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Electromyography
Kinds of Electromyography Selected AbstractsCHEWING PATTERNS OF VARIOUS TEXTURE FOODS STUDIED BY ELECTROMYOGRAPHY IN YOUNG AND ELDERLY POPULATIONSJOURNAL OF TEXTURE STUDIES, Issue 4 2002KAORU KOHYAMA ABSTRACT The effects of food texture on the chewing patterns of elderly and young people, masticatory recordings using electromyography (EMG) were carried out. Fourteen French adults (mean 29.4 years) and 23 elderly (mean 67.7 years) participated. Six food products (rice, beef, cheese, crispy bread, apple and peanuts) were tested. The chewing pattern of elderly subjects was characterized by a significant increase of number of chews and chewing duration for all foods except rice. Whatever the food type, muscle activity per chew (mean amplitude × burst duration) was lower for elderly than for young subjects. Single chews appeared less effective for food reduction in elderly than in young subjects. This can be partly compensated for by increasing the chewing duration and number of chews. No significant difference was found between both groups of subject for the total amount of EMG activity required prior to swallow whatever the food chewed. [source] Long-term follow-up of children with obstetric brachial plexus palsy II: neurophysiological aspectsDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 3 2007Christina Strömbeck MD The aim of this study was to examine long-term neurophysiological outcomes and sensory function in patients with obstetric brachial plexus palsy (OBPP). The same 70 children/adolescents examined in part I: functional aspects (35 males, 35 females; age range 7-20y, mean 13y 6mo [SD 4y 3mo], median 13y) were examined with neurophysiological methods at 3 to 7 months and at 7 to 20 years of age. Thirteen of the 70 participants underwent nerve reconstruction before 1 year of age. Electromyography (EMG) was performed on deltoid and first interossei muscles; Quantitative Sensory Test was used for C6 and C8 dermatomes. Tests for functional sensibility and 2-point discrimination for C6 and C8 were performed. This study shows that considerable EMG changes can be observed in OBBP, even in those fully recovered. EMG changes in the deltoid were shown to deteriorate over time, and sensibility is considerably less affected than motor function. [source] Charcot-Marie-Tooth neuropathy type 1A combined with Duchenne muscular dystrophyEUROPEAN JOURNAL OF NEUROLOGY, Issue 10 2007P. Vondracek We report a 24-year-old male with an unusual combination of two inherited neuromuscular disorders , Charcot-Marie-Tooth (CMT) disease type 1A and Duchenne muscular dystrophy (DMD). A phenotypic presentation of this patient included features of both these disorders. Nerve conduction studies revealed demyelinating peripheral neuropathy. Electromyography showed a profound myogenic pattern. The serum creatine kinase level was highly elevated. Muscle biopsy revealed a dystrophic picture with deficient dystrophin immunostaining. CMT1A duplication on chromosome 17p11.2 was found. The frame-shift mutation c.3609,3612delTAAAinsCTT (p.K1204LfsX11) was detected in the dystrophin gene by analysing mRNA isolated from the muscle tissue. The patient inherited both these mutations from his mother. The combination of CMT1A and DMD has not been reported as yet. [source] Lesion of the anterior branch of axillary nerve in a patient with hereditary neuropathy with liability to pressure palsiesEUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2000S. Simonetti We report the case of a 30-year-old woman affected by hereditary neuropathy with liability to pressure palsies (HNPP), who developed a painless left axillary neuropathy after sleeping on her left side, on a firm orthopaedic mattress, in her eighth month of pregnancy. Electromyography (EMG) showing neurogenic signs in the left anterior and middle deltoid, and normal findings in the left teres minor, posterior deltoid and other proximal upper limb muscles, demonstrated that the lesion was at the level of the axillary anterior branch. A direct compression of this branch against the surgical neck of the humerus seems the most likely pathogenic mechanism. This is the first documented description of an axillary neuropathy in HNPP. Knowledge of its possible occurrence may be important for prevention purposes. [source] An unusual cause of calf hypertrophy: severe lumbar canal stenosis with S1 nerve root radiculopathyINTERNATIONAL JOURNAL OF RHEUMATIC DISEASES, Issue 4 2007V. ONG Abstract We report an unusual case of calf hypertrophy in a 62-year-old woman who developed progressive enlargement of the left calf in association with chronic lower back pain. Magnetic resonance imaging (MRI) of the affected calf confirmed enlargement of the soleus muscle. MRI of the lumbar spine showed multilevel degenerative changes. Electromyography revealed neurogenic features consistent with S1 radiculopathy. Our case illustrates that muscular hypertrophy may follow chronic denervation as a consequence of spinal neural compressive disease. The various mechanisms postulated for this distinct condition and therapeutic strategies are outlined. [source] Influence of gum-chewing on the haemodynamics in female masseter muscleJOURNAL OF ORAL REHABILITATION, Issue 4 2009N. ABE Summary, Blood flow in active skeletal muscles provides energy substrate, oxygen and reduction of excessive heat and metabolic by-products. Although cyclic jaw motions such as those during mastication and speech articulation are the primitive oro-facial functions, possible effects of the cyclic muscle contractions on the intramuscular haemodynamics of the jaw muscles remains scarcely known. We investigated the masseteric haemodynamics during and after gum-chewing. Ten healthy female adults participated in the study. Electromyography, kinetics of masseter muscle oxygenation, electrocardiogram and blood pressure were recorded simultaneously. The subjects were asked to perform gum-chewing and cyclic jaw motion without gum bolus (empty-chewing task). The haemodynamics