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PubMed1985

Accurate diagnosis of detrusor areflexia using combined uroflowmetry and abdominal wall electromyography.

Twenty-three patients who previously demonstrated no detrusor contraction during cystometry were evaluated using a combined uroflowmetry and abdominal wall electromyography. Ten patients voided without abdominal straining (normal detrusor reflexia), 11 could not void without abdominal straining (detrusor areflexia, detrusor weakness, or bladder outlet obstruction), and 2 had equivocal findings with the method.

Abdominal Muscles↗

PubMed1991

A comparison of turns analysis and motor unit analysis in electromyography.

We compared the results of turns analysis and motor unit analysis on 4056 electromyographic interference patterns (IPs) from normal subjects and patients with neuromuscular disorders. The motor unit analysis involved decomposing the IPs into their component motor unit action potentials (MUAPs) using automatic decomposition electromyography (ADEMG). We checked the accuracy of the decompositions by attempting to reconstruct some of the IPs from their identified MUAPs using computer simulations. The simulations revealed that ADEMG typically identified more than 60% (but not all) of the MUAPs in a given IP. Both turns and MUAP properties showed regular and related changes with force, age, muscle, and recording electrode type. The number of turns in each IP was highly correlated with the number of active MUAPs (r = 0.65), the mean MUAP firing rate (r = 0.72), the mean number of turns per MUAP (r = 0.34), and the product of these 3 properties (r = 0.83). The mean amplitude change per turn was highly correlated with the mean MUAP amplitude (r = 0.82), but also depended on the number of turns per MUAP. Due to the lack of a one-to-one relationship between the turns analysis properties and the MUAP properties, the turns analysis properties by themselves did not provide sufficient information to infer unambiguous physiological information about motor unit morphology or firing behavior.

Action Potentials↗

PubMedDate not supplied

A personal computer based system used in electromyography for interpretation and reporting.

Programs for rule based electromyography (EMG) interpretation and reporting are described. A number of parameters are obtained during an EMG investigation. The combination of these data leads to a neurophysiological conclusion. Knowledge from the literature, research and experience is the basis for rule development. Rules have been developed for 14 of the most commonly used classifications of an EMG. The syntax is relatively easy and the user may change the rules, add rules or apply the system for other types of data. The results are displayed in a new graphical way. The system presented here is part of an integrated EMG laboratory with administrative routines, distributed databases for storage of results and routines for automatic report generation.

Computer Graphics↗

PubMed1990

Electromyography of the suprahyoid musculature following mandibular advancement with and without rigid fixation.

The purpose of this investigation was to determine if the activity of the suprahyoid musculature changes following advancement of the mandible and the use of rigid or nonrigid fixation. Ten monkeys underwent mandibular advancement; six underwent 6 weeks of maxillomandibular fixation (MMF), and four had rigid fixation without MMF. Electromyography (EMG) of the suprahyoid musculature was performed preoperatively, and at 3, 7, and 10 weeks postoperatively. The results of this study fail to demonstrate an increase in suprahyoid EMG activity following mandibular advancement. Furthermore, there were no differences between the groups with different types of fixation.

Analysis of Variance↗

PubMed1988

Objective assessment of opioid action by facial muscle surface electromyography (SEMG).

1. Activity of the mimetic muscles of the upper face were recorded from awake and anesthetized patients by surface electromyography (SEMG). 2. High amplitude SEMG accompanied ketamine anesthesia and/or the presentation of pain-provoking stimuli. 3. During periods of elevated facial muscle activity, fentanyl or butorphanol decreased SEMG amplitude. 4. The opioid-induced SEMG depression was not consistently associated with either lowered vigilance or analgesia but did provide an objective measure of drug effect.

Adult↗

PubMedDate not supplied

Vocal cord paralysis in children studied by monopolar electromyography.

Twelve children with symptoms of vocal cord paralysis were studied by monopolar needle electromyography. Recordings were used to verify complete or partial paralysis as well as to evaluate the etiology of the problem, paralytic or mechanical. These results then were useful in patient management. The monopolar electromyographic technique is of value in evaluating and treating vocal cord problems.

