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PubMed2001

Electromyography of the pelvic floor musculature in the assessment of obstructed defecation symptoms.

PURPOSE: The purpose of this study was to use electromyography to examine the behavior of the external sphincter, puborectalis muscle, and pubococcygeus muscle during attempted defecation in patients with symptoms of obstructed defecation and in normal subjects to highlight differences of clinical significance. METHODS: A total of 35 patients (31 females) aged 20 to 80 (mean, 53.7 +/- 13.3) years with unprepared bowel who had normal colon transit time and obstructed defecation symptoms and 12 voluntary control subjects (7 females) aged 23 to 68 (mean, 48 +/- 11.5) years underwent an electromyography evaluation of the activity of the external sphincter, puborectalis muscle, and pubococcygeus muscle during attempted defecation. The patients were also examined in separate sessions with defecography and anal manometry. RESULTS: During attempted defecation, puborectalis muscle and external sphincter always reacted in the same manner. When evaluated with pubococcygeus muscle, three main patterns of activity were observed either in patients or in controls: 1) coordinated activation pattern; 2) coordinated inhibition pattern; and 3) uncoordinated or equivocal pattern: activation of pubococcygeus muscle with inhibition of puborectalis muscle/external sphincter, activation followed by inhibition of the three muscles, and activation followed by inhibition of pubococcygeus muscle and no change in the others. We never observed activation of puborectalis muscle/external sphincter concomitant with inhibition of pubococcygeus muscle. The inhibitory coordinated pattern occurred significantly (P = 0.01) more frequently in controls than in patients. These subjects also presented a significantly (P = 0.01) lower frequency of pubococcygeus muscle inhibition. CONCLUSIONS: Either activation or inhibition appears as a physiological behavior, possibly adopted in different circumstances, of the pelvic floor muscles during attempted defecation. The higher prevalence of coordinated inhibitory patterns in normal subjects and the lower frequency of pubococcygeus muscle inhibition in patients with symptoms of obstructed defecation, however, suggests that a loss of inhibition capacity progressing from pubococcygeus muscle to puborectalis muscle/external sphincter muscles could determine the insurgence of obstructed defecation symptoms in some subjects, who should therefore benefit from biofeedback retraining aimed at reacquisition of the inhibition capacity of all muscles of the pelvic floor during defecation.

Adult↗
PubMed2004

The application of surface electromyography in the assessment of ergonomic risk factors associated with manual lifting tasks.

The purpose of this study was to evaluate the ergonomic risk factors associated with manual lifting tasks using surface electromyography (EMG). 13 volunteers lifted loads of 6 and 13 kg at two speeds and at two horizontal distances in 3 different postures and three boxes of different sizes, from floor to knuckle height, performing 72 lifting tasks. For each lift, the surface electromyography signals from the erector spinae muscles, bilaterally at T10 and L3, was recorded. The ergonomic risk factors associated with manual lifting tasks were evaluated by comparing the average amplitude of EMG signals from the erector spinae muscles. The EMG average amplitude for lifting the load of 13 kg was 14.3% greater than that for lifting the load of 6 kg (t=-10.93, P<0.01). The EMG average amplitude at the site of L3 was 10.3% greater than that at the site of T10 (t=-7.98, P<0.01). The EMG average amplitude when performing "fast" lift was 5.9% greater than the "slow" lift (t=-4.63, P<0.01). The posture of lifting affected the EMG average amplitude. It was lowest with semi-squat posture and greatest with squat posture (F=27.76, P<0.01). The result of multiple stepwise regression analysis showed that the loads of lifting, the size of box, horizontal distance, posture of lifting, the site of the spine subjected to force, lifting speed were the factors affecting the EMG average amplitude. The most significant factor was the loads of lifting, followed by the site of the spine subjected to force and the lifting speed in terms of risk. The ergonomic risk factors associated with manual lifting tasks includes the loads, posture, lifting speed, horizontal distance, the site of the spine subjected to force etc. The results of signal amplitude of EMG from the erector spinae muscles showed that semi-squat posture is the best posture for lifting tasks.

Adult↗
PubMed1994

Information effect on the perception of pain during electromyography.

