Muscle Tone Assessment by Machine Learning Using Surface Electromyography.

Muscle tone is defined as the resistance to passive stretch, but this definition is often criticized for its ambiguity since some suggest it is related to a state of preparation for movement. Muscle tone is primarily regulated by the central nervous system, and individuals with neurological disorders may lose the ability to control normal tone and can exhibit abnormalities. Currently, these abnormalities are mostly evaluated using subjective scales, highlighting a lack of objective assessment methods in the literature. This study aimed to use surface electromyography (sEMG) and machine learning (ML) for the objective classification and characterization of the full spectrum of muscle tone in the upper limb. Data were collected from thirty-nine individuals, including spastic, healthy, hypotonic and rigid subjects. All of the classifiers applied achieved high accuracy, with the best reaching 96.12%, in differentiating muscle tone. These results underscore the potential of the proposed methodology as a more reliable and quantitative method for evaluating muscle tone abnormalities, aiming to address the limitations of traditional subjective assessments. Additionally, the main features impacting the classifiers' performance were identified, which can be utilized in future research and in the development of devices that can be used in clinical practice.

Bibliometric Analysis of Botulinum Toxin and Bruxism: Impact, Visualization, and Collaborative Networks.

AIM: To analyze the scientific production related to the use of botulinum toxin (BTX-A) in the management of bruxism and evaluate its scope, impact, networks, and new research trends. MATERIALS AND METHODS: A descriptive and retrospective study of publications indexed in Scopus from January 2018 to May 2024 was conducted. The bibliometric indicators evaluated were a number of publications, citations, h-index, SCImago Journal Rank 2022, CiteScore 2022, Lotka's Law, Bradford's Law, and keyword co-occurrence analysis. Data were processed using SciVal and VOSviewer. RESULTS: We obtained 98 publications, including original articles, reviews, and other types of documents. Among the most productive authors, most were from South Korea and Turkey. Wonkwang University (South Korea) had the highest number of publications, while Baylor College of Medicine (USA) had the highest impact with 66.5 citations per publication. Toxins had the highest number of publications and the best Cite Score in 2022. Six main topics related to BTX-A in bruxism were identified, highlighting "reviews," "electromyography" and "controlled clinical trials". CONCLUSIONS: The use of BTX-A for the treatment of bruxism has generated increasing interest and scientific output in recent years, especially in South Korea and Brazil. However, there is a disparity in the productivity of authors, with most authors presenting only one publication. CLINICAL SIGNIFICANCE: This study highlights the need for further research and collaborations to optimize clinical practice and better understand the efficacy and management of BTX-A for treating bruxism. How to cite this article: Villanueva-García M, Ruck-Sanchez N, Tinedo-López PL, et al. Bibliometric Analysis of Botulinum Toxin and Bruxism: Impact, Visualization, and Collaborative Networks. J Contemp Dent Pract 2024;25(6):599-604.

Sexual function in women with endometriosis and pelvic floor myofascial pain syndrome.

Objective: To evaluate and compare the sexual function and pelvic floor muscles (PFM) function of women with endometriosis and chronic pelvic pain (CPP) with and without Myofascial Pelvic Pain Syndrome (MPPS). Methods: Cross-sectional study conducted between January 2018 and December 2020. Women with deep endometriosis underwent assessments for trigger points (TP) and PFM function using the PERFECT scale. Electromyographic activity (EMG) and sexual function through Female Sexual Function Index (FSFI) were assessed. Statistical analyses included chi-square and Mann-Whitney tests. Results: There were 46 women. 47% had increased muscle tone and 67% related TP in levator ani muscle (LAM). Weakness in PFM, with P≤2 was noted in 82% and P≥3 in only 17%. Incomplete relaxation of PFM presented in 30%. EMG results were resting 6.0, maximal voluntary isometric contraction (MVIC) 61.9 and Endurance 14.2; FSFI mean total score 24.7. We observed an association between increased muscle tone (P<.001), difficulty in relaxation (P=.019), and lower Endurance on EMG (P=.04) in women with TP in LAM. Participants with TP presented lower total FSFI score (P=.02). TP in the right OIM presented increased muscle tone (P=.01). TP in the left OIM presented lower values to function of PFM by PERFECT (P=.005), and in MVIC (P=.03) on EMG. Conclusion: Trigger points (TP) in pelvic floor muscles (PFM) and obturator internus muscle (OIM) correlates with poorer PFM and sexual function, particularly in left OIM TP cases. Endometriosis and chronic pelvic pain raise muscle tone, weaken muscles, hinder relaxation, elevate resting electrical activity, lower maximum voluntary isometric contraction, and reduce PFM endurance.