Adolescent↗

PubMed1991

Becker muscular dystrophy or spinal muscular atrophy?--Dystrophin studies resolve conflicting results of electromyography and muscle biopsy.

We studied a 29-year-old man with slowly progressive proximal leg weakness, calf hypertrophy, and high serum levels of creatine kinase activity. Clinically, it was not possible to identify his as a sporadic instance of Becker muscular dystrophy (BMD) or one of spinal muscular atrophy. The problem arose because electromyography and elevated creatine kinase suggested a myopathy whereas changes in the muscle biopsy resembled a neurogenic disorder. The diagnosis of BMD was made by DNA analysis which detected a deletion at Xp21 and by immunoelectrophoresis and immunohistochemical tests that identified an abnormal form of gene product, dystrophin. These studies were important for genetic counselling, identifying an X-linked disease instead of one that is autosomal recessive.

Adult↗

PubMedDate not supplied

Biofeedback training of nasal muscles using internal and external surface electromyography of the nose.

BACKGROUND: The purpose of this paper is to describe the outcome of biofeedback training of nasal muscles in cases of nasal valve stenosis and collapse. The present study was performed to investigate the best way of using surface electromyography (sEMG) in biofeedback training of muscles involved in nasal valve function. In the present study, we present the way of biofeedback training of these muscles introducing the intranasal placement of sEMG electrodes and a home exercise program. METHODS: A nonrandomized pilot study of patients presenting with symptoms of obstructed nasal breathing was conducted. All selected patients (n = 15) demonstrated nasal valve stenosis with a positive Cottle maneuver and clinically evident nasal valve collapse. Follow-up ranged from 9 to 12 months. Treatment included surface and intranasal EMG biofeedback-assisted specific strategies for nasal muscle education and a home exercise program of specific nasal movements. RESULTS: All patients exhibited variable subjective improvement. In 86.66% (n = 13), the improvement was proved objectively and there was no need for operation. In 13.33% (n = 2), an endonasal operation was recommended. CONCLUSION: Relieve of obstructed nasal breathing after nasal valve stenosis and/or collapse can be achieved with biofeedback training of nasal muscles and a home exercise program as described. It helps a significant cohort of patients with symptoms of obstructed nasal breathing to avoid surgical intervention.

Adolescent↗

PubMed2006

Back from the brink: electromyography-triggered stimulation combined with modified constraint-induced movement therapy in chronic stroke.

OBJECTIVE: To determine the efficacy of a regimen that combines electromyography-triggered neuromuscular stimulation (ETMS) with modified constraint-induced movement therapy (mCIMT) in patients with chronic stroke. DESIGN: Pre-post, case series. SETTING: Outpatient rehabilitation hospital. PARTICIPANTS: Six subjects who had had a stroke more [corrected] than 1 year before the study and who had upper-limb hemiparesis. All subjects were only able to activate the affected wrist extensors. INTERVENTION: Subjects underwent ETMS twice every weekday in 35-minute increments during an 8-week period. One week after they completed the ETMS regimen, and after the outcome measures were readministered, subjects participated in mCIMT, which consisted of structured therapy sessions that emphasized use of the more affected arm in valued activities. The sessions were held 3 times a week for 10 weeks. The less affected arms were also restrained 5 days a week for 5 hours. MAIN OUTCOME MEASURES: The Fugl-Meyer Assessment (FMA) of motor recovery, Action Research Arm Test (ARAT), and goniometry. RESULTS: Subjects had nominal changes on the ARAT (mean change, 0.3), and no functional changes after ETMS. However, they had a mean increase of 21.5 degrees in affected wrist extension and an improved ability to perform the wrist items of the FMA (reflected by a mean increase of 4.1 points on the FMA), which qualified them for mCIMT. After mCIMT, subjects had a 15.5-point change on the FMA, an 11.4-point change on the ARAT, and a new ability to perform valued activities. CONCLUSIONS: ETMS alone does not result in functional changes. However, it may elicit sufficient active affected wrist and finger extension increases to permit possible participation in mCIMT, which can result in marked functional gains. This study is among the first to show improved function in stroke patients who initially had little hand motor control, and it is among the first to effectively combine 2 singularly efficacious regimens.

