Electromyography and clinical neurophysiology最新文献

The aim of this study was to evaluate the electromyographic activity during masticatory function, in patients with stomatognathic system dysfunctions, treated with interocclusal splints. Electromyography was carried out through a computer diagnostic system K6-l DIAGNOSTIC SYSTEM (Myo-Tronics, Inc.; Tukwila, WA; USA). Study sample involved 20 individuals, age 18-53 years, both genders. Electromyographic activity of the masticatory muscles (masseter and anterior temporalis) was measured before and 90, 120, and 150 days after treatment with interocclusal splints, which were modified at days 90 (in canine guidance) and 120 (in group function). Data were statistically analyzed through a simple linear regression model. There was no statistically significant difference (p > 0.05) among the 3 periods assessed. Bilateral equilibrium of electromyographic activity was observed for the masseter and anterior temporalis muscles during the treatment.

Evaluating the ability to rectify and maintain lumbar adjustment can contribute toward the understanding of the behavior of abdominal muscles and their participation in the stability of pelvic muscles in dancers during the posterior pelvic tilt and double straight leg lowering tests. Nine healthy volunteers (male and female ballet dancers; age mean: 25.9 +/- 7.37 years) underwent maximal isometric voluntary contraction (MIVC), isometric voluntary contraction at 50% of MIVC, posterior pelvic tilt (PPT) and double straight leg lowering (DSLL) tests. The tests were carried out in a single day, with 3 repetitions each. During the tests, electromygraphic signals of the rectus abdominis, obliquus internus and obliquus externus were recorded. The signal acquisition system was made up of bipolar surface electrodes, electrogoniometer and an electromechanic device (pressure sensor), which were connected to a signal conditioner module. Root mean square values of each muscle during the DSLL and PPT were converted into percentage of activation of 50% MIVC. Lower back pressure was submitted to the same process. ANOVA with repeated measures was performed, with the level of significance set at p < 0.05. The results revealed that all dancers were able to maintain posterior pelvic tilt and there was trend toward greater activation of the bilateral obliquus internus muscle. In an attempt to keep the pelvic region stabilized during DSLL, there was a greater contribution from the obliquus externus muscle in relation to other abdominal muscles.

We report on the combination of biopsy-proven idiopathic livedo reticularis and mononeuropathy multiplex, mild to moderate in severity and remitting-relapsing in course, observed in a young otherwise healthy woman. Neurologic relapses were always accompanied or preceded by exacerbation of the skin lesion. After 18 years followup we did not detect clinical or instrumental evidence of brain or visceral involvement. This excludes the classical Sneddon's syndrome and points at an unusual variant of this syndrome in our patient.

It is necessary for brain-computer interfaces (BCIs) to be non-offensive devices for daily use to improve the quality of life of users, especially for the motor disabled. Some BCIs which are based on steady-state visual evoked potentials (SSVEPs), however, are unpleasant because users have to gaze at high-speed blinking light as visual stimuli. Furthermore, these kinds of BCIs may not be used as universal devices because SSVEPs are not detectable by some users. Considering these facts, we previously proposed a BCI using a non-direct gazing method based on transient VEPs. This interface used a low-speed blinking lattice pattern as visual stimuli and visual targets displayed on the right and the left sides of the stimuli. The gazing direction was determined by the waveform difference of transient VEPs detected when users gazed at either target. Compared with SSVEP-based BCLs, this BCI was less annoying because it used low-speed blinking visual stimuli, and it was not necessary for users to gaze at the stimuli directly. In this study, we propose an improved version of the BCI. Specifically, the gazing direction is determined in real time, and another gazing direction in which users gaze at a visual target displayed on the center of the screen is introduced while maintaining the annoyance-free advantage of the BCI. Experiments with 6 volunteer subjects showed an 84.2% accuracy rate in gazing direction judgments. The result suggests that the proposed BCI is more practical than the previous one because it can adapt to the change of gazing direction in real time.

Introduction: Most medical treatments for carpal tunnel syndrome (CTS) have focused on suppressing the inflammatory process. An injection of autologous blood might provide the necessary cellular and humoral mediators to induce a healing cascade. The purpose of this study was to evaluate prospectively autologous blood injection in CTS.