Influence of vitamin D on muscle strength and botulinum toxin dosage through surface electromyography.

PURPOSE: To evaluate the influence of patients' serum vitamin D levels on muscle strength characteristics and whether it impacts the durability of botulinum toxin (BT) treatment. METHODS: The muscle strength of the frontal and corrugator muscles was evaluated before and after the application of TB with pre- and post-application control measurements, and at weeks 2, 5 and 12. The effect of vitamin D on muscle strength and its interaction with BT were investigated in 20 patients. The muscle contraction force was measured by surface electromyography. RESULTS: The results revealed statistically significant differences between the frontal measurement groups at weeks 2 and 5, as well as for the corrugator in the same weeks and at week 12. Regarding vitamin D, significant differences were observed only in the initial group with vitamin D > 30 ng/mL compared to < 30 ng/mL for the frontal muscles. Patients with higher levels of vitamin D had higher average muscle strength compared to those with lower levels in all evaluations. CONCLUSIONS: It was observed that vitamin D influences muscle strength and the necessary dosage of BT.

Music therapy with adult burn patients in the intensive care unit: short-term analysis of electrophysiological signals during music-assisted relaxation.

Burn patients often face elevated pain, anxiety, and depression levels. Music therapy adds to integrative care in burn patients, but research including electrophysiological measures is limited. This study reports electrophysiological signals analysis during Music-Assisted Relaxation (MAR) with burn patients in the Intensive Care Unit (ICU). This study is a sub-analysis of an ongoing trial of music therapy with burn patients in the ICU. Electroencephalogram (EEG), electrocardiogram (ECG), and electromyogram (EMG) were recorded during MAR with nine burn patients. Additionally, background pain levels (VAS) and anxiety and depression levels (HADS) were assessed. EEG oscillation power showed statistically significant changes in the delta (p < 0.05), theta (p = 0.01), beta (p < 0.05), and alpha (p = 0.05) bands during music therapy. Heart rate variability tachograms high-frequencies increased (p = 0.014), and low-frequencies decreased (p = 0.046). Facial EMG mean frequency decreased (p = 0.01). VAS and HADS scores decreased - 0.76 (p = 0.4) and - 3.375 points (p = 0.37) respectively. Our results indicate parasympathetic system activity, attention shifts, reduced muscle tone, and a relaxed state of mind during MAR. This hints at potential mechanisms of music therapy but needs to be confirmed in larger studies. Electrophysiological changes during music therapy highlight its clinical relevance as a complementary treatment for ICU burn patients.Trial registration: Clinicaltrials.gov (NCT04571255). Registered September 24th, 2020. https//classic.clinicaltrials.gov/ct2/show/NCT04571255.

Electromyographic and behavioral analysis of horses submitted to medial patellar desmotomy.

