Selective Facial Muscle Activation with Acute and Chronic Multichannel Cuff Electrode Implantation in a Feline Model.

OBJECTIVES: Facial paralysis is a debilitating condition with substantial functional and psychological consequences. This feline-model study evaluates whether facial muscles can be selectively activated in acute and chronic implantation of 16-channel multichannel cuff electrodes (MCE). METHODS: Two cats underwent acute terminal MCE implantation experiments, 2 underwent chronic MCE implantation in uninjured facial nerves (FN) and tested for 6 months, and 2 underwent chronic MCE implantation experiments after FN transection injury and tested for 3 months. The MCE were wrapped around the main trunk of the skeletonized FN, and data collection consisted of EMG thresholds, amplitudes, and selectivity of muscle activation. RESULTS: In acute experimentation, activation of specific channels (ie, channels 1-3 and 6-8) resulted in selective activation of orbicularis oculi, whereas activation of other channels (ie, channels 4, 5, or 8) led to selective activation of levator auris longus with higher EMG amplitudes. MCE implantation yielded stable and selective facial muscle activation EMG thresholds and amplitudes up to a 5-month period. Modest selective muscle activation was furthermore obtained after a complete transection-reapproximating nerve injury after a 3-month recovery period and implantation reoperation. Chronic implantation of MCE did not lead to fibrosis on histology. Field steering was achieved to activate distinct facial muscles by sending simultaneous subthreshold currents to multiple channels, thus theoretically protecting against nerve damage from chronic electrical stimulation. CONCLUSION: Our proof-of-concept results show the ability of an MCE, supplemented with field steering, to provide a degree of selective facial muscle stimulation in a feline model, even following nerve regeneration after FN injury. LEVEL OF EVIDENCE: N/A.

Timing of Acupuncture Treatment in Peripheral Facial Paralysis: A Systematic Review and Meta-Analysis.

OBJECTIVE: Investigate the optimum time of acupuncture treatment in peripheral facial paralysis in order to provide evidence for clinical treatment. METHODS: CNKI, Wanfang, PubMed, Cochrane Library, and EMBASE databases were systematically searched from the inception dates to February 20, 2020. Studies limited to participants with acute peripheral facial paralysis treated with acupuncture and patients without information of the stage were excluded. The primary outcomes were effective rate and cure rate (based on facial nerve function scores). This meta-analysis is registered with PROSPERO, number CRD42020169870. RESULTS: 15 randomized controlled trials that enrolled 2847 participants met the selection criteria. There was no significant differences in the effective rate (RR, 1.22; 95% CI, 0.70-2.11) when comparing acupuncture to prednisone therapy in acute facial paralysis. Acupuncture treatment in the acute stage increased both the effective rate (RR, 1.03; 95% CI, 1.00-1.07) and the cure rate (RR, 1.34; 95% CI, 1.14-1.58) compared to that in the nonacute stage. CONCLUSIONS: In this meta-analysis, acupuncture showed a better effect in the acute stage than the nonacute stage for participants with peripheral facial paralysis. There was no statistical difference in the effective rate no matter the choice of acupuncture or prednisone therapies in the acute stage. These findings encourage early acupuncture treatment in peripheral facial paralysis.

Observation on the Clinical Effect of Acupuncture and Moxibustion Combined with Repeated Transcranial Magnetic Stimulation on Facial Paralysis.

In view of the difficulty in the treatment of facial paralysis and the poor effect of traditional methods, this paper proposes a strategy based on acupuncture and repeated transcranial magnetic stimulation. The three groups of patients were tested for efficacy using the H-B scale and the symptom characteristics and physical signs measurement scale. Acupuncture combined with repetitive transcranial magnetic stimulation can improve the clinical efficacy of facial paralysis. And it is significantly better than traditional paralysis and repetitive translational magnetic stimulation in the degree of healing.

The research for the function evaluation of facial nerve and the mechanisms of rehabilitation training.

