Muscles In Normal Subjects Research Articles

Functional Tests of the Abdominal Wall Muscles in Normal Subjects and in Patients with Diastasis and Oblique Inguinal Hernias in a Pilot Study.

To identify typical patterns of abdominal wall muscle activation in patients with diastasis recti and inguinal hernias compared to controls during the Valsalva maneuver, voluntary coughing, and physical activity. The study included 15 subjects: 5 with diastasis recti, 4 with inguinal hernias, and 6 healthy controls. The functions of rectus abdominis (RA) and external oblique (OE) muscles were measured by surface electromyography (sEMG). Using ultrasound, the thicknesses of the RA, OE, internal oblique (IO), and transversus abdominis (TA) muscles were assessed as well as the echo intensity (EI) of RA and OE. We found a significant effect of the type of abdominal wall pathology on the maximum sEMG amplitude (p = 0.005). There was a reliable trend in maximum sEMG amplitude, with the highest one in diastasis recti and a significantly lower one in inguinal hernias. Duncan's test showed a significant difference in muscle thickness, both on the right and left sides, between patients with diastasis and controls, but only on the left side between patients with diastasis and those with inguinal hernia (p < 0.05). The abdominal wall pathology results in a change in the function and structure of the abdominal muscles, which can be detected using electromyography and ultrasound examination. The presence of diastasis recti is accompanied by an increase in bioelectrical activity and a decrease in thickness.

Loop analysis of the anal sphincter complex in fecal incontinent patients using functional luminal imaging probe.

Cardiac loops have been used extensively to study myocardial function. With changes in cardiac pump function, loops are shifted to the right or left. Functional luminal imaging probe (FLIP) recordings allow for loop analysis of the anal sphincter and puborectalis muscle (PRM) function. The goal was to characterize anal sphincter area-pressure/tension loop changes in fecal incontinence (FI) patients. Fourteen healthy subjects and 14 patients with FI were studied. A custom-designed FLIP was placed in the vagina and then in the anal canal, and deflated in 20-ml steps, from 90 to 30 ml. At each volume, subjects performed maximal voluntary squeezes. Area-pressure (AP) and area-tension (AT) loops were generated for each squeeze cycle. Three-dimensional ultrasound imaging of the anal sphincter and PRM were obtained to determine the relationship between anal sphincter muscle damage and loop movements. With the increase in bag volume, AP loops and AT loops shifted to the right and upward in normal subjects (both anal and vaginal). The shift to the right was greater, and the upward movement was less in FI patients. The difference in the location of AP loops and AT loops was statistically significant at volumes of 50 ml to 90 ml (P < 0.05). A similar pattern was found in the vaginal loops. There is a significant relationship between the damage to the anal sphincter and PRM, and loop location of FI patients. We propose AP and AT loops as novel ways to assess the anal sphincter and PRM function. Such loops can be generated by real-time measurement of pressure and area within the anal canal.NEW & NOTEWORTHY We describe the use of area-pressure (AP) and area-tension (AT)-loop analysis of the anal sphincters and puborectalis muscles in normal subjects and fecal incontinent patients using the functional luminal imaging probe (FLIP). There are differences in the magnitude of the displacement of the loops with increase in the FLIP bag volume between normal subjects and patients with fecal incontinence. The latter group shifts more to the right in AP and AT space.

High-frequency ultrasound imaging of the anal sphincter muscles in normal subjects and patients with fecal incontinence.