The passive stay apparatus works by blocking flexion of the knee and tarsus joints in the horse, preventing muscle fatigue. During ambulation, if this mechanism fails to release, the animal will present upward fixation of the patella, which in severe cases, can only be treated by medial patellar desmotomy (MPD). The objective of this study was to investigate the possible electromyographic and behavioral changes, after the impairment of the passive stay apparatus, in horses who have undergone MPD surgery. Five horses presenting dorsal fixation of the patella underwent electromyographic measurements at preoperatively and immediately postoperatively, 24 h, seven, 14 and 21 days after surgery. The samples were collected on a computerized surface electromyograph designed in accordance with the standards of international society of electrophysiology and kinesiology (ISEK). To capture the signals, electrodes positioned on the tensor fasciae lata, vastus lateralis, biceps femoris and semitendinosus muscles were used, bilaterally. These muscles were chosen due to their participation in the passive stay apparatus. The electromyographic signals were collected and processed using a software calibrated to collect data with a sampling frequency of 1000 Hz per channel. The collections took place over 60 min periods, and the results were obtained from the root means square (RMS) analysis. It was noted that the preoperative average of rest in tripedal support was 62%. On the other hand, change in weight bearing member and rest in three limbs in the postoperative period did not occur. This inability to maintain tripedal support in the postoperative period prevents the horse from resting while standing. Furthermore, there was a gradual increase in the need for post-surgical muscle recruitment, resulting in long periods of decubitus due to muscle fatigue, which is less than ideal for such large animals. Therefore, it was concluded that the animals submitted to medial patellar desmotomy, in this study, presented an inability to maintain tripedal support, in addition to a greater need for recruitment of muscle fibers, evidenced by the gradual increase in the electromyographic tracing and total RMS value of the muscles evaluated.

Impact of a mandibular advancement device on corticomotor plasticity in patients with obstructive sleep apnea.

BACKGROUND: Neuroplasticity induced by mandibular advancement appliance (MAD) in patients with obstructive sleep apnoea (OSA) is poorly documented. OBJECTIVE: This randomised placebo-controlled crossover mechanistic study assessed the effects of short-term use of a MAD on corticomotor excitability of the masseter and tongue in patients with OSA. METHODS: Adults (n = 28) with mild or moderate OSA were randomly allocated to sleep with a MAD for 2-weeks with 40% of the maximal protrusion (MAD active position) and without any jaw protrusion (MAD placebo position). The outcomes were assessed at baseline, and after 2 and 6 weeks, with a 2-week washout period. The primary outcome was the amplitude of motor evoked potential (MEP) assessed on the right masseter, right side of tongue and right first dorsal interosseous with transcranial magnetic stimulation. Corticomotor map volume of the same muscles was also assessed. Repeated-measures ANOVAs followed by Tukey test were applied to the data (p < .050). RESULTS: There was a significant increase in the MEP amplitude of the masseter and tongue following the MAD active position compared with the baseline and MAD placebo (Tukey: p < .001). There were no significant MEP amplitude differences between the baseline and placebo positions (p > .050). Moreover, there was a significant increase in corticomotor map volume for the masseter and tongue muscles following the MAD active position compared with baseline and MAD placebo (Tukey: p < .003). CONCLUSION: Excitability of the masseter and tongue motor pathways is, at least transiently, increased in patients with OSA following a short-term use of MAD. This novel finding of MAD-induced neuroplasticity in corticomotor pathways may contribute to a further understanding of the mechanisms of oral appliances for treating OSA.

Acute effects of the short-foot exercise in runners with medial tibial stress syndrome: A quasi-experimental study.

OBJECTIVES: Analyze whether there are immediate changes in peak soleus activation and peak hindfoot eversion after short-foot exercise (SFE) in runners with medial tibial stress syndrome (MTSS). Secondarily, establish differences in peak soleus activation and peak hindfoot eversion between asymptomatic individuals and those presenting MTSS. DESIGN: Quasi-experimental study. SETTING: University Laboratory. PARTICIPANTS: Thirty-two runners participated: 16 with MTSS and 16 in the no-pain group (NPG). MAIN OUTCOME MEASURES: Soleus activation was measured using electromyography, and hindfoot eversion via 3D kinematic analysis. Participants performed SFE, and running data were collected at 9,12 and 15 km/h pre- and post-intervention. RESULTS: SFE reduced peak soleus activation at 9 (p = 0.017) and 15 km/h (p = 0.019) for the MTSS group and at 15 km/h (p < 0.001) for the NPG, suggesting improved neuromuscular efficiency and potentially reduced tibial stress. SFE did not significantly affect peak hindfoot eversion. Significant correlations were found between ankle dorsiflexion range of motion and muscle activation (r = 0.585 to 0.849, p < 0.05). These findings suggest SFE could improve neuromuscular efficiency and reduce tibial stress, and highlights ankle flexibility's role in muscle activation. CONCLUSIONS: SFE significantly reduces soleus activation, potentially improving neuromuscular efficiency and decreasing tibial stress.