parameters were compared between the two experimental conditions. During gum-chewing task, deoxygenated haemoglobin and sympathetic nerve activity increased, while tissue blood oxygen saturation decreased. Blood pressure and parasympathetic nerve activity did not change. The overall behaviour of haemodynamic parameters during empty-chewing task was similar to that observed during gum-chewing task. However, the latency periods from the end of chewing until significant changes in the haemodynamic parameters were notably shorter (P < 0·05) in gum-chewing task as compared with those associated with empty-chewing task. The duration of the changes was shorter with empty-chewing than with gum-chewing. Fluctuations in masseter muscle haemodynamics associated with chewing jaw movement differed depending on the level of muscle contraction during movement. The differences became statistically significant immediately after the commencement of chewing and after the cessation movement. During the chewing movement, automatic nerve activities increased in response to the level of muscle contraction during movement. [source] Characteristics of a jaw reflex in humans with temporomandibular disorders: a preliminary reportJOURNAL OF ORAL REHABILITATION, Issue 5 2007P. MAILLOU summary, Electromyography was used to compare characteristics of an inhibitory jaw reflex in 10 temporomandibular disorder patients and 10 age- and sex-matched healthy controls. The methodology was novel in that the reflex was that evoked in the active masseter muscle, by electrical stimulation of perioral skin. This response has advantages over those previously studied as it avoids problems associated with stimulating in the moist intra-oral environment and it is monophasic, thus permitting easy quantification. The results have shown that (i) with the stimulation parameters employed, the reflex was present in all 10 control subjects, but in only eight of 10 temporomandibular disorder patients. (ii) When stimulation intensities were expressed as multiples of sensory threshold, there was no significant difference in the minimum level of stimulation required to evoke the reflex between the groups, although there was a trend for the patients with temporomandibular disorders to require higher intensities. (iii) Comparison of data from subjects giving responses at the same stimulus intensity (6 × sensory threshold: seven temporomandibular disorder patients, eight controls), showed no significant differences in the latencies or magnitudes of the reflex between the groups. However, the overall duration of the reflex was significantly shorter for the patients with temporomandibular disorders, with the reflex finishing significantly earlier. Thus even within the limitations of this study, it appears that an inhibitory jaw reflex evoked from stimulation around the mouth, may be weaker in temporomandibular disorder patients. This conclusion is consistent with previous studies on more complex jaw reflexes evoked by intra-oral stimuli. [source] Electromyography of scoliotic patients treated with a braceJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2003Daniel Odermatt Abstract When a brace is used to correct spinal deviation, patients may seek to ease the discomfort from the pressure exerted by the orthosis by actively recruiting specific trunk muscles. The effect of bracing on trunk electromyography (EMG) has been reported in only one study where a limited number of electrodes were placed mainly in the thoracic region. Our hypothesis was that a multi-electrode mapping of the activity of the thoracic, lumbar, and abdominal trunk muscles would provide a more representative picture of the muscular reaction in response to bracing. With a larger number of EMG measuring sites, the presence of any brace-induced trunk muscle activity should be detected. Therefore, EMG signals of 11 adolescent idiopathic scoliosis patients who had been undergoing Boston brace treatment for 0.7-3 years were collected during four isometric tasks to evaluate the response of trunk muscles in the minutes following the application of the brace. Twenty-two pairs of bipolar electrodes were used to measure the EMG signals of the main superficial trunk muscles during four isometric tasks. EMG signals of trunk muscles were compared in braced and unbraced conditions. Brace-induced increases in EMG activity were significant in 43% of the individual measurements and in three of the four tasks for the group mean values. Increases were greater in the lumbar area, especially on the convex side of the secondary (lumbar) curve. These results thus suggest that immediately following the application of the brace, significant muscular responses can be observed in some patients. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Simultaneous feedforward recruitment of the vasti in untrained postural tasks can be restored by physical therapyJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2003Sallie M. Cowan Abstract Background and purpose: Physical therapy rehabilitation strategies are commonly directed at the alteration of muscle recruitment in functional movements. The aim of this study was to investigate whether feedforward strategies of the vasti in people with patellofemoral pain syndrome can be changed by a physical therapy treatment program in a randomised, double blind, placebo controlled trial. Subjects: Forty (25 female, 15 male) subjects aged 40 yrs or less (27.2 ± 7.8 yrs). Methods: Subjects were allocated to either a placebo treatment or a physical therapy intervention program. The postural challenge used as the outcome measure was not included in the training program. Electromyography (EMG) onsets of vastus medialis obliquus (VMO), vastus lateralis (VL), tibialis anterior and soleus were assessed before and after the six week standardised treatment programs. Results: At baseline the EMG onset of VL occurred prior to that of VMO in both subject groups. Following physical therapy intervention there was a significant change in the time of onset of EMG of VMO compared to VL with the onsets occurring simultaneously. This change was associated with a reduction in symptoms. In contrast, following placebo intervention the EMG onset of VL still occurred prior to that of VMO. Conclusion and discussion: The results indicate that the feedforward strategy used by the central nervous system to control the patella can be restored. Importantly, the data suggest that this intervention produced a change that was transferred to a task that was not specifically included in the training program. Furthermore, the change in motor control was associated with clinical improvement in symptoms. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] INFLUENCE OF CHEWING AND SWALLOWING BEHAVIOR ON VOLATILE RELEASE IN TWO CONFECTIONERY SYSTEMSJOURNAL OF TEXTURE STUDIES, Issue 5 2006A. BLISSETT ABSTRACT Electromyography, electroglottography and turbine airflow technology were used to characterize the chewing, swallowing and breath flow profiles of 35 subjects during the consumption of two different (a gum Arabic- and carrageenan-based) confectionery chews. Simultaneous volatile release measurements were obtained using atmospheric pressure chemical ionization mass spectrometry. Subgroups of subjects displaying different eating characteristics were identified for both products. Parameters accounting for the maximum variance (product 1, 42% and product 2, 52%) between the subgroups were chewing force, chewing rate, proportion of work and total number of chews. Volatile release measurements were significantly different between the subgroups from product 1. The impact of the different eating characteristics on volatile release from product 2 was less defined, and postulated to be a result of the contrasting textural properties. Manipulating in vivo breakdown of chewy confectionery products, by texture modification, may influence consumer's volatile release and subsequent flavor perception. [source] Effects of SZ1677, a new non-depolarizing steroidal neuromuscular blocking drug, and rocuronium on two laryngeal muscles and the anterior tibial muscle in guinea pigsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2006A. Michalek-Sauberer Background:, SZ1677 is a new neuromuscular blocking drug structurally related to rocuronium. We compared the effect of an ED90 of SZ1677 (25 ,g/kg) with that of rocuronium (100 ,g/kg) in guinea pig laryngeal and peripheral muscles. Methods:, Electromyography was used to quantify neuromusc-ular blockade at the posterior cricoarytenoid muscle, the thyroarytenoid muscle and the anterior tibial muscle after SZ1677 (n = 10) and rocuronium (n = 9). Results:, Maximum neuromuscular blockade was similar after SZ1677 and rocuronium (83 ± 11% vs. 89 ± 11%; thyroarytenoid muscle: 91 ± 8% vs. 97 ± 3%; anterior tibial muscle: 91 ± 15% vs. 96 ± 3%, respectively). Onset time of neuromuscular blockade at the laryngeal muscles was similar for the two neuromuscular blocking drugs; it was shorter at the thyroarytenoid muscle (67 ± 32 s vs. 42 ± 40 s) than at the posterior cricoarytenoid muscle (101 ± 26 s vs. 102 ± 108 s). Onset time at the anterior tibial muscle was longer after SZ1677 (114 ± 34 s) than after rocuronium (68 ± 46 s); P < 0.05. Neuromuscular recovery was faster after SZ1677 (interval 25%,75%: posterior cricoarytenoid muscle: 222 ± 66 s; thyroarytenoid muscle: 192 ± 92 s; tibial muscle 149 ± 55 s) than after rocuronium (450 ± 148 and 464 ± 183 s, 292 ± 86 s, respectively); P < 0.05. Conclusions:, In guinea pigs, SZ1677 offers a rapid onset of neuromuscular blockade at a laryngeal adductor muscle with a shorter duration than rocuronium. Regardless of the drug used, the course of neuromuscular blockade differs not only between peripheral muscles and the larynx but also between antagonistic laryngeal muscles. The differences seem to be species specific. [source] Evaluation of Jitter by Stimulated Single-Fiber Electromyography in Normal DogsJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 4 2003Sonia Añor Single-fiber electromyography (SFEMG), a technique used to investigate neuromuscular transmission, has been described previously in the pelvic limb of dogs. Because preferential involvement of isolated muscle groups can occur in disorders of neuromuscular transmission, SFEMG waabone in the peroneus longus (PL), extensor carpi radialis (ECR), and orbicularis oculi (OO) muscles of 10 adult, clinically normal dogs. Jitter was calculated as the mean absolute value of the consecutive differences in latency of 50 single muscle fiber action potentials after stimulation of intramuscular nerve bundles at the level of the motor point in at least 20 muscle fibers per muscle. Bilateral recordings were performed in 3 dogs. Mean jitter values were determined for each muscle, and differences among muscle groups and among dogs were compared. The upper limits of mean consecutive difference (mean plus 3 standard deviations) for the PL, ECR, and OO muscles were 21.94, 22.53, and 23.39 ,s, respectively, and the upper limit of mean consecutive difference for individual muscle fibers in the respective fiber pools was 28.62, 36.39, and 35.68 (JLs. Jitter values for the ECR and OO were significantly higher than the jitter value for the PL muscle (P < .05). Significant differences among muscles or dogs or between sides were not observed for the ECR. Significant differences among dogs were observed for OO jitter values and were attributed to extremely low jitter values in 1 dog. Significant differences were demonstrated between sides for the PL and were attributed to small sample size. Results of this study provide normative data that can be used in the application of the stimulated SFEMG technique to dogs with suspected disorders of neuromuscular transmission. [source] Electroacupuncture attenuates visceral hyperalgesia and inhibits the enhanced excitability of colon specific sensory neurons in a rat model of irritable bowel syndromeNEUROGASTROENTEROLOGY & MOTILITY, Issue 12 2009G.