Excitability of facial nucleus and related brain-stem reflexes in hemifacial spasm, post-facial palsy synkinesis and facial myokymia

Facial synkinesis: A distressing sequela of facial palsy

INTRODUCTION

Synkinesis refers to abnormal involuntary facial movements that accompany volitional facial movements. Despite a 55% incidence of synkinesis reported in patients with enduring facial paralysis, there is still a lack of complete understanding of this debilitating condition, leading to functional limitations and decreased quality of life.1 This article reviews the diagnostic assessment, etiology, pathophysiology, rehabilitation, and nonsurgical and surgical treatments for facial synkinesis.

METHODS

A PubMed and Cochrane search was done with no date restrictions for English-language literature on facial synkinesis. The search terms used were "facial," "synkinesis," "palsy," and various combinations of the terms.

RESULTS

The resultant inability to control the full extent of one's facial movements has functional and psychosocial consequences and may result in social withdrawal with a significant decrease in quality of life. An understanding of facial mimetic musculature is imperative in guiding appropriate intervention. While chemodenervation with botulinum toxin and neurorehabilitation have continued to be the primary treatment strategy for facial synkinesis, novel techniques such as selective myectomy, selective neurolysis, free-functioning muscle transfer, and nerve grafting techniques are becoming increasingly utilized in treatment regimens. Facial rehabilitation, including neuromuscular retraining, soft tissue massage, and relaxation therapy in addition to chemodenervation with botulinum toxin, remains the cornerstone of treatment. In cases of severe, intractable synkinesis and non-flaccid facial paralysis, surgical interventions, including selective neurectomy, selective myectomy, nerve grafting, or free muscle transfer, may play a more significant role in alleviating symptoms.

DISCUSSION

A multidisciplinary approach involving therapists, clinicians, and surgeons is necessary to develop a comprehensive treatment regimen that will result in optimal outcomes. Ultimately, therapy should be tailored to the severity and pattern of synkinesis, and each patient approached on a case-by-case basis. A multidisciplinary approach involving therapists, clinicians, and surgeons is necessary to develop a comprehensive treatment regimen that will result in optimal outcomes.

The blink reflex and its modulation - Part 2: Pathophysiology and clinical utility

The blink reflex (BR) is integrated at the brainstem; however, it is modulated by inputs from various structures such as the striatum, globus pallidus, substantia nigra, and nucleus raphe magnus but also from afferent input from the peripheral nervous system. Therefore, it provides information about the pathophysiology of numerous peripheral and central nervous system disorders. The BR is a valuable tool for studying the integrity of the trigemino-facial system, the relevant brainstem nuclei, and circuits. At the same time, some neurophysiological techniques applying the BR may indicate abnormalities involving structures rostral to the brainstem that modulate or control the BR circuits. This is a state-of-the-art review of the clinical application of BR modulation; physiology is reviewed in part 1. In this review, we aim to present the role of the BR and techniques related to its modulation in understanding pathophysiological mechanisms of motor control and pain disorders, in which these techniques are diagnostically helpful. Furthermore, some BR techniques may have a predictive value or serve as a basis for follow-up evaluation. BR testing may benefit in the diagnosis of hemifacial spasm, dystonia, functional movement disorders, migraine, orofacial pain, and psychiatric disorders. Although the abnormalities in the integrity of the BR pathway itself may provide information about trigeminal or facial nerve disorders, alterations in BR excitability are found in several disease conditions. BR excitability studies are suitable for understanding the common pathophysiological mechanisms behind various clinical entities, elucidating alterations in top-down inhibitory systems, and allowing for follow-up and quantitation of many neurological syndromes.

Blink reflex excitability in patients with Hemifacial spasm exhibiting different abnormal discharge patterns: from early isolated discharges to later grouped bursts or tonic spasms

OBJECTIVE

We studied blink reflex (BR) and BR excitability recovery (BRER) in patients with hemifacial spasm (HFS) exhibiting different abnormal discharge patterns. We hypothesized that patients with groups of clonic or tonic burst activities appear later in the disease course and may have more excitability of the BR circuit at the brainstem compared to patients with isolated twitchings, which occur earlier.

METHODS

We included 124 patients with botulinum toxin-naive HFS (mean age 50.6 ± 13.3 years) and 40 healthy subjects. We performed surface polymyography on facial muscles in patients and classified them according to the abnormal discharge pattern: isolated discharges, grouped bursts forming random sequences, tonic spasms, and a combination of these activities. Then, we recorded BR and BRER at 200, 600, and 1000 ms interstimulus intervals. We compared disease duration, R1 and R2 latencies, R2 area-under-the-curve (AUC), and BRER% (i) between healthy subjects and patients and (ii) among groups of patients with different abnormal discharge patterns.

RESULTS

There were isolated discharges in 28 patients, grouped bursts forming random sequences in 42, and continuous muscle activity with tonic spasms in one. The remaining patients had combinations. Mean R1 and R2 latencies were significantly longer, and mean R2 AUC was significantly higher on the symptomatic side of patients compared to healthy subjects. The mean BRER was enhanced on both sides in patients than in healthy subjects (p < 0.001). However, it was similar among patient groups with different abnormal discharge patterns (p > 0.05). The mean disease duration in patients with isolated discharges was shorter (3.3 ± 2.0 years) than those with grouped bursts or tonic spasms (p = 0.002; Kruskal-Wallis test).

CONCLUSION

Our study observed that excitability at the brainstem was similar in HFS patients with different abnormal discharge patterns, suggesting that the difference in discharge patterns in HFS may be due to a reason other than the difference in BR excitability.

Microvascular decompression for hemifacial spasm after Bell's palsy: a retrospective clinical study

OBJECTIVE

This study aimed to investigate the clinical characteristics of hemifacial spasm (HFS) after Bell's palsy and to evaluate the therapeutic efficacy of microvascular decompression (MVD).

METHODS

A retrospective analysis was conducted on 18 patients who underwent MVD for HFS after Bell's palsy at our institution between January 1, 2017, and December 31, 2021. Clinical presentations, intraoperative findings, postoperative outcomes, and complications were comprehensively assessed.

RESULTS

Neurovascular compression (NVC) was identified in all the 18 patients. The offending vessels included anterior inferior cerebellar artery (AICA) in 6 patients (33.3%), posterior inferior cerebellar artery (PICA) in 7 patients (38.9%), vertebral artery (VA) combined with AICA in 3 patients (16.7%), and VA alongside PICA in 2 patients (11.1%). Notably, marked arachnoid membrane adhesion was evident in 11 patients (61.1%). 15(83.3%) patients were cured immediately after MVD, delayed relief was found in 3 (16.7%) patients. During the follow-up period, recurrence was not documented. Surgical complications were limited to facial paralysis in 3 patients and auditory impairment in 1 patient. No additional surgical complications were recorded.