Adolescent↗

PubMed2006

An observational electromyography study of the effect of trunk flexion in low-velocity frontal whiplash-type impacts.

OBJECTIVE: To examine the effect of forward and lateral trunk flexion on the cervical electromyogram and head kinematic response to whiplash-type frontal impacts. DESIGN: Observational study of sled impacts. SETTING: Laboratory. PARTICIPANTS: Twenty healthy volunteers. INTERVENTION: Twenty volunteers were subjected to increasing low-velocity (<8km/h) frontal impacts of 4.4, 7.6, 10.3, and 13.3m/s(2) acceleration with trunk forward flexed by 45 degrees and laterally flexed to the right and left by 45 degrees . MAIN OUTCOME MEASURES: Bilateral electromyography of the sternocleidomastoids, trapezii, and splenii capitis and acceleration of the sled, torso, and head were recorded. RESULTS: With either direction of lateral trunk flexion at impact, the trapezii electromyographic activity increased with increasing acceleration (P<.05). With the trunk flexed to the left, the left trapezius generated 39% of its maximal voluntary contraction (MVC) electromyographic activity, while the right trapezius generated 31% of its MVC electromyographic activity. The left splenius (ipsilateral to leftward trunk flexion) generated 24% of its MVC electromyographic activity, with all other muscles generating 15% or less of this measure. With the trunk flexed to the right, the right trapezius generated 38% of its MVC electromyographic activity, while the left trapezius generated 32% of this value. Again, the ipsilateral (to trunk flexion) splenius capitis generated 27% of its MVC electromyographic activity, and all other muscles 11% or less of this measure. CONCLUSIONS: When subjects sit with trunk flexed out of neutral posture at the time of frontal impact, the cervical muscle response is low and unlikely to be injurious.

Acceleration↗

PubMed2004

Multivariate AR modeling of electromyography for the classification of upper arm movements.

OBJECTIVE: We compared the performance of two feature extraction methods for multichannel electromyography (EMG) based arm movement classification. One method was to use a scalar autoregressive model (sAR) for each channel. Another was to model all channels as a whole by a multivariate AR model (mAR). METHODS: The classified arm movements included elbow flexion, elbow extension, forearm pronation and internal shoulder rotation. Six-channel bipolar EMG signals were collected from four electrodes fixed on the biceps, triceps, brachioradialis and deltoid. Fifteen two-channel and four three-channel configurations were formed out of these six-channel signals for a comparison of different channel combinations. Leave-one-out cross-validation was adopted for evaluating the classification performance using a parametric statistical classifier. RESULTS: We processed a total of 216 EMG segments obtained from repeated 18 performances by three normal subjects. mAR model based feature set achieved a better classification accuracy than sAR did for each configuration. Moreover, significance of improvement was greater than 0.95 for those configurations which consisted of EMG channels that were close spatially. CONCLUSIONS: The stronger the cross-correlation among EMG channels the more improvement of classification accuracy one would expect from using a mAR model.

Arm↗

PubMed2005

The role of electromyography in the management of the brachial plexus palsy of the newborn.

Despite being the foremost examination in the management of traumatic nerve damage electromyography (EMG) has an uncertain and ill-defined role in the investigation of brachial plexus palsy of the newborn (BPPN). This may be because EMG, which is used most commonly several months after birth, fails to answer adequately two of the most important questions posed by this condition: its aetiology and the likely prognosis. In this review, we contend that EMG has important contributions to the solution of both of these questions but only if the timing of the investigation is altered. Used early on in the first few days after birth, EMG can separate the rare palsies that occurred during the intrauterine period from those caused by events at the time of birth, and thus have an important role in directing the investigations of the aetiology more appropriately. EMG alone would still not be able to determine which of the perinatal events were responsible. If the EMG is then repeated before reinnervation complicates interpretation, it seems probable that it would identify accurately those cases, where neurotmesis and avulsion have occurred, much earlier than 3 months of age, the crucial age in the clinical assessment of BPPN for consideration for surgery. This might have very important implications for the future directions of treatment.