Variability in quantitative outcomes of instrumental swallowing assessments in adults: a scoping review. / Variabilidade dos desfechos quantitativos nas avaliações instrumentais da deglutição em adultos: uma revisão de escopo.

PURPOSE: To map scientific evidence on the variability of quantitative parameters extracted by instrumental swallowing assessment tests in adults, using the coefficient of variation. RESEARCH STRATEGIES: The methodological procedures recommended by the Joanna Briggs Institute and the extension for scoping reviews of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA-ScR) were followed. SELECTION CRITERIA: The search was carried out in the Pubmed/Medline, Lilacs, Cochrane Library, Embase, Web of Science, Scopus and CINAHL databases, as well as in Google Scholar to consult the gray literature. DATA ANALYSIS: Two blind and independent reviewers screened the articles by title and abstract. Subsequently, the articles were read in full and selected according to the eligibility criteria. Data were extracted according to a standardized instrument. RESULTS: 363 studies were found, 13 of which were eligible. Most studies had a sample size of less than 30 participants and were made up of healthy individuals. The instrumental exams used were diverse: videofluoroscopy, electrical impedance tomography, laryngeal sensors, high-resolution manometry and surface electromyography. The studies searched for intra-individual variability and the coefficient of variation ranged from low to high variability, as the instruments, parameters and collection procedures were very heterogeneous and non-standardized. CONCLUSION: Intra-individual variability of the quantitative outcomes of instrumental swallowing assessments in adults ranged from low to high according to the exam, outcome, presence or absence of underlying disease, consistency and volume of the bolus.

OBJETIVO: Mapear as evidências científicas sobre a variabilidade dos parâmetros quantitativos extraídos por exames instrumentais de avaliação da deglutição em adultos, mediante o coeficiente de variação. ESTRATÉGIA DE PESQUISA: Foram seguidos os procedimentos metodológicos recomendados pelo Joanna Briggs Institute e a extensão para revisões de escopo do Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA-ScR). CRITÉRIOS DE SELEçÃO: A busca foi realizada nas bases de dados Pubmed/Medline, Lilacs, Cochrane Library, Embase, Web of Science, Scopus e CINAHL, assim como no Google Scholar para consultar a literatura cinzenta. ANÁLISE DOS DADOS: Dois revisores cegos e independentes fizeram o rastreamento dos artigos por título e resumo. Posteriormente, os artigos foram lidos na íntegra e selecionados de acordo com os critérios de elegibilidade. Os dados foram extraídos de acordo com um instrumento padronizado. RESULTADOS: Foram encontrados 363 estudos, sendo 13 elegíveis. A maioria dos estudos teve amostra menor que 30 participantes e foi composta por indivíduos saudáveis. Os exames instrumentais utilizados foram diversos: videofluoroscopia, tomografia de impedância elétrica, sensores laríngeos, manometria de alta resolução e eletromiografia de superfície. Os estudos investigaram principalmente a variabilidade intraindividual e os valores do coeficiente de variação oscilaram entre baixa e alta variabilidade, pois os instrumentos, parâmetros e procedimentos de coleta foram heterogêneos e não padronizados. CONCLUSÃO: A variabilidade intraindividual dos parâmetros quantitativos da deglutição obtidos por meio de exames instrumentais em adultos oscila entre baixa e alta conforme o exame, parâmetro testado, presença ou não de doença de base, consistência e volume do bolo alimentar.

Electrodiagnosis for mitigating false-negative non-responsiveness in electrical evoked contractions: A case series exploring probable polyneuromyopathy induced by nonuse.

