Search Results (26)

Background: Surface electromyography (sEMG) enables the non-invasive assessment of muscle activity and is widely used in orthodontics for evaluating masticatory muscles. However, little is known about the dynamic changes in facial expression muscles during orthodontic treatment. This study aimed to investigate alterations in facial muscle tone during the leveling and alignment phase in adult female patients undergoing fixed appliance therapy. Methods: The study included 30 female patients aged 20–31 years who underwent sEMG assessment at four time points: before treatment initiation (T0), at the start of appliance placement (T1), three months into treatment (T2), and six months into treatment (T3). Muscle activity was recorded during four standardized facial expressions: eye closure, nasal strain, broad smile, and lip protrusion. Electrodes were placed on the orbicularis oris, orbicularis oculi, zygomaticus major, and levator labii superioris alaeque nasi muscles. A total of 1440 measurements were analyzed using Friedman and Conover-Inman tests (α = 0.05). Results: Significant changes in muscle tone were observed during treatment. During lip protrusion, the orbicularis oris and zygomaticus major showed significant increases in peak and minimum activity (p < 0.01). Eye closure was associated with altered orbicularis oris activation bilaterally at T3 (p < 0.01). Nasal strain induced significant changes in zygomaticus and levator labii muscle tone, particularly on the right side (p < 0.05). No significant changes were noted during broad smiling. Conclusions: Orthodontic leveling and alignment influence the activity of selected facial expression muscles, demonstrating a dynamic neuromuscular adaptation during treatment. These findings highlight the importance of considering soft tissue responses in orthodontic biomechanics and suggest potential implications for facial esthetics and muscle function monitoring. Full article

Background and Objectives: The effects of face yoga, which continues to be popular as an anti-aging technique, on facial muscles in relation to aging represent an area of interest. The aim of this study was to investigate the effect of 8 weeks of intensive face yoga on facial muscles’ tonus, stiffness, and elasticity in middle-aged women. Materials and Methods: Twelve female participants with a mean age of 49.75 ± 3.76 were included in this pre-experimental clinical trial. Face yoga was applied to the participants for 8 weeks, 2 days a week face-to-face, and 5 days a week as a home program. At the beginning and the end of 8 weeks, the tonus, stiffness, and elasticity of the participants’ facial muscles were evaluated with the Myoton^®PRO device. Results: Following the face yoga program, the tonus and stiffness of the frontalis (p = 0.008, p = 0.002), corrugator supercilii (p = 0.008, p = 0.019), orbicularis oculi (p = 0.023, p = 0.034), and orbicularis oris (p = 0.007, p = 0.015) muscles decreased significantly, while the tonus and stiffness of the buccinator (p = 0.008, p = 0.002) and digastric (p = 0.008, p = 0.023) muscles increased. Elasticity values increased in all evaluated facial muscles (p = 0.045, p = 0.045, p = 0.034, p = 0.023, p = 0.028, p = 0.005, respectively). Conclusions: The results reveal that face yoga has different effects depending on the physiological structure and function of the muscles and positively affects connective tissue. Future studies should reproduce the results presented here to further our understanding of the effects of face yoga. Full article

Background/Objective: The orbicularis oculi muscle (OOM) is crucial for eyelid function and ocular protection. Surface electromyography (sEMG) is a useful tool for assessing OOM activity, but interpretation remains limited due to a lack of standardized reference values. This study investigates the influence of gender, laterality, and age on OOM activity using sEMG. Methods: In total, 84 healthy adult participants (44 females and 40 males) underwent sEMG measurements for both eyes during gentle (GEC) and maximal (MVC) voluntary eyelid closure. Results: The average age was 62.5 years (ranging from 27 to 86; SD = 13.79) for males, and 63.12 years (ranging from 27 to 87; SD = 13.8) for females. The mean Root Mean Square (RMS) MVC values were 157.80 ± 56.43 for men and 146.45 ± 56.48 for women. The mean RMS GEC values were 7.42 ± 2.94 for men and 8.35 ± 4.86 for female. No significant gender-based differences were found (p-value = 0.195 and 0.138, respectively). No significant differences between sides were found: The mean RMS MVC values were 152.24 ± 57.73 for left eyes and 151.47 ± 55.74 for right eyes (p-value = 0.93). The mean RMS GEC values were 8.29 ± 5.04 for left eyes and 7.53 ± 2.79 for right eyes (p-value = 0.227). The age of participants correlated negatively with maximal amplitude, mean amplitude, RMS and the difference between RMS and RMS baseline in MVC (p-value < 0.001). Conclusions: While OOM function remains consistent across gender and between eyes, aging contributes to a decline in OOM performance. Age-adjusted reference values may be beneficial in clinical and research applications assessing facial muscle function. Full article