CONCLUSIONS

In patients manifesting HFS after Bell's palsy, NVC predominantly underlies the etiology. MVD is a reliably safe and efficacious therapeutic intervention.

Optimal method for reliable lateral spread response monitoring during microvascular decompression surgery for hemifacial spasm

In this study, we propose an optimal method for monitoring the key electrophysiological sign, the Lateral Spread Response (LSR), during microvascular decompression (MVD) surgery for hemifacial spasm (HFS). Current monitoring methods and interpretations of LSR remain unclear, leading to potential misinterpretations and undesirable outcomes." We prospectively collected data from patients undergoing MVD for HFS, including basic demographics, clinical characteristics, and surgical outcomes. Stimulation intensity was escalated by 1 mA increments to identify the optimal range for effective LSR. We designated the threshold at which we can observe LSR as THR1 and THR2 for when LSR disappears, with high-intensity stimulation (30 mA) designated as THR30. Subsequently, we compared abnormal muscle responses (AMR) between the optimal range (between THR1 and THR2) and THR30. Additionally, we conducted an analysis to identify and assess factors associated with artifacts and their potential impact on clinical outcomes. As stimulation intensity increases, the onset latency to detect AMR was shortened. The first finding of the study was high intensity stimulation caused artifact that mimic the wave of LSR. Those artifacts were observed even after decompression thus interfere interpretation of disappearance of LSR. Analyzing the factors related to the artifact, we found the AMR detected at onset latency below 9.6 ms would be the lateral spreading artifact (LSA) rather than true LSR. To avoid false positive LSR from LSA, we should stepwise increase stimulation intensity and not to surpass the intensity that cause LSR onset latency below 10 ms.

Influence of Minimum Alveolar Concentration and Inhalation Duration of Sevoflurane on Facial Nerve Electromyography in Hemifacial Spasm: A Randomized Controlled Trial

BACKGROUND

The lateral spread response (LSR) is an electromyography feature of hemifacial spasm; intraoperative reduction in the LSR is associated with positive surgical outcomes. This study examined the effects of different minimum alveolar concentrations (MACs) and durations of sevoflurane inhalation on the LSR.

METHODS

Eighty patients undergoing microvascular decompression surgery for hemifacial spasm were randomly allocated to receive propofol-remifentanil total intravenous anesthesia alone or in combination with sevoflurane at 0.5, 0.75, or 1 MAC. The LSR and orbicularis oculi muscle wave were recorded before and at 15 and 30 minutes after the start of sevoflurane administration.

RESULTS

Sevoflurane reduced the LSR amplitude in a dose-dependent and duration-dependent manner. The curve representing the LSR amplitude preservation ratio change according to sevoflurane concentration is best fitted by regression analysis using a cubic model, as the cubic equations had the largest coefficient of determination; at 15 minutes ( R2 =0.76, F =78.36, P <0.05) and at 30 minutes ( R2 =0.882, F =189.94, P <0.05). The inhibitory effect of sevoflurane on the LSR amplitude was greater in the first 15 minutes than in the second 15 minutes of sevoflurane administration. Sevoflurane at 1 MAC for 30 minutes mildly decreased the amplitude of the orbicularis oculi muscle wave. The latencies of the LSR and the orbicularis oculi muscle wave were not affected by sevoflurane at all MACs studied.

CONCLUSIONS

The combination of intravenous propofol-remifentanil anesthesia with 0.5 MAC sevoflurane allows reliable intraoperative LSR monitoring in hemifacial spasm patients. Our findings support the central rather than peripheral hypothesis of the LSR.

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.

In the spotlight: How the brainstem modulates information flow

OBJECTIVE

The blink reflex (BR) to supraorbital nerve (SON) stimulation is reduced by either a low-intensity prepulse stimulus to digital nerves (prepulse inhibition, PPI) or a conditioning SON stimulus (SON_-1) of the same intensity as the test (SON_-2) stimulus (paired-pulse paradigm). We studied how PPI affects BR excitability recovery (BRER) to paired SON stimulation.

METHODS

Electrical prepulses were applied to the index finger 100 ms before SON_-1, which was followed by SON_-2 at interstimulus intervals (ISI) of 100, 300, or 500 ms.

RESULTS

BRs to SON_-1 showed PPI proportional to prepulse intensity, but this did not affect BRER at any ISI. PPI was observed on the BR to SON_-2 only when additional prepulses were applied 100 ms before SON_-2, regardless of the size of BRs to SON_-1.

CONCLUSIONS

In BR paired-pulse paradigms, the size of the response to SON_-2 is not determined by the size of the response to SON_-1. PPI does not leave any trace of inhibitory activity after it is enacted.

SIGNIFICANCE

Our data demonstrate that BR response size to SON_-2 depends on SON_-1 stimulus intensity and not SON_-1 response size, an observation that calls for further physiological studies and cautions against unanimous clinical applicability of BRER curves.

Botulinum toxin A treatment in facial palsy synkinesis: a systematic review and meta-analysis

BACKGROUND

Synkinesis is defined as involuntary movements accompanying by voluntary movements and can occur during the aftermath of peripheral facial palsy, causing functional, aesthetic and psychological problems in the patient. Botulinum toxin A (BTX-A) is frequently used as a safe and effective treatment; however, there is no standardized guideline for the use of BTX-A in synkinesis. The purpose of this article is to review and summarize studies about the BTX-A treatment of synkinesis in patients with a history of peripheral facial palsy; including given dosages, injection sites and time intervals between injections.

MATERIALS AND METHODS

A multi-database systematic literature search was performed in October 2020 using the following databases: Pubmed, Embase, Medline, and The Cochrane Library. Two authors rated the methodological quality of the included studies independently using the 'Newcastle-Ottawa Quality Assessment Scale' for non-randomised studies' (NOS).

RESULTS

Four-thousand-five-hundred-and-nineteen articles were found of which 34 studies met the inclusion criteria, in total comprising 1314 patients. Most studies were assessed to be of 'fair' to 'good' methodological quality. The Cohen's kappa (between author FJ and AS) was 0.78. Thirty-one studies investigated the reported dosage injected, 17 studies reported injection location and 17 studies investigated time intervals. A meta-analysis was performed for three studies comprising 106 patients, on the effects of BTX-A treatment on the Synkinesis Assessment Questionnaire (SAQ) scores. The mean difference was 11.599 (range 9.422-13.766), p < 0.01. However, due to inconsistent reporting of data of the included studies, no relationship with the dosage and location could be assessed.