INTRODUCTION: The revised international standards for neurological classification of spinal cord injury (ISNCSCI) have facilitated the documentation of non-spinal cord injury-related impairments, such as chronic peripheral nerve injuries and muscle weakness due to immobility. This advancement addresses potential biases in muscle strength examinations. Utilizing electrically evoked contractions from paralyzed muscles, enhanced by electrodiagnosis, holds promise in identifying false-negative diagnoses of non-responsiveness to neuromuscular electrical stimulation. This concept prompts the exploration of polyneuromyopathy arising from nonuse in paralyzed muscles. CASE SERIES PRESENTATION: To substantiate our hypothesis, we recruited nine participants for a case series aimed at elucidating the potential benefits of incorporating the stimulus electrodiagnostic test (SET) to mitigate non-responsiveness during preparation for functional electrical stimulation (FES)-assisted cycling. In our convenience sample (n = 5), we conducted neurological mapping based on ISNCSCI and applied SET on the quadriceps. The SET guided optimal dosimetry for evoking contractions and revealed responses similar to those observed in peripheral neuropathies, with α coefficients equal to or lower than 2.00. This observation is likely attributable to nonuse of paralyzed muscles, indicative of an ongoing polyneuropathy in individuals with chronic spinal cord injury (SCI). DISCUSSION: Among the nine initially recruited subjects, seven exhibited responsiveness to neuromuscular electrical stimulation (78% responsiveness), with two participants excluded based on exclusion criteria. In the final five reported cases, all displayed α coefficient values indicating impaired neuromuscular accommodation, and one presented no α coefficient within the normal range. The inclusion of electrodiagnosis appears effective in averting non-responsiveness, suggesting the presence of ongoing polyneuropathies in paralyzed muscles.

Effectiveness of orofacial myofunctional intervention to mitigate facial aging signs: a clinical trial. / Efetividade da intervenção miofuncional orofacial para atenuar sinais do envelhecimento facial: ensaio clínico.

PURPOSE: Propose and verify the efficiency of myofunctional intervention program to attenuate facial aging signs and balance the orofacial functions. METHODS: Thirty women, aged 50 to 60 years, randomly divided into: therapy group (TG) submitted to Orofacial Myofunctional Therapy and electromyographic biofeedback group (EBG), submitted to the same program associated with electromyographic biofeedback for chewing, swallowing, and smiling functions training. Aesthetic and oromyofunctional aspects were assessed from photographs, videos, MBGR Protocol and scales for assessing facial aging signs, described in the literature. 50-minute sessions were held weekly for nine weeks and monthly for six months after washout period. Three assessments, identical to the initial one, were performed in the tenth week, eighth week after washout and conclusion of the research. The participants responded to the Satisfaction Questionnaire on the tenth week. RESULTS: The statistical analysis using the ANOVA, Tukey and Mann Whitney tests, for inter and intragroup comparison, showed that: intervention promoted attenuation of facial aging signs mainly in TG group, balance of chewing and swallowing functions in both groups; there was an impact of electromyographic biofeedback on the degree of participants' satisfaction, greater for EBG; interruption of the program for eight weeks resulted in aesthetic losses, mainly in TG, yet not functional losses, in both groups; the six monthly sessions had a limited impact on overcoming the esthetic losses that occurred after washout. CONCLUSION: The proposed program resulted in attenuation of aging signs, mainly in the TG group and improvement in orofacial functions, in both groups.

OBJETIVO: Propor e verificar a eficiência de um programa de intervenção miofuncional para atenuar sinais do envelhecimento facial e equilibrar as funções orofaciais. MÉTODO: 30 mulheres, entre 50 e 60 anos, divididas aleatoriamente em: grupo terapia (GT), submetido ao programa de terapia miofuncional orofacial e grupo biofeedback eletromiográfico (GBE), submetido ao mesmo programa associado ao biofeedback eletromiográfico para treinamento da mastigação, deglutição e sorriso. Aspectos estéticos e oromiofuncionais foram avaliados a partir da documentação das fotografias e vídeos, do Protocolo de avaliação miofuncional orofacial MBGR e escalas de avaliação dos sinais de envelhecimento facial descritas na literatura. Sessões de 50 minutos foram realizadas semanalmente, durante nove semanas e mensalmente, durante seis meses, após washout. Três avaliações, idênticas à inicial, foram realizadas na décima semana, oitava semana após washout e conclusão da pesquisa. As participantes responderam ao Questionário de Satisfação na décima semana. RESULTADOS: A análise estatística realizada, por meio dos testes ANOVA, Tukey e Mann Whitney, para comparação inter e intragrupos, demonstrou que: houve atenuação dos sinais do envelhecimento facial, principalmente no GT e equilíbrio das funções mastigação e deglutição nos dois grupos; houve impacto do biofeedback eletromiográfico sobre o grau de satisfação das participantes, sendo maior no GBE; a interrupção do programa durante oito semanas resultou em perdas estéticas, principalmente no GT, mas não em perdas funcionais, nos dois grupos; as seis sessões realizadas mensalmente tiveram impacto limitado para superação das perdas estéticas ocorridas após washout. CONCLUSÃO: O programa proposto resultou em atenuação dos sinais de envelhecimento, principalmente no grupo GT e melhoria nas funções orofaciais, nos dois grupos.