Birth Injuries↗

PubMed2005

Comparison of different outlier criteria in quantitative anal sphincter electromyography.

OBJECTIVE: Analysis based on 'outliers' has been demonstrated to be a useful adjunct to mean value analysis in quantitative needle electromyography (EMG). However, the outlier criteria applied have been arbitrarily chosen. The aim of the present study was to determine the most useful outlier criteria in motor unit potential (MUP) analysis. METHODS: The external anal sphincter (EAS) muscles were examined by multi-MUP analysis. From 115 muscles of 64 normative subjects, the 0/100, 5/95, 10/90, 15/85, 20/80, and 25/75 percentile MUP parameter values were grouped individually. From these, the 5/95, 2.5/97.5, 1/99 and 0/100% confidence limits were determined. Thus, 24 sets of outlier limits were formed. To calculate sensitivity and specificity, data from 79 patients with cauda equina lesions (189 muscles), and from 77 controls (119 muscles) were compared to normative outlier limits. RESULTS: Sensitivities were highest with outlier limits formed from the 10-90 percentile ranges, followed by the 5-95 and 15-85 percentile ranges, while specificity was highest using the 15-85, followed by the 20-80, and 25-75 percentile ranges. On direct head-to-head comparison the 10-90 percentile ranges were more sensitive and 5-95 were more specific. CONCLUSIONS: The study demonstrated considerable differences in the sensitivity and specificity of outlier limits calculated from different percentile ranges, with outlier criteria calculated from the 10-90 and from the 5-95 percentile ranges appearing to be the most useful for detection of neuropathy in the EAS muscle. SIGNIFICANCE: In future EAS muscle EMG I propose that outlier criteria calculated from the 10-90 percentile ranges be used.

Adolescent↗

PubMed2026

Predictive value of anal sphincter electromyography for sacral neuromodulation test-phase outcomes.

BACKGROUND: Sacral neuromodulation (SNM) is an established therapy for refractory pelvic organ dysfunction. Anal sphincter electromyography (EMG) is commonly used preoperatively to assess sacral and peripheral nerve integrity. However, the prognostic significance of chronic neurogenic EMG changes for SNM outcomes remains unclear. OBJECTIVE: To evaluate whether chronic neurogenic changes on preoperative anal sphincter EMG predict the outcome of the SNM test phase. METHODS: We retrospectively analysed 62 consecutive patients with bladder and/or bowel dysfunction or pelvic pain who were candidates for SNM treatment and who underwent preoperative anal sphincter EMG. EMG findings were classified as normal or showing chronic neurogenic changes. SNM test-phase success was defined as a ≥50% improvement of symptoms at 24 days. Outcomes were compared between EMG groups. RESULTS: Of the 62 patients (49 women, 13 men), 30 (48%) had normal EMG findings and 32 (52%) showed chronic neurogenic changes. Overall, the SNM test phase was successful in 47 patients (76%). Success rates were similar in patients with normal EMG (72%) and neurogenic EMG changes (79%), with no statistically significant difference (p = 0.878). Sex-stratified analyses revealed no significant association between EMG findings and test-phase success in women or men. CONCLUSIONS: Chronic neurogenic changes on anal sphincter EMG do not predict SNM test-phase outcomes. These findings suggest that abnormal sphincter EMG results should not be used as a standalone criterion to exclude patients from SNM therapy. SIGNIFICANCE: Signs of neurogenic damage on anal sphincter EMG are not an indicator of reduced neuromodulatory capacity or diminished clinical response to SNM.

Humans↗

PubMed2006

Electromyography and nerve conduction studies of the lower extremity: uses and limitations.

Electrodiagnostic testing (EDX), the combination of electromyography and nerve conduction studies, is a useful extension of the physical exam. In the proper clinical context, it can help distinguish between the various nerve processes that may contribute to foot pain. This article discusses those processes, their clinical presentation, and the relative usefulness of EDX for each.

Electrodiagnosis↗

PubMed2005

Pain induced by low-grade stress in patients with fibromyalgia and chronic shoulder/neck pain, relation to surface electromyography.

