PNF技术对脑卒中患者躯干控制的疗效观察及躯干屈伸肌群表面肌电指标分析

目的：观察本体感觉神经肌肉促进技术（PNF）对脑卒中患者躯干控制的疗效及躯干屈伸肌群表面肌电信号的变化。方法：将30例脑卒中偏瘫患者随机分为观察组和对照组各15例,对照组给予常规康复干预,观察组在此基础上给予PNF躯干模式训练。在治疗前及治疗4周后,采用躯干控制能力测试(TCT)、Berg平衡功能量表(BBS)、Fugl-Meyer运动功能量表(FMA)以及表面肌电均方根值(RMS)对患者进行评定。结果：治疗4周后,2组患者TCT、BBS及FMA评分较治疗前均明显提高（均P＜0.05）,且观察组各项评分较对照组均明显提高（均P＜0.05）。治疗前,2组患者患侧腹直肌及竖脊肌RMS组内比较均小于健侧（均P＜0.05）;治疗4周后,2组患者患侧腹直肌及竖脊肌RMS较治疗前均明显提高（均P＜0.05）,且观察组健侧腹直肌及竖脊肌RMS较治疗前均明显提高（均P＜0.05）;观察组患者健患侧腹直肌及竖脊肌RMS较对照组均明显提高（均P＜0.05）。结论：PNF躯干训练技术可以明显增强脑卒中偏瘫患者躯干肌群力量,提高躯干控制能力,改善平衡功能,从而促进患者运动功能恢复。     

延髓型重症肌无力喉肌电指标变化的临床价值

目的探讨延髓型重症肌无力患者电视胸腔镜下胸腺扩大切除术（video-assisted thoracoscopic extended thymectomy,VATET）后喉肌电指标测定的临床价值。方法回顾分析2002年6月～2011年7月我科36例延髓型重症肌无力（延髓型组）行VATET的临床资料,对术前后喉肌电指标进行分析,选取同期36例健康受试者作为对照组。结果延髓型组术前喉内肌肌电振幅（210．68±75．42）μV,较对照组（309．40±55．33）μV明显缩窄（t=6．332,P=0．000）;时程（7．68±0．57）ms较对照（5．42±0．34）mB明显延长（t=-20．431,P=0．000）;募集相最大电位（1132．18±467．19）μV较对照组（1675．00±532．85）μV明显缩窄（t=4．596,P=0．000）,术后2组比较仅时程有明显差异（t=6．375,P=0．000）。延髓型组喉内肌群术后肌电振幅（312．91±69．43）μV,较术前（210．68±75．42）μV明显变宽（t=-5．983,P=0．000）;术后时程（6．19±0．64）m8较术前（7．68±0．57）m8明显缩短（t=10．431,P=0．000）;术后募集相最大电位（1557．67±521．45）斗V较术前（1132．18±467．1）μV明显变宽（t=-3．646,P=0．000）;喉外肌仅肌电振幅差异显著[（139．36±74．26）μV vs．（102．75±63．22）μV,t=-2．252,P=0．027]。术后喉肌电图正常的患者疗效有效率89．3％（25／28）,喉肌电图异常的患者疗效有效率37．5％（3／8）,2组比较有统计学差异（χ2=6．891,P=0．009）。结论延髓型重症肌无力患者肌电指标异常,VATET可有效改善各项指标,缓解相关的临床症状。     

Differences in muscle synergies between healthy subjects and transfemoral amputees during normal transient-state walking speed