BACKGROUND: Peripheral facial paralysis (PFP) is a common peripheral neural disease. Acupuncture treatment combined with PFP rehabilitation exercises is a routine method of PFP treatment. This article is to provide a new visual and objective evaluation method for exploring the mechanism and efficacy of acupuncture treatment on PFP, and develop an interactive augmented facial nerve function rehabilitation training system with multiple training models. METHODS: This prospective and observational trial will recruit 200 eligible participants for the following study. In the trial, the laser speckle contrast analysis (LASCA) technology will be applied to monitor the microcirculation of facial blood flow during acupuncture, and real-time monitoring algorithms, data sampling, and digital imaging methods will be conducted by machine learning and image segmentation. Then, a database of patient facial expressions will be built, the correlation between surface blood flow perfusion volume and facial structure symmetry will be analyzed, combined with scale assessment and electrophysiological detection. In addition, we will also explore the objectivity and effectiveness of LASCA in the evaluation of facial paralysis (FP), and the changes in blood flow microcirculation before and after acupuncture treatment will be analyzed. RESULTS: The standard image of the facial target area with facial nerve injury will be manually segmented by the convolutional neural network method. The blood flow images of the eyelid, cheek, and mandible of the patients' affected and healthy side will be compared and evaluated. Laser speckle blood flow symmetry Pr and its changes in FP condition evolution and prognosis outcome will be measured, and relevant characteristic signals values will be extracted. Finally, COX regression analysis method is conducted to establish a higher accuracy prediction model of FP with cross-validation based on laser speckle blood flow imaging technology. CONCLUSIONS: We use modern interdisciplinary high-tech technologies to explore the mechanism of acupuncture rehabilitation training in PFP. And we will provide evidence for the feasibility of using the LASCA technique as a typing diagnosis of FP in the acupuncture rehabilitation treatment of PFP. REGISTRATION NUMBER: ChiCTR1800019463.

Surface electrical stimulation for facial paralysis is not harmful.

INTRODUCTION: Does electrical stimulation (ES) of denervated muscles delay or prevent reinnervation, or increase synkinesis? In this retrospective study we evaluate the outcome, with and without ES, of patients with acutely denervated facial muscles. METHODS: The effect of ES was analyzed in two experiments. In the first experiment, 39 patients (6 with home-based ES, median 17.5 months) underwent facial nerve reconstruction surgery. Time to recovery of volitional movements was analyzed. The second experiment involved 13 patients (7 with ES, median 19 months) during spontaneous reinnervation. Sunnybrook and eFACE scores provided functional outcome measures. RESULTS: No difference in time of reinnervation after facial nerve reconstruction surgery was seen between the patients with and without ES (median [interquartile range]: 4.5 [3.0-5.25] vs 5.7 [3.5-9.5] months; P = .2). After spontaneous reinnervation, less synkinesis was noted (Sunnybrook synkinesis score: 3.0 [2.0-3.0] vs 5.5 [4.75-7.0]; P = .02) with ES. DISCUSSION: We find no evidence that ES prevents or delays reinnervation or increases synkinesis in facial paralysis.

Give me a kiss! An integrative rehabilitative training program with motor imagery and mirror therapy for recovery of facial palsy.

BACKGROUND: Peripheral facial nerve palsy (FNP) can have various causes, such as Bell's palsy or after surgery for acoustic neuroma. Rehabilitation is often required but there is no evidence that any rehabilitation approach is more efficacious than another. AIM: The purpose of this research was to determine the effects of neurocognitive-rehabilitative approach through mirror-therapy (MT) and motor-imagery (MI), integrated into the traditional rehabilitation with mime-therapy and myofascial-approach. DESIGN: This study was designed as a double-blind, randomized, controlled trial. SETTING: This study took place from January 2016 to June 2018 at the Unit of Physical Medicine and Rehabilitation of Umberto I Polyclinic Hospital, Rome, Italy. POPULATION: Twenty-two patients were randomized into two groups: the mirror therapy group (N.=11, MT and MI) and the traditional rehabilitation group (N.=11, mime-therapy and a myofascial-approach). METHODS: Outcome assessments were performed before treatment (T0), after one month (T1=10 session, twice/week), after the second and third months (T2=10 twice/week + 5 of MT+MI one/week and T3=10 twice/week + 5 of MT+MI 1/week), and at the 4-week follow-up (T4=2 months follow-up). RESULTS: The analysis of the functional evaluations show that both groups experienced progressive improvement T0 to T3, with stabilization of the results at the follow-up. There was a significant difference in House-Brackmann-Scale scores between T0 and follow-up in favor of the experimental group. In terms of quality of life (FaCE scale), total scores and social function items improved in both groups from T0 to T3. The experimental group obtained better results with regard to quality of life and emotional depression. CONCLUSIONS: The integrated use of MT and MI is efficacious in the rehabilitation of FNP, improving facial physical function. Further studies are needed to determine the predictive factors of the recovery of facial mimic. CLINICAL REHABILITATION IMPACT: The ability of patients with unilateral facial paralysis to recognize and appropriately judge facial expressions and perceive the judgments of others remains underexplored. The likelihood of recovering near-normal facial-function after grade VI facial paralysis is low. Procedures, such as the immediate repair of the facial nerve with an interposed donor graft, might improve facial function in patients with partially injured facial nerves.