Background/Objectives: Blepharospasm (BSP) is a focal dystonia characterized by involuntary, bilateral spasms of the orbicularis oculi muscle. While botulinum toxin (BoNT) is the standard treatment, cognitive tasks such as reading and writing may exert transient modulatory effects on spontaneous blinking and dystonic spasms. This study investigates the potential of cognitive training, including reading and writing tasks, as a complementary therapeutic approach to BoNT in BSP patients. Methods: A total of 16 BSP patients were randomly assigned to two groups: Group A (n = 6) received cognitive training alongside BoNT, while Group B (n = 10) received only BoNT. Cognitive training included structured reading and writing exercises over three months. Blink rate (BR) and dystonic spasms were assessed at baseline (T0), one month (T1), and three months (T2) post-treatment. Results: Both groups exhibited a significant reduction in BR at T1 (p = 0.001), but Group A exhibited a greater improvement in BR (45.4%) compared to that of Group B (12.6%, p = 0.04). Reading and writing tasks were the most effective in reducing BR and dystonic spasms (p < 0.001). No significant correlation was found between the clinical and demographic features (p > 0.05). Conclusions: Cognitive training significantly enhances the therapeutic effects of BoNT on BR in BSP patients, suggesting its potential as a non-invasive complementary intervention. These preliminary findings warrant further investigation using larger cohorts and employing neurophysiological assessments. Full article

Study design: literature review. Introduction: Irreversible facial paralysis is a chronic condition characterized by an absence of mimetic muscle tone and function. This disruption of facial expressions not only has functional, but also psychological and social consequences. In facial dynamic reanimation, techniques are proposed partly recovering facial reanimation and function. To date, a vast amount of literature is available on dynamic reanimation techniques. However, no review has yet been published that delineates in detail the musculature and techniques used for dynamic reanimation in irreversible facial paralysis. Objective: the aim of the present paper is to offer a complete overview of possible techniques. Methods: A chapter division is made between the lower, mid-, and upper face. Each chapter is subdivided between local transposition, free muscle flaps, and for the upper face, implantable devices. Results: The literature discussing reanimation of the lower face is limited. In midfacial reanimation, temporalis transposition and gracilis free flap transfer are popular. In upper facial reanimation, no consensus on muscle choice is available, and information is limited too. Suggested techniques include orbicularis oculi transpositioning, temporalis transpositioning, and platysma free muscle transfer. Conclusions: This paper discusses the current techniques for dynamic facial reanimation. Yet, studies comparing different techniques are lacking, setting ground for future research. This paper highlights the importance of a personalized approach in selecting a fitting reconstruction method. Full article