Pain during the performance of electromyography (EMG) is an important clinical problem because pain distresses the patient and can interfere with diagnostic accuracy. We hypothesized that anxiety and pain perception associated with EMG would decrease if patients received written material describing the EMG before examination. Forty-two subjects received written material and 30 did not. Information before the test significantly decreased pain perception for women during the nerve conduction studies (p = .008), but not during the needle examination. A similar effect was not identified for the men. Other results indicate that women perceive the test as more painful than do men, older subjects perceive more pain and experience greater anxiety than do younger subjects, and all subjects perceive greater pain during the performance of (concentric, bipolar) needle electromyography than during the nerve conduction studies.

Adult↗
PubMed1990

Devices for the diagnosis and treatment of temporomandibular disorders. Part II: Electromyography and sonography.

This second article in the three-part series on temporomandibular disorder (TMD) devices compares the claimed diagnostic usefulness of electromyography and sonography with the present scientific evidence. This review concludes that there is no evidence to support the use of either surface electromyography or silent period duration for the evaluation or diagnosis of TMD. Furthermore, in view of the available evidence, sonography and Doppler ultrasound have no particular advantage over a conventional stethoscope or direct auscultation.

Auscultation↗
PubMed1996

[Presymptomatic injury of the recurrent laryngeal nerve in benign thyroid disease: contribution of electromyography].

Diagnosis of recurrent laryngeal nerve palsy is usually possible through a clinical, laryngoscopical and electromyographical approach, but at a critical stage of the nerve injury. We observed four cases of benign thyroïd tumoral processes with a preoperative electromyographic examination showing neurogenic abnormalities in the thyroarytenoid muscle without any clinical symptoms. We presume that only laryngeal electromyography permits the diagnosis of mild, even asymptomatic laryngeal recurrent nerve injury. A recurrent laryngeal nerve palsy occurs in thyroid tumors, most often in malignant conditions, rarely in benign ones. Nevertheless early forms of nerve injury with benign thyroïd pathology could be underrated. Since the functional prognosis of symptomatic laryngeal nerve palsy is doubtful, laryngeal electromyography, through its ability to diagnose early nerve injury, provides helpful indications in thyroïd benign tumoral diseases for the therapeutic decision.

Adult↗
PubMed2005

Comparing uterine electromyography activity of antepartum patients versus term labor patients.

OBJECTIVE: The purpose of this study was to compare uterine electromyography of patients delivering>24 hours from measurement with laboring patients<or=24 hours from measurement. STUDY DESIGN: Fifty patients (group 1: labor, n=24; group 2: antepartum, n=26) were monitored using transabdominal electrodes. Group 2 was recorded at several gestations. Uterine electrical "bursts" were analyzed by power-spectrum from 0.34 to 1.00 Hz. Average power density spectrum (PDS) peak frequency for each patient was plotted against gestational age, and compared between group 1 and group 2. Frequency was partitioned into 6 bins, and associated burst histograms compared. RESULTS: Group 1 was significantly higher than group 2 for gestational age (39.87+/-1.08 vs 32.96+/-4.26 weeks) and average PDS peak frequency (0.51+/-0.10 vs 0.40+/-.03 Hz). Histograms were significantly different. A correlation coefficient of .41, with significance, was found with PDS vs gestation. CONCLUSION: Uterine electromyography in antepartum patients is significantly lower than in laboring patients delivering<or=24 hours from measurement.

Adolescent↗
PubMed2004

Changes in macro electromyography over time in patients with a history of polio: a comparison of 2 muscles.

OBJECTIVE: To investigate whether changes over time are different in a weight-bearing leg muscle than in a less heavily used arm muscle. DESIGN: Prospective study. SETTING: University hospital laboratory. PARTICIPANTS: Twenty-three patients with a history of poliomyelitis. INTERVENTION: Two investigations were performed 5 years apart, using macro electromyography and the patients' own assessments of symptoms in the tibial anterior and the biceps brachii muscles. Test-retest of macro electromyography was performed in controls and in patients with old polio. MAIN OUTCOME MEASURES: Macro motor unit potential (MUP) and symptoms in the tibial anterior and biceps brachii over time. RESULTS: The macro MUP amplitude increased by 24% (P<.05) in the tibial anterior but was unchanged in the biceps brachii muscle. CONCLUSIONS: An increase in the macro MUP amplitude of the tibial anterior muscle, but not of the biceps brachii, most likely indicates a more pronounced ongoing denervation-reinnervation process over time in the tibial anterior. This difference could be activity dependent, but other factors cannot be excluded.