Altered facial muscle innervation pattern in patients with postparetic facial synkinesis.

OBJECTIVES/HYPOTHESIS: Using surface electrostimulation, we aimed to use facial nerve mapping (FNM) in healthy subjects and patients with postparetic facial synkinesis (PPFS) to define functional facial target regions that can be stimulated selectively. STUDY DESIGN: Single-center prospective cohort study. METHODS: FNM was performed bilaterally in 20 healthy subjects and 20 patients with PPFS. Single-pulse surface FNM started at the main trunk of the facial nerve and followed the peripheral branches in a distal direction. Stimulation started with 0.1 mA and increased in 0.1 mA increments. The procedure was simultaneously video recorded and evaluated offline. RESULTS: A total of 1,873 spots were stimulated, and 1,875 facial movements were evaluated. The stimulation threshold was higher on the PPFS side (average = 9.8 ± 1.0 mA) compared to the contralateral side (4.1 ± 0.8 mA) for all stimulation sites or compared to healthy subjects (4.1 ± 0.5 mA; all P < .01). In healthy subjects, selective electrostimulation ± one unintended coactivation was possible at all sites in >80% of cases, with the exception of pulling up the corner of the mouth (65%-75%). On the PPFS side, stimulation was possible for puckering lips movements in 60%/75% (selective stimulation ± one coactivation, respectively), blinking in 55%/80%, pulling up the corner of the mouth in 50%/85%, brow raising in 5%/85, and raising the chin in 0%/35% of patients, respectively. CONCLUSIONS: FNM mapping for surgical planning and selective electrostimulation of functional facial regions is possible even in patients with PPFS. FNM may be a tool for patient-specific evaluation and placement of electrodes to stimulate the correct nerve branches in future bionic devices (e.g., for a bionic eye blink). LEVEL OF EVIDENCE: 2b Laryngoscope, 130:E320-E326, 2020.

Facial muscle reanimation by transcutaneous electrical stimulation for peripheral facial nerve palsy.

Reanimation of paralysed facial muscles by electrical stimulation has been studied extensively in animal models, but human studies in this field are largely lacking. Twenty-four subjects with a peripheral facial nerve palsy with a median duration of three years were enrolled. We studied activations of four facial muscles with electrical stimulation using surface electrodes. In subjects whose voluntary movement was severely impaired or completely absent, the electrical stimulation produced a movement that was greater in amplitude compared with the voluntary effort in 10 out of 18 subjects in the frontalis muscle, in 5 out of 14 subjects in the zygomaticus major muscle, and in 3 out of 8 subjects in the orbicularis oris muscle. The electrical stimulation produced a stronger blink in 8 subjects out of 22 compared with their spontaneous blinks. The stimulation could produce a better movement even in cases where the muscles were clinically completely paretic, sometimes also in palsies that were several years old, provided that the muscle was not totally denervated. Restoring the function of paralysed facial muscles by electrical stimulation has potential as a therapeutic option in cases where the muscle is clinically paretic but has reinnervation.

Effects of laser acupuncture in a patient with a 12-year history of facial paralysis: A case report.

Background: Traumatic facial palsy, whether accidental or iatrogenic, is a common cause of facial paralysis. Laser acupuncture therapy (LAT) is a non-invasive, pain-free method to stimulate traditional acupuncture points with non-thermal laser irradiation. Low-level laser therapy has proven beneficial in the regeneration of peripheral nerves. This case report describes the feasibility of this innovative treatment in a patient with a 12-year history of traumatic facial palsy and severe sequelae. Case summary: A52-year-old male presented with a severe left-sided facial paralysis that had lasted for 12 years. At initial presentation, the man could not fully close his left eye and had difficulty eating solid foods. The paralysis of his left-sided facial muscles had resulted in dysarthria. He was administered 30 LAT sessions in the Acupuncture Department of China Medical University Hospital, Taichung, Taiwan, over a 4-month period. His recovery was monitored by scores on the Facial Disability Index, the Sunnybrook Facial Nerve Grading System and measurements of the vertical palpebral distance in his left eye. Photographs were taken after every treatment. On the 10th treatment, a change in closure of the left eye was noticed and facial muscle strength was improved. After 22 treatments, the patient could fully close his left eye. Conclusion: LAT significantly improved the sequelae of long-term facial paralysis in this patient. Large-scale prospective studies are needed to confirm this observation [added]