The current "gold standard" to diagnose anal sphincter morphology and disruptions utilizes low-frequency (3-9MHz) ultrasound (US) imaging techniques that provide a general outline of the sphincter muscles, but not their microstructural details. High-frequency US transducers (7-15MHz) have been used to study the muscle architecture (direction of muscle fascicles) in the limb muscle. The goal of our study was to visualize the microstructural anatomy of the anal sphincters, specifically the external anal sphincter (EAS), using high-frequency US imaging. Studies were conducted in asymptomatic female and male subjects and patients with fecal incontinence. US images were acquired using a low-frequency US (3-9MHz) and high-frequency (7-15MHz) US transducer. The latter was placed intra-anally to image the anal canal at 12, 9, 3, and 6 o'clock positions. The low-frequency US images revealed the general outline of the anal sphincter muscles. On the other hand, high-frequency imaging visualized muscle fascicles and connective tissue inside the external anal sphincter (EAS). In FI patients, there was loss of muscle fascicles and alteration in the echo-intensity pattern in the region of damaged EAS suggestive of muscle fibrosis. High-frequency ultrasound imaging is a powerful tool to visualize the microstructural details of the EAS. Our studies show that damage to the EAS muscle results in the alteration of its myoarchitecture, that is, loss of muscle fascicles and increase in the muscle connective tissue.

Effect of Neuromuscular Electrical Stimulation Training on the Finger Extensor Muscles for the Contralateral Corticospinal Tract in Normal Subjects: A Diffusion Tensor Tractography Study.

Objectives: Neuromuscular electrical stimulation (NMES) is a popular rehabilitative modality to improve motor function of the extremities and trunk. In this study, we investigated changes of hand function and the contralateral corticospinal tract (CST) with treatment by NMES on the finger extensor muscles for 2 weeks, using serial diffusion tensor tractography (DTT).Methods: Thirteen right handed normal subjects were recruited. Treatment was applied to the left hand (the NMES side), and the right hand was the control side. NMES was applied for 30 min/day, 7 days per week, for 2 weeks. Hand motor function was evaluated twice at pre-NMES and post-NMES training using grip strength (GS), Purdue pegboard test (PPT) and tip pinch. The fractional anisotropy (FA), mean diffusivity (MD) and tract volume (TV) of the CST in both hemispheres were measured using DTT.Results: On the control side, the clinical scores did not differ significantly between pre- and post-NMES training (p > 0.05). However, on the NMES side, PPT and tip pinch improved significantly (p < 0.05), although GS did not. TV of the right CST increased significantly at post-NMES training (p < 0.05) whereas FA and MD did not differ significantly (p > 0.05). By contrast, FA, MD and TV on the left CST did not change significantly (p > 0.05).Conclusion: We demonstrated facilitation of the contralateral CST with improvement of fine motor activity by 2 weeks of NMES training of peripheral muscles in normal subjects. We think our results can be applied to the normal subjects and patients with brain injury to improve the fine motor function of the hand and facilitate the normal CST or healing of the injured CST.

Effect of Pulsed Shortwave Diathermy on Average Isometric Peak Torque of Quadriceps Muscle in Normal Subjects

Effect of Pulsed Shortwave Diathermy on Average Isometric Peak Torque of Quadriceps Muscle in Normal Subjects

CVEMP morphology changes with recording electrode position, but single motor unit activity remains constant.

Cervical vestibular evoked myogenic potentials (cVEMPs) recorded over the lower quarter of the sternocleidomastoid (SCM) muscle in normal subjects may have opposite polarity to those recorded over the midpoint. It has thus been suggested that vestibular projections to the lower part of SCM might be excitatory rather than inhibitory. We tested the hypothesis that the SCM muscle receives both inhibitory and excitatory vestibular inputs. We recorded cVEMPs in 10 normal subjects with surface electrodes placed at multiple sites along the anterior (sternal) component of the SCM muscle. We compared several reference sites: sternum, ipsilateral and contralateral earlobes, and contralateral wrist. In five subjects, single motor unit responses were recorded at the upper, middle, and lower parts of the SCM muscle using concentric needle electrodes. The surface cVEMP had the typical positive-negative polarity at the midpoint of the SCM muscle. In all subjects, as the recording electrode was moved toward each insertion point, p13 amplitude became smaller and p13 latency increased, then the polarity inverted to a negative-positive waveform (n1-p1). Changing the reference site did not affect reflex polarity. There was a significant short-latency change in activity in 61/63 single motor units, and in each case this was a decrease or gap in firing, indicating an inhibitory reflex. Single motor unit recordings showed that the reflex was inhibitory along the entire SCM muscle. The cVEMP surface waveform inversion near the mastoid and sternal insertion points likely reflects volume conduction of the potential occurring with increasing distance from the motor point.