Method & materials: Twenty patients with CTS were recruited using strict inclusion and exclusion criterias. All patients were injected with 1 ml of autologous blood and 0.5 ml lidocaeine 1% under the carpal tunnel. Pain intensity (based on VAS) and electrophysiologic parameters of median nerve (transcarpal SNCV, DML and DSL) were recorded before and 3 weeks after autologous blood injection.

Results: The average pain scores before and 3 weeks after autologous blood injection was 8.70 +/- 0.92 and 4.30 +/- 0.76 respectively (P < 0.005). Also transcarpal SNCV of median nerve was 33.7 +/- 6.3 m/s and 24.5 +/- 6.8 m/s (P = 0.001); DML of medin nerve was 5.16 +/- 1.04 ms and 4.70 +/- 0.53 ms (P = 0.001) and DSL of median nerve was 4.84 +/- 0.77 ms and 4.2 +/- 0.6 ms (P = 0.001), respectively.

Conclusions: After autologous blood injection, pain intensity and electerophysiologic parameters were significantly improved. This study offers encouraging results for an alternative minimally invasive treatment for CTS. This study cannot prove conclusively whether the blood itself induced an inflammatory cascade or the injury created by the injection was responsible.

The detrusor-sphincteric dyssynergia is analyzed by comparing the natural impulse patterns of secondary muscle spindle afferents (SP2) contributing to continence (SP2 fibre activity changes are similar to detrusor pressure changes) and sphincteric motoneurons in a brain-dead human with those in patients with spinal cord injuries. In the brain-dead the sphincteric motoneurons, subserving continence, were inhibited at a time, when preganglionic parasympathetic efferents and a SP2 fibre increased their activity (physiologic). In paraplegics the sphincteric motoneurons were not inhibited (pathophysiologic). In the brain-dead, an SP2 fibre showed doublet firing (interspike interval (II) 10 to 14 ms) for low level parasympathetic activation and multi-ending regular firing for high parasympathetic activation. In one paraplegic with strong bladder dysfunction, the multi-ending regular firing was replaced by a repeated burst firing with a shortest II of 0.2 ms (transmission frequency = 5000 Hz). The pathologic firing patterns of the SP2 fibres, the detrusor-sphincteric dyscoordination, and hyperreflexia in paraplegics are most likely a result of neuronal network changes in the parasympathetic and somatic nervous system divisions of the sacral micturition center after spinal cord injury. It is discussed that urinary bladder functions can be re-learned.

Peripheral Facial palsy (PFP) is generally considered a benign condition with good recovery and no sequelae. Yet, a distortion in the gesture and abnormal blinking, as those typically found in blepharospasm, can potentially develop early on. Such abnormal movements seem to be related to remodelling mechanisms that take place in the process of recovery. We report 2 cases where such clinical features became evident following an idiopathic PFP, as a result of reciprocal inhibition of orbicularis oculi and levator palpebrae. Hence, the neurophysiological study revealed an increased frequency in the blinking, with bilateral trigeminal-facial facilitation and, most notably, a disturbance that only became evident when the eyes were maintained wide open. Interestingly, those features were not reproduced in other tasks where the blinking conditions had not been altered. Our findings suggest that sensory inputs (reflex afferent pathways) are involved in such abnormal movements. The insufficient eyelid closure (lagophthalmus) in the context of PFP is likely to account for the exaggerated corneal vulnerability, thus resulting in abnormal mechanisms of adaptation.

Unlabelled: Single-fibre extracellular action potentials were recorded with 2 pairs of wire electrodes from lower human sacral nerve roots during surgery. The roots from which was recorded from were used for morphometry. Nerve fibre groups were identified by conduction velocity distribution histograms of single afferent and efferent fibres and partly by nerve fibre diameter distribution histograms. The values of group conduction velocity and group nerve fibre diameter measured in the paraplegics were very similar to those obtained from brain-dead humans and patients with no spinal cord injury. Thus the classification and identification of nerve fibre groups remained preserved following spinal cord injury. Upon retrograde bladder filling the urinary bladder stretch and tension receptor afferent activities were increased; on two occasions they even fired when the bladder was empty. Two reasons are brought forward for a too small storage volume of the urinary bladder in paraplegics: too high afferent activity of the bladder due to changed receptor field transduction mechanisms and too low compliance.