CONCLUSIONS

Many treatment strategies for synkinesis exist, consisting of varying BTX-A brands, dosages, time intervals and different injection locations. Moreover, the individual complaints are very specific, which complicates creating a standardized chemodenervation treatment protocol. The BTX-A treatment of long-term synkinesis is very individual and further studies should focus on a patient-tailored treatment instead of trying to standardize treatment.

Surgical Treatment for Postparalytic Facial Synkinesis - A 35 Year Experience

BACKGROUND

Surgical intervention with Combined myectomy & neurectomy followed by functioning free muscle transplantation (FFMT) has been proposed to effectively resolve the problem of postparalytic facial synkinesis (PPFS) since 1985, and continues to be our standard-of-care. We aim to provide evidence that this surgical strategy is effective for treatment of synkinesis and smile quality.

METHODS

103 patients with PPFS were investigated (1985-2020). They all underwent extensive removal of the synkinetic muscles and triggered facial nerve branches in the cheek, nose and neck regions, followed by gracilis FFMT for facial reanimation. Ninety-four patients with 50 Type II and 44 Type III PPFS patients, all of whom had at least one year of postoperative follow-up were included in the study. Patient's demographics, functional and aesthetic evaluations before and after surgery were collected.

RESULTS

In the yearly distribution of the facial paralysis reconstruction, the incidence of surgical intervention increased from 15% prior to 2012 up to 24% in the years after. Young adults (79%) and female patients (63%) were the dominant population. Results showed a significant improvement of the facial smile quality with more teeth visible while smiling, and a long-lasting decrease of facial synkinesis. Ninety six percent of patients did not require botulinum-A toxin injection after surgery. Revision surgery for secondary deformity was 53%.

CONCLUSION

Combined myectomy & neurectomy followed by FFMT for Type II and III synkinetic patients leads to promising and long-lasting results despite high revision rates. Refined techniques to decrease the revision rates are needed in the future.

Monitoring cerebellopontine angle and skull base surgeries

Cerebellopontine angle (CPA) surgery represents a challenge for neurosurgeons due to the high risk of iatrogenic injury of vital neurological structures. Therefore, important efforts in improving the surgical techniques and intraoperative neurophysiology have been made in the last decades. We present a description and review of the available methodologies for intraoperative neuromonitoring and mapping during CPA surgeries. There are three main groups of techniques to assess the functional integrity of the nervous structures in danger during these surgical procedures: (1) Electrical identification or mapping of motor cranial nerves (CNs), which is essential in order to locate the nerve in their different parts during the tumor resection; (2) Monitoring, which provides real-time information about functional integrity of the nervous tissue; and (3) Brainstem reflexes including blink reflex, masseteric reflex, and laryngeal adductor reflex. All these methods facilitate the removal of lesions and contribute to notable improvement in functional outcome and permit on the investigation of their physiopathology in certain neurosurgically treated diseases. Such is the case of hemifacial spasm (HFS). We describe the methodology to evaluate the efficacy of microvascular decompression for HFS treatment at the end of this chapter.

Efficacy of Mirror Biofeedback Rehabilitation on Synkinesis in Acute Stage Facial Palsy in Children

OBJECTIVES

To evaluate the efficacy of mirror biofeedback rehabilitation for synkinesis in severe acute facial paralysis in children.

METHODS

Eight pediatric patients with facial paralysis with an initial electroneurography (ENoG) value less than 10% who underwent mirror biofeedback rehabilitation (the child-rehabilitation group) were enrolled. Seven infants (under age 2 yr) who were unable to undergo rehabilitation (the infant-and-toddler control group) and adult patients (n = 13, range, 33-56 yr) who underwent rehabilitation (the adult-rehabilitation group) comprised the control groups. All the patients enrolled were baseline House-Brackmann (H-B) grade VI at onset. The patients began daily facial biofeedback rehabilitation using a mirror at the first sign of muscle contraction on the affected side and were instructed to keep their eyes symmetrically open using a mirror during mouth movements. The training was continued for 12 months after the onset of facial paralysis. The degree of oral-ocular synkinesis was evaluated by the degree of asymmetry in eye opening width during mouth movements. The synkinesis index was calculated as a percentage of the interpalpebral space width ([normal side - affected side]/normal side). Statistical analyses used non-parametric tests (the Kruskal-Wallis test and Steel-Dwass posthoc test).

RESULTS

The synkinesis index was significantly lower in the child-rehabilitation group than in the infant-and-toddler control group or the adult-rehabilitation group (p < 0.001).

CONCLUSION

Children who underwent mirror biofeedback rehabilitation had less synkinesis than the infant-and-toddler control group, suggesting that mirror biofeedback rehabilitation is more effective in preventing the exacerbation of synkinesis in children.

Epineurectomy of Facial Nerve Trunk for Refractory Oral-Ocular and Oculo-Oral Synkinesis Following Bell Palsy

BACKGROUND

Synkinesis is a common sequelae after incomplete recovery from Bell palsy. Current first-line treatments include botulinum toxin injection and physical therapy. However, patients unresponsive to these treatments may require further surgery. Various surgical treatments have been reported, but no consensus has been reached for the optimal surgery. In a guinea pig model of synkinesis, the facial nerve trunk (FNT) was observed using a scanning electron microscope. Based on the results of scanning electron microscope and clinical ultrasonography, the authors chose FNT as the therapeutic target.

METHODS

The authors performed epineurectomy of FNT for 11 patients with refractory oral-ocular and oculo-oral synkinesis under abnormal muscle response and facial electromyography monitoring. The postoperative assessments at 1 year were conducted using Sunnybrook Facial Grading System and Facial Disability Index scale. Furthermore, the epineurium excised during the operation was collected as the specimen and submitted for histopathological examination; the cadaveric FNT served as the control group.

RESULTS

The follow-up results showed significant relief from synkinesis (4.91 ± 0.37 versus 10.18 ± 0.64, P < 0.01), improvement of physical (84.55 ± 1.96 versus 73.18 ± 3.65, P < 0.01) and social functions (77.09 ± 3.24 versus 61.82 ± 6.28, P < 0.01), with no worsening of facial paralysis in the patients. The histopathological examination revealed many nerve fibers in the epineurium, suggesting that FNT was the area of aberrant axon regeneration.