Background: Age-related changes to the orbicularis oculi muscle include impaired eyelid function, such as lagophthalmos, alterations in tear film dynamics, and aesthetic changes like wrinkles, festoons, and the descent of soft tissue. To date, the structural and functional changes that would comprehensively increase our understanding of orbicularis aging have not been analyzed. This study aims to investigate functional outcomes using surface electromyography and correlate them with ultrastructural changes in orbicularis during aging. Methods: This study enrolled 26 patients aged 37 to 78 years with a clinical diagnosis of dermatochalasis. Patients were divided into two age groups (<60 years; ≥60 years). Ultrastructural and electromyographical examinations were performed, and the electromyographical signals were correlated with the ultrastructural damage in the orbicularis. Results: This study revealed significantly lower values of average voluntary contraction and RMS of the surface electromyography signals in the older age group compared to the younger age group (p = 0.029 and p = 0.045, respectively). There was no statistically significant association between age and muscle damage (χ²(2) = 2.86, p > 0.05). There was no correlation between average voluntary contraction and the degree of ultrastructural damage in both groups (Spearman’s coefficient equaled 0.06923 and 0.64366, respectively). Conclusions: sEMG measurements are valuable for monitoring age-related functional changes in the orbicularis. Aging diminishes the functional capacity of the orbicularis, as evidenced by reduced contraction strength. This study, the first to compare ultrastructural and electromyographical changes in the orbicularis among dermatochalasis patients of different ages, finds that ultrastructural damage to muscle fibers is not directly responsible for the contraction strength decline. Full article

Botulinum neurotoxin type-A (BoNT/A), which blocks quantal acetylcholine (ACh) release at the neuromuscular junction (NMJ), has demonstrated its efficacy in the symptomatic treatment of blepharospasm. In 3.89% of patients treated for blepharospasm at Tenon Hospital, BoNT/A was no longer effective in relieving the patient’s symptoms, and a partial upper myectomy of the Orbicularis oculi muscle was performed. We used surgical waste samples from 14 patients treated with repeated injections of either abobotulinumtoxinA (Dysport^®) or incobotulinumtoxinA (Xeomin^®). These muscle fragments were compared to others from 4 normal subjects, naïve of BoNT/A. The morphological study was performed blinded to the BoNT/A treatment and between treated and control samples. Neuromuscular specimens analyzed by confocal laser scanning microscopy, using fluorescent staining and immune-labeling of presynaptic proteins, revealed that the pattern of innervation (e.g., polyneuronal and convergent innervation), the muscle nicotinic ACh receptors (nAChRs), and the NMJs exhibited marked differences in BoNT/A-treated muscles (regardless of the toxin clinically used), with respect to controls. BoNT/A-treated junctions exhibited profuse polyneuronal innervation in which 2–6 axons innervated 74.84% of single muscle fibers, while 99.47% of control junctions were mono-innervated. Another new finding was the stable convergent innervation, in which several motor axons end onto the same endplate. Morphological signs of synapse elimination included the presence of retraction bulbs in axons and nerve terminals and a reduced extension of postsynaptic nAChRs. These outcomes suggest that synapse elimination is altered and raise questions on the origin and factors contributing to the plasticity changes observed and the functioning of NMJs. Full article

Background: Due to the high incidence of malignant tumors of the lower eyelids and the widespread use of surgery for their treatment, the reconstruction of tissues in this area is a frequent task for surgeons. Methods for restoring full-thickness lower eyelid defects are often invasive, pose a significant risk of complications, and do not provide optimal results. Methods: The authors developed a simple technique for the reconstruction of full-wall defects of the lower eyelids. It is a V-Y-type musculocutaneous island flap from the lower eyelid, with the orbicularis oculi muscle folded in the upper part and partially left for spontaneous healing, called by the authors a “floating island flap”. Between 2012 and 2023, 39 patients were operated on using this method. Results: Surgical procedures performed under local anesthesia were well tolerated by the patients. The healing process was quick and well accepted. Complications were rare. The most common were: eye irritation and temporary swelling of the flap. In 37 patients, proper protection of the eyeball and good esthetic results were achieved; only in two cases was the cosmetic result assessed as poor. Corneal defects occurred in two cases and healed after conservative treatment. In no cases was reoperation necessary. Conclusions: The developed method is simple and effective. It can be widely used in the reconstruction of full-thickness defects of the lower eyelids. Full article