Aged↗
PubMed2004

Distribution and extent of involvement in brachial plexopathies caused by gunshot wounds, motor vehicle crashes, and other etiologies: a 10-year electromyography study.

OBJECTIVE: To examine the differences in the extent and distribution of brachial plexopathy involvement caused by gunshot wounds (GSW), motor vehicle crashes (MVCs), and other etiologies, based on electrophysiologic data. DESIGN: Retrospective review of electrophysiologic data from 1993 to 2002. SETTING: A large urban county hospital. PARTICIPANTS: Sequential patients (N=109) with the diagnosis of brachial plexopathy established by electromyography testing. This included 35 patients with GSW, 25 involved in an MVC, and 49 with other etiologies. INTERVENTIONS: Not applicable. Main Outcome Measures The brachial plexus was divided into 9 regions: upper, middle, and lower root; upper, middle, and lower trunks; and lateral, posterior, and medial cords. Regions involved by needle study on electromyography were denoted as positive or negative. The total number of regions involved was also recorded. RESULTS: Injury was most common in the trunks (52%), cords (36%), and roots (12%) (Pearson chi(2), P<.000). Specifically, the "other" category had the greatest number of injuries to the trunks (54%) (Pearson chi(2), P<.000), whereas the trunks (46%) and cords (45%) were more evenly affected in GSW cases (Pearson chi(2), P=.585). In the MVC group, there was a trend toward more trunks (56%) being affected (Pearson chi(2), P=.076). CONCLUSIONS: Differences were noted in the distribution of injury when examining subtypes of traumatic brachial plexopathies.

Accidents, Traffic↗
PubMed2005

The logical choice of muscles for the needle-electromyography evaluation of cervical radiculopathy.

OBJECTIVE: To find the theoretically smallest subsets of muscles for needle-electromyography screening of cervical radiculopathies that meet or exceed the American Association of Electrodiagnostic Medicine (AAEM) guideline: ascertaining that each root and its adjacent roots are represented by at least 2 muscles each, innervated by those roots via different peripheral nerves. DESIGN: Twenty-two and 36 muscle sets and their myotomal innervation were derived from the literature, and rearranged into 15 and 23 unique muscle groups by root and peripheral nerve innervation. All 2 circumflex 15 and 2 circumflex 23 subsets thereof were respectively identified. The best approximations that met or exceeded the AAEM criteria were computed for each subset and the smallest subsets that qualified were retained. SETTING: Electromyography laboratory. PARTICIPANTS: None. INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Compliance with or exceeding the AAEM guideline in the number of muscles sampled per damaged root and the number of muscles sampled per adjacent normal roots. RESULTS: The smallest subsets satisfying or exceeding the AAEM guideline are of 8, 9, and 10 muscles each, and are enumerated in tables 3 and 4 in this article. CONCLUSIONS: Electromyographers may choose a set or sets from tables in this article that best suits them, with confidence that they comply with or exceed the AAEM guideline while causing minimal pain to their patients and using the shortest possible procedure. All the roots can be screened at once to best differentiate between normal and damaged roots, and, in most cases, to reach a final diagnosis. Nonetheless, when needed, each set may be the basis for a more extensive workup.

Electromyography↗
PubMed2006

Surface electromyography activity of trunk muscles during wheelchair propulsion.

BACKGROUND: Trunk instability due to paralysis can have adverse effects on posture and function in a wheelchair. The purpose of this study was to record trunk muscle recruitment patterns using surface electromyography from unimpaired individuals during wheelchair propulsion under various propulsion speed conditions to be able to design trunk muscle stimulation patterns for actual wheelchair users with spinal cord injury. METHODS: Fourteen unimpaired subjects propelled a test wheelchair on a dynamometer system at two steady state speeds of 0.9 m/s and 1.8 m/s and acceleration from rest to their maximum speed. Lower back/abdominal surface electromyography and upper body movements were recorded for each trial. Based on the hand movement during propulsion, the propulsive cycle was further divided into five stages to describe the activation patterns. FINDINGS: Both abdominal and back muscle groups revealed significantly higher activation at early push and pre-push stages when compared to the other three stages of the propulsion phase. With increasing propulsive speed, trunk muscles showed increased activation (P<0.0001). Back muscle activity was significantly higher than abdominal muscle activity across the three speed conditions (P<0.0005), with lower back muscles predominating. INTERPRETATION: Abdominal and back muscle groups cocontracted at late recovery phase and early push phase to provide sufficient trunk stability to meet the demands of propulsion. This study provides an indication of the amount and duration of stimulation needed for a future application of electrical stimulation of the trunk musculature for persons with spinal cord injury.