CONCLUSIONS

Epineurectomy of FNT is a safe and effective surgical remedy. It can be considered as a surgical option for patients with refractory oral-ocular and oculo-oral synkinesis following Bell palsy.

Demystifying the spontaneous phenomena of motor hyperexcitability

Possessing a discrete functional repertoire, the anterior horn cell can be in one of two electrophysiological states: on or off. Usually under tight regulatory control by the central nervous system, a hierarchical network of these specialist neurons ensures muscular strength is coordinated, gradated and adaptable. However, spontaneous activation of these cells and their axons can result in abnormal muscular twitching. The muscular twitch is the common building block of several distinct clinical patterns, namely fasciculation, myokymia and neuromyotonia. When attempting to distinguish these entities electromyographically, their unique temporal and morphological profiles must be appreciated. Detection and quantification of burst duration, firing frequency, multiplet patterns and amplitude are informative. A common feature is their persistence during sleep. In this review, we explain the accepted terminology used to describe the spontaneous phenomena of motor hyperexcitability, highlighting potential pitfalls amidst a bemusing and complex collection of overlapping terms. We outline the relevance of these findings within the context of disease, principally amyotrophic lateral sclerosis, Isaacs syndrome and Morvan syndrome. In addition, we highlight the use of high-density surface electromyography, suggesting that more widespread use of this non-invasive technique is likely to provide an enhanced understanding of these motor hyperexcitability syndromes.

Tracking whole-brain connectivity dynamics in the resting-state fMRI with post-facial paralysis synkinesis

BACKGROUND

Resting-state functional magnetic resonance imaging (rs-fMRI) is widely applied to explore abnormal functional connectivity (FC) in patients with post-facial paralysis synkinesis (PFPS). However, most studies considered steady spatial-temporal signal interactions between distinct brain regions during the period of scanning.

OBJECTIVE

In this study, we aim to investigate abnormal dynamic functional connectivity (dFC) in PFPS patients.

METHODS

We enrolled 31 PFPS patients and 19 healthy controls. All participants underwent rs-fMRI. Sliding windows approach was applied to construct dFC matrices. Next, these matrices were clustered into distinct states using the k-means clustering algorithm.

RESULTS

We found that it was not the dFC patterns, but rather the temporal properties including the mean dwell time (MDT) and occurrence frequencies, that showed a significant difference between PFPS patients and healthy controls. Two randomly clustered dFC states were recognized for both groups. Among them, State 1 showed significantly lower connectivity compared to State 2 in patients group. Compared to healthy controls, the duration spent by the PFPS patients in the state with lower connectivity significantly increased and is positively correlated with the better facial function.

CONCLUSIONS

In conclusion, aberrant dFC is a fundamental feature of brain dysfunction in PFPS patients, which is associated with the facial nerve function. These findings may contribute to a better understanding of the abnormal brain reorganization mechanisms in PFPS patients.

Bell’s Palsy—Retroauricular Pain Threshold

Background and objectives: Non-motor symptoms in the form of increased sensitivity are often associated with the onset of idiopathic Bell’s palsy (IBP). The aims were to determine whether the pain threshold in the retroauricular regions (RAR) in IBP patients and the time of its occurrence is related to IBP severity. Materials and Methods: The study was conducted among 220 respondents (142 IBP patients, 78 healthy subjects (HS)). The degree of IBP was graded using the House–Brackmann and Sunnybrook Grading Scales (II—mild dysfunction, VI—total paralysis), whereas the pain thresholds were measured using the digital pressure algometer. Results: We found no difference in the degree of the pain threshold between the right and left RAR in the HS group. IBP patients belonging to groups II, III, IV, and V had lower pain thresholds in both RARs than HS and IBP patients belonging to group VI. There was no difference in the degree of pain threshold in RAR between the affected and unaffected side in IBP patients. The incidence of retroauricular pain that precedes paralysis and ceases after its occurrence in groups II and III of IBP patients is noticeably lower and the incidence of retroauricular pain that occurred only after the onset of paralysis is more frequent. Also, we found that the incidence of retroauricular pain that precedes paralysis and ceases after its occurrence in groups V and VI of IBP patients was more frequent. Conclusions: The degree of pain threshold lowering in RAR (bilaterally) is inversely related to the severity of IBP. We suggest that the occurrence of retroauricular pain before the onset of facial weakness is associated with higher severity of IBP while the occurrence after the onset is associated with lower severity of IBP.

Facial nerve electrodiagnostics for patients with facial palsy: a clinical practice guideline

PURPOSE

Facial nerve electrodiagnostics is a well-established and important tool for decision making in patients with facial nerve diseases. Nevertheless, many otorhinolaryngologist-head and neck surgeons do not routinely use facial nerve electrodiagnostics. This may be due to a current lack of agreement on methodology, interpretation, validity, and clinical application. Electrophysiological analyses of the facial nerve and the mimic muscles can assist in diagnosis, assess the lesion severity, and aid in decision making. With acute facial palsy, it is a valuable tool for predicting recovery.

METHODS

This paper presents a guideline prepared by members of the International Head and Neck Scientific Group and of the Multidisciplinary Salivary Gland Society for use in cases of peripheral facial nerve disorders based on a systematic literature search.

RESULTS

Required equipment, practical implementation, and interpretation of the results of facial nerve electrodiagnostics are presented.

CONCLUSION

The aim of this guideline is to inform all involved parties (i.e. otorhinolaryngologist-head and neck surgeons and other medical specialists, therapeutic professionals and the affected persons) and to provide practical recommendations for the diagnostic use of facial nerve electrodiagnostics.

Structural remodeling secondary to functional remodeling in advanced-stage peripheral facial neuritis

BACKGROUND

Structural remodeling is a classic manifestation of disease decompensation. Facial synkinesis is the most troubling sequela of peripheral facial neuritis, and its structural remodeling, especially in white matter (WM), is still poorly understood. Therefore, understanding WM microstructure is important for predicting WM pathology and for early intervention in facial synkinesis patients.

METHODS

A total of 20 facial synkinesis patients (18 men and 2 women; mean age, 33.35 ± 6.97 years old) and 19 healthy controls (17 men and 2 women; mean age, 33.21 ± 6.75 years old) were enrolled in this study. rs-fMRI data, diffusion tensor imaging (DTI) data, and Beck's Depression Inventory (BDI) data were collected, and tract-based spatial statistics (TBSS) and voxel-mirrored homotopic connectivity (VMHC) values were used to analyze changes in WM microstructure and interhemispheric coordination.

