The uniqueness of speech among motor systems

This paper considers evidence that the speech muscles are unique in their genetic, developmental, functional and phenotypical properties. The literature was reviewed using PubMed, ScienceDirect, ComDisDome and other literature‐retrieval systems to identify studies reporting on the craniofacial and laryngeal muscles. Particular emphasis was given to studies of muscle fibre composition. A number of studies on mandibular, lingual, palatal and laryngeal muscles in humans show that these muscles are distinct from limb and other muscles. These speech‐related muscles typically contain diverse fibre types and these types can vary regionally within a muscle. In general, the muscles of the speech production system are designed for fast and/or variable contraction and fatigue resistance. The craniofacial and laryngeal muscles are unique among the muscle systems of the human body and the specialized properties of these muscles are relevant to understanding the biomechanics of speech and various speech disorders.     

寒区陆航某部飞行人员多裂肌功能超声评价

目的应用高频定量超声方法比较寒区陆航某部飞行人员不同体位、不同军龄多裂肌收缩功能。方法医务人员携带设备在驻地将飞行人员分为A组(军龄>10年,n=22)与B组(军龄<10年,n=36),在L5平面定量超声测量放松体位、燕飞体位及bird dog体位3种体位的多裂肌厚度及截面积,并进行组间统计学分析。结果 3种体位中,多裂肌收缩最显著的为bird dog体位,其次为燕飞体位。B组多裂肌截面积收缩率明显高于A组(P<0.05);多裂肌厚度收缩率,两组间比较,差异无统计学意义(P>0.05)。结论多裂肌收缩功能可能会随飞行时间延长而降低。针对性加强多裂肌功能,可能会降低飞行人员腰背痛。超声可作为一种无创伤、无辐射、连续、便携、实时影像检查技术用于评估多裂肌功能。     

ORAL MYOFUNCTIONAL AND ELECTROMYOGRAPHIC EVALUATION OF THE ANTERIOR SUPRAHYOID MUSCLES AND TONGUE THRUST IN PATIENTS WITH CLASS II/1 MALOCCLUSION SUBMITTED TO FIRST PREMOLAR EXTRACTION

Objective:

The aim of this study was to assess the existence of myofunctional alterations before and after first premolar extraction in Class II/1 malocclusion patients that could endanger the long-term dental arch stability.

Materials and Methods:

The study was performed by means of morphological, functional and electromyographic analyses in 17 Class II/1 malocclusion patients (group T) and 17 Class I malocclusion patients (group C), both groups with 12-30-year age range (mean age: 20.93 ± 4.94 years).

Results:

Data analyzed statistically by Student’s t-test showed a significant decrease in the maxillary and mandibular dental arch perimeters after orthodontic treatment (p<0.05). The Kruskal-Wallis test analyzed data from tongue posture at rest and during swallowing, not showing significant differences after treatment (groups Tb and Ta) (p>0.05). However, group T differed significantly from group C (p<0.05). The electromyographic data showed that the anterior right and left suprahyoid muscles acted synergistically in both groups, while having a lower myoelectric activity in group T during swallowing.

Conclusions:

Myofunctional alterations observed after the orthodontic treatment in Class II/1 malocclusion seemed to jeopardize the long-term orthodontic stability, making recurrence possible. Further research should be conducted to compare electromyographic data before and after orthodontic treatment in order to corroborate the results of the present investigation.     

Electromyographic activity of masticatory, neck and trunk muscles of subjects with different skeletal facial morphology--a cross-sectional evaluation

The electromyographic pattern activity of masticatory, neck and trunk muscles was assessed using surface electromyography (sEMG) in 60 Caucasian adult females (20 subjects in skeletal class I, 20 subjects in skeletal class II and 20 subjects in skeletal class III), classified on the base of their skeletal class (ANB angle), corrected on the base of maxillary and mandibular rotations. The sEMG activity was recorded at mandibular rest position and during maximal voluntary clenching. At mandibular rest position, the sEMG activities of masseter and anterior temporal muscles were significantly higher in class III subjects than in class I and class II subjects, that showed no significant difference between them. Then, the sEMG activities of posterior cervicals and upper trapezius were significantly higher in skeletal class III subjects than in the other two groups. During maximal voluntary clenching, no significant difference was observed in the sEMG activity of masticatory muscles among the three considered groups. However, the sEMG activities of posterior cervicals and upper trapezius were significantly higher in skeletal class III subjects than in the other two groups, which showed no significant difference between them. In conclusion, the skeletal class seems to affect the sEMG pattern activity of masticatory, neck and trunk muscles.     

Review of clinical EMG studies related to muscle and occlusal factors in healthy and TMD subjects

Several electronic instruments have been developed as adjuncts to objectively record the dysfunctional features of temporomandibular disorders and to study the effectiveness of various treatment interventions. The aim of this review was to assess the value and contribution of clinical electromyographic research in the understanding of asymptomatic and dysfunctional muscle function and the therapeutic effects of interocclusal appliances. For this purpose MedLine and PubMed searches were conducted with the following main keywords alone and in various combinations: electromyography, muscles of mastication, masseter, temporalis, temporomandibular, TMD, utility, validity, repeatability, rest, postural, vertical dimension, occlusal, splint, treatment. The review includes critical evaluation, discussion and conclusions regarding electromyographic studies in asymptomatic and dysfunctional muscles, rest position, occlusal parameters and interocclusal appliances, as well as a critical summary and proposals for further research. Much of earlier critique of many electromyographic studies still applies regarding comparative sample selections, research designs, analyses and conclusions. The areas not well-understood include normal biological variation, capacity for adaptation, fluctuations regarding the clinical course and multidimensional features of temporomandibular disorders and long-term follow-up data, especially in studies that evaluate the effectiveness of therapeutic measures. Considering the required improvements in technical and research designs features and critical appraisal electromyographic research could have value as an adjunct research tool to study features of craniofacial muscle-related dysfunction. Until electromyographic measures are correlated with other multidimensional, especially subjective and pain-related methods, the clinical use of this method for diagnostic purposes of temporomandibular disorders remains in doubt, and is not at present recommended.     

Respiratory phenotypes of neuromuscular diseases: A challenging issue for pediatricians

Neuromuscular disease (NMDs) encompass a heterogeneous group of genetic disorders, with respiratory problems of variable intensity and progression described at any pediatric age, from infancy to adolescence, and they are largely associated with significant lifelong morbidity and high mortality. Restriction of breathing, impaired gas exchange, decline of lung function and sleep disordered breathing progressively develop because of muscular weakness and culminate in respiratory failure. Depending on the disease progression, airways manifestations can take weeks to months or even years to evolve, thus depicting two major respiratory phenotypes, characterized by rapid or slow progression to respiratory failure. Assessing type and age at onset of airways problems and their evolution over time can support pediatricians in the diagnostic assessment of NMD. In addition, knowing the characteristics of patients' respiratory phenotype can increase the level of awareness among neonatologists, geneticists, neurologists, pulmonologists, nutritionists, and chest therapists, supporting them in the challenging task of the multidisciplinary medical care of patients. In this review we examine the issues related to the pediatric respiratory phenotypes of NMD and present a novel algorithm that can act as a guide for the diagnostic agenda and the key preventive or therapeutic interventions of airways manifestations. With prolonged survival of children with NMD, the advent of neuromuscular respiratory medicine, including accurate assessment of the respiratory phenotype, will help physicians to determine patients’ prognoses and to design studies for the evaluation of new therapies.     

Mibefradil可改善肥胖小鼠骨骼肌的质量、功能和结构

目的 探讨mibefradil对肥胖小鼠骨骼肌质量、功能及结构的影响。方法 将15只6周龄C57BL/6小鼠随机分为普通饮食组（Con组,n=5）、高脂饮食组（HFD组,n=5）和高脂饮食+mibefradil干预组（HFD+Mibe组,n=5）。电子抓力仪测量小鼠前肢抓力,DXA分析小鼠后肢肌肉含量,GPO-PAP法测定甘油三酯和总胆固醇,HE染色观察小鼠腓肠肌肌纤维横截面积,Westernblot和免疫荧光技术检测自噬水平变化,Western blot检测Akt/mTOR信号通路的激活情况。结果 与Con组相比,HFD组体质量增加,相对抓力、后肢肌肉比率降低（P<0.05）,给予mibefradil干预后体质量减轻,相对抓力升高、后肢肌肉比率升高（P< 0.05）;HE染色结果显示,与Con组相比,HFD组平均肌纤维横截面积降低,给予mibefradil干预后平均肌纤维横截面积得到改善（P<0.05）;免疫荧光结果显示,HFD组和HFD+Mibe组的LC3多均匀分布于细胞浆,呈浅淡红色荧光;而在HFD组检测到不同程度的明亮斑点状红色荧光;Western blot结果显示,与Con组相比,HFD组LC3Ⅱ蛋白表达水平升高,P62蛋白表达水平降低,AKT和mTOR的磷酸化表达降低,给予mibefradil干预后LC3Ⅱ蛋白表达水平降低,P62蛋白表达水平升高,AKT和mTOR的磷酸化表达升高（P<0.05）。结论 给予mibefradil干预可以抵抗高脂诱导的体质量增加,改善肥胖小鼠的肌肉质量和功能,这可能与其改善脂代谢和通过激活AKT/mTOR信号通路来抑制肥胖诱导的过度自噬有关。