Summary: 1. Single nerve fibre action potentials (APs) of lower sacral nerve roots were recorded extracellularly with 2 pairs of wire electrodes during an operation for implanting an anterior root stimulator for bladder control in 9 humans with a spinal cord injury and a dyssynergia of the urinary bladder. Roots that were not saved and that were used to record from were later used for morphometry. 2. Nerve fibre groups were identified by conduction velocity distribution histograms of single afferent and efferent fibres and partly by nerve fibre diameter distribution histograms, and correlation analysis was performed. Group conduction velocity values were obtained additionally from compound action potentials (CAPs) evoked by electrical stimulation of nerve roots and the urinary bladder. 3. The group conduction velocities and group nerve fibre diameters had the following pair-values at 35.5 degrees C: Spindle afferents: SP1 (65 m/s / 13.1 microm), SP2 (51/12.1); touch afferents: T1 (47/11.1), T2 (39/10.1), T3 (27/9.1), T4 (19/8.1); urinary bladder afferents: S1 (41 m/s / -), ST (35/-); alpha-motoneurons: alpha 13 (-/14.4), alpha 12 (65 m/s /13.1 microm), alpha 11 (60?/12.1)[FF], alpha 2 (51/10.3)[FR], alpha 3 (41/8.2)[S]; gamma-motoneurons: gamma(beta) (27/7.1), gamma 1 (21/6.6), gamma 21 (16/5.8), gamma 22 (14/5.1); preganglionic parasympathetic motoneurons: (10 m/s / 3.7 microm). 4. The values of group conduction velocity and group nerve fibre diameter measured in the paraplegics were very similar to those obtained earlier from brain-dead humans and patients with no spinal cord injury. Also, the axon number and the axon density of myelinated fibres of lower sacral nerve roots remain unchanged following spinal cord injury. Thus the classification and identification of nerve fibre groups remained preservedfollowi

Dental absence interferes in the physiological functioning of the masticatory system, promoting occlusal and functional alterations. The purpose of this study was to verify maximal bite force and maximal bite force correlated with electromyographic activity in 14 partially edentulous and 14 dentate individuals. Bite force in right and left molar and incisor regions were registered using a dynamometer with capacity of up to 1000N, adapted for oral conditions and at the same time electromyography was performed using Myosystem-Br1 with electrodes positioned on right and left masseter and temporalis muscles, and one reference electrode on the frontal bone. The highest value out of three recordings was considered the individual's maximal bite force. Statistical analysis of the bite force data was performed by means of t-test and Pearson's bivariate correlation test was used for the analysis between bite and electromyographic activity using SPSS 12.0 software. Dentate individuals showed greater maximal bite force in the three regions. Correlations between electromyographic activity and bite force in the dentate group obtained positive coefficients for every muscle in the right molar region, for the left temporalis in the left molar region, and for every muscle in the incisive region. For the partially edentulous group, only the left temporalis muscle presented a positive correlation in the right molar region, there was positive correlation for the right masseter and right and left temporalis in the left molar region, and, in the incisive region, every muscle presented negative correlation. These data evidence the strong influence of dental loss over the maximal bite force and small correlation between bite force and electromyographic activity.

The objective of this study is to verify the coincidence between the occurrence of the electromyographic fatigue threshold (EMGth) and the ventilatory threshold (Vth) in an incremental test in the cyclosimulator, as well as to compare the calculation of the RMS from the EMG signal using different time windows. Thirteen male cyclists (73.7 +/- 12.4 kg and 174.3 +/- 6.2 cm) performed a ramp incremental test (TI) in a cyclosimulator until voluntary exhaustion. Before the start of each TI subjects had the active bipolar electrodes placed over the superficial muscles of the quadriceps femoris (QF) of the right leg: rectus femoris (RF), vastus medialis (VM) and vastus lateralis (VL). The paired student's t test, pearson's correlation coefficient and the analysis method described by Bland and Altman for the determination of the concordance level were used for statistical analysis. The significance level adopted was P < 0.05. Although no significant differences were found between Vth and the EMGth calculated from windows of 2, 5, 10, 30 and 60 seconds in the studied muscles, it is suggested that the EMGth values determined from the calculation of the RMS curve with windows of 5 and 10 seconds seem to be more appropriate for the calculation of the RMS curve and determination of EMGth from visual inspection.