MRI study of the thickness and width of the extraocular muscles in normal subjects

To study the thickness and width of extraocular muscles by high-resolution magnetic resonance imaging (MRI). Cross-sectional study. Sixty eight normal subjects between 2.0 and 50.0 years of age, mean age was (21.2 ± 2.1) (SD) years old, male 34, female 34. Extraocular muscles in the orbits were scanned with SE/T2WI coronal and oblique-coronal planes perpendicular to optic nerve, and within 1.5 mm thick planes. The thickness and width of the extraocular muscles in the maximum planes were measured in 68 normal subjects on oblique-coronal planes MR images. The vertical diameter of the medial rectus muscle and lateral rectus muscle indicated width, horizontal diameter indicated thickness. The vertical diameter of the superior rectus muscle and inferior rectus muscle indicated thickness, horizontal diameter indicated width. Vertical diameter of the muscle belly is from the top edge to the bottom edge, horizontal diameter of the muscle belly is from the innermost to the outermost edge. The differences in diameters of bilateral extraocular muscles were evaluated by the independent sample t statistical test. Superior oblique muscle was considered as a reference in each subject to calculate the ratio of the other rectus muscles and the superior oblique muscle in diameter and to compare the relationship of the extraocular muscles in the same plane. The extraocular muscles of normal subjects were symmetrical on the two sides. There were no statistically significant differences between the bilateral extraocular muscles (medial rectus muscle, lateral rectus muscle, inferior rectus muscle and superior rectus muscle) in the thickness and width (t values respectively were 0.043, 0.025, 0.043, 0.032, 0.001, 0.601, 0.667, 0.021, 0.032, 0.005, all P > 0.05). The ratio of the rectus muscles (medial rectus muscle, lateral rectus muscle, superior rectus muscle, inferior rectus muscle) and the superior oblique muscle in thickness respectively were (1.15 ± 0.14), (1.04 ± 0.14), (1.07 ± 0.19), (1.39 ± 0.22). The relationship of the thickness of extraocular muscles in the maximum planes were: inferior rectus muscle > medial rectus muscle > superior rectus muscle > lateral rectus muscle, and the thickness of 91% superior rectus muscle was close to lateral rectus muscle. The ratio of the rectus muscles (medial rectus muscle, lateral rectus muscle, superior rectus muscle, inferior rectus muscle) and the superior oblique muscle in width respectively were (1.71 ± 0.27), (2.07 ± 0.28), (1.62 ± 0.29), (1.50 ± 0.21). The relationship of the width of extraocular muscles in the maximum planes were: lateral rectus muscle > medial rectus muscle > superior rectus muscle > inferior rectus muscle. The thickness and width of all the extraocular muscles follows a certain rule. Measurements of extraocular muscles using MRI should be done on coronal and oblique-coronal planes MRI scan simultaneously. The sizes of extraocular muscles can be assessed by observing the symmetry of the extraocular muscles on the two sides on coronal plane and the usual rule of extraocular muscles on oblique-coronal plane.