Abdominal Muscles↗
PubMedDate not supplied

Shoulder electromyography in multidirectional instability.

We studied shoulder muscle activity in multidirectional instability (MDI) and multidirectional laxity (MDL) of the shoulder, our hypothesis being that altered muscle activity plays a role in their pathogenesis. Six muscles (supraspinatus, infraspinatus, subscapularis, anterior deltoid, middle deltoid, and posterior deltoid) were investigated by use of intramuscular dual fine-wire electrodes in 7 normal shoulders, 5 MDL shoulders, and 6 MDI shoulders. Each subject performed 5 types of exercise (rotation in neutral, 45 degrees of abduction, 90 degrees of abduction, flexion/extension, and abduction/adduction) on an isokinetic muscle dynamometer at two rates, 90 degrees /s and 180 degrees /s. After filtering, rectification, and smoothing, the electromyography signal was normalized by using the peak voltage of the movement cycle. In subjects with MDI, compared with normal subjects, activity patterns of the anterior deltoid were different during rotation in neutral and 90 degrees of abduction, whereas those of the middle and posterior deltoid were different during rotation in 90 degrees of abduction. In subjects with MDL, the posterior deltoid showed increased activity compared with normal subjects during adduction. Activity patterns of the supraspinatus, infraspinatus, and subscapularis appeared similar in both groups. Dual fine-wire electromyography offers insight into the complex role of shoulder girdle muscle function in normal movement and in instability. Altered patterns of shoulder girdle muscle activity and imbalances in muscle forces support the theory that impaired coordination of shoulder girdle muscle activity and inefficiency of the dynamic stabilizers of the glenohumeral joint are involved in the etiology of MDI. Interestingly, the abnormalities are in the deltoid rather than the muscles of the rotator cuff.

Adult↗
PubMed2003

Nerve conduction studies, electromyography and sympathetic skin response in Fabry's disease.

We prospectively performed neurophysiologic studies in nine Fabry's Disease (FD) patients (8 male and 1 female) in order to describe the results of nerve conduction studies (NCS) and electromyography (EMG) and to verify whether the sympathetic skin response (SSR) is impaired in these patients. The investigation protocol included SSR, sensory and motor NCS and EMG. SSR was performed not only in FD patients, but also in 18 normal controls. All FD patients had normal nerve conduction studies and electromyography. SSR was present in all controls with a mean amplitude of 1453.6+/-682.3 microV. However, the SSR was absent in six and lower than 500 microV in the remaining FD patients. All patients had normal sensory and motor NCS and EMG. SSR, on the other hand, was significantly altered in all patients and this test could, therefore, be useful in the diagnostic evaluation of FD patients.

Adolescent↗
PubMed1982

Experience with electromyography of the external urethral sphincter in spinal cord injury patients.

Simultaneous recordings of electromyography of the external urethral sphincter and bladder pressure during voiding were done for 71 male patients with spinal cord injury. Discordant activities between the anal and the external urethral sphincters were noted in 39 per cent of the patients. The degree of bladder dysfunction was related more to the degree of dyssynergia of the urethral than the anal sphincter. This detrusor-sphincter dyssynergia was found in 67 per cent of our patients regardless of the differences in cystometric patterns and the level of spinal injury. The importance of electromyography of the external urethral sphincter in the diagnosis of neurogenic bladder dysfunction was stressed. The management of detrusor-sphincter dyssynergia is discussed briefly.

Anal Canal↗
PubMed1980

Choice of electrode in electromyography of the external urethral and anal sphincters.

The needle, anal and catheter methods of performing simultaneous cystometry and pelvic floor electromyography were compared in 29 patients. Urethral sphincter electromyographic recordings consistently were satisfactory with a needle electrode, whereas the catheter surface electrode caused recording artifacts and was fragile. Anal sphincter electromyography was more reliable with a needle electrode than with an anal surface electrode.