RESULTS

Compared with the healthy controls, facial synkinesis patients exhibited significantly lower regional fractional anisotropy (FA) in the genu of the corpus callosum and the body of the corpus callosum, significantly higher regional FA in the retrolenticular part of the internal capsule, and significantly decreased VMHC values bilaterally in the orbital inferior frontal gyri, the fusiform gyri, the superior temporal gyri, the superior frontal gyri, and the supplementary motor areas. Furthermore, a lower regional FA in the genu of the corpus callosum was correlated with higher BDI scores in facial synkinesis patients.

CONCLUSION

Structural remodeling, especially changes in white matter microstructure, may be the central mechanism for severe sequelae of peripheral facial neuritis.

Intraoperative Neurophysiological Monitoring during Microvascular Decompression Surgery for Hemifacial Spasm

Hemifacial spasm (HFS) is due to the vascular compression of the facial nerve at its root exit zone (REZ). Microvascular decompression (MVD) of the facial nerve near the REZ is an effective treatment for HFS. In MVD for HFS, intraoperative neurophysiological monitoring (INM) has two purposes. The first purpose is to prevent injury to neural structures such as the vestibulocochlear nerve and facial nerve during MVD surgery, which is possible through INM of brainstem auditory evoked potential and facial nerve electromyography (EMG). The second purpose is the unique feature of MVD for HFS, which is to assess and optimize the effectiveness of the vascular decompression. The purpose is achieved mainly through monitoring of abnormal facial nerve EMG that is called as lateral spread response (LSR) and is also partially possible through Z-L response, facial F-wave, and facial motor evoked potentials. Based on the information regarding INM mentioned above, MVD for HFS can be considered as a more safe and effective treatment.

Decreased Distance between Representation Sites of Distinct Facial Movements in Facial Synkinesis-A Task fMRI Study

This study aimed to investigate the cortical functional alterations in patients with unilateral facial synkinesis using the task-designed functional magnetic resonance imaging. Fourteen unilateral synkinesis followed by peripheral facial nerve palsy patients and eighteen healthy adults were recruited in this study. Four facial motor tasks, i.e. left/right blinking and left/right smiling, were performed by each subject during the scans. Based on the activation maps, the spatial distance between the representation sites in the contralateral pre-/post-central gyrus of left or right blinking and smiling tasks (i.e. left/right B-S-distance) were calculated. Patients with unilateral facial synkinesis showed decreased B-S-distances during blinking and smiling tasks on the affected half face (9.68 ± 3.92 mm) compared to both average distances in healthy controls (14.95 ± 5.55 mm; p = 0.002) and unaffected half face tasks in patients (16.19 ± 7.87 mm; p = 0.011). These findings demonstrated cortical reorganization in facial synkinesis and suggested a conceivable mechanism corresponding to the simultaneous facial movement. This potentially provides a new modulation target for preventive, therapeutic and rehabilitative maneuver of this disease.

Patterns of cortical reorganization in facial synkinesis: a task functional magnetic resonance imaging study

Facial synkinesis, a sequela of peripheral facial nerve palsy, is characterized by simultaneous involuntary facial movement during a voluntary desired one. Maladaptive cortical plasticity might be involved in the dysfunction of facial muscles. This cohort study investigated the cortical functional alterations in patients with unilateral facial synkinesis, using the task functional magnetic resonance imaging. Facial motor tasks, including blinking and smiling, were performed by 16 patients (aged 30.6 ± 4.5 years, 14 females/2 males) and 24 age- and sex-matched healthy controls (aged 29.1 ± 4.2 years, 19 females/5 males). Results demonstrated that activation in the cortico-facial motor representation area was lower during tasks in patients with facial synkinesis compared with healthy controls. Facial movements on either side performed by patients caused more intensive activation of the supplementary motor area on the contralateral side of the affected face, than those on the unaffected side. Our results revealed that there was cortical reorganization in the primary sensorimotor area and the supplementary motor area. This study was registered in Chinese Clinical Trial Registry (registration number: ChiCTR1800014630).

Individualized management of facial synkinesis based on facial function

OBJECTIVES

The researchers analyzed facial patterns in subjects with facial synkinesis after facial paralysis and evaluated the involved muscles to aid in the development of effective treatments for facial synkinesis.

METHODS

A total of 142 subjects were included in the study, the primary measure for synkinesis was determined by video analysis involving the strongest combination of two muscle groups that contributed to facial expression. The secondary measure of synkinesis was the analysis of its severity using the SB grading system, while observing the number of facial synkinetic movements.

RESULTS

The most common type of facial synkinesis was oral-ocular synkinesis (n = 137). Other synkinesis such as ocular-oral, ocular-nasal, ocular-chin, ocular-stapedial, chin-ocular and chin-oral synkinesis continued to coexist together with oral-ocular synkinesis. The results of BTX-A treatment are assessed based on the number of facial synkinetic movements observed and the evaluation of initial facial function.

CONCLUSION

The effectiveness of botulinum toxin A (BTX-A) treatment should be considered on an individual basis, according to the initial state of facial function. A patient with mild facial synkinesis restricted to the oral-ocular area and with a high score on the Sunnybrook (SB) facial nerve grading system would be the best candidate for BTX-A treatment.

Thread lifting: a minimally invasive surgical technique for long-standing facial paralysis

BACKGROUND

Chronic facial paralysis induces degenerative facial muscle changes on the involved side, thus, making the individual seem as older than their actual age. Furthermore, contralateral facial hypertrophy aggravates facial asymmetry. A thread-lifting procedure has been used widely for correction of a drooping or wrinkled face due to the aging process. In addition, botulinum toxin injection can be used to reduce facial hypertrophy. The aim of study was to evaluate the effectiveness of thread lifting with botulinum toxin injection for chronic facial paralysis.

METHODS

A total 34 of patients with chronic facial paralysis were enrolled from March to October 2014. Thread lifting for elevating loose facial muscles on the ipsilateral side and botulinum toxin A for controlling the facial muscle hypertrophy on the contralateral side were conducted. Facial function was evaluated using the Sunnybrook grading system and dynamic facial asymmetry ratios 1 year after treatment.

RESULTS

All 34 patients displayed improved facial symmetry and showed improvement in Sunnybrook scores (37.4 vs. 83.3) and dynamic facial asymmetry ratios (0.58 vs 0.92). Of the 34 patients, 28 (82.4%) reported being satisfied with treatment.