Hamstring and psoas length of crouch gait in cerebral palsy: a comparison with induced crouch gait in age- and sex-matched controls

BackgroundPrevious studies have shown that hamstring lengths are often not short in patients with cerebral palsy, which raises concerns over the benefits of distal hamstring lengthening in patients with crouch gait. In this study, the authors measured lengths of hamstrings and psoas muscles in normal subjects mimicking crouch gait and compared these with lengths in cerebral palsy patients with crouch gait.MethodsThirty-six patients with cerebral palsy and crouch gait were included in this study, and in addition, 36 age- and sex-matched normal controls were recruited. Hamstring and psoas muscle lengths in patients were evaluated using gait analysis and interactive musculoskeletal modeling software. Muscle lengths were also measured in the normal control group during normal gait and while mimicking crouch gait, and these were compared with those of cerebral palsy patient with crouch gait.ResultsNo significant differences were observed between maximum hamstring (p=0.810) and maximum psoas (p=0.456) lengths of patients and controls mimicking crouch gait. However, patients showed significantly shorter excursions of hamstring (p=0.022) and psoas (p=0.036) muscles than controls, whereas no significant excursion differences were observed between controls during normal gait and mimicking crouch gait.ConclusionsNormal controls mimicking crouch gait and cerebral palsy patients with crouch gait demonstrate similar muscle length patterns. However, mimicked crouch gait did not reproduce the excursion pattern shown by patients with crouch gait, which suggests that reduced hamstring and psoas excursion is an innate characteristic of pathologic crouch gait.

Electrical stimulation to the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle induces involuntary reflex contraction of the frontalis muscles

The levator and frontalis muscles lack interior muscle spindles, despite consisting of slow-twitch fibres that involuntarily sustain eyelid-opening and eyebrow-raising against gravity. To compensate for this anatomical defect, this study hypothetically proposes that initial voluntary contraction of the levator fast-twitch muscle fibres stretches the mechanoreceptors in Müller's muscle and evokes proprioception, which continuously induces reflex contraction of slow-twitch fibres of the levator and frontalis muscles. This study sought to determine whether unilateral transcutaneous electrical stimulation to the trigeminal proprioceptive fibres that innervate the mechanoreceptors in Müller's muscle could induce electromyographic responses in the frontalis muscles, with monitoring responses in the orbicularis oculi muscles. The study population included 27 normal subjects and 23 subjects with aponeurotic blepharoptosis, who displayed persistently raised eyebrows on primary gaze and light eyelid closure. The stimulation induced a short-latency response in the ipsilateral frontalis muscle of all subjects and long-latency responses in the bilateral frontalis muscles of normal subjects. However, it did not induce long-latency responses in the bilateral frontalis muscles of subjects with aponeurotic blepharoptosis. The orbicularis oculi muscles showed R1 and/or R2 responses. The stimulation might reach not only the proprioceptive fibres, but also other sensory fibres related to the blink or corneal reflex. The experimental system can provoke a monosynaptic short-latency response in the ipsilateral frontalis muscle, probably through the mesencephalic trigeminal proprioceptive neuron and the frontalis motor neuron, and polysynaptic long-latency responses in the bilateral frontalis muscles through an unknown pathway. The latter neural circuit appeared to be engaged by the circumstances of aponeurotic blepharoptosis.

The effect of a Lucia jig for 30 minutes on neuromuscular re-programming, in normal subjects

The Lucia jig is a technique that promotes neuromuscular reprogramming of the masticatory system and allows the stabilization of the mandible without the interference of dental contacts, maintaining the mandible position in harmonic condition with the musculature in normal subjects or in patients with temporomandibular dysfunction (TMD). This study aimed to electromyographically analyze the activity (RMS) of the masseter and temporal muscles in normal subjects (control group) during the use of an anterior programming device, the Lucia jig, in place for 0, 5, 10, 20 and 30 minutes to demonstrate its effect on the stomatognathic system. Forty-two healthy dentate individuals (aged 21 to 40 years) with normal occlusion and without parafunctional habits or temporomandibular dysfunction (RDC/TMD) were evaluated on the basis of the electromyographic activity of the masseter and temporal muscles before placement of a neuromuscular re-programming device, the Lucia jig, on the upper central incisors. There were no statistically significant differences (p < 0.05) in the electromyographic activity of the masticatory muscles in the different time periods. The Lucia jig changed the electromyographic activity by promoting a neuromuscular reprogramming. In most of the time periods, it decreased the activation of the masticatory muscles, showing that this device has wide applicability in dentistry. The use of a Lucia jig over 0, 5, 10, 15, 20 and 30 minutes did not promote any statistically significant increase in muscle activity despite differences in the data, thus showing that this intra-oral device can be used in dentistry.