-y. Xu Abstract, The causes of irritable bowel syndrome remain elusive and there are few effective treatments for pain in this syndrome. Electroacupunture (EA) is used extensively for treatment of various painful conditions including chronic visceral hyperalgesia (CVH). However, mechanism of its analgesic effect remains unknown. This study was designed to investigate effect of EA on colon specific dorsal root ganglion (DRG) neurons in rats with CVH. CVH was induced by intracolonic injection of acetic acid (AA) in 10-day-old rats. Electromyography and patch clamp recordings were performed at age of 8,10 weeks. Colon DRG neurons were labelled by injection of DiI into the colon wall. EA was given at ST36 in both hindlimbs. As adults, neonatal AA-injected rats displayed an increased sensitivity to colorectal distension (CRD) and an enhanced excitability of colon DRG neurons. EA treatment for 40 min significantly attenuated the nociceptive responses to CRD in these rats; this attenuation was reversed by pretreatment with naloxone. EA treatment for 40 min per day for 5 days produced a prolonged analgesic effect and normalized the enhanced excitability of colon DRG neurons. Furthermore, in vitro application of [D-Ala2, N -MePhe4, Gly5 -Ol] enkephalin (DAMGO) suppressed the enhanced excitability of colon neurons from rats with CVH. These findings suggest that EA produced-visceral analgesia, which might be mediated in a large part by endogenous opioids pathways, is associated with reversal of the enhanced excitability of colon DRG neurons in rats with CVH. [source] The feasibility and reliability of using circular electrode for sphincter of Oddi electromyography in anaesthetised rabbitsNEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2009F. Chen Abstract, Sphincter of Oddi manometry (SOM) is the gold standard for assessing sphincter of Oddi dysfunction (SOD), but is considered a diagnostic sensitivity of 30,80% and associated with significant complications of pancreatitis. Electromyography (EMG) of sphincter of Oddi (SO) using a circular electrode (CE) may be useful in improving diagnostic accuracy and reducing complications. To evaluate the feasibility and reliability of the CE, we record myoelectric activity of SO in rabbits using the CE to compare with the traditional needle electrode (NE). The CE was prepared using a double-channel biogel catheter with two silver rings at the head of the catheter. The CE was then inserted into the lumen of the SO through the duodenal papilla, and myoelectric activity was recorded in the SO in 30 rabbits. An EMG recorded using an NE was performed at the same time, when the SO was in basal state, after injection of cholecystokinin and N-butylscopolamine bromide. Electromyographs recorded by the two methods were then evaluated. Satisfactory SO EMGs were acquired using the CE without any injury. Simultaneous recording revealed a very similar traces and one-to-one correspondence of SO spike bursts (SOSB). Linear regression analysis showed a significant direct correlation between the two methods for SOSB duration and amplitude. The results suggested that CE was comparable with NE in terms of recording efficacy. The CE also has advantages of easy fixation, accurate localisation, broad applicability and ease of achieving satisfactory outcomes without trauma, compared with the NE. [source] Neural mechanisms of early postinflammatory dysmotility in rat small intestineNEUROGASTROENTEROLOGY & MOTILITY, Issue 12 2006I. Demedts Abstract, Although human postinflammatory dysmotility is known, so far animal studies have primarily investigated changes during inflammation. Here, we focused on postinflammatory changes in rat jejunal myenteric plexus and jejunal motility. Evolution of ethanol/2,4,6-tri-nitrobenzene sulphonic acid (TNBS)-induced inflammation was assessed histologically and by measuring myeloperoxidase activity (MPO). Electromyography and immunohistochemistry were performed 1 week after ethanol/TNBS and also after NG -nitro- l -arginine methyl ester (l -NAME) administration. Ethanol/TNBS induced a transient inflammation, with normalization of MPO and histological signs of an early phase of recovery after 1 week. The number of cholinergic neurones was not altered, but myenteric neuronal nitric oxide synthase (nNOS)-immunoreactivity was significantly lower in the early phase of recovery after TNBS compared with water (1.8 ± 0.2 vs 3.5 ± 0.2 neurones ganglion,1, P < 0.001). Interdigestive motility was disrupted with a loss of phase 1 quiescence, an increase of migrating myoelectric complex cycle length, a higher number of non-propagated activity fronts and a decrease of adequately propagated phase 3 s after TNBS. Administration of l -NAME resulted in a similar disruption of interdigestive motility patterns. In the early phase of recovery after ethanol/TNBS-induced jejunal inflammation, a loss of motor inhibition occurs due to a decrease of myenteric nNOS activity. These observations may provide a model for early postinflammatory dysmotility syndromes. [source] Feasibility of Gait Event Detection Using Intramuscular Electromyography in the Child with Cerebral PalsyNEUROMODULATION, Issue 3 2004Richard T. Lauer PhD Abstract The objective of this study was to develop and test the feasibility of a model that employs electromyographic (EMG) signals to predict the occurrence of gait events in the child with cerebral palsy (CP). This model could be the basis of a future functional electrical stimulation (FES) control system to assist gait. Two children were implanted with bifilar intramuscular electrodes into the quadriceps muscle bilaterally. Muscle activity and gait parameters were recorded, and a fuzzy inference system was used to correlate EMG to five distinct gait events. For nine of the 10 gait events evaluated, the model predicted gait events to within 82 ms on average, as referenced to the VICON motion analysis system. For eight of the 10 events, prediction errors were 0.3% or less. Results indicate that EMG from the proximal musculature could be used to predict the occurrence of gait events in these two children with CP. [source] Physical Medicine and Rehabilitation (87)PAIN PRACTICE, Issue 