synkinesis in overall facial palsy-specific quality of life: A cross-sectional study in 80 patients.

The Facial Clinimetric Evaluation scale underestimates social well-being and synkinesis in overall facial palsy-specific quality of life: A cross-sectional study in 80 patients.

Neuromuscular retraining therapy combined with preceding botulinum toxin A injection for chronic facial paralysis

Background Neuromuscular retraining therapy (NMRT) is the central treatment for synkinesis. The efficacy of botulinum toxin type A (BTX-A) may be enhanced with the addition of physical therapy. Objectives To investigate the effects of NMRT combined with preceding BTX-A injection (NMRT-B) on facial synkinesis and asymmetry in chronic facial paralysis. Materials and Methods We recruited 99 patients with unilateral facial paralysis and no recovery for > 6 months who underwent NMRT-B for > 1 year. The patients were scheduled to receive NMRT after 1–2 weeks of BTX-A injection. We used a computer-based numerical scoring system to evaluate the facial functions. Primary, secondary, and final facial movement scores were evaluated before and after 1 year of treatment. Results Patients with chronic facial paralysis who underwent NMRT-B exhibited improved facial movement after 1 year of treatment. NMRT-B provided satisfactory control of synkinesis and improved the primary movements. The mean primary and final facial movement scores were significantly increased after treatment, while the mean secondary facial movement scores were significantly decreased. Conclusions and significance NMRT-B improved the final facial movement in patients with chronic facial paralysis and synkinesis, regardless of the degrees of facial synkinesis and asymmetry before treatment.

Neuromuscular retraining therapy for early stage severe Bell's palsy patients minimizes facial synkinesis.

To explore whether early physical interventions, including neuromuscular retraining therapy, can minimize excessive movement or any unwanted co-contraction after a severe Bell's palsy. From March 2021 to August 2022, the therapist treated Bell's palsy patients for the acute (<3 months, Group A), subacute (3-6 months, Group B) and chronic (> 6 months, Group C) stages of the condition. We explored whether early physical interventions, including neuromuscular retraining therapy, can minimize facial synkinesis after a severe episode of Bell's palsy. Each patient was informed about the potential for synkinesis and the therapist explained that the main purpose of neuromuscular retraining therapy is to learn new patterns to minimize synkinesis. The facial function of Group A was compared to that of Groups B and C using the 'Synkinesis' scale of the Sunnybrook Facial Grading System. The final facial function score after neuromuscular retraining therapy was significantly associated with both the initial electroneuronographic degeneration rate and initial facial function. Early therapy did not prevent synkinetic movement in 84.7% of the patients. But, there was a significant difference between patients who started early neuromuscular retraining therapy and other groups in final facial function. Synkinesis in Bell's palsy patients can be minimized if physiotherapy commences before synkinesis develops; appropriate neuromuscular retraining therapy timing is essential. A patient with sudden severe Bell's palsy should receive oral steroids as soon as possible, along with physical therapy (including neuromuscular retraining therapy) within 3 months, to minimize synkinesis just before synkinesis onset.

Objectifying the Role of the Depressor Anguli Oris Muscle Using High-Resolution Ultrasound: A Prospective Study.

In the setting of facial palsy, synkinesis of the depressor anguli oris (DAO) muscle is a common pathology, impairing dynamic and resting facial symmetry.In this prospective study, the authors used high-resolution ultrasound (HRUS) to evaluate the morphologic features of DAO and to quantify bilateral differences in DAO cross-sectional diameter (CSD) in individuals with unilateral synkinesis. From June of 2020 to May of 2021, 30 patients (19 women, 11 men) with clinically diagnosed unilateral synkinesis underwent evaluation with HRUS. DAO CSD was measured bilaterally, 1 cm inferior to the modiolus, in both the resting and smiling positions. The Sunnybrook Facial Grading System Synkinesis Score was 6.20 ± 2.48 (range, 0 to 10). DAO CSD at rest measured 2.41 ± 0.67 mm (range, 1.40 to 4.00 mm) on the control side and 2.66 ± 0.98 mm (range, 1.60 to 5.10 mm) on the affected side. On the control side, DAO CSD was reduced by -0.19 ± 0.43 mm (range, -1.10 to 1.12 mm) during smiling. In contrast, the synkinetic DAO CSD increased by 0.64 ± 0.38 mm (range, 0.00 to 1.59 mm) ( P < 0.001) with animation. The pattern of increased CSD in synkinetic DAO muscles and decreased or unchanged CSD on the control side during smiling was identified in 70% of patients. HRUS demonstrates increased CSD in synkinetic DAO muscles during active smiling. The opposite is true for DAO muscles on the control side, which exhibit decreased CSD with animation. HRUS can be performed preoperatively to objectify DAO dysfunction and guide targeted therapy. Diagnostic, IV.

Machine-Learning-Based Detecting of Eyelid Closure and Smiling Using Surface Electromyography of Auricular Muscles in Patients with Postparalytic Facial Synkinesis: A Feasibility Study.

Surface electromyography (EMG) allows reliable detection of muscle activity in all nine intrinsic and extrinsic ear muscles during facial muscle movements. The ear muscles are affected by synkinetic EMG activity in patients with postparalytic facial synkinesis (PFS). The aim of the present work was to establish a machine-learning-based algorithm to detect eyelid closure and smiling in patients with PFS by recording sEMG using surface electromyography of the auricular muscles. Sixteen patients (10 female, 6 male) with PFS were included. EMG acquisition of the anterior auricular muscle, superior auricular muscle, posterior auricular muscle, tragicus muscle, orbicularis oculi muscle, and orbicularis oris muscle was performed on both sides of the face during standardized eye closure and smiling tasks. Machine-learning EMG classification with a support vector machine allowed for the reliable detection of eye closure or smiling from the ear muscle recordings with clear distinction to other mimic expressions. These results show that the EMG of the auricular muscles in patients with PFS may contain enough information to detect facial expressions to trigger a future implant in a closed-loop system for electrostimulation to improve insufficient eye closure and smiling in patients with PFS.