Shear wave elastography properties of vastus lateralis and vastus medialis obliquus muscles in normal subjects and female patients with patellofemoral pain syndrome

The aim of our study was to define and compare the mechanical properties of the vastus lateralis (VL) and vastus medialis obliquus muscles (VMO) by the way of quantitative shear-wave elastography in male and female healthy control (HC) subjects, and in female patients with patellofemoral pain syndrome (PFPS). Twenty-two healthy volunteers (11 male and 11 female) and 11 female patients with anterior knee pain were included in the study. The SWE examinations for VL and VMO were performed while the subjects were performing open kinetic chain exercises in neutral and 30° hip abduction. The contraction capacity (CC) and contraction ratio (CR) values were determined in resting and contraction phases in both hip positions. The mean elasticity values in the CC for VL and VMO muscles were significantly higher in male HC subjects when compared to female HC subjects (p < 0.05). The CR of the VL muscle in female patients with PFPS was not significantly different than the female HC group. The CR for the VMO muscle was significantly lower in female patients with PFPS when compared to female HC subjects (p < 0.05). We found a significant VMO weakness, and this method may provide quantitative data that might influence the diagnosis of muscle weakness, in female patients with PFPS.

MUAP values of two facial muscles in normal subjects and comparison of two methods for data analysis

This study aimed to obtain normal MUAP values in 2 facial muscles and to compare the results of different analysis methods. The frontalis muscle of 36 and the mentalis muscle of 28 normal subjects were examined, and mean and outlier values of all MUAP parameters were calculated with the automatic method. Next, manual editing of the recorded raw data provided new sets of values for comparison. The frontalis muscle MUAPs have significantly shorter duration, smaller amplitude and a lower number of turns and phases compared with those of mentalis. Higher MUAP duration values in the frontalis were the only significant difference after the comparison of the different analysis methods. The set of normal values for frontalis and mentalis in this study could be useful in routine practice. Careful manual editing of the frontalis MUAPs is recommended for more accurate determination of their duration.

S115 The effect of posture on the 2nd intercostal space surface parasternal electromyogram (EMGpara): validating a novel clinical tool to measure neural respiratory drive

IntroductionAlthough neural respiratory drive (NRD), as measured by diaphragm EMG, has been shown to reflect the balance between the respiratory muscle load and capacity providing a marker of disease severity,...

Feedback effects of masticatory muscles with submaxmal clenching differences between the temporal and the masseter muscles in normal subjects

Feedback effects of masticatory muscles with submaxmal clenching differences between the temporal and the masseter muscles in normal subjects

Combined Effects of Short-term Calorie Restriction and Exercise on Insulin Action in Normal Rats

The present study examined the effect of combination of short-term calorie restriction (CR) and moderate exercise on insulin action in normal rats. Rats were divided randomly into 4 groups: ad libitum, sedentary (A-Sed); calorie restriction, sedentary (CR-Sed); ad libitum, exercise (A-Ex); and calorie restriction, exercise (CR-Ex). Rats in the exercise groups were run on a rodent treadmill. Rats in the CR groups were fed every alternate day. Oral glucose tolerance test (OGTT) showed improvements in both CR-Sed and A-Ex groups compared with the A-Sed group; no further improvement in glucose tolerance was observed in the CR-Ex group. In contrast, glucose infusion rates (GIRs) determined by the hyperinsulinemic-euglycemic clamp method indicated that the GIR of the CR and exercise combination was significantly better than that of the sole intervention of CR or exercise. There was no difference in the levels of fasting glucose, insulin, or high-molecular weight forms of adiponectin among the 4 groups. Protein expression of GLUT-4 in the skeletal muscle increased by exercise, but not by CR. Our findings indicate that the combination of exercise and CR may be effective in enhancing insulin sensitivity at the skeletal muscle in normal subjects.