The Contribution of Surface Electromyographic Assessment for Defining the Stage of Peripheral Facial Paralysis: Flaccid or Sequelae Stage

Abstract Introduction Surface electromyographic activity may not be symmetric, even in subjects with no facial paralysis history. Objective To evaluate the contribution of the index of electromyographic (IEMG) activity in the identification of the two extremes of the facial paralysis course. Methods Thirty-four subjects with unilateral peripheral facial paralysis were selected. A control group was composed of volunteers without a history of facial paralysis. The electromyographic assessment of the facial muscle was performed by placing surface electrodes during movements of the forehead, eyes and lips using MIOTEC equipment, such as the MIOTOOL (Miotec, Porto Alegre, Brazil) software. The electromyographic activity was also recorded in other channels during the primary activity to identify the presence of synkinesis. The statistical analysis was performed using the Statistical Package for Social Sciences for Macintosh (SPSS Inc, Chicago, IL, USA). The IEMG activity was obtained from the division of the electromyographic activity root mean square (RMS) values on both sides. Results There was a statistically significant difference among the groups in all the analyzed indexes. The ocular-oral synkinesis in all patients must be correctly identified (with 100% sensitivity and specificity) using an IEMG activity of 1.62 as a cutoff point. The oral-ocular synkinesis must be correctly identified (93.3% sensitivity and 95.9% specificity) using the IEMG activity of 1.79 as a cutoff point. Conclusion The IEMG activity is below the normal scores in patients in the flaccid stage, whereas patients in the sequelae stage can either show normal values or values above or below the normal scores. The IEMG activity was shown to have high sensitivity and specificity in the identification of synkinesis.

Augmentation effect of acupuncture on Bi'nao for hypophasis in patients with Bell's palsy: study protocol for a randomized controlled trial.

BACKGROUND: Hypophasis is one of the most frequently observed sequelae of patients with Bell's palsy, who have not recovered completely, creating a clinical difficulty for physicians. Acupuncture therapy has been widely used to treat Bell's palsy as a reasonable resolution for management of symptoms such as hypophasis. The number of acupuncture points (acu-points) is frequently selected in the approach of acupuncture therapy; however, whether these had high efficiency has not been proved. According to the literature review, Bi'nao was useful for treating eye and eye lipid diseases, which could be proved only by some successful cases. Thus, a randomized controlled trial was designed to evaluate the efficiency of the acu-point Bi'nao. METHODS/DESIGN: Participants with hypophasis as the major symptom are selected among patients with Bell's palsy and randomly allocated into one of the three groups at a 1:1:1 allocation ratio. All participants receive conventional acupuncture therapy; however, those assigned to the real acupuncture group will be given added acupuncture therapy on the acu-point Bi'nao, while those assigned to the sham acupuncture group were given extra acupuncture therapy on the sham Bi'nao as a placebo. The efficacy of the acupuncture therapy on the acu-point Bi'nao for hypophasis will be evaluated by Eye Crack Width Measurement (ECWM) and Eyelid Strength Assessment (ESA) before and after therapy. DISCUSSION: This is the first study assessing the safety and efficiency of Bi'nao in treating the hypophasis of patients with Bell's palsy that might support the application of this acupuncture therapy. However, evaluating hypophasis is challenging, and, thus, ECWM and ESA were applied to measure the eyelid movement. TRIAL REGISTRATION: Chinese Clinical Trials Registry, ChiCTR-INR-17012955 . Registered on 12 October 2017.

Selective Stimulation of Facial Muscles Following Chronic Intraneural Electrode Array Implantation and Facial Nerve Injury in the Feline Model.

