Electromyography and clinical neurophysiology
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Electromyogr Clin Neurophysiol · Apr 2002
Inhibitory and excitatory circuits of cerebral cortex after ischaemic stroke: prognostic value of the transcranial magnetic stimulation.
The motor cortex excitatory responses and inhibitory effects after transcranial magnetic stimulation were studied in 20 patients with hemiparesis after ischaemic stroke in the MCA territory within 24 hours from the beginning of the symptomatology, in order to evaluate prognostic utility of these techniques and to compare they with the conventional MEP examination. Central motor conduction time was abnormal in two patient. ⋯ The motor cortex threshold measurement is easily performed and the most sensitive parameter in our group of patients with hemispheric infarct. Our study suggested that the evaluation of the modifications in the intrinsic excitatory properties rather than in the inhibitory cortical circuits may offer a prognostic tool for predicting functional outcome following ischaemic stroke.
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Electromyogr Clin Neurophysiol · Apr 2002
On the evaluation of muscle fiber conduction velocity considering waveform properties of an electromyogram in M. biceps brachii during voluntary isometric contraction.
The surface myoelectric signal during 20% maximum voluntary contraction was measured in m. biceps brachii using array electrodes for ten subjects in order to evaluate the distribution of muscle fiber conduction velocity (MFCV) in a whole muscle. MFCV was estimated by two calculating methods of the peak maximum method and the cross-correlation method from the myoelectric signals which were processed by techniques of the averaging and the non-averaging. It was found that the values of MFCV depended on the location irrespective of the kind of calculating method used and the kind of processing technique of myoelectric signal. ⋯ The values of MFCV significantly increased in the regions of the motor end-plate zone and the tendon zone, where the maximum correlation coefficient and amplitude ratio significantly decreased. The values of the coefficient of variance (CV) of three parameters in those regions were larger than those in other regions, i.e., the regions other than the motor end-plate zone and the tendon zone. A high maximum correlation coefficient and a high amplitude ratio were necessary for a reliable measurement of the MFCV.
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Electromyogr Clin Neurophysiol · Dec 2000
Case ReportsThe lumbar multifidus muscle in polysegmentally innervated.
We conducted a prospective case study to determine whether the lumbar multifidus muscle is polysegmentally innervated. A 49-year-old man with chronic mechanical low back pain underwent bilateral percutaneous radiofrequency neurotomy of the medial branches of the L3 dorsal rami. ⋯ This study provides electrophysiological evidence in the human lumbar spine that the medial branch of the lumbar root innervates the multifidus muscle at multiple levels, i.e., the lumbar multifidus muscle is polysegmentally innervated. As a result, electromyography of the multifidus cannot identify a specific level of lumbar radiculopathy.
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Electromyogr Clin Neurophysiol · Jun 2000
Comparative StudyTwo consecutive fasciculation potentials having different motor unit origins are an electromyographically pathognomonic finding of ALS.
To electrophysiologically diagnose amyotrophic lateral sclerosis (ALS), fasciculation potentials (FPs) were evaluated in each wasted muscle in 12 ALS and 14 other neurogenic disorders (non-ALS patients). Various types of FPs were observed in ALS. ⋯ Although nine of 12 ALS patients showed two consecutive FPs having different motor unit origins, non-ALS patients did not show such FPs. Since the two consecutive FPs having different motor unit origins reflect an involvement of both upper and lower motor neurons, these potentials are an electrophysiologically pathognomonic finding to ALS.
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Electromyogr Clin Neurophysiol · Mar 2000
Intrasession and intersession reliability of the soleus H-reflex in supine and standing positions.
The Hoffmann reflex (H-reflex) is a measure of motoneuron pool excitability, which is valuable in determining muscle inhibition caused by joint damage (arthrogenic muscle inhibition). In order to detect changes in H-reflex due to injury, the reliability of such a measurement must be established. The purpose of this study was to establish the intrasession and intersession reliability of soleus H-reflex in a supine and standing position. ⋯ These results indicate that the H-reflex measured using our protocol in a supine and standing position is a reliable assessment within sessions and between sessions. Five measurements are sufficient to observe reliable measurements within a single session. Most importantly, this data shows that the H-reflex is a reliable assessment that may be used to measure small changes in motoneuron pool excitability over time.