CONCLUSION

The application of subdermal suspension with a reabsorbable thread in conjunction with botulinum toxin A to optimize facial rejuvenation of the contralateral side constitutes an effective and safe procedure for face lifting and rejuvenation of a drooping face as a result of long-lasting facial paralysis.

Postparalysis facial synkinesis: clinical classification and surgical strategies

Supplemental Digital Content is available in the text.

Background:

Postparalysis facial synkinesis (PPFS) can occur after any cause of facial palsy. Current treatments are still inadequate. Surgical intervention, instead of Botox and rehabilitation only, for different degrees of PPFS was proposed.

Methods:

Seventy patients (43 females and 27 males) with PPFS were enrolled since 1986. They were divided into 4 patterns based on quality of smile and severity of synkinesis. Data collection for clinically various presentations was made: pattern I (n = 14) with good smile but synkinesis, pattern II (n = 17) with acceptable smile but dominant synkinesis, pattern III (n = 34) unacceptable smile and dominant synkinesis, and pattern IV (n = 5) poor smile and synkinesis. Surgical interventions were based on patterns of PPFS. Selective myectomy and some cosmetic procedures were performed for pattern I and II patients. Extensive myectomy and neurectomy of the involved muscles and nerves followed by functioning free-muscle transplantation for facial reanimation in 1- or 2-stage procedure were performed for pattern III and many pattern II patients. A classic 2-stage procedure for facial reanimation was performed for pattern IV patients.

Results:

Minor aesthetic procedures provided some help to pattern I patients but did not cure the problem. They all had short follow-up. Most patients in patterns II (14/17, 82%) and III (34/34, 100%) showed a significant improvement of eye and smile appearance and significant decrease in synkinetic movements following the aggressively major surgical intervention. Nearly, all of the patients treated by the authors did not need repeated botulinum toxin A injection nor require a profound rehabilitation program in the follow-up period.

Conclusions:

Treatment of PPFS remains a challenging problem. Major surgical reconstruction showed more promising and long-lasting results than botulinum toxin A and/or rehabilitation on pattern III and II patients.

Altered spontaneous brain activity in patients with hemifacial spasm: a resting-state functional MRI study

Resting-state functional magnetic resonance imaging (fMRI) has been used to detect the alterations of spontaneous neuronal activity in various neurological and neuropsychiatric diseases, but rarely in hemifacial spasm (HFS), a nervous system disorder. We used resting-state fMRI with regional homogeneity (ReHo) analysis to investigate changes in spontaneous brain activity of patients with HFS and to determine the relationship of these functional changes with clinical features. Thirty patients with HFS and 33 age-, sex-, and education-matched healthy controls were included in this study. Compared with controls, HFS patients had significantly decreased ReHo values in left middle frontal gyrus (MFG), left medial cingulate cortex (MCC), left lingual gyrus, right superior temporal gyrus (STG) and right precuneus; and increased ReHo values in left precentral gyrus, anterior cingulate cortex (ACC), right brainstem, and right cerebellum. Furthermore, the mean ReHo value in brainstem showed a positive correlation with the spasm severity (r = 0.404, p = 0.027), and the mean ReHo value in MFG was inversely related with spasm severity in HFS group (r = -0.398, p = 0.028). This study reveals that HFS is associated with abnormal spontaneous brain activity in brain regions most involved in motor control and blinking movement. The disturbances of spontaneous brain activity reflected by ReHo measurements may provide insights into the neurological pathophysiology of HFS.

Spread of Muscle Spasms in Hemifacial Spasm

Hemifacial spasm (HFS) is a clinical condition characterized by involuntary contractions in facial muscles. The aim of the study was to investigate, systematically in 178 patients with HFS, the frequency of spread from the site of origin to other facial muscles. Patients enrolled underwent a complete neurological examination and a face-to-face interview. Spread of the spasm to other facial muscles was considered to be present in those patients whose spasms onset in a single site and involved both upper and lower facial muscles at the time of examination. We also collected information about gender, age, age at HFS onset, symptom duration, muscles involved by the spasm at the time of onset, and spread of spasm to other facial muscles. Spread of spasms to the other facial muscles of the same side of the face was present in 93.4% of patients with HFS, and latency of spread was related to disease duration and age at onset. In patients with HFS, spread of muscle spasms represents the natural history of HFS.

Half-mirror biofeedback exercise in combination with three botulinum toxin A injections for long-lasting treatment of facial sequelae after facial paralysis

OBJECTIVES/HYPOTHESIS

The present study was conducted to develop a new method for maintaining the effect of botulinum toxin treatment for facial sequelae. We used a combination strategy including the administration of botulinum toxin three times at 6-8-month intervals followed by daily newly developed half-mirror biofeedback rehabilitation for about 2 years from the first injection.

STUDY DESIGN

This was a prospective study.

METHODS

Seventeen patients with unilateral facial palsy for >1 year were included in the study. The amount injected per site varied from 1.5 to 3 U. The purpose of the first injection was to reduce the most inconvenient facial problem such as facial synkinesis or hyperkinetic movement at the points of the periocular area and the zygomaticus major and minor muscles with an average dosage of 17.4 ± 13.9 U. The second injection was to enhance facial symmetry at prominent hypertrophic areas on the contralateral side with 36.5 ± 15.4 U, and the third injection was to add cosmetic configuration at the points of deep furrows and creases caused by facial muscular hyperkinesis or atrophy with 15.6 ± 8.4 U.

RESULT

After three injections of botulinum toxin A and 2 years of half-mirror biofeedback exercises, all patients showed marked relief of facial synkinesis and facial asymmetry. Before treatment, the mean ± standard deviation (SD) Sunnybrook (SB) score was 36.8 ± 8.76. After the first injection, the score increased by 11.4. After the second injection, the score increased by 14.6; it further increased by 15.6 after the third injection.

CONCLUSION

This facial rehabilitation strategy, consisting of three injections of botulinum toxin and half-mirror biofeedback exercises, proceeds over the course of 2 years and offers a long-lasting cure for facial synkinesis and facial symmetry as well as improved facial aesthetics.

Effect of endoscopic brow lift on contractures and synkinesis of the facial muscles in patients with a regenerated postparalytic facial nerve syndrome

BACKGROUND

Delayed recovery after facial palsy results in aberrant nerve regeneration with symptomatic movement disorders, summarized as the postparalytic facial nerve syndrome. The authors present an alternative surgical approach for improvement of periocular movement disorders in patients with postparalytic facial nerve syndrome. The authors proposed that endoscopic brow lift leads to an improvement of periocular movement disorders by reducing pathologically raised levels of afferent input.