1 2001A.J. Haig Paraspinal electromyography in high lumbar and thoracic lesions. (University of Michigan, Ann Arbor, MI) Am J Phys Med Rehabil 2000;79:336,342. This study aimed to use needle electromyography in the paraspinal muscles to localize the root level of a radiculopathy. Nine cases of clinically proven, isolated high lumbar or thoracic disk herniations of patients who underwent MiniPM were collected. Four were from a prospective study of 114 persons with low back pain (MiniPM had 100% sensitivity to magnetic resonance imaging-documented high disks). In the most medial "S" column, mean MiniPM scores were 0.7 for the level above the radiologically documented lesion (3.1 at the lesion and 1.6, 1.6, and 1.1 at the 3 spinous processes below the lesion). Similar numbers were obtained in the "M" column (slightly lateral), with no significant differences between S and M. Differences were significant between and at the level of the lesion for S (P < 0.06) and M (P < 0.01), and between the lesion level and 3 levels below for the M column (P < 0.01). Conclude that paraspinal electromyography has a higher than previously reported sensitivity for high lumbar lesions. Electromyography using MiniPM can localize some radiculopathies. The individual cases suggest that, consistent with the anatomy of the caudi equina, thoracic lesions and lateral lumbar lesions denervate only at 1 level, but more central lumbar lesions also denervate distally innervated paraspinal muscles. Comment by Miles Day, MD. This study is designed to assess the sensitivity of many MiniPM for higher-level rediculopathies, ie, lower thoracic and high lumbar, and to determine if findings are specific to the root level involved. The MiniPM is thought to assess the multifidus portion of the paraspinal muscles that are innervated from L2 to the sacrum. The clinical protocol tests the paraspinal extensively and provides a numerica score, thus eliminating some subjectivity of the EMG. The study demonstrates that MiniPM has good sensitivity for high lumbar and thoracic lesions and provides information on the level of the lesion independent of limb EMG. After reviewing the study, I agree with the authors that MiniPM is in itself not diagnostic for radiculopathy, but is only an additional test to help support other neuro physiological studies when evaluating for radiculopathy. It is not specific for diagnosing radiculopathy. [source] On functional motor adaptations: from the quantification of motor strategies to the prevention of musculoskeletal disorders in the neck,shoulder regionACTA PHYSIOLOGICA, Issue 2010P. Madeleine Abstract Background:, Occupations characterized by a static low load and by repetitive actions show a high prevalence of work-related musculoskeletal disorders (WMSD) in the neck,shoulder region. Moreover, muscle fatigue and discomfort are reported to play a relevant initiating role in WMSD. Aims: To investigate relationships between altered sensory information, i.e. localized muscle fatigue, discomfort and pain and their associations to changes in motor control patterns. Materials & Methods:, In total 101 subjects participated. Questionnaires, subjective assessments of perceived exertion and pain intensity as well as surface electromyography (SEMG), mechanomyography (MMG), force and kinematics recordings were performed. Results:, Multi-channel SEMG and MMG revealed that the degree of heterogeneity of the trapezius muscle activation increased with fatigue. Further, the spatial organization of trapezius muscle activity changed in a dynamic manner during sustained contraction with acute experimental pain. A graduation of the motor changes in relation to the pain stage (acute, subchronic and chronic) and work experience were also found. The duration of the work task was shorter in presence of acute and chronic pain. Acute pain resulted in decreased activity of the painful muscle while in subchronic and chronic pain, a more static muscle activation was found. Posture and movement changed in the presence of neck,shoulder pain. Larger and smaller sizes of arm and trunk movement variability were respectively found in acute pain and subchronic/chronic pain. The size and structure of kinematics variability decreased also in the region of discomfort. Motor variability was higher in workers with high experience. Moreover, the pattern of activation of the upper trapezius muscle changed when receiving SEMG/MMG biofeedback during computer work. Discussion:, SEMG and MMG changes underlie functional mechanisms for the maintenance of force during fatiguing contraction and acute pain that may lead to the widespread pain seen in WMSD. A lack of harmonious muscle recruitment/derecruitment may play a role in pain transition. Motor behavior changed in shoulder pain conditions underlining that motor variability may play a role in the WMSD development as corroborated by the changes in kinematics variability seen with discomfort. This prognostic hypothesis was further, supported by the increased motor variability among workers with high experience. Conclusion:, Quantitative assessments of the functional motor adaptations can be a way to benchmark the pain status and help to indentify signs indicating WMSD development. Motor variability is an important characteristic in ergonomic situations. Future studies will investigate the potential benefit of inducing motor variability in occupational settings. [source] Vastus lateralis surface and single motor unit electromyography during shortening, lengthening and isometric contractions corrected for mode-dependent differences in force-generating capacityACTA PHYSIOLOGICA, Issue 3 2009T. M. Altenburg Abstract Aim:, Knee extensor neuromuscular activity, rectified surface electromyography (rsEMG) and single motor unit EMG was investigated during isometric (60° knee angle), shortening and lengthening contractions (50,70°, 10° s,1) corrected for force,velocity-related differences in force-generating capacity. However, during dynamic contractions additional factors such as shortening-induced force losses and