Electrodes↗
PubMed1980

Correlation among cystometry, urethral pressure profilometry and pelvic floor electromyography in the evaluation of female patients with voiding dysfunction symptoms.

We herein evaluate the correlation among cystometry, urethral pressure profilometry and pelvic floor electromyography in 137 female patients. The predominant symptom was frequency in 40 patients, urge incontinence in 31 and stress incontinence in 66. There appeared to be a correlation between urge incontinence and a hyperreflexic cystometrogram but no correlation was noted between either frequency or stress incontinence and the cystometrogram profile. The urethral pressure profile showed a correlation between stress incontinence and the lowest profile measurements. Frequency and urge incontinence had similar profile measurements except for maximum urethral planimetry. Electromyography showed that the external urethral sphincter had a different finding than the levator ani or the external anal sphincters in all 3 groups of female patients. The external urethral sphincter had a higher percentage of denervation than the other 2 muscles, especially in the stress incontinence group.

Anal Canal↗
PubMed1977

A new approach to electromyography of the external urethral sphincter.

Detailed electromyographic investigation of the external urethral sphincter was done as part of a urodynamic evaluation of 119 patients. The sphincter was located by inserting electrodes alongside the urethra. The electromyogram was viewed on an oscilloscope and recorded on paper. Normal and abnormal sphincter electromyograms were defined and the role of sphincter electromyography in urodynamic studies was discussed. It was observed that electromyographic activity does not always correlate with urethral resistance but must be interpreted in conjunction with other urodynamic parameters, such as urethral pressures, urinary flow rates and voiding cystourethrography. In addition, sphincter electromyography provides valuable information to define the various neural pathways involved in micturition and continence.

Electromyography↗
PubMed2003

Predicting term and preterm delivery with transabdominal uterine electromyography.

OBJECTIVE: To determine whether delivery can be predicted using transabdominal uterine electromyography. METHODS: A total of 99 patients were grouped as either term (37 weeks or more) or preterm (less than 37 weeks). Uterine electrical activity was recorded for 30 minutes in clinic. Electromyographic "bursts" were evaluated to determine the power density spectrum. Measurement-to-delivery time was compared with the average power density spectrum's peak frequency. Receiver operating characteristic curve analysis was performed for 48, 24, 12, and 8 hours from term delivery, and 6, 4, 2, and 1 day(s) from preterm delivery. RESULTS: The power density spectrum peak frequency increased as the measurement-to-delivery interval decreased. Receiver operating characteristic curve analysis gave high positive and negative predictive values for both term and preterm delivery. At term, the average power density spectrum peak frequency was significantly higher for the 24-or-fewer-hours-to-delivery group than for the more-than-24-hours-to-delivery group, whereas at preterm, the average power density spectrum peak frequency was significantly higher in the 4-or-fewer-days-to-delivery group than in the more-than-4-days-to-delivery group (P <.05). CONCLUSION: Transabdominal uterine electromyography predicts delivery within 24 hours at term and within 4 days preterm. This methodology offers many advantages and benefits that are not available with present uterine monitoring systems.

Adolescent↗
PubMed2000

Correlation of intraurethral ultrasonography and needle electromyography of the urethra.

OBJECTIVE: To correlate structural intraurethral ultrasound findings with needle electromyography of striated urethral sphincters in young continent nulliparas. METHODS: Twenty-three nulliparas, each less than 35 years old and without pelvic floor disorders, were recruited at Methodist Hospital in Indianapolis, Indiana, and the University of Louisville in Louisville, Kentucky. Each had concentric needle electromyography of their urethra to localize their striated urethral sphincter. Intraurethral ultrasound was used to identify the needle tip and layer in which it was found, examine the sonographic appearance of periurethral anatomy, and measure the thickness of hypoechoic and outer hyperechoic layers. RESULTS: Three layers were seen on intraurethral ultrasound: a mildly hyperechoic inner layer, a hypoechoic middle layer, and a hyperechoic outer layer. The concentric needle tip was seen in all subjects and showed motor unit action potentials when located in the outer hyperechoic layer. The mean thickness of the hypoechoic layer was 2.5 mm, and the mean thickness of the outer hyperechoic layer was 2.6 mm. CONCLUSION: Motor unit action potentials showed that striated muscle was present in the outer hyperechoic layer on intraurethral ultrasound, implying that it contains the striated urethral sphincter.

Action Potentials↗