Background: The superficial musculoaponeurotic system (SMAS) is crucial for the structural integrity and dynamics of facial expressions and is a particularly important consideration during facelift surgeries. This study investigated the anatomical structure and continuity of the SMAS at the site where the zygomaticus major (Zmj) originates, which is where the SMAS extends from the lateral to the anterior aspects of the face. Knowledge of these aspects is crucial for understanding the mechanics of facial movements and also the aging process. Methods: Dissections of 66 specimens and histological analyses were used to explore the intricate relationships and attachments between the SMAS and facial muscles. Results: The findings indicated that at the Zmj origin site, the SMAS—connected to the inferior margin of the orbicularis oculi—covered the superficial surface of the Zmj fibers. As it tracked downward, the SMAS was observed to split into two layers lateral to the Zmj fibers, enveloping them both superficially and deeply. Additionally, as the SMAS continued forward, it ceased to be distinctly visible in the buccal area. Conclusions: These results provide a deeper understanding of the complex layering and interconnectivity of the SMAS, which supports facial dynamics and structural integrity. This information could be particularly useful in surgical and aesthetic procedures in the midfacial area. Full article

Background: Vestibular schwannoma (VS) surgery may cause facial nerve damage. However, a comprehensive evaluation of post-operative facial outcomes may be difficult to achieve. Surface electromyography (sEMG) is a promising non-invasive evaluation tool. However, its use in the follow-up after VS surgery has not been reported yet. The main objective was to develop and validate a new sEMG application specifically for the post-VS surgery setting. Secondary goals were to provide a systematic description of facial muscle activity after VS surgery and assess the association between sEMG parameters and Sunnybrook scale scores. Methods: Thirty-three patients with facial palsy following VS surgery were included. The clinical outcomes (Sunnybrook symmetry, movement, and synkinesis scores) and sEMG parameters (signal amplitude normalized by the maximal voluntary contraction (NEMG) and sEMG synkinesis score (ESS, number of synkinesis per movement sequence)) were evaluated at the end of the follow-up. Results: In all tested muscles, NEMG variance was significantly higher on the affected side than the contralateral (variance ratio test, p < 0.00001 for each muscle). In total, 30 out of 33 patients (90.9%) showed an ESS ≥ 1 (median: 2.5, IQR: 1.5–3.0). On the affected side, NEMG values positively correlated with both dynamic and overall Sunnybrook scores (Spearman’s model, p < 0.05 for each muscle, except orbicularis oculi). ESS significantly correlated with the Sunnybrook synkinesis score (Spearman’s rho: 0.8268, p < 0.0001). Conclusions: We described and preliminarily validated a novel multiparametric sEMG approach based on both signal amplitude and synkinesis evaluation specifically for oto-neurosurgery. Large-scale studies are mandatory to further characterize the semiological and prognostic value of facial sEMG. Full article

The role of TRPA1 in the thermosensitivity of the corneal cold thermoreceptor nerve endings was studied in young and aged mice. The contribution of the TRPA1-dependent activity to basal tearing and thermally-evoked blink was also explored. The corneal cold thermoreceptors’ activity was recorded extracellularly in young (5-month-old) and aged (18-month-old) C57BL/6WT (WT) and TRPA1^−/− knockout (TRPA1-KO) mice at basal temperature (34 °C) and during cooling (15 °C) and heating (45 °C) ramps. The blink response to cold and heat stimulation of the ocular surface and the basal tearing rate were also measured in young animals using orbicularis oculi muscle electromyography (OOemg) and phenol red threads, respectively. The background activity at 34 °C and the cooling- and heating-evoked responses of the cold thermoreceptors were similar in WT and TRPA1-KO animals, no matter the age. Similar to the aged WT mice, in the young and aged TRPA1-KO mice, most of the cold thermoreceptors presented low frequency background activity, a low cooling threshold, and a sluggish response to heating. The amplitude and duration of the OOemg signals correlated with the magnitude of the induced thermal change in the WT but not in the TRPA1-KO mice. The basal tearing was similar in the TRPA1-KO and WT mice. The electrophysiological data suggest that the TRPA1-dependent nerve activity, which declines with age, contributes to detecting the warming of the ocular surface and also to integrating the thermally-evoked reflex blink. Full article