lengthening-induced force gains may also affect force capacity and thereby neuromuscular activity. Therefore, even after correction for force,velocity-related differences in force capacity we expected neuromuscular activity to be higher and lower during shortening and lengthening, respectively, compared to isometric contractions. Methods:, rsEMG of the three superficial muscle heads was obtained in a first session [10 and 50% maximal voluntary contraction (MVC)] and additionally EMG of (46) vastus lateralis motor units was recorded during a second session (4,76% MVC). Using superimposed electrical stimulation, force-generating capacity for shortening and lengthening contractions was found to be 0.96 and 1.16 times isometric (Iso) force capacity respectively. Therefore, neuromuscular activity during submaximal shortening and lengthening was compared with isometric contractions of respectively 1.04Iso (=1/0.96) and 0.86Iso (=1/1.16). rsEMG and discharge rates were normalized to isometric values. Results:, rsEMG behaviour was similar (P > 0.05) during both sessions. Shortening rsEMG (1.30 ± 0.11) and discharge rate (1.22 ± 0.13) were higher (P < 0.05) than 1.04Iso values (1.05 ± 0.05 and 1.03 ± 0.04 respectively), but lengthening rsEMG (1.05 ± 0.12) and discharge rate (0.90 ± 0.08) were not lower (P > 0.05) than 0.86Iso values (0.76 ± 0.04 and 0.91 ± 0.07 respectively). Conclusion:, When force,velocity-related differences in force capacity were taken into account, neuromuscular activity was not lower during lengthening but was still higher during shortening compared with isometric contractions. [source] Facial electromyography in newborn and young infants with congenital facial weaknessDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 6 2001Francis Renault MD First page of article [source] Quantification of surface EMG signals to monitor the effect of a Botox treatment in six healthy ponies and two horses with stringhalt: Preliminary studyEQUINE VETERINARY JOURNAL, Issue 3 2009I. D. Wijnberg Summary Reasons for performing the study: Therapeutic options for stringhalt in horses are limited, whereas medical experiences with botulinum toxin type A (Botox) have been positive. To evaluate its effectiveness in horses, surface electromyography (sEMG) signals before and after injection need to be quantified. Hypothesis: Treatment of healthy ponies and cases with Botox should reduce muscle activity in injected muscles and reduce spastic movements without adverse side effects. Methods: Unilaterally, the extensor digitorum longus, extensor digitorum lateralis and lateral vastus muscles of 6 healthy mature Shetland ponies and 2 talented Dutch Warmblood dressage horses with stringhalt were injected (maximum of 400 iu per pony and 700 iu per case; 100 iu in 5 ml NaCl divided into 5 injections) with Botox under needle EMG guidance. Surface EMG data were evaluated using customised software, and in the individuals gait was analysed using Proreflex. Statistical analysis was performed using mixed models and independent sample t test (P<0.05). Results: Surface EMG signals were quantified using customised software. The area under the curve (integrated EMG) in time was used as variable. It became significantly reduced in injected muscles after injection of Botox in normal ponies (P<0.05). This effect was present from Day 1 until Day 84 after injection. In the 2 cases, after injection of 3 muscles, the integrated EMG in time became significantly reduced in all 3 muscles. Kinematic measurements confirmed reduction of frequency and amplitude of hyperflexing or hyperabducting strides of the affected hindlimbs. The duration of effect was also seen in the cases until around 12 weeks after injection. Conclusions and potential relevance: After EMG guided injections of Botox, sEMG signals recorded from injected muscle were reduced, which proves this to be a useful tool in statistically evaluating a treatment effect. The positive results of this pilot study encourage further research with a larger group of clinical cases. [source] The role of electromyography in clinical diagnosis of neuromuscular locomotor problems in the horseEQUINE VETERINARY JOURNAL, Issue 8 2004I. D. WIJNBERG Summary Reasons for performing study: Systematically performed EMG needle examination of muscles provides essential information about the functional aspects of the motor unit. However, clinical studies in which information is given on the diagnostic and discriminative values of electromyography (EMG) in the horse are scarce. Objectives: To determine to what extent inclusion of EMG analysis in clinical examination contributes to determination of type and localisation of abnormality. Methods: EMG analysis, complete clinical examination and diagnosis of 108 horses (mean ± s.d. age 7.5 ± 3.8 years; bodyweight 548 ± 86 kg; height 1.67 ± 0.07 m) were performed, and results without and with EMG analysis compared. Results: Without EMG, myopathy and neuropathy were diagnosed in 20 and 58 horses, respectively, and with EMG in 17 and 82 horses. EMG changed localisation in myopathy and neuropathy in 12 and 37% of cases, respectively. Lesions in the C1-T2, T2-L3 and L3-S3 segments were, respectively, diagnosed without EMG in 7, 11 and 30%, and with EMG in 27, 7 and 17% of cases. Where no clinical diagnosis could be made prior to EMG, many patients appeared to be suffering from localised cervical lesions (29%) or generalised neuropathy (54%). Conclusions and potential relevance: The assistance of EMG in discriminating between normal, neuropathy and myopathy, and in locating pathology, contributes to diagnosis of neuromuscular problems. [source] Co-morbidity of Emery,Dreifuss muscular dystrophy and a congenital myasthenic syndrome possibly affecting the phenotype in a large Bedouin kindredEUROPEAN JOURNAL OF NEUROLOGY, Issue 3 2007G. Ifergane Emery,Dreifuss muscular dystrophy (EDMD) is an X-linked humero-peroneal muscular dystrophy associated with contractures and cardiomyopathy. In a 90 member family, we found 11 affected male individuals, three of whom displayed areflexia