Electrophysiological pattern of involuntary limb movements in the restless legs syndrome

Patients with restless legs syndrome (RLS) suffer from involuntary limb movements during the day. We studied these leg movements in 18 idiopathic (n = 8) and uremic (n = 10) patients at rest. Electromyographically measured muscle contractions were preceded by sensory discomfort in all patients. The mean duration of the contractions ranged between 0.67 and 5.71 s with a mean frequency of 244 epochs of muscle activity per hour. Seven of 18 patients showed a constant order of recruitment with propagation of muscle activity up or down spinal segments (L3 to S1 and vice versa). No difference in electrophysiologically recorded patterns was observed between patients with idiopathic and uremic RLS. We suggest a brainstem disinhibition phenomenon as the pathological mechanism that activates a spinal generator. The spinal origin of the involuntary limb movements in patients with RLS is confirmed by the long duration of jerks, the recruitment characteristics, and the periodicity of the jerks. No jerk could be elicited by sensory reflexes. © 1996 John Wiley & Sons, Inc.     

Combined electromyography-31P-magnetic resonance spectroscopy study of human muscle fatigue during static contraction

Metabolic changes measured by ³¹P-magnetic resonance spectroscopy and surface electromyograms were simultaneously recorded during isometric contraction of forearm flexor muscles sustained at 60% of maximal force until exhaustion. Throughout the fatigue trial, energy in the low-frequency (L) band continuously increased whereas energy in the high-frequency (H) band first increased and then fell only prior to exhaustion. PCr content decreased linearly. Intracellular pH (pHi) transiently increased during the first 22 s of trial. The triggering of acidosis was associated with critical PCr values (35–70% of initial content) and decreased electromyogram (EMG) energy in the H band. Linear relationships were only found between energy in the L band, pHi, and PCr content. The interindividual variability of metabolic and EMG changes was high despite standardized conditions of contraction. Maximal PCr consumption was correlated with the maximal pHi decrease measured at the end of the trial. Overall, there was no correlation between H/L EMG ratio and changes in muscle metabolism. © 1996 John Wiley & Sons, Inc.     

Urinary dysfunction in Duchenne muscular dystrophy

In Duchenne muscular dystrophy (DMD), sphincter muscles tend to be clinically spared. However, urinary incontinence is occasionally reported, usually late in the course of the disease. We wished to determine the etiology of urinary dysfunction in patients with DMD. Seven boys with DMD and urinary dysfunction were examined by a neurologist and a urologist, followed by urodynamic and electrophysiological assessment. Based on the results of these evaluations, patients were defined as having an upper motor neuron (UMN), lower motor neuron (LMN), or myopathic lesion. Five of the patients had UMN abnormalities consisting of either uninhibited contractions or bladder/sphincter dyssynergy. One patient had a LMN lesion with prolonged duration and high-amplitude motor units. No patient demonstrated myopathic motor units. Five boys had undergone spinal fusion for scoliosis. We conclude that urinary incontinence in DMD is most often due to UMN dysfunction and not due to a severe myopathy of the detrusor or external sphincter. The most likely causes of the UMN abnormalities are severe scoliosis or a complication of spinal fusion surgery. © 1996 John Wiley & Sons, Inc.     

Diagnosis of thoracic outlet syndrome Relative value of electrophysiological studies

The diagnostic utility of various electrophysiological techniques was evaluated in patients with thoracic outlet compression syndrome (TOCS). Our results suggest that in true neurogenic TOCS, there is no standard electrophysiological picture, but that this evolves with the severity of the syndrome. The first changes observed are electromyographic, followed by changes in F-wave and SEPs, followed finally by changes in nerve conduction parameters. EMG study was certainly more informative, showing neurogenic damage not only in limbs with neurological signs but also in about 1/4 of limbs with only subjective symptoms. The study of F-wave and SEPs does not seem to be particularly helpful, however, in view of the peculiar changes found in these patients, SEPs may be a useful complement to EMG. Nerve conduction studies were of little utility since changes in these parameters are only found in patients with long-standing anomalies and severe atrophy.     

不同体位下指压不同穴位对脑卒中患者胫前肌和腓骨长、短肌的表面肌电影响

摘要 目的：优化指压穴位刺激法在脑卒中偏瘫治疗中的应用。 方法：30例偏瘫患者,分别在仰卧伸膝0°位和屈膝90°位下指压偏瘫侧足三里、足临泣穴,对比刺激即刻3s、停止刺激后第一个3s、第二个3s、第三个3s的胫前肌和腓骨长、短肌最大等长收缩的积分肌电值（iEMG）。 结果：①刺激前后比较：两种体位下,指压两个穴位,刺激即刻的iEMG明显高于刺激前（P<0.05）,停止刺激后的三个3s的iEMG呈逐渐下降趋势。②穴位间比较：两种体位下,均表现为指压足三里穴,胫前肌刺激即刻的iEMG、停止刺激后的三个3s的iEMG均明显高于足临泣穴（P<0.05）;指压足临泣穴,腓骨长、短肌刺激即刻的iEMG、停止刺激后的三个3s的iEMG均明显高于足三里穴（P<0.05）。③体位间比较：仰卧屈膝90°位指压两个穴位,胫前肌刺激即刻、停止刺激后第一个3s的iEMG明显高于伸膝0°位（P<0.05）;腓骨长、短肌刺激即刻的iEMG明显高于伸膝0°位（P<0.05）。 结论：①指压刺激偏瘫侧足三里、足临泣穴均可诱发偏瘫侧胫前肌和腓骨长、短肌收缩,且即刻效应和延续效应良好。②指压足三里穴对诱发胫前肌收缩的即刻效应和延续效应优于足临泣穴;指压足临泣穴对诱发腓骨长、短肌收缩的即刻效应和延续效应优于足三里穴。③仰卧屈膝90°位,指压刺激足三里、足临泣穴对诱发胫前肌和腓骨长、短肌收缩的即刻效应明显优于伸膝0°位,延续效应无明显差异。