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PubMed1976

Measurement of intravesical and rectal pressures simultaneously with electromyography of anal sphincter in children with myelomeningocele.

This paper reports a technique for simultaneous measurement of intravesical pressure, intra-abdominal pressure, electromyographic activity of the external and sphincter and urinary flow. Using this technique during filling of the bladder and during micturition in 38 children with myelomeningocele and neurogenic bladder disturbance, it was possible to identify four main types of bladder dysfunction in these children. Once the type of bladder dysfunction is established for each child, adequate management can be planned far in advance of the detection of inherent upper urinary tract damage. This is particularly important in children with upper somatomotor lesions of bladder innervation in which detrusor-spincter dyssynergia may be present; this dyssynergia always causes some degree of obstruction at the level of the external urethral sphincter and is a constant threat to renal function.

Abdomen↗
PubMed1990

Facial electromyography and emotional reactions.

The aim of this paper is to review data from my laboratory, which were collected in an attempt to determine whether the facial EMG response is a general component of the emotional reaction. In a number of studies it was found that facial reactions: first, are spontaneously elicited and differ according to the kind of emotional stimuli to which subjects are exposed; second, are sensitive to learning; third, are consistent with how the subjects perceive the stimuli and their own specific emotions; fourth, are congruent with autonomic responses; fifth, are more pronounced for females than for males; and finally, differ among subjects with specific fears. These data converge to indicate that facial muscle activity is a general component of the emotional reaction and demonstrate that the facial EMG technique is a sensitive tool for measuring emotional reactions.

Adult↗
PubMed1982

Quantitative electromyography in polymyositis and dermatomyositis.

Twelve patients with polymyositis or dermatomyositis were examined repeatedly during the course of the illness by muscle strength tests, serum enzyme determinations, frequency analysis of the electromyographic signal, and estimations of the spontaneous activity. All methods can be used to follow the course of the disease. Increasing muscle strength was correlated to decreasing serum enzyme values, decreasing spontaneous activity, and decreasing proportion of high-frequency components in the EMG signal, except during the initial period of treatment, when a temporary increase in high-frequency components was recorded.

Adolescent↗
PubMed1994

Ultrasound, computed tomography and magnetic resonance imaging in myopathies: correlations with electromyography and histopathology.

Imaging of examinations by ultrasound (US), computerized tomography (CT) and low field magnetic resonance imaging (MRI) were compared with EMG and muscle biopsy findings in the same muscles of 33 patients with different neuromuscular diseases. None of the imaging methods revealed specific diagnostic details, but gave valuable information on the extent and distribution of muscle involvement. In myopathies all imaging modalities corresponded well with the EMG and histopathology findings, but in the neuropathies with minimal tissue destruction EMG was, understandably, more sensitive. The imaging characteristics of MR were as good as those of CT, but MRI has the advantage of not requiring ionizing radiation. US is the most economical method and it was found to be, despite its lower resolution, very informative in the hands of an experienced examiner, especially for the detection of fibrosis. The good agreement of histopathology with pathologic imaging and EMG findings implies that the accuracy of muscle biopsy increases, if its site is selected on the basis of imaging and/or EMG examination.

Adipocytes↗
PubMed1992

Ultrasound image of human masseter muscle related to bite force, electromyography, facial morphology, and occlusal factors.

The thickness of the human masseter muscle, corresponding approximately to a cross-section at the most bulky part of the superficial portion, was measured by ultrasound scanning at three sites 1 cm apart. The study included 13 women, 21-28 yr of age, with a minimum of 24 teeth and without craniomandibular disorders. Ultrasonography produced a well-defined depiction of the muscle with distinct tendinous structures. The average thickness at the measuring sites varied from 8.83 to 11.08 mm with the muscle relaxed, and increased significantly during contraction to average values between 9.84 and 12.57 mm. The study showed a connection between measures of masseter thickness and function of the muscle, as well as parameters generally associated with masseter muscle function. Muscle thickness at the voluminous anterior part of the superficial portion was systematically and significantly correlated to bite force, occlusal tooth contact and cephalometric data (anterior face height, vertical jaw relation and mandibular inclination). In conclusion, ultrasound scanning gave an uncomplicated and a reproducible access to parameters of jaw muscle function and its interaction with the craniomandibular system.