BackgroundLower limb amputation is a major public health issue globally, and its prevalence is increasing significantly around the world. Previous studies on lower limb amputees showed analogous complexity implemented by the neurological system which does not depend on the level of amputation.Research questionWhat are the differences in muscle synergies between healthy subjects (HS) and transfemoral amputees (TFA) during self-selected normal transient-state walking speed?Methodsthirteen male HS and eleven male TFA participated in this study. Surface electromyography (sEMG) data were collected from HS dominant leg and TFA intact limb. Concatenated non-negative matrix factorization (CNMF) was used to extract muscle synergy components synergy vectors (S) and activation coefficient profiles (C). Correlation between a pair of synergy vectors from HS and TFA was analyzed by means of the coefficient of determination (R²). Statistical parametric mapping (SPM) was used to compare the temporal components of the muscle synergies between groups.Resultsthe highest correlation was perceived in synergy 2 (S2) and 3 (S3) and the lowest in synergy 1 (S1) and 4 (S4) between HS and TFA. Statistically significant differences were observed in all of the activation coefficients, particularly during the stance phase. Significant lag in the activation coefficient of S2 (due mainly to activated plantarflexors) resulted in a statistically larger portion of the gait cycle (GC) in stance phase in TFA.SignificanceUnderstanding the activation patterns of lower limb amputees’ muscles that control their intact leg (IL) and prosthetic leg (PL) joints could lead to greater knowledge of neuromuscular compensation strategies in amputees. Studying the low-dimensional muscle synergy patterns in the lower limbs can further this understanding. The findings in this study could contribute to improving gait rehabilitation of lower limb amputees and development of the new generation of prostheses.     

Stretch reflex changes in ACL-deficient individuals and healthy controls during normal and surprise landings

No studies in ACL-D individuals have examined neuromuscular adaptations during landing from a jump where an unexpected mechanical event changes the pre-programmed course of movement. The purpose of this study was to compare pre- and post-landing muscle activation in ACL-D individuals and uninjured controls during normal and surprise landings. Nineteen ACL-D and 17 uninjured volunteered. Participants performed repeated single leg landings from 30 and 15 cm heights. During 15 cm landings, a single surprise landing was performed where participants unexpectedly fell through a false surface at 15 cm to the solid floor a further 15 cm below. Electromyography (EMG) amplitude from vastus lateralis (VL), lateral hamstrings (LH), and soleus (Sol) was recorded. Pre-landing (−60 to 0 ms), post-landing short latency (31-60 ms), and post-landing medium latency (61-90 ms) periods were examined. Comparisons in EMG amplitudes were made across limbs (ACL-D, ACL intact, and control) in 30 cm landings. Additionally, the ratio of EMG amplitude in surprise:30 cm normal landings was analyzed. Post-landing LH EMG was reduced in the ACL-D compared to control limbs at short latencies (P < 0.05). Post-landing VL EMG was reduced in the ACL-D and ACL intact compared to the control limb at both latencies (P < 0.05). Surprise landings notably increased post-landing EMG in all muscles, across all limbs (P < 0.001). However, the gain in VL EMG was significantly greater in ACL-D and ACL intact limbs (P < 0.05). These changes in neuromuscular control of ACL-D individuals during expected and surprise landings may have important implications for rehabilitation, instability, and the risk of secondary injury.     

Power spectral analysis of surface electromyography (EMG) at matched contraction levels of the first dorsal interosseous muscle in stroke survivors

ObjectiveThe objective of this study was to help assess complex neural and muscular changes induced by stroke using power spectral analysis of surface electromyogram (EMG) signals.MethodsFourteen stroke subjects participated in the study. They were instructed to perform isometric voluntary contractions by abducting the index finger. Surface EMG signals were collected from the paretic and contralateral first dorsal interosseous (FDI) muscles with forces ranging from 30% to 70% maximum voluntary contraction (MVC) of the paretic muscle. Power spectral analysis was performed to characterize features of the surface EMG in paretic and contralateral muscles at matched forces. A Linear Mixed Model was applied to identify the spectral changes in the hemiparetic muscle and to examine the relation between spectral parameters and contraction levels. Regression analysis was performed to examine the correlations between spectral characteristics and clinical features.ResultsDifferences in power spectrum distribution patterns were observed in paretic muscles when compared with their contralateral pairs. Nine subjects showed increased mean power frequency (MPF) in the contralateral side (>15 Hz). No evident spectrum difference was observed in 3 subjects. Only 2 subjects had higher MPF in the paretic muscle than the contralateral muscle. Pooling all subjects’ data, there was a significant reduction of MPF in the paretic muscle compared with the contralateral muscle (paretic: 168.7 ± 7.6 Hz, contralateral: 186.1 ± 8.7 Hz, mean ± standard error, F = 36.56, p < 0.001). Examination of force factor on the surface EMG power spectrum did not confirm a significant correlation between the MPF and contraction force in either hand (F = 0.7, p > 0.5). There was no correlation between spectrum difference and Fugl–Meyer or Chedoke scores, or ratio of paretic and contralateral MVC (p > 0.2).ConclusionsThere appears to be complex muscular and neural processes at work post stroke that may impact the surface EMG power spectrum. The majority of the tested stroke subjects had lower MPF in the paretic muscle than in the contralateral muscle at matched isometric contraction force. The reduced MPF of paretic muscles can be attributed to different factors such as increased motor unit synchronization, impairments in motor unit control properties, loss of large motor units, and atrophy of muscle fibers.SignificanceSurface EMG power spectral analysis can serve as a useful tool to indicate complex neural and muscular changes after stroke.     