and neurogenic electromyographic changes. Muscle biopsy performed in one case demonstrated type grouping suggestive of a neurogenic disorder. These three individuals and another family member, who suffers from mild, static limb weakness but is clinically and genetically unaffected by EDMD showed an abnormal incremental response of over 100% to tetanic stimulation. In contrast, one affected family member showed myopathic features on needle electromyography and no definite pathology in repetitive stimulation studies. The diagnosis of EDMD was established by demonstrating a 1712_1713insTGGGC mutation in the emerin gene. This family apparently expresses co-morbidity of EDMD with an exceptionally mild form of pre-synaptic congenital myasthenic syndrome resembling the Lambert,Eaton myasthenic syndrome (LEMS). The superimposed pre-synaptic disorder may have contributed to the development of the neurogenic features demonstrated in these patients. [source] Seronegative myasthenia gravis: comparison of neurophysiological picture in MuSK+ and MuSK, patientsEUROPEAN JOURNAL OF NEUROLOGY, Issue 3 2006L. Padua The aim of this study was to compare the neurophysiological and clinical pictures of a large sample of seronegative myasthenia gravis (SNMG) patients with and without anti-MuSK antibodies. Fifty-two consecutive SNMG patients were retrospectively evaluated. They had undergone an extended neurophysiological evaluation: repetitive nerve stimulation (RNS), single fiber EMG (SFEMG), and electromyography (EMG) with nerve conduction study. A muscle biopsy was performed in 11 of 52 patients, the edrophonium test in 44 of 52 patients and anti-AChR antibodies and anti-MuSK antibodies were tested in all patients. Anti-MuSK antibodies were detected in 25 SNMG patients (48.1%). The number of women in the MuSK+ group was significantly higher (P = 0.01) than in the MuSK, group. Seronegative MuSK+ patients are more severely affected and the deficit often involves the bulbar and the respiratory muscles. No statistically significant differences were observed in the edrophonium test between MuSK+ and MuSK, groups. The RNS test was abnormal in a significantly higher number of MUSK, patients than MUSK+ patients (P < 0.00001). With regard to SFEMG data, MuSK, patients were characterized to have more severe neurophysiological pattern. Our observations showed several differences between the clinical and neurophysiological pictures of MUSK+ and MUSK, patients. [source] Critical reappraisal of referrals to electromyography and nerve conduction studies,EUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2005S. Podnar A large number of examinees referred to electromyographic (EMG) laboratories do not have symptoms or signs suggestive of a peripheral nervous system disorder, and the aim of the present study was to check this. All examinees evaluated by the author in a ,general' EMG laboratory in the first 4 months of 2002 were included. Data on examinees, referral physicians and diagnoses, clinical symptoms and signs, and electrodiagnostic findings were statistically evaluated. Three hundred examinees, 42% men, were included. A neurological diagnosis was provided in 55% of referrals. Electrodiagnostic abnormalities were found in 45% of examinees. Using multivariate statistics, a positive effect of neurological referral diagnosis, history of paraesthesias and of weakness and sensory loss on examination, and a negative effect of history of pain on pathological electrodiagnostic findings were found. Except 20 patients with carpal tunnel syndrome, no patient with normal clinical examination had abnormal electrodiagnostic findings. Our study confirmed the inappropriateness of referrals to electrodiagnostic examination to screen patients for peripheral nervous disorders. We propose electrodiagnostic examination mainly of patients with unequivocal clinical signs of a peripheral nervous system lesion and of patients with typical symptoms of the carpal tunnel syndrome. [source] Chronic inflammatory demyelinating polyneuropathy, phrenic nerve and respiratory symptomsEUROPEAN JOURNAL OF NEUROLOGY, Issue 1 2005J. Costa Respiratory involvement in chronic inflammatory demyelinating polyneuropathy (CIDP) has been very recently described. Phrenic nerve conduction studies have been described as useful to detect respiratory impairment in these patients. This study describes two patients with CIDP, in whom neurophysiological studies of the respiratory muscles were performed. The first patient had severe respiratory insufficiency, and phrenic nerve studies disclosed no motor responses and electromyography (EMG) of the diaphragm confirmed severe loss of motor units, bilaterally. On treatment, we documented clinical and neurophysiological improvement. In the second patient, phrenic nerve studies showed abnormal results; however, EMG of the diaphragm ruled out loss of motor units. The first case represents the risk of phrenic nerve involvement in this disorder, and the potential recovery on treatment. The second case illustrates that the temporal dispersion of the motor responses can be misleading, and EMG of diaphragm should be performed to confirm the loss of motor units. [source] Neurophysiological tests and neuroimaging procedures in non-acute headache: guidelines and recommendationsEUROPEAN JOURNAL OF NEUROLOGY, Issue 4 2004G. Sandrini The use of instrumental examinations in headache patients varies widely. In order to evaluate their usefulness, the most common instrumental procedures were evaluated, on the basis of evidence from the literature, by an EFNS Task Force (TF) on neurophysiological tests and imaging procedures in non-acute headache patients. The conclusions of the TF regarding each technique are expressed in the following guidelines for clinical use. 1Interictal electroencephalography (EEG) is not routinely indicated in the diagnostic evaluation of headache patients. Interictal EEG is, however, indicated if the clinical history suggests a possible diagnosis of epilepsy (differential diagnosis). Ictal EEG could be useful in certain patients suffering from hemiplegic and basilar migraine. 