METHODS

Eleven patients (seven women and four men) with a mean age of 54 years (range, 33 to 85 years) and with postparalytic facial nerve syndrome underwent endoscopic brow lift under general anesthesia. Patients' preoperative condition was compared with their postoperative condition using a retrospective questionnaire. Subjects were also asked to compare the therapeutic effectiveness of endoscopic brow lift and botulinum toxin type A.

RESULTS

Mean follow-up was 52 months (range, 22 to 83 months). No intraoperative or postoperative complications occurred. During follow-up, patients and physicians observed an improvement of periorbital contractures and oculofacial synkinesis. Scores on quality of life improved significantly after endoscopic brow lift. Best results were obtained when botulinum toxin type A was adjoined after the endoscopic brow lift. Patients described a cumulative therapeutic effect.

CONCLUSIONS

These findings suggest endoscopic brow lift as a promising additional treatment modality for the treatment of periocular postparalytic facial nerve syndrome-related symptoms, leading to an improved quality of life. Even though further prospective investigation is needed, a combination of endoscopic brow lift and postsurgical botulinum toxin type A administration could become a new therapeutic standard.

Botulinum toxin injection of both sides of the face to treat post-paralytic facial synkinesis

OBJECTIVE

An attempt has been made to produce a new 'balance' in facial dynamics between a paralysed and a non-paralysed face with reduction of synkinesis, by concomitant injection of botulinum toxin A (BTX-A) on both sides in patients with long-lasting facial sequelae.

STUDY DESIGN

Prospective clinical study.

SETTING

University hospital.

SUBJECTS AND METHODS

Forty-two consecutive patients who recovered partially from facial nerve paralysis were enrolled for this study. The amount injected per site of the paralysed side with synkinesis varied from 1.5 to 2.5 U, and the total dose used per patient was 10-26 U (mean 17.12±5.3 U). That of the non-paralysed side with muscular hypertrophy varied from 2.5 to 5 U, and the total dose used per patient was 35-72 U (mean 52.6±9.7 U). All patients had been evaluated by the Sunnybrook (SB) facial nerve grading systems and developed dynamic facial asymmetry ratio.

RESULTS

After administration of injection of BTX-A on both sides of the face, relief of facial synkinesis and enhancement of facial symmetry were observed in all patients. Before the injection, the patients showed an SB score of 38.8±10.68. After the injection, changes of synkinesis and symmetry score were 7.9±1.81 and 8.4±3.25, respectively, resulting in a 58.4±12.46 score at the last evaluation. Before the administration, the mean±standard deviation (SD) value of dynamic facial asymmetry was 0.83±0.06 and it was increased significantly to 0.90±0.05 1 month after administration.

CONCLUSION

After BTX-A injection on both sides for synkinesis and contralateral hypertrophy, the patients showed significant suppression of the synkinesis and improvement of facial symmetry with resulting elevated quality of life, social interaction, personal appearance and food intake.

Blink reflex in patients with postparalytic facial syndrome and blepharospasm: trigeminal and auditory stimulation

OBJECTIVE

The enhancement of blink reflex (BR) excitability was shown in patients with postparalytic facial syndrome (PFS) and essential blepharospasm (EB). We prospectively investigated patients with PFS and EB whether BR alterations demonstrated by trigeminal stimulation will similarly be observed upon auditory stimulation.

METHODS

Fifteen patients with PFS, 15 patients with EB, and 30 healthy volunteers were involved. Electrically stimulated trigeminal BR and auditory BR were studied bilaterally.

RESULTS

The mean R2 amplitude and duration values were highest in EB patients, being significantly higher than PFS patients (p < 0.05) and control group (p < 0.01). The mean R2 duration in PFS patients were also significantly longer in compared to control group (p = 0.025). EB patients showed a higher mean R (auditory) amplitude and duration than PFS patients (p < 0.05) and controls (p < 0.04). The mean R (auditory) duration was longer on symptomatic side of PFS patients in compared to controls (p = 0.05).

CONCLUSIONS

We observed that there is an enhanced excitability of BR circuit in postparalytic facial syndrome and essential blepharospasm, which could be evoked by auditory stimulation in addition to trigeminal stimulation.

SIGNIFICANCE

The enhanced excitability in patients with EB and PFS probably originates from the final common pathway of BR circuit, namely facial motor or premotor neurons.

Therapeutic strategies in post-facial paralysis synkinesis in pediatric patients

Synkinetic movements comprise abnormal involuntary contractions of one or more facial muscle groups which follow the desired contraction of another facial muscle group. They are frequently encountered in patients with long standing facial paralysis and seriously affect their psychological status due to the impairment of their facial appearance, function and emotional expressivity.

PATIENTS AND METHODS

Eleven pediatric patients (2 male and 9 female) presenting with post-facial paralysis synkinesis were included in the study. Mean age was 10.3±4 years and mean denervation time 72.5 months.

RESULTS

Patients underwent the following types of treatment: --Cross facial nerve grafting (CFNG) and secondary microcoaptations with botulinum toxin injection which had an improvement of 100% (3 in the 3 grade synkinesis scale) (n=2). --Cross facial nerve grafting (CFNG) and secondary microcoaptations without botulinum toxin injection which had an improvement of 66%(2 in the 3 grade synkinesis scale) (n=5). --CFNG and direct muscle neurotization with (n=2) or without (n=1) botulinum toxin injection where the improvement was 33%. --Contralateral nasalis muscle myectomy was performed in one patient along with CFNG and secondary microcoaptations which resulted in 66% synkinesis improvement. Biofeedback was invariably undertaken by all patients. Postoperative improvement in eye closure and smile was also noted in the respective cases treated for synkinesis ranging from 25 to 50%, with all patients achieving optimum functional return.

CONCLUSION

CFNG with secondary microcoaptations and botulinum toxin injections was found to be a very efficient surgical modality addressing post-facial palsy synkinesis with high improvement in facial function and symmetry. Facial neuromuscular re-education contributes considerably in the treatment.

Ocular-jaw synkinesia in normal, Parkinson's disease, and multiple system atrophy subjects: Clinical and electrophysiological findings

OBJECTIVE

We occasionally observe cranial synkinesias that involve a lateral jaw movement ipsilateral to the horizontal gaze deviation in Parkinson's disease (PD) patients and normal subjects. We term this conjugated movement 'ocular-jaw synkinesia' (OJS). The clinical and electrophysiological features of OJS are described in this study.