BACKGROUND: Our group has previously shown that activation of specific facial nerve (FN) fiber populations and selective activation of facial musculature can be achieved through acute intraneural multichannel microelectrode array (MEA) implantation in the feline model. HYPOTHESIS: Selective stimulation of facial muscles will be maintained in the setting of 1) chronic and 2) acute MEA implantation after FN injury and subsequent recovery. METHODS: This study included seven cats. In three cats with normal facial function, 4-channel penetrating MEAs were implanted chronically in the FN and tested biweekly for 6 months. Electrical current pulses were delivered to each channel individually, and elicited electromyographic (EMG) voltage outputs were recorded for each of several facial muscles. For FN injury experiments, two cats received a standardized hemostat-crush injury, and two cats received a transection-reapproximation injury to the FN main trunk. These four underwent acute implantation of MEA and EMG recording in terminal experiments 4 months postinjury. RESULTS: Stimulation through individual channels selectively activated restricted nerve populations, resulting in activation of individual muscles in cats with chronic MEA implantation and after nerve injury. Increasing stimulation current levels resulted in increasing EMG voltage responses in all patients. Nerve histology showed only minor neural tissue reaction to the implant. CONCLUSION: We have established in the animal model the ability of a chronically implanted MEA to selectively stimulate restricted FN fiber populations and elicit activations in specific facial muscles. Likewise, after FN injury, selective stimulation of restricted FN fiber populations and subsequent activation of discrete facial muscles can be achieved after acute MEA implantation.

Long-term facial improvement after repeated BoNT-A injections and mirror biofeedback exercises for chronic facial synkinesis: a case-series study.

BACKGROUND: Only few studies have considered the effects of the combined treatment with onabotulinumtoxinA (BoNT-A) injections and biofeedback (BFB) rehabilitation in the recovery of postparetic facial synkinesis (PPFS). AIM: To explore the presence of a persistent improvement in facial function out of the pharmacological effect of BoNT-A in subjects with established PPFS, after repeated sessions of BoNT-A injections combined with an educational facial training program using mirror biofeedback (BFB) exercises. Secondary objective was to investigate the trend of the presumed persistent improvement. STUDY DESIGN: Case-series study. SETTING: Outpatient Clinic of Physical Medicine and Rehabilitation Unit. POPULATION: Twenty-seven patients (22 females; mean age 45±16 years) affected by an established peripheral facial palsy, treated with a minimum of three BoNT-A injections in association with mirror BFB rehabilitation. The interval between consecutive BoNT-A injections was at least five months. METHODS: At baseline and before every BoNT-A injection+mirror BFB session (when the effect of the previous BoNT-A injection had vanished), patients were assessed with the Italian version of Sunnybrook Facial Grading System (SB). The statistical analysis considered SB composite and partial scores before each treatment session compared to the baseline scores. RESULTS: A significant improvement of the SB composite and partial scores was observed until the fourth session. Considering the "Symmetry of Voluntary Movement" partial score, the main improvement was observed in the muscles of the lower part of the face. CONCLUSIONS: In a chronic stage of postparetic facial synkinesis, patients may benefit from a combined therapy with repeated BoNT-A injections and an educational facial training program with mirror BFB exercises, gaining an improvement of the facial function up to the fourth session. This improvement reflects the acquired ability to use facial muscle correctly. It doesn't involve the injected muscles but those trained with mirror biofeedback exercises and it persists also when BoNT-A action has vanished. CLINICAL REHABILITATION IMPACT: The combined therapy with repeated BoNT-A injections and an educational facial training program using mirror BFB exercises may be useful in the motor recovery of the muscles of the lower part of the face not injected but trained.

The effective stimulating pulse for restoration of blink function in unilateral facial nerve paralysis rabbits, verified by a simple FES system.

