EMG Evaluation Research Articles

Repeatability of the Calibration Protocol for Emg Evaluation of the Occlusion With the Teethan Device

Abstract Objective The aim of the study was to investigate the repeatability of the calibration protocol performed by the Teethan® device (Teethan S.p.A. Italy) for surface electromyography (sEMG) when biting on cotton rolls to eliminate the effect of occlusal contacts. Materials and methods Thirty-three fully dentate subjects aged 13-43 years (mean 21.33 years) of which 15 men and 18 women were enrolled in the study All subjects had a good state of dental and periodontal health without temporomandibular disorders (TMDs). Each examined participant performed two distinct maximal voluntary clenches on cotton rolls: the first one for calibration of the device and the second one for recording of the signals. The results were presented as the indices: Percentage overlapping coefficient (POC), Barycenter (BAR), Torsion (TORS), Impact (IMPACT), Global index and Asymmetry (ASIM). Results All the examined indices showed good repeatability during the test, compared with the normal values, determined by the manufacturer of the device. Some of the recorded indices were insignificantly lower than the norm (POC TA, POC MM, BAR and TORS). Global index and IMPACT were within the reference values and showed highest repeatability in this study. Conclusion Instrument calibration is an important prerequisite for exact testing. The indices, recorded by this device are rather repeatable, with Global index and Impact found to be the most repeatable ones. The values of the measured indices show that the process of calibration is highly reliable.

EMG Evaluation of Passive Assist Suit for Prolonged Postural Retention

EMG Evaluation of Passive Assist Suit for Prolonged Postural Retention

Intramuscular EMG feature extraction and evaluation at different arm positions and hand postures based on a statistical criterion method.

Prostheses control using electromyography signals have shown promising aspects in various fields including rehabilitation sciences and assistive technology controlled devices. Pattern recognition and machine learning methods have been observed to play a significant role in evaluating features and classifying different limb motions for enhanced prosthetic executions. This paper proposes feature extraction and evaluation method using intramuscular electromyography (iEMG) signals at different arm positions and hand postures based on the RES Index value statistical criterion method. Sixteen-time domain features were selected for the study at two main circumstances; fixed arm position (FAP) and fixed hand posture (FHP). Eight healthy male participants (30.62 ± 3.87 years) were asked to execute five motion classes including hand grip, hand open, rest, hand extension, and hand flexion at four different arm positions that comprise of 0°, 45°, 90°, and 135°. The classification process is accomplished via the application of the k-nearest neighbor (KNN) classifier. Then RES index was calculated to investigate the optimal features based on the proposed statistical criterion method. From the RES Index, we concluded that Variance (VAR) is the best feature while WAMP, Zero Crossing (ZC), and Slope Sign Change (SSC) are the worst ones in FAP conditions. On the contrary, we concluded that Average Amplitude Change (AAC) is the best feature while WAMP and Simple Square Integral (SSI) resulted in least RES Index values for FHP conditions. The proposed study has possible iEMG based applications such as assistive control devices, robotics. Also, working with the frequency domain features encapsulates the future scope of the study.

SY2.3. Evaluation of dystonia

Dystonia is a syndrome characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both. It can be primary or secondary and the patient can present with pure dystonia or dystonia along with other movement disorders such as tremor, myoclonus, parkinsonism, etc. Evaluation of a patient presenting primarily with dystonia includes detailed clinical evaluation, haematologic and neurometabolic work up, imaging and neurophysiological/ electrophysiological studies. This presentation will focus on the electrophysiological evaluation of dystonia, which helps in understanding the pathophysiology and better characterization of the abnormal movement. Compared to tremor and myoclonus, electrophysiological evaluation of muscle spasms and dystonia is difficult. The first step is recording surface EMG from the involved muscles for prolonged periods during abnormal movements (dystonia), rest, and with voluntary contraction. The agonists and antagonists should be included to detect co-contraction, and the unaffected muscles of the same or opposite limbs should also be studied to document overflow dystonia if present. During EMG evaluation, patients are also asked to perform various tasks which can induce dystonia, such as mental arithmetic, finger tapping and opening and closing fist of the unaffected hand, writing (in patients with writer’s cramp). EMG is analyzed to determine: (i) the pattern of EMG activity in agonists and antagonists during dystonia (spasm) (ii) duration of each EMG burst (iii) the regularity of occurrence of EMG bursts, (iv) presence of overflow activity in remote muscles while performing discrete voluntary acts, and (v) the difference in the degree of EMG activity (area of rectified EMG) between epochs with and without muscle spasms. Other investigations which are often useful to characterize dystonia or a dystonic syndrome include: (i) H-reflex recovery curve (ii) mechanically and electrically induced long-latency muscle stretch reflex (iii) reciprocal inhibition between antagonistic muscles (iv) brainstem reflexes such as blink reflex (v) cortical SEP (vi) Bereitschaftpotential (BP) and Contingent negative variation (CNV) and (viii) transcranial magnetic stimulation (TMS). TMS specifically helps to study the excitatory and inhibitory changes in the brain in patients with dystonia and may also be a useful tool to monitor therapeutic interventions.