The mechanisms of pain causation in fibromyalgia (FMS) and chronic shoulder/neck pain (SNP) are still debated. We wanted to compare muscle activity and pain development during and after low-grade mental stress in FMS and SNP patients. Twenty-three women with FMS, 29 women with chronic SNP and 35 healthy women performed a stressful task lasting 60 min followed by a 30 min recovery period. We recorded surface electromyography over the trapezius, neck, temporalis and frontalis muscles. Subjects reported their pain at the corresponding locations together with the development of fatigue and perceived tension. Significant differences between FMS and SNP groups were not observed either for muscular or subjective responses. SNP patients and controls responded with more pain in the trapezius and neck regions than in the forehead, in contrast to FMS patients who had a more generalized pain response. Development of pain, tension and fatigue was not related to muscle activity for any group. We conclude that FMS and SNP patients have similar pain and electromyographic responses. The results suggest that similar pathophysiological mechanisms are involved although the responses are more generalised in FMS than in SNP patients. Muscular activity did not explain the pain which developed during the stressful task for either group. Pain lasted longer during recovery in both FMS and SNP patients compared to healthy controls, possibly a result of disease-related sensitisation in pain pathways.

Adult↗

PubMed2004

The methodology of corpus cavernosum electromyography revisited.

OBJECTIVE: The methodology of corpus cavernosum electromyography (CC-EMG) was revisited, in order to overcome current methodological difficulties that hinder its clinical application. MATERIALS AND METHODS: Using an 8-channel device, CC-EMG was performed in 12 healthy volunteers. Surface electrodes were placed bilaterally on the penile shaft and the kneecap (reference electrode), the pubis region and the anterior superior iliac spine (ASIS). A band pass filter with cut-off frequencies of 0.1 and 20 Hz was used. At least 2 sessions of recordings were performed in each subject. RESULTS: Thirty-five of 46 recordings were interpretable. Significant time delays between potentials recorded from different sites of the CC were detected. Clear spatial voltage gradients related to CC-potentials were observed on the pubis region. No voltage changes related to CC-potentials, but electrical activity from other sources were recorded from the ASIS. In contrast to frequency, a clear correlation could be demonstrated between amplitude, duration and polyphasity of CC-potentials recorded in 2 different sessions in the same individual. CONCLUSIONS: Multichannel monopolar recording of CC-EMG with surface electrodes is practical and has several advantages compared with bipolar recording. The results provide evidence that the recorded signals indeed reflect electrical activity of the CC and therefore offer a basis to pursue further clinical validation studies.

Adult↗

PubMed2005

Cross-correlation as a method for comparing dynamic electromyography signals during gait.

Current clinical interpretation of dynamic electromyography (EMG) data is usually based on qualitative assessments of muscle timing. Cross-correlation may provide a method for objectively comparing the timing and shape of EMG signals. This study used cross-correlation to compare EMG signals from different walking trials, different test sessions, and different individuals in able-bodied adults. Cross-correlation results (R-values) for different walking trials within a single test session were high, averaging > or = 0.90 for all muscles tested (R = 1.0 indicates exact agreement). Cross-correlation values were also high among trials from different test sessions conducted by the same and different examiners (average R > or = 0.78 for all muscles). R-values were much more variable when comparing different subjects (average 0.40-0.81, range 0.00-0.91). R-values were lower for the medial hamstrings and rectus femoris compared with the other muscles tested. These results suggest that cross-correlation may be useful for evaluating changes in an individual patient's muscle activation patterns, such as before and after surgery, but not for comparing EMG patterns among different individuals, such as between patients and normative data. This is especially true for biarticular muscles such as the hamstrings and rectus femoris, which may have variable activation patterns and/or increased sensitivity to electrode placement. Cross-correlation may also be useful for identifying appropriate muscles for transfer, identifying "outlier" trials within a test session, and selecting representative EMG curves for a given patient. The advantages of cross-correlation are that it considers shape of the EMG signal in addition to timing and that the assessments it provides are objective, rather than subjective.

Adult↗