2Recording of evoked potentials is not recommended for the diagnosis of headache disorders. 3There is no evidence to justify the recommendation of autonomic tests for the routine clinical examination of headache patients. 4Manual palpation of pericranial muscles, with standardized palpation pressure, can be recommended for subdividing patient groups but not for diagnosis. Pressure algometry and electromyography (EMG) cannot be recommended as clinical diagnostic tests. 5In adult and paediatric patients with migraine, with no recent change in attack pattern, no history of seizures, and no other focal neurological signs or symptoms, the routine use of neuroimaging is not warranted. In patients with atypical headache patterns, a history of seizures and/or focal neurological signs or symptoms, magnetic resonance imaging (MRI) may be indicated. 6If attacks can be fully accounted for by the standard headache classification [International Headache Society (IHS)], a positron emission tomography (PET) or single-photon emission computerized tomography (SPECT) and scan will generally be of no further diagnostic value. 7Nuclear medicine examinations of the cerebral circulation and metabolism can be carried out in subgroups of headache patients for diagnosis and evaluation of complications, when patients experience unusually severe attacks, or when the quality or severity of attacks has changed. 8Transcranial Doppler examination is not helpful in headache diagnosis. Although many of the examinations described are of little or no value in the clinical setting, most of the tools have a vast potential for further exploring the pathophysiology of headaches and the effects of pharmacological treatment. [source] Pure quadriceps myopathy in two sistersEUROPEAN JOURNAL OF NEUROLOGY, Issue 4 2003I. Mahjneh The authors carried out a clinical, laboratory and muscle computed tomographgy CT follow-up study of 18,21 years on two sisters affected by quadriceps myopathy (QM). The onset in the fourth decade was a weakness in the thighs. During the follow-up study, the patients showed only vasti muscles involvement, normal creatine kinase (CK) levels, myopathic muscle biopsy and electromyography (EMG) and normal membrane protein expression on immunocytochemical analysis. Therefore, all muscle pathologies known to have quadriceps involvement as a leading feature have been ruled out. We conclude that our patients have pure QM with probable autosomal recessive inheritance. [source] Effect of vitamin E supplementation in patients with ataxia with vitamin E deficiencyEUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2001S. Gabsi Ataxia with vitamin E (Vit E) defciency (AVED) is an autosomal recessive disorder caused by mutations of the , tocopherol transfer protein gene. The Friedreich ataxia phenotype is the most frequent clinical presentation. In AVED patients, serum Vit E levels are very low in the absence of intestinal malabsorption. As Vit E is a major antioxidant agent, Vit E deficiency is supposed to be responsible for the pathological process. Twenty-four AVED patients were fully investigated (electromyography, nerve conduction velocity (NVC) studies, somatosensory evoked potentials, cerebral computed tomography scan, sural nerve biopsy, genetic studies) and supplemented with Vit E (800 mg daily) during a 1-year period. Clinical evaluation was mainly based on the Ataxia Rating Scale (ARS) for cerebellar ataxia assessment and serum Vit E levels were monitored. Serum Vit E levels normalized and ARS scores decreased moderately but significantly suggesting clinical improvement. Better results were noted with mean disease duration , 15 years. Reflexes remained abolished and posterior column disturbances unchanged. Vitamin E supplementation in AVED patients stabilizes the neurological signs and can lead to mild improvement of cerebellar ataxia, especially in early stages of the disease. [source] Electromyographic evaluation of cervical dystonia for planning of botulinum toxin therapyEUROPEAN JOURNAL OF NEUROLOGY, Issue 6 2000D. Dressler The success of botulinum toxin (BT) injections for treatment of cervical dystonia depends on precise identification of dystonic muscles and on quantification of their dystonic involvement. Conventionally, this is attempted by clinical examination analysing the dystonic head position. In this presentation, a more systematic approach is sought by using an electromyography (EMG)-based evaluation procedure. In 10 consecutive patients with cervical dystonia not previously exposed to BT clinical examination, analysing the dystonic head position was performed to classify patients into four groups with similar dystonic head positions. Additionally, a 2-channel concentric needle EMG was used to measure the amplitudes of dystonic and maximal voluntary activities in sternocleidomastoid (SCM), splenius capitis (SC) and trapezius/semispinalis capitis (T/SS) muscles bilaterally. The ratio between both amplitudes, the dystonia ratio, was used to quantify dystonic muscle involvement. In all patients dystonia ratios could be calculated. In patients with similar head positions, EMG evaluation revealed different qualitative and quantitative dystonic involvement patterns. In six patients, there were discrepancies in identification of dystonic muscles between clinical examination and EMG evaluation. EMG evaluation excluded dystonic involvement in five patients. All excluded muscles were SCM. In one of these patients, additional T/SS involvement was detected by EMG evaluation. In one patient, SC involvement was revealed by EMG evaluation. All dystonic muscle involvement detected by EMG evaluation represented genuine dystonic muscle coactivation rather than compensatory muscle activity. The EMG evaluation presented allows quantitative and qualitative identification of dystonic muscle involvement which cannot be achieved by clinical examination. Both pieces of information may be helpful for optimization of BT therapy. [source] | ||||||||||||||||||||||||||||||||||