METHODS

Eighty-two subjects were enrolled, 33 PD, 33 non-ill caregivers, and 16 multi system atrophy (MSA-p) patients. The subjects and patients were assessed clinically and electrophysiologically. The data were registered using two scales. The clinical findings were registered using the OJS scale, and the electrophysiological findings were registered using the eyes and chin ipsilateral deviation (ECD) scale. All subjects underwent a video recording.

RESULTS

Twenty-eight out of the 33 PD patients (84.7%) (P: 0.0141) and 25 out of the 33 normal subjects (83.3%) (P: 0.0144) displayed signs of OJS. None of the MSA-p patients showed signs of OJS, and 13 of the 16 control subjects (81.2%) showed OJS (p: 0.014). Twenty-nine out of the 33 PD patients (87.8%) (P: 0.0123) and 27 out of the 33 normal subjects (90%) (P: 0.0112) showed ECD at the electrophysiological examination. None of the MSA-p patients displayed ECD, showing a strong statistical significance when compared to control subjects (K: 0.0011).

CONCLUSIONS

OJS is a normal and common synkinetic cranial movement easy to observe in PD and normal subjects on both physical and electrophysiological examinations. In contrast, the MSA-p patients showed no physical or electrophysiological signs of OJS in this study.

SIGNIFICANCE

The presence of OJS is supportive of the clinical diagnosis of PD; its absence is uncommon in PD and may suggest an alternative Parkinsonism such as MSA-p.

Auditory evoked blink reflex and posterior auricular muscle response: observations in patients with HFS and PFS

Our goal was to investigate the characteristics of the auditory brainstem reflexes in patients with hemifacial spasm (HFS) and postparalytic facial syndrome (PFS). The spasm activities and responses by supraorbital and auditory stimuli were recorded from the orbicularis oculi, the posterior auricular and the mentalis muscles in 27 HFS and 21 PFS patients. The results were compared with those of 20 controls. Blink reflex (BR) was obtained by supraorbital stimulation in normal controls and on both sides of HFS and PFS patients whereas sound evoked bilateral auditory blink reflex (ABR) in 96.3%, 90.5% and 100%, respectively. Both BR and ABR showed synkinetic spread on symptomatic sides in all patients. The posterior auricular muscle response (PAMR) was observed bilaterally in 59.3%, 42.9% and 75.0% of groups, respectively. However, there was no synkinetic spread of PAMR. Since PAMR does not show synkinetic spread even in the presence of synkinetic spread of ABR and BR, we may suggest that a distal origin may be responsible of the synkinetic spread, or PAM is probably governed by a smaller nucleus in the brainstem. Thus it may be speculated that its excitability is insufficient to stimulate the ABR nucleus, whereas the reverse process is possible.

Motor unit number estimation in facial paralysis

The value of motor unit number estimation (MUNE) in determining the prognosis of acute peripheral facial paralysis (PFP) was evaluated in 89 patients with PFP on days 6, 8, 11, 14, 20, and 30 of PFP and repeated once per month until complete recovery or the end of the first year. The symptomatic/asymptomatic side ratios of the compound muscle action potential (CMAP) amplitudes recorded from nasalis muscles and MUNEs studied using the incremental method by recording from the same muscle were assessed with regard to three outcome groups (Group I, complete recovery; Group II, mild dysfunction; Group III, moderate-moderately severe dysfunction). CMAP and MUNE ratios were parallel to each other in all patient groups throughout the observation period with lower values in the more severe groups. However, CMAP amplitude loss was significantly greater than the MUNE loss in the first 3 weeks of PFP. The MUNE method is not superior to CMAP size in determining prognosis in PFP. However, the significant disparity between the CMAP and MUNE ratios in the early period may have some physiological relevance with regard to the pathophysiology of the Wallerian degeneration process and deserves further research into its potential sources.

Hemifacial spasm associated with an intracranial mass in two dogs

Two dogs were presented with hemifacial spasm. Computed tomography images of both the dogs revealed an intracranial mass. In the first dog, a lesion at the level of the medulla oblongata was thought to cause primary irritation of the facial nucleus, with consequently permanent contraction of the ipsilateral facial muscles. In the second dog, a mass seemingly arising from the middle cranial fossa presumably isolated the facial motor neurons from upper motor neuron control, which resulted in hemifacial spasm as a result of loss of inhibitory interneuronal activity.

Spastic paretic hemifacial contracture in multiple sclerosis: a neglected clinical and EMG entity

Background

Spastic paretic hemifacial contracture (SPHC) is an uncommon condition, originally described as a sign of brainstem neoplasia, characterized by sustained unilateral contraction of the facial muscles associated with mild ipsilateral facial paresis. SPHC has only rarely been reported in the context of multiple sclerosis (MS). To further study and assess the frequency of SPHC in patients with MS.

Methods

We screened clinically 500 consecutive patients with MS for the presence of SPHC and further studied electrophysiologically any cases identified.

Results

We identified two patients who developed the condition during the course of an MS relapse. The estimated frequency of the condition was 0.4%. Both patients had relapsing–remitting MS. SPHC was characterized on Electromyography (EMG) by continuous resting activity of irregularly firing motor unit potentials, associated with impaired recruitment of motor units on voluntary contraction. Myokymic discharges were not present. Blink reflex studies were partly consistent with midpontine lesions in the vicinity of the facial nucleus ipsilateral to SPHC. MRI showed lesions in the ipsilateral dorsolateral midpontine tegmentum.

Conclusions

SPHC constitutes a rare but distinct clinical and EMG entity in patients with MS.

Cortical excitability in Duchenne muscular dystrophy

OBJECTIVE

To investigate the probable cortical excitability changes in DMD by electrophysiological means.

METHODS

Sixteen cases with DMD, 10 age-matched control children (CC) and 10 healthy adult volunteers (AC) were studied with a transcranial magnetic stimulation (TMS) test battery composed of central conduction time, cortical silent period and paired TMS paradigm.

RESULTS

There were no significant differences between DMD and CC groups except for lower amplitude motor responses in DMD cases. These two groups showed a similar pattern of excitability with less short interval intracortical inhibitions and shorter silent period durations as compared to the AC subjects.

CONCLUSIONS

The electrophysiological tests performed in our DMD patients did not reveal abnormalities caused particularly by the disorder.

SIGNIFICANCE

TMS excitability studies performed in DMD boys may not provide findings other than those related to the developmental age.