Ultrasound guidance increases diagnostic yield of needle EMG in plegic muscle

ObjectivesTo increase the specificity of motor unit potential (MUPs) detection by using ultrasound guided electromyography (USG-EMG) in patients with muscle plegia due to traumatic nerve lesions. MethodsForty-six patients with recent nerve trauma underwent baseline standard EMG (ST-EMG) evaluation with evidence of absent MUPs. In 41 of them, ST-EMG was repeated after 2–3 months (T1) and the patients were accordingly divided in two groups: ST-EMG+ (if MUPs were detected) or ST-EMG- (MUPs not detected). Then, ST-EMG- patients underwent muscle ultrasound evaluation (M-US) and, if isles of muscular contractility were found, they also had USG-EMG. The same protocol was repeated 4–6 months after baseline (T2). ResultsAt T1, 22/41 patients were ST-EMG+. While 19/41 were ST-EMG-; 9 of these patients had M-US consistent with residual muscular activity, for that reasons underwent USG-EMG with 7 of 9 demonstrating MUPs (at T2 all of these 7 patients resulted ST-EMG). In the other 2 patients, we found no MUPs at T1 but they became ST-EMG+ or USG-EMG positive at T2. The remaining 10 ST-EMG- patients had no EMG or US evidence of muscle contraction at T1, but at T2 2 of 10 became ST-EMG+ and 2 had USG-EMG showing MUPs. In the remaining 6 patients still M-US negative at T2, complete denervation was diagnosed. Concerning the 22 patients who were ST-EMG+ at T1, all but one showed increase of MUPs at T2. ConclusionsIn this study, we demonstrated the utility of US guidance when performing EMG evaluation in locating isles of muscular contractility in patients who have no detectable MUPs on EMG after nerve trauma. SignificanceUSG-EMG significantly increases the specificity of needle EMG allowing earlier detection of MUPs.

P32-S Application of decomposition based quantitative EMG (DQEMG) to focal neuropathies

Background EMG signals can be decomposed into their constituent motor unit potential trains and further analyzed using specific signal processing algorithms which provide novel and useful information regarding the temporal and electrophysiological behaviour and morphological attributes of motor units. In low to moderate stages of focal neuropathies (when only focal demyelination or low axonal sensory affection is registered) traditional needle EMG evaluation is usually normal. However, DQEMG provides evidence of motor unit instability in a significant portion of otherwise normal muscles. Material and methods 20 case and 9 control subjects were studied with median and ulnar ENG, quantitative EMG and DQEMG (abductor pollicis brevis, first dorsal interosseus or abductor digiti minimi). Patients with symptoms suggesting focal median or ulnar neuropathies were selected as cases, except for those showing low-median compound muscle action potential amplitudes or needle EMG abnormalities. Control subjects were included when no ENG nor needle EMG abnormalities findings were encountered. Results 75% of cases with any focal demyelinating finding showed instability features in DQEMG, which were also found in 43% of the normal ENG and control groups. Applying more restrictive DQEMG criteria, instability was found in 63% of cases with focal ENG alterations and 43% with normal ENG, while the control group showed no abnormalities. Conclusions Decomposition-based quantitative EMG is a novel and more powerful tool for detecting abnormalities in motor unit potentials, compared with the classical quantitative or semi-quantitative needle EMG analysis.

Subclinical sensory-motor deficit after surgical correction of the spinal deformity

A quantitative evaluation of the relationship between the level of postoperative motor deficit and the intensity of reaction of pyramidal tract to the correction of spinal deformity. The correction of spinal deformities of different etiology was performed under neurophysiological control for 87 patients (30 men, 57 women), aged 15.6±0.6 years. Reaction intensity of pyramidal tract was evaluated using the scale developed by the authors. The relationship between the intensity of intraoperative reaction of somatic motor system and EMG-signs of postoperative subclinical motor deficit in temperature-and-pain sensitivity disorders was shown. EMG evaluation of the level of intensity of subclinical motor deficit in combination with changes in temperature-and-pain sensitivity after the spinal deformity correction complies the reaction intensity of somatic motor system to surgical aggression. Neurologists should pay more attention to the patients with V type reaction not only during postoperative period, but before the next stage of surgery.

Electro Clinical Profiles of Motor Neuron Disease and Atypical Motor Neuron Disorders: A Case Series

Amyotrophic lateral sclerosis (ALS) is the commonest MND phenotype. Although many of the atypical motor neuron disorders share some features with ALS, they often can be distinguished by their clinical and electrophysiologic characteristics. Here we present five different cases with varied clinical findings. All the patients were referred from outpatient department to neurophysiology laboratory where electrodiagnostic (EDX) correlations helped to come to a conclusion. The nerve conduction study protocol for a suspected atypi¬cal motor neuron disorder is the same as that for ALS. Akin to the nerve conduction studies, the EMG evaluation of patients with suspected atypical motor neuron disorders is similar to that of ALS. An extensive study is indicated, often of all four limbs, the paraspinal muscles, