肌电生物反馈对肝豆状核变性患者下肢肌张力障碍的影响

目的观察肌电生物反馈对肝豆状核变性患者下肢肌张力障碍的疗效。方法 40例肝豆状核变性并发肌张力障碍患者分为治疗组和对照组,每组20例。所有患者均接受正规驱铜治疗、改善肌张力药物治疗及针刺治疗。治疗组在此基础上对双下肢进行肌电触发生物反馈治疗。治疗前后用改良Ashworth量表及改良Barthel指数对患者进行评定,并测量踝背屈主动关节活动度变化。结果治疗后,两组患者的观察指标均有不同程度改善(P<0.05),治疗组疗效优于对照组(P<0.05)。结论肌电生物反馈能够改善肝豆状核变性患者下肢肌张力障碍,提高患者日常生活能力。     

冻结肩三维运动表面肌电信号特征分析

目的 通过肩周肌肉手法治疗前、后积分肌电值差异,探讨肩周肌肉功能变化。方法选取冻结肩患者7例,利用AMT-8肌电仪对手法治疗前、后肌肉肌电值进行采集,将数据用MATLAB软件进行分析,求积分肌电值。用Stata11.0软件统计。结果①外展时三角肌、冈下肌治疗前、后积分肌电值差异有统计学意义(P＜0.05),肱二头肌、肱...     

Distribution of affected muscles and degree of neurogenic lesion in patients with spina bifida

Introduction

Patients with spina bifida in the lumbosacral region usually have various degrees of motor and sensory dysfunctions of the lower extremities and anal sphincter. The aim of our study was to evaluate the distribution and differences in frequencies of affected muscles, number of affected muscles and degree of neurogenic lesion between patients with spina bifida occulta (SBO) and spina bifida aperta (SBA).

Material and methods

In 100 patients with SB, 6 muscles in the lower limbs were separately analysed. Due to the number of affected muscles, we evaluated 5 groups of patients: with 1 affected muscle, 2 affected muscles, 3 affected muscles, 4 affected muscles and 5 affected muscles. Three degrees of neurogenic lesions were assessed: mild, moderate and severe.

Results

The tibialis anterior muscle was most frequently affected in SB patients. The outer anal sphincter was frequently affected in the group of SBA patients. Single muscle affection is frequent in the group of patients with SBO, while in the group of patients with SBA, 4 muscles were significantly frequently affected. The great majority of patients (45.46%) with affected outer anal sphincter (OAS) in the group of SBO were without affection of other muscles, while for the SBA group it was for every third patient. Mild neurogenic lesion was significantly frequent in SBO patients, while severe form was significantly frequent in SBA patients.

Conclusions

Patients with SBO usually present with mild to moderate clinical presentation, while multiple root involvement and severe degree of neurogenic lesion is associated more frequently with SBA.     

Effects of different stimulus locations on inhibitory responses in human jaw-closing muscles

The aim of this study was to examine the inhibitory responses in bilateral masseter and temporalis muscle activity when electrical stimulation with short or long duration was applied to six oro-facial locations. The exteroceptive suppression period (ES2) and inhibitory responses were recorded in the surface electromyogram (EMG) of bilateral masseter and temporalis muscles in 16 healthy subjects. Two stimulus durations (1 ms single pulse and 450 ms pulse train) adjusted to a perceived intensity of 7 (distinct painful) on a 0-10 Numerical Rating Scale (NRS) were applied to the following six oro-facial locations on the right side while the subject was biting at 50% of the maximal voluntary contraction: masseter muscle, temporalis muscle, temporomandibular joint, infraorbital nerve, supraorbital nerve, and mental nerve. The stimulus intensity required to reach an NRS score of 7 was significantly lower for 450 ms train stimuli than for 1 ms single stimuli (P<0·001). There were no significant differences in the magnitude of ES2 suppression among the six different locations (P>0·876) for the 1 ms single stimuli. There were significant decreases in Root-Mean-Square-EMG values in the 400-500 ms post-stimulus epoch compared with the pre-stimulus epoch (P<0·023) for 450 ms train stimuli, but there were no significant differences in the magnitude of inhibition among the six different locations (P<0·893). Short- and long-lasting electrical stimulation of various oro-facial locations induces similar bilateral inhibitory effects in the jaw-closing muscles but with different propensity which may reflect the somatotopic organisation of these responses.     

EMG analysis of trapezius and masticatory muscles: experimental protocol and data reproducibility

We aimed to define a standardised protocol for the electromyographic evaluation of trapezius muscle in dentistry and to assess its within- and between-session repeatability. Surface electromyography of trapezius, masseter and temporal muscles was performed in 40 healthy subjects aged 20-35 years during shoulder elevation, and maximum teeth clenching with and without cotton rolls. Two repetitions were made both within (same electrodes) and between sessions (different electrodes). Maximum voluntary clench on cotton rolls was used to standardise the potentials of the six analysed muscles with tooth contact; shoulder elevation was used to standardise the upper trapezius potentials. From the standardised electromyographic potentials, several indices (muscle symmetry; masticatory muscle torque and relative activity; total masticatory muscle activity; trapezius cervical load, percentage co-contraction of trapezius during teeth clenching) were computed; random (technical error of measurement) and systematic (Student's t-test, Analysis of Variance) errors were assessed. For all indices, no systematic errors were found between the two separate data collection sessions. Within session, limited (lower than 8%) technical errors of measurement were found for temporalis and masseter symmetry, torque and activity indices, and the trapezius cervical load. Larger random errors were obtained for trapezius symmetry and total masticatory muscle activity (up to 20%). Between sessions, no significant differences were found for trapezius co-contraction. In conclusion, a protocol for the standardisation of trapezius muscle that may be used within dental clinical applications was defined, and the repeatability of masseter, temporalis and trapezius electromyographic recordings for serial assessments was assessed in healthy subjects.     

Finger muscle control in children with dystonia

Background: Childhood dystonia is a disorder that involves inappropriate muscle activation during attempts at voluntary movement. Few studies have investigated the muscle activity associated with dystonia in children, and none have done so in the hands. Methods: In this study, we measured surface electromyographic activity in four intrinsic hand muscles while participants attempted to perform an isometric tracking task using one of the muscles. Results: Children with dystonia had greater tracking error with the task‐related muscle and greater overflow to non‐task muscles. Both tracking error and overflow correlated with the Barry‐Albright Dystonia scale of the respective upper limb. Overflow also decreased when participants received visual feedback of non‐task muscle activity. Dicussion: We conclude that two of the motor deficits in childhood dystonia—motor overflow and difficulties in actively controlling muscles—can be seen in the surface electromyographic activity of individual muscles during an isometric task. As expected from results in adults, overflow is an important feature of childhood dystonia. However, overflow may be at least partially dependent on an individual's level of awareness of their muscle activity. Most importantly, poor single‐muscle tracking shows that children with dystonia have deficits of individual muscle control in addition to overflow or co‐contraction. These results provide the first quantitative measures of the muscle activity associated with hand dystonia in children, and they suggest possible directions for control of dystonic symptoms. © 2011 Movement Disorder Society     

Reinnervation by the contralateral facial nerve in patients with peripheral facial palsy

Introduction: Reinnervation activity is triggered after complete unilateral peripheral facial palsy (PFP). Methods: In 27 patients with PFP we recorded electromyographic activity with a concentric needle electrode inserted 1 cm lateral to the oral commissure of the affected side. We applied electrical stimuli to the unaffected (contralateral) facial nerve from the tragus to the mid‐lower lip and measured the response latency variability and segmental conduction velocity. Results: Responses to electrical stimulation of the unaffected facial nerve were found in all patients. Mean conduction velocity was 49.6 ± 6.2 m/s between tragus and oral commissure, and 6.0 ± 1.9 m/s between oral commissure and mid‐lower lip. Latency variability was 0.27 ms to facial nerve stimulation and 0.08 ms to oral commissure stimulation. Conclusion: Short distance sprouting of axons that innervate muscle fibers, which originate from the unaffected facial nerve, results in propagation of impulses to muscle fibers in the midline. Muscle Nerve 2011     

Electromyography and kinematic changes of gait cycle at different cadences in diabetic neuropathic individuals

Introduction: Changes in gait cadence caused by challenging situations in daily life might induce higher demand for strength and propulsion in diabetic neuropathic (DN) subjects. Methods: Forty‐six subjects (healthy and DN) walked at two cadences (self‐selected and 25% higher). Kinematic and electromyographic data were obtained from lower limbs and compared across the gait cycle. Results: DN subjects showed a delayed peak in plantarflexor activity along the whole cycle (irrespective of cadence) compared with healthy subjects. However, during the imposed cadence, DN individuals showed reduced ankle range of motion along the entire cycle compared with the self‐selected condition and healthy individuals walking at both cadences (P = 0.002). Conclusions: These findings suggest that when diabetic individuals face a new challenging situation that induces a higher demand for muscle strength and propulsion, the necessary range of motion and neuromuscular control around distal joints are insufficient. Muscle Nerve, 2011     

Strength and fatigue of lumbar extensor muscles in older adults

Introduction: Loss of lumbar extensor muscle strength and fatigue resistance may contribute to functional disability. Methods: Two groups of subjects were recruited: young (n = 26, 20–35 years of age) and old (n = 26, ≥65 years of age) adults. Lumbar extensor muscle strength was measured with a load cell, and electromyographic activities were recorded to study muscle fatigue at 60% of maximum voluntary contraction. Results: We found that the muscle moments generated by the extensor muscles decreased with age (P < 0.05). Aging was associated with a significant increase in the power of the lower frequency band (101–200 Hz) of the electromyographic signals (P < 0.05), but the spectral characteristics did not appear to change with sustained contraction (P > 0.05). Conclusions: The changes in strength and spectral properties of the electromyographic signals of lumbar extensor muscles may be related to age‐related alterations in muscle fiber composition and recruitment. These changes should be considered in clinical functional task evaluation. Muscle Nerve 44: 74–79, 2011     

Passive trunk loading influences muscle activation during dynamic activity

Introduction: Repetitive loading of the low back tissues induces tension relaxation with a corresponding variation in the myoelectric response of the neuromuscular system, which may influence low back health. The purpose of this study was to observe trunk muscle activities before and after a passive cyclic trunk flexion–extension exercise. Methods: Nineteen participants were subjected to sagittal plane loading of the low back tissues. These individuals performed toe‐touching before and over 1 hour after load termination. Results: Lumbar paraspinal activity cessation occurred significantly sooner over time during lumbar and pelvic flexion post‐loading, as compared with pre‐loading. Lumbar paraspinal activity then re‐initiated later in lumbar extension. There was no change in peak or average muscle activity during the procedures. Conclusions: It is apparent that passive loading of the viscoelastic lumbar tissues results in a prolonged neuromuscular adaptation, followed by possible neuromuscular compensation sustained within 1 hour of load termination. Muscle Nerve, 2011