P13-16 Turns amplitude analysis of facial muscles in normal subjects and myopathic patients

P13-16 Turns amplitude analysis of facial muscles in normal subjects and myopathic patients

Discriminating neurogenic from myopathic disease via measurement of muscle anisotropy

Skeletal muscle is electrically anisotropic, with a tendency for applied electrical current to flow more readily along muscle fibers than across them. In this study, we assessed a method for non-invasive measurement of anisotropy to determine its potential to serve as a new technique for distinguishing neurogenic from myopathic disease. Measurements were made on the biceps brachii and tibialis anterior muscles in 15 normal subjects and 12 patients with neuromuscular disease (6 with amyotrophic lateral sclerosis and 6 with various myopathies) using 50 kHZ applied current. Consistent multi-angle anisotropic patterns were found for reactance and phase in both muscles in normal subjects. Normalized anisotropy differences for each subject were defined, and group average values identified. The amyotrophic lateral sclerosis (ALS) patients demonstrated increased and distorted anisotropy patterns, whereas myopathic patients demonstrated normal or reduced anisotropy. These results suggest that non-invasive measurement of muscle anisotropy has potential for diagnosis of neuromuscular diseases.

A new method for measuring compound muscle action potentials in facial palsy: A preliminary study

To establish a simple, reproducible procedure for studying facial motor nerve conduction (MNC), we determined the optimal electrode position to record evoked compound muscle action potentials (CMAPs) from perioral muscles in normal subjects. We examined three new electrode positions in which the electrode connected to the one input of the amplifier was placed on the mental protuberance, and the one connected to the other input was placed on the skin over the orbicularis oris muscle (the philtrum, mouth angle, or lower lip). We then compared the morphology and amplitudes of the CMAPs, right-left differences, and the reproducibility of CMAP amplitudes with recordings taken from the standard electrode position in which one electrode was placed on the nasolabial fold closely lateral to the ala nasi, and the other was placed on the skin over the orbicularis oris. Percutaneous supramaximal electrical stimulation was applied to the main trunk of the facial nerve. All three of the new recording positions showed greater amplitudes and more obvious biphasic CMAPs than the standard method. Positioning the electrode connected to the negative input on the philtrum was optimal in terms of right-left differences and the reproducibility of CMAP amplitudes. Therefore, this midline recording is a simple, reproducible method for calculating the CMAP amplitude ratio. However, prior to clinical use of this procedure, analyses of patients with facial palsy are required.

P02. Sound and vibration evoked vestibular potentials in the active masseter muscles of normal subjects

P02. Sound and vibration evoked vestibular potentials in the active masseter muscles of normal subjects

Comparison of standard and pediatric size concentric needle EMG electrodes

Objective To compare motor unit action potential (MUAP) metrics recorded by standard and pediatric size concentric EMG electrodes. Methods Commercial electrodes were used to record MUAPs from biceps brachii, first dorsal interosseous and tibialis anterior muscles in normal subjects and those with amyotrophic lateral sclerosis (ALS). Results In normal subjects, peak amplitude and area were significantly higher when recorded by the pediatric size electrode in tibialis anterior muscles and peak amplitude recorded in first dorsal interosseous muscles. In ALS subjects, peak amplitude was higher recorded by the pediatric size electrode in tibialis muscle but lower when recorded in first dorsal interosseous muscles. Conclusions Differences of MUAP metrics when recording with standard and pediatric size electrodes do not seem to have a clinical relevance. Significance Pediatric and standard concentric electrodes record similar MUAP metrics.