The trains of 200 ms biphasic square pulses with the width of 9 ms delivered at 50 Hz were found to be the most suitable and effective mean as stimulation in FES system of restoring the blink function in unilateral facial nerve paralysis rabbit model. FES system is a reliable tool for these patients. Facial paralysis affects thousands of people every year. Many will have long term facial difficulties and the loss of the ability to blink the eye, which can lead to potential loss of the eye. Although many treatments exist, no one approach corrects all the deficits associated with the loss of orbicularis oculi function. FES is a means of providing movement in paralysed muscles to assist with practical activities and one possible way of restoring blink and other functions in these patients. Although some previous researches had investigated the effect of simple FES system on restoration of paralyzed facial muscles, there is still controversy about the appropriate details of the most effective stimulating pulses, such as the frequency, wave pattern and pulse width. Our aim is to find out the parameters of the most appropriate and effective stimulatin verify it by a simple FES system. 24 healthy adult male New Zealand white rabbits were accepted the surgery of right side facial nerve main trunk transaction under general anesthesia as the unilateral facial nerve paralysis models. The platinum tungsten alloy electrodes were implanted in orbicularis oculi muscle. The parameters of stimulus pulses were set to a 200 ms biphasic pulse with different waveforms (square, sine and triangle), different frequencies (25, 50, 100 Hz) and different widths from 1 to 9 ms. Next, we set up a simple FES system to verify the previous results as the stimulus signal. We observed the movement of the both sides of eyelid when eye blink induced by different kinds of pulses. In all animals, the three kinds of waveforms pulse with frequency of 25 Hz could not evoke the smooth blink movement. But the pulses with frequency of 50 and 100 Hz can achieve this effect. The voltage threshold of the square pulse was lower than that of the sine pulse and triangle pulse. With the increase of pulse width from 1 to 9 ms, the voltage threshold decreased gradually. The voltage threshold of the pulse with frequency of 100 Hz was obviously lower than that of 50 Hz. But the amount of total charge of the stimulation pulse of 100 Hz was significantly more than that of 50 Hz. In addition, when the FES system was turned on, the eye blink on the affected side with the stimulation pulses that were set by the previous step results was successfully aroused by the blink movement as a trigger on the contralateral.

[Clinical observation of peripheral facial palsy treated with electro-acupuncture based on surface electromyography].

OBJECTIVE: To observe the difference in the clinical efficacy on peripheral facial palsy between electro-acupuncture (EA) assisted with surface electromyography (sEMG) and conventional EA. METHODS: Sixty cases of peripheral facial palsy were randomized into an observation group and a control group, 30 cases in each one. EA was applied during the first 15 days of sickness in the two groups, at Xiaguan (ST 7), Jiache (ST 6), Dicang (ST 4), Yangbai (GB 14), Taiyang (EX-HN 5), Quanliao (SI 18) and Hegu (LI 4), once a day. In the observation, group, 15 days after sickness, according to the situation in sEMG, on the basis of the acupoints in the previous treatment, the corresponding acupoints were reselected for EA. In the control group, the conventional EA was kept on. The treatment was given once every two days till the 35th day of sickness. Separately, on the 5th, 15th and 35th days of sickness, according to the detection of sEMG in the patients of two groups, the means ratios of: root mean square (RMS) of musculi buccinators, orbicularis oris, frontalis and nasalis on the healthy and affected sides were recorded and analyzed. RESULTS: The differences of ratio in RMS of musculi buccinators, orbicularis oris, frontalis and nasalis on the healthy and affected sides were significant statistically in comparison between the, 15th day and the 5th day, and between the 35th day and the 15th day of sickness within each group (all P<0. 01). The differences of ratio in RMS of the muscles on the healthy and affected sides were significant statistically on the 15th and 35th days between the two groups (all P<0. 05). CONCLUSION: EA assisted with sEMG achieves the significant efficacy on peripheral facial palsy, better than the conventional EA.

Auditory evoked blink reflex in peripheral facial paresis.

PURPOSE: The auditory blink reflex (ABR) is a teleceptive reflex consisting of an early brief muscle contraction of the orbicularis oculi in response to sound stimuli. Constriction of the orbicularis oculi in response to auditory stimulation is accepted as a part of the startle reaction. The blink reflex and ABR might share a final common pathway, consisting of facial nerve nuclei and the facial nerve and may have common premotor neurons. METHODS: In this study, the authors evaluated the value of the ABR in patients with peripheral facial palsy (PFP), cross-checking the results with commonly used blink reflex changes. RESULTS: In total, 83 subjects with PFP and 34 age-matched healthy volunteers were included. Auditory blink reflex was elicited in all control subjects and in 36 PFP cases on the paralytic sides (43.3%), whereas it was asymmetric in 30.1% of the patients. Auditory blink reflex positivity was significantly lower in PFP cases with increasing severity. Blink reflex results were largely correlated with ABR positivity. CONCLUSIONS: Auditory blink reflex is a useful readily elicited and sensitive test in PFP cases, providing parallel results to blink reflex and being affected by disease severity.

[Ophthalmic complications and local anesthesia. Pathophysiology and types of eye complications after intraoral dental anesthesia, and clinical recommendations]. / Ophthalmologische Komplikationen und Lokalanästhesie. Pathophysiologie und Formen der Augenkomplikationen nach intraoraler zahnärztlicher Lokalanästhesie und klinische Empfehlungen.