Rheumatoid Arthritis and Osteoarthritis in Adult Women: A Functional Approach to the Stomatognathic System.

Rheumatoid arthritis and osteoarthritis both affect the articular cartilage, and are characterized by signs and symptoms that can affect the functions of the human body. This cross-sectional observational study evaluated electromyographic activity in the masseter and temporalis muscles, molar bite force, and mandibular mobility in adult women with rheumatoid arthritis or osteoarthritis. A total of 42 women were distributed into 3 groups: rheumatoid arthritis group (ARG, n=14); osteoarthritis group (OAG, n=14); and a healthy control group (CG, n=14). Electromyography was used to evaluate mandibular tasks at rest, right and left laterality, protrusion, and dental clenching during maximum voluntary contraction, with and without parafilm, and a dynamometer was used to analyse the right and left molar bite forces. A digital caliper was used to measure the range of mandibular movement for maximum mouth opening, right and left laterality, and protrusion. Statistical analyses were performed, including analysis of variance and Tukey's test (P<0.05). Electromyography showed no significant differences between the groups when evaluating the masticatory muscles during the mandibular tasks. Significant difference was observed between the ARG and CG, however, in the maximum right (P=0.007) and left (P=0.02) molar bite forces. Significant difference was observed in the maximum mouth opening of the ARG and OAG groups compared with that of the CG (P=0.009), suggesting that adult women with rheumatoid arthritis or osteoarthritis experience functional alterations in the stomatognathic system, particularly in molar bite force and maximum mouth opening.

Assessing the Feasibility of EMG Biofeedback to Reduce the Upper Trapezius Muscle Excitation during a Seated Row Exercise, a Non-randomized Comparative Study.

The upper trapezius muscle is often excessively excited during resistance training exercises, increasing the shoulder's liability to musculoskeletal disorders of individuals participating in overhead sports or throwing activities. Different approaches have been proposed for reducing the potentially harmful loading of the upper trapezius. None, however, has been devised to deal directly with the main culprit: the muscle excitation. This non-randomized comparative study explores the feasibility of biofeedback based on surface electromyograms (EMGs) in suppressing undue excitation of the upper trapezius during a seated row exercise. Eight male volunteers were instructed to perform the wide-grip seated row exercise without and with the EMG biofeedback of the upper trapezius. Surface EMGs from the three portions of the trapezius and the serratus anterior were sampled with pairs of surface electrodes. A triaxial accelerometer was positioned on the weight stack for the identification of the exercise phase and repetition. This study showed that during the "with biofeedback" condition, the participants were able to activate the upper trapezius and serratus anterior to a lower degree (~ 10%) compared to the "without biofeedback" condition. Future studies should explore if this can lead to greater gains in muscle performance and/or reduce the risk of shoulder injury.

Reciprocal Inhibition and Coactivation of Ankle Muscles in Low- and High-Velocity Forward and Backward Perturbations.