Adult↗
PubMedDate not supplied

Diagnosis of sciatic nerve tumour in two dogs by electromyography and magnetic resonance imaging.

Sciatic nerve tumour was diagnosed in a Staffordshire Bull Terrier cross-bred and a Bichon Frise, both presenting with chronic left hind limb lameness. Neurological examination in each case was consistent with left sciatic nerve deficits and this was confirmed by EMG studies. Rectal examination of both dogs revealed a palpable intrapelvic mass that was not apparent on survey radiographs. A sciatic nerve tumour was identified using MRI in each case. Histological examination of tissue taken from the Staffordshire Bull Terrier cross-bred was consistent with a malignant peripheral nerve sheath tumour.

Animals↗
PubMed2002

Three-layer volume conductor model and software package for applications in surface electromyography.

On comparing multichannel surface electromyographic measurements of the m. biceps brachii with simulations performed with a previously developed two-layer volume conduction model, we found substantial discrepancies. To incorporate an apparent distorting effect of the skin tissue, the model was extended to three layers. This new model describes the potential resulting from an eccentric bioelectric source in a finite, cylindrical, and anisotropic volume conductor consisting of three layers, representing muscle, subcutaneous fat, and skin tissue. This contribution presents the governing mathematical equations of the three-layer volume conductor model as well as our approach to their solution. A comparison of various models shows that the three-layer model best describes measured potential distributions. Furthermore, we present the "ANVOLCON" (analytical volume conductor) software package. This package has been developed to facilitate the use of the model for scientific and educational purposes and is freely available from http://www.mbfys.kun.nl/knf

Action Potentials↗
PubMed2007

Electromyography of superficial and deep neck muscles during isometric, voluntary, and reflex contractions.

Increasingly complex models of the neck neuromusculature need detailed muscle and kinematic data for proper validation. The goal of this study was to measure the electromyographic activity of superficial and deep neck muscles during tasks involving isometric, voluntary, and reflexively evoked contractions of the neck muscles. Three male subjects (28-41 years) had electromyographic (EMG) fine wires inserted into the left sternocleidomastoid, levator scapulae, trapezius, splenius capitis, semispinalis capitis, semispinalis cervicis, and multifidus muscles. Surface electrodes were placed over the left sternohyoid muscle. Subjects then performed: (i) maximal voluntary contractions (MVCs) in the eight directions (45 deg intervals) from the neutral posture; (ii) 50 N isometric contractions with a slow sweep of the force direction through 720 deg; (iii) voluntary oscillatory head movements in flexion and extension; and (iv) initially relaxed reflex muscle activations to a forward acceleration while seated on a sled. Isometric contractions were performed against an overhead load cell and movement dynamics were measured using six-axis accelerometry on the head and torso. In all three subjects, the two anterior neck muscles had similar preferred activation directions and acted synergistically in both dynamic tasks. With the exception of splenius capitis, the posterior and posterolateral neck muscles also showed consistent activation directions and acted synergistically during the voluntary motions, but not during the sled perturbations. These findings suggest that the common numerical-modeling assumption that all anterior muscles act synergistically as flexors is reasonable, but that the related assumption that all posterior muscles act synergistically as extensors is not. Despite the small number of subjects, the data presented here can be used to inform and validate a neck model at three levels of increasing neuromuscular-kinematic complexity: muscles generating forces with no movement, muscles generating forces and causing movement, and muscles generating forces in response to induced movement. These increasingly complex data sets will allow researchers to incrementally tune their neck models' muscle geometry, physiology, and feedforward/feedback neuromechanics.

Adult↗