Electrodiagnostic features of true neurogenic thoracic outlet syndrome

Introduction: We report the electrodiagnostic (EDX) features of 32 patients with surgically verified true neurogenic thoracic outlet syndrome (TN‐TOS). Methods: Retrospective record review. Results: We found uniform EDX evidence of a chronic axon loss process that affected the lower portion of the brachial plexus and disproportionately involved the T1 more than the C8 sensory and motor fibers. Because of this relationship, the medial antebrachial cutaneous sensory nerve (T1) and median motor (T1 > C8) study combination was abnormal in 89%, whereas response combinations that primarily assessed the C8 fibers were less frequently affected. Conclusions: The characteristic EDX features of TN‐TOS are T1 > C8 nerve fiber involvement. A comprehensive EDX examination of the lower plexus with contralateral comparison studies is imperative to diagnose this disorder accurately. Muscle Nerve 49 : 724–727, 2014     

Innervation zone locations in 43 superficial muscles: Toward a standardization of electrode positioning

Introduction: We describe the innervation zone (IZ) location in 43 muscles to provide information for appropriate positioning of bipolar electrodes for clinical and research applications. Methods: The IZ was studied in 40 subjects (20 men and 20 women) using multichannel surface electromyography (sEMG). Signal quality was checked visually to identify motor unit action potentials and estimate muscle fiber conduction velocity. Results: Results in 33 muscles were classified as excellent or good, because it was possible to identify an area which is favorable for appropriate positioning of an electrode pair without the need to previously determine the IZ location. Conclusions: Knowledge of IZ location will increase standardization and repeatability of sEMG measures. Muscle Nerve 49 :413–421, 2014     

Muscle intrusion as a potential cause of carpal tunnel syndrome

Introduction: The aim of this study was to determine whether there is an association between flexor digitorum and lumbrical muscle intrusion into the carpal tunnel and carpal tunnel syndrome (CTS). Methods: Five hundred thirteen manual laborers (1026 wrists) were evaluated with ultrasound to determine whether those with CTS had more muscle intrusion into the carpal tunnel than those without CTS. One hundred ninety of the participants without CTS at baseline (363 wrists) were followed over 1 year to determine whether muscle intrusion at baseline predicted the development of CTS. Results: Participants with CTS had more muscle within the carpal tunnel with the wrist in the neutral (P = 0.026) and flexed (P = 0.018) positions than those without CTS. Baseline muscle intrusion did not predict development of CTS at 1 year. Conclusions: Muscle intrusion into the carpal tunnel is associated with CTS, but muscle intrusion alone does not predict the development of CTS over the course of a year. Muscle Nerve 50: 517–522, 2014     

Value of short exercise and short exercise with cooling tests in the diagnosis of myotonic dystrophies (DM1 AND DM2)

Introduction: Standard electromyography (EMG) is useful in the diagnosis of myotonic dystrophy type 1 (DM1) and type 2 (DM2), but it does not differentiate between them. The aim of this study was to estimate the utility of the short exercise test (SET) and short exercise test with cooling (SETC) in differentiating between DM1 and DM2. Methods: SET and SETC were performed in 32 patients with DM1 (mean age 35.8 ± 12.7 years) and 28 patients with DM2 (mean age 44.5 ± 12.5 years). Results: We observed a significant decline in compound motor action potential (CMAP) amplitude in DM1 with both SET and SETC immediately after effort. In DM2, there was no marked change in CMAP amplitude with either SET or SETC. Conclusions: SET and SETC may serve as useful tools for clinical differentiation between DM1 and DM2, and they may be used as a guide for molecular testing. Muscle Nerve 49 : 277–283, 2014