Ramsay Hunt syndrome (RHS) has a poor prognosis because of varicella-zoster virus (VZV) infection. This is most closely related to severe inflammation in the geniculate ganglion of the facial nerve due to VZV infection or reactivation. This study investigated whether there were differences in the prognosis and accompanying symptoms of facial paralysis based on the presence or absence of VZV IgM and IgG antibodies. This study was conducted as a retrospective chart analysis of 105 patients with RHS who were admitted to our hospital between 2015 and 2021. The House–Brackmann (HB) grade and electroneurography (ENoG) was used to evaluate the degree of facial paralysis. Patients’ subjective symptoms were evaluated by dividing them into dizziness, tinnitus, hyperacusis, and hearing loss. No difference was observed in the initial HB grade with or without IgM; however, the final HB grade was significantly higher in IgM-positive patients than in IgM-negative patients (p < 0.05). Further, when IgM was positive, the value of the orbicularis oculi muscle in the ENoG test results was significantly higher (p < 0.05), and symptoms of tinnitus and hyperacusis occurred more frequently (p < 0.05). The initial and final HB grades were significantly higher in IgG-positive patients than in IgG-negative patients (p < 0.05). When IgG was positive, the values of nasalis and oris muscles in the ENoG test results were significantly higher (p < 0.05), and symptoms of dizziness occurred more frequently (p < 0.05). This study confirmed that the more active the immunological action of the VZV in the body, the greater the damage to the facial and vestibulocochlear nerves, which are associated with the degree of facial paralysis and the accompanying otologic symptoms. Full article

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

The aim of this study was to assess changes in headaches, eyebrow height, and electromyographic (EMG) outcomes of the frontalis and orbicularis oculi muscles, after an upper blepharoplasty with or without resecting a strip of orbicularis oculi muscle. In a randomized controlled trial, 54 patients received an upper blepharoplasty involving either only removing skin (group A) or removing skin with an additional strip of orbicularis muscle (group B). Preoperative, and 6 and 12 months postoperative headache complaints were assessed using the HIT-6 scores and eyebrow heights were measured on standardised photographs. Surface EMG measurements, i.e., electrical activity and muscle fatigue, were assessed for the frontalis and orbicularis oculi muscles preoperatively and 2, 6, and 12 months postoperatively. Significantly fewer headaches were reported following a blepharoplasty. The eyebrow height had decreased, but did not differ between groups. Regarding the surface EMG measurements, only group A’s frontalis muscle electrical activity had decreased significantly during maximal contraction 12 months after surgery (80 vs. 39 mV, p = 0.026). Fatigue of both the frontalis and the orbicularis oculi muscles did not change significantly postoperatively compared to baseline. EMG differences between groups were minor and clinically insignificant. The eyebrow height decreased and patients reported less headaches after upper blepharoplasty irrespective of the used technique. Full article

Facial nerve stimulation (FNS) is a potential complication which may affect the auditory performance of children with cochlear implants (CIs). We carried out an exploratory prospective observational study to investigate the effects of the electrical stimulation pattern on FNS reduction in young children with CI. Ten ears of seven prelingually deafened children with ages up to 6 years old who undergone a unilateral or bilateral CI surgery were included in this study. Electromyographic (EMG) action potentials from orbicularis oculi muscle were recorded using monopolar biphasic stimulation (ST1) and multi-mode monophasic stimulation with capacitive discharge (ST2). Presence of EMG responses, facial nerve stimulation thresholds (T-FNS) and EMG amplitudes were compared between ST1 and ST2. Intra-cochlear electrodes placement, cochlear-nerve and electrode-nerve distances were also estimated to investigate their effects on EMG responses. The use of ST2 significantly reduced the presence of intraoperative EMG responses compared to ST1. Higher stimulation levels were required to elicit FNS with ST2, with smaller amplitudes, compared to ST1. No and weak correlation was observed between cochlea-nerve and electrode-nerve distances and EMG responses, respectively. ST2 may reduce FNS in young children with CI. Differently from the electrical stimulation pattern, the cochlea-nerve and electrode-nerve distances seem to have limited effects on FNS in this population. Full article