The present article reviews the different types of ophthalmologic complications following administration of intraoral local anesthesia. Since the first report by Brain in 1936, case reports about that topic have been published regularly in the literature. However, clinical studies evaluating the incidence of ophthalmologic complications after intraoral local anesthesia are rarely available. Previous data point to a frequency ranging from 0.03% to 0.13%. The most frequently described ophthalmologic complications include diplopia (double vision), ptosis (drooping of upper eyelid), and mydriasis (dilatation of pupil). Disorders that rather affect periorbital structures than the eye directly include facial paralysis and periorbital blanching (angiospasm). Diverse pathophysiologic mechanisms and causes have been reported in the literature, with the inadvertent intravascular administration of the local anesthetic considered the primary reason. The agent as well as the vasopressor is transported retrogradely via arteries or veins to the orbit or to periorbital structures (such as the cavernous sinus) with subsequent anesthesia of nerves and paralysis of muscles distant from the oral cavity. In general the ophthalmologic complications begin shortly after administration of the local anesthesia, and disappear once the local anesthesia has subsided.

Update in facial nerve paralysis: tissue engineering and new technologies.

PURPOSE OF REVIEW: To present the recent advances in the treatment of facial paralysis, emphasizing the emerging technologies. This review will summarize the current state of the art in the management of facial paralysis and discuss the advances in nerve regeneration, facial reanimation, and use of novel biomaterials. This review includes surgical innovations in reinnervation and reanimation as well as progress with bioelectrical interfaces. RECENT FINDINGS: The last decade has witnessed major advances in the understanding of nerve injury and approaches for management. Key innovations include strategies to accelerate nerve regeneration, provide tissue-engineered constructs that may replace nonfunctional nerves, approaches to influence axonal guidance, limiting of donor-site morbidity, and optimization of functional outcomes. Approaches to muscle transfer continue to evolve, and new technologies allow for electrical nerve stimulation and use of artificial tissues. SUMMARY: The fields of biomedical engineering and facial reanimation increasingly intersect, with innovative surgical approaches complementing a growing array of tissue engineering tools. The goal of treatment remains the predictable restoration of natural facial movement, with acceptable morbidity and long-term stability. Advances in bioelectrical interfaces and nanotechnology hold promise for widening the window for successful treatment intervention and for restoring both lost neural inputs and muscle function.

[EMG biofeedback training at home for patient with chronic facial palsy and defective healing]. / EMG Biofeedback Training zuhause zur Therapie der Defektheilung bei chronischer Fazialisparese.

BACKGROUND: There is no standard for the adjuvant treatment of patients with chronic facial palsy and defective healing. There is a lack of standard for mimic training programs with biofeedback technique. The advantages of modern EMG based biofeedback training have not been evaluated yet. MATERIAL AND METHODS: After detailed instruction 8 patients with facial palsy tested several types of electrodes and different EMG biofeedback programs without and with electrostimulation for selected mimic muscle activation, muscle relaxation, coordinated movements with the healthy contralateral side, as well as synchronous activation and relaxation of synkinetic muscle pairs at home. Feasibility, practical handling, training intensity and compliance were evaluated. RESULTS: Because of the mobility of the facial skin connected to the mimic muscles and the smallness of the muscles on the other hand, only one type of electrodes and one size was suitable. A step-wise treatment algorithm for the use of the different EMG biofeedback program was developed supporting the patient to specifically exercise deficits of defective healing at home. CONCLUSION: The proposed standardized algorithm to treat facial defective healing with EMG biofeedback is the basis for the evaluation of its efficacy in a subsequent clinical trial.

A blink restoration system with contralateral EMG triggered stimulation and real-time artifact blanking.

Patients suffering from facial paralysis are on the hazard of disfigurement and loss of vision due to loss of blink function. Functional-electrical stimulation (FES) is one possible way of restoring blink and other functions in these patients. A blink restoration system for uni-lateral facial paralyzed patients is described in this paper. The system achieves restoration of synchronized blink through processing the myoelectric signal of orbicularis oculi at the normal side in real-time as the trigger to stimulate the paralyzed eyelid. Design issues are discussed, including EMG processing, stimulating strategies and real-time artifact blanking. Two artifact removal approaches based on sample and hold and digital filtering technique are proposed and implemented. Finally, the whole system has been verified on rabbit models.