Secretome of Mesenchymal Stromal Cells as a Possible Innovative Therapeutic Tool in Facial Nerve Injury Treatment.

Facial nerve palsy is a serious neurological condition that strongly affects patient everyday life. Standard treatments provide insufficient improvement and are burdened with the risk of severe complications, e.g., facial synkinesis. Mesenchymal stromal cell-based therapies are a novel and extensively developed field which offers new treatment approaches with promising results in regards to the nervous tissue regeneration. The potential of mesenchymal stromal cells (MSCs) to aid the regeneration of damaged nerves has been demonstrated in several preclinical models, as well as in several clinical trials. However, therapies based on cell transplantation are difficult to standardize in the manner similar to that of routine clinical practices. On the other hand, treatments based on mesenchymal stromal cell secretome harness the proregenerative features of mesenchymal stromal cells but relay on a product with measurable parameters that can be put through standardization procedures and deliver a fully controllable end-product. Utilization of mesenchymal stromal cell secretome allows the controlled dosage and standardization of the components to maximize the therapeutic potential and ensure safety of the end-product.

Myomodulation with Facial Fillers: A Comprehensive Technical Guide and Retrospective Case Series

BackgroundPlacement of fillers in close proximity to the mimetic or sphincter muscles of the face appears to enhance or suppress muscle action in a relatively predictable way.MethodsFrom June 2016 to June 2021, patients who underwent the first author’s technique of myomodulation with dermal fillers to address aesthetic concerns or to manage facial spasms or synkinesis were evaluated in a retrospective case series. Additionally, the authors provide a technical guide for a whole-face approach to treatment with fillers and a conceptual map for treatment of each facial subunit with a focus on myomodulation.ResultsA total of 1352 patients (1108 women, 244 men; mean age, 51 years) underwent at least 1 treatment session during the 5-year study period. The treatment patterns of the study population and details of 2 representative cases are presented.ConclusionsAlthough not well understood mechanistically, myomodulation with injectable fillers shows promise for significant and reliable results of facial rejuvenation.Level of Evidence IVThis journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Synkinesis in patients with neuropathy of the facial nerve

Facial synkinesis is involuntary contractions of unrelated groups of facial muscles that occur during voluntary movement. The article presents a review of scientific literature of the problem pathological synkinesis as a complication of facial neuropathy. The mechanism of their development and the main theories of occurrence are described. We describе the types (patterns) of synkinesis, methods for theirs detecting, description of clinical manifestations, methods of instrumental diagnostics. We reviewed approaches to treatment and rehabilitation, the main types of conservative and surgical treatment.

A Surgeon's Armamentarium for Ocular Management in Facial Paralysis: A Comprehensive Review.

To review the current management paradigm of the eye in patients with facial paralysis. A PubMed and Cochrane search was done with no date restrictions for English-language literature on facial synkinesis. The search terms used were "ocular," "facial," "synkinesis," "palsy," "neurotization," and various combinations of the terms. A total of 65 articles were included. Facial paralysis may result in devastating ocular sequelae. Therefore, assessment of the eye in facial paralysis is a critical component of patient management. Although the management should be individualized to the patient, the primary objective should include an ophthalmologic evaluation to implement measures to protect the ocular surface and preserve visual acuity. The degree of facial paralysis, lacrimal secretion, corneal sensation, and position of the eyelids should be assessed thoroughly. Patients with the anticipated recovery of facial nerve function may respond to more conservative temporizing measures to protect the ocular surface. Conversely, patients with expected prolonged paralysis should be appropriately identified as they will benefit from surgical reconstruction and rehabilitation of the periorbital complex. The majority of reconstructive measures within a facial surgeon's armamentarium augment coverage of the eye but are unable to restore blink. Eyelid reanimation restores the esthetic proportionality of the eye with blinking and reestablishes protective functions necessary for ocular preservation and function. Ocular preservation is the primary priority in the initial management of the patient with facial paralysis. An accurate assessment is a critical component in identifying the type of paralysis and developing an individualized treatment plan.

Exploratory Study of the Brain Response in Facial Synkinesis after Bell Palsy with Systematic Review and Meta-analysis of the Literature.

Facial synkinesis, characterized by unintentional facial movements paired with intentional movements, is a debilitating sequela of Bell palsy. Our aim was to determine whether persistent peripheral nerve changes arising from Bell palsy result in persistent altered brain function in motor pathways in synkinesis. A literature search using terms related to facial paralysis, Bell palsy, synkinesis, and fMRI through May 2021 was conducted in MEDLINE and EMBASE. Additionally, an fMRI study examined lip and eyeblink movements in 2 groups: individuals who fully recovered following Bell palsy and individuals who developed synkinesis. Task-based data of the whole brain that required lip movements in healthy controls were extracted from 7 publications. Three studies contributed similar whole-brain analyses in acute Bell palsy. The meta-analysis of fMRI in healthy control and Bell palsy groups determined common clusters of activation within each group using activation likelihood estimates. A separate fMRI study used multivariate general linear modeling to identify changes associated with synkinesis in smiling and blinking tasks. A region of the precentral gyrus contralateral to the paretic side of the face was hypoactive in synkinesis during lip movements compared with controls. This region was centered in a cluster of activation identified in the meta-analysis of the healthy controls but absent from individuals with Bell palsy. The meta-analysis relied on a small set of studies. The small sample of subjects with synkinesis limited the power of the fMRI analysis. Premotor pathways show persistent functional changes in synkinesis first identifiable in acute Bell palsy.