Reciprocal inhibition and coactivation are strategies of the central nervous system used to perform various daily tasks. In automatic postural responses (APR), coactivation is widely investigated in the ankle joint muscles, however reciprocal inhibition, although clear in manipulative motor actions, has not been investigated in the context of APRs. The aim was to identify whether reciprocal inhibition can be observed as a strategy in the recruitment of gastrocnemius Medialis (GM), Soleus (So) and Tibialis Anterior (TA) muscles in low- and high-velocity forward and backward perturbations. We applied two balance perturbations with a low and a high velocity of displacement of the movable platform in forward and backward conditions and we evaluated the magnitude and latency time of TA, GM and So activation latency, measured by electromyography (EMG). In forward perturbations, coactivation of the three muscles was observed, with greater activation amplitude of the GM and lesser amplitude of the So and TA muscles. For backward, the pattern of response observed was activation of the TA muscle, a decrease in the EMG signal, which characterizes reciprocal inhibition of the GM muscle and maintenance of the basal state of the So muscle. This result indicates that backward perturbations are more challenging.

Characterization and classification of kinesthetic motor imagery levels.

Objective.Kinesthetic Motor Imagery (KMI) represents a robust brain paradigm intended for electroencephalography (EEG)-based commands in brain-computer interfaces (BCIs). However, ensuring high accuracy in multi-command execution remains challenging, with data from C3 and C4 electrodes reaching up to 92% accuracy. This paper aims to characterize and classify EEG-based KMI of multilevel muscle contraction without relying on primary motor cortex signals.Approach.A new method based on Hurst exponents is introduced to characterize EEG signals of multilevel KMI of muscle contraction from electrodes placed on the premotor, dorsolateral prefrontal, and inferior parietal cortices. EEG signals were recorded during a hand-grip task at four levels of muscle contraction (0%, 10%, 40%, and 70% of the maximal isometric voluntary contraction). The task was executed under two conditions: first, physically, to train subjects in achieving muscle contraction at each level, followed by mental imagery under the KMI paradigm for each contraction level. EMG signals were recorded in both conditions to correlate muscle contraction execution, whether correct or null accurately. Independent component analysis (ICA) maps EEG signals from the sensor to the source space for preprocessing. For characterization, three algorithms based on Hurst exponents were used: the original (HO), using partitions (HRS), and applying semivariogram (HV). Finally, seven classifiers were used: Bayes network (BN), naive Bayes (NB), support vector machine (SVM), random forest (RF), random tree (RT), multilayer perceptron (MP), and k-nearest neighbors (kNN).Main results.A combination of the three Hurst characterization algorithms produced the highest average accuracy of 96.42% from kNN, followed by MP (92.85%), SVM (92.85%), NB (91.07%), RF (91.07%), BN (91.07%), and RT (80.35%). of 96.42% for kNN.Significance.Results show the feasibility of KMI multilevel muscle contraction detection and, thus, the viability of non-binary EEG-based BCI applications without using signals from the motor cortex.

End-to-side neurorrhaphy in the reconstruction of peripheral segmental neural loss: an experimental study.

PURPOSE: To evaluate the effects on peripheral neural regeneration of the end-to-side embracing repair technique compared to the autograft repair technique in Wistar rats. METHODS: Fifteen male Wistar rats were divided into three groups with five animals each: denervated group (GD), autograft group (GA), and embracing group (EG). For the evaluation, the grasping test, electroneuromyography (ENMG), and muscle weight assessment were used. RESULTS: Muscle weight assessment and ENMG did not show significant neural regeneration at the end of 12 weeks in the DG and GE groups, but only in GA. The grasping test showed an increase in strength between the surgery and the fourth week in all groups, and only the GA maintained this trend until the 12th week. CONCLUSIONS: The present study indicates that the neural regeneration observed in the end-to-side embracing neurorrhaphy technique, in the repair of segmental neural loss, is inferior to autograft repair in Wistar rats.

Effects of a passive upper-body exoskeleton on whole-body kinematics, leg muscle activity, and discomfort during a carrying task.

OBJECTIVE: To compare whole-body kinematics, leg muscle activity, and discomfort while performing a 10-min carrying task with and without a passive upper-body exoskeleton (CarrySuitⓇ), for both males and females. BACKGROUND: Diverse commercial passive exoskeletons have appeared on the market claiming to assist lifting or carrying task. However, evidence of their impact on kinematics, muscle activity, and discomfort while performing these tasks are necessary to determine their benefits and/or limitations. METHOD: Sixteen females and fourteen males carried a 15kg load with and without a passive exoskeleton during 10-min over a round trip route, in two non-consecutive days. Whole-body kinematics and leg muscle activity were evaluated for each condition. In addition, leg discomfort ratings were quantified before and immediately after the task. RESULTS: The gastrocnemius and vastus lateralis muscle activity remained constant over the task with the exoskeleton. Without the exoskeleton a small decrease of gastrocnemius median activation was observed regardless of sex, and a small increase in static vastus lateralis activation was observed only for females. Several differences in sagittal, frontal, and transverse movements' ranges of motion were found between conditions and over the task. With the exoskeleton, ROM in the sagittal plane increased over time for the right ankle and pelvis for both sexes, and knees for males only. Thorax ROMs in the three planes were higher for females only when using the exoskeleton. Leg discomfort was lower with the exoskeleton than without. CONCLUSION: The results revealed a positive impact on range of motion, leg muscle activity, and discomfort of the tested exoskeleton.

Continuous reach-to-grasp motion recognition based on an extreme learning machine algorithm using sEMG signals.

Recognizing user intention in reach-to-grasp motions is a critical challenge in rehabilitation engineering. To address this, a Machine Learning (ML) algorithm based on the Extreme Learning Machine (ELM) was developed for identifying motor actions using surface Electromyography (sEMG) during continuous reach-to-grasp movements, involving multiple Degrees of Freedom (DoFs). This study explores feature extraction methods based on time domain and autoregressive models to evaluate ELM performance under different conditions. The experimental setup encompassed variations in neuron size, time windows, validation with each muscle, increase in the number of features, comparison with five conventional ML-based classifiers, inter-subjects variability, and temporal dynamic response. To evaluate the efficacy of the proposed ELM-based method, an openly available sEMG dataset containing data from 12 participants was used. Results highlight the method's performance, achieving Accuracy above 85%, F-score above 90%, Recall above 85%, Area Under the Curve of approximately 84% and compilation times (computational cost) of less than 1 ms. These metrics significantly outperform standard methods (p < 0.05). Additionally, specific trends were found in increasing and decreasing performance in identifying specific tasks, as well as variations in the continuous transitions in the temporal dynamics response. Thus, the ELM-based method effectively identifies continuous reach-to-grasp motions through myoelectric data. These findings hold promise for practical applications. The method's success prompts future research into implementing it for more reliable and effective Human-Machine Interface (HMI) control. This can revolutionize real-time upper limb rehabilitation, enabling natural and complex Activities of Daily Living (ADLs) like object manipulation. The robust results encourages further research and innovative solutions to improve people's quality of life through more effective interventions.

Obturator prostheses with intramucosal retention system in patients with maxillectomy.

PURPOSE: To evaluate the intramucosal retention system in patients' masticatory efficiency and quality of life in this case series. MATERIAL AND METHODS: A total of 3 individuals with maxillectomy were included for rehabilitation with a complete obturator prostheses with an intramucosal retention system (OPI). The complete obturator prostheses was made for 60 days, and electromyography assessments and bite force were applied before, after 30, 60, and 90 days of surgery and prostheses installation. The University of Washington Quality of Life Questionnaire (UW-QoL) and the Obturator Functional Scale (OFS) were also administered at baseline and in the same follow-up periods. The electromyography was evaluated on both sides of the masseter, temporalis, and buccinator muscles while chewing hard and soft food. The maximum bite force was recorded in the central incisors and both sides of the first molar region. RESULTS: Bite force values increased in the first molar region, and muscular electrical activity remained constant. Items related to the taste and swallowing of the UW-QOL impacted. Most OFS questionnaire data responses indicated that patients improved in swallowing liquid foods and appearance. CONCLUSIONS: The rehabilitative capacity improves masticatory efficiency and QoL in adults maxilectomized and rehabilitated with OPI analysis in the study. Further clinical studies should be encouraged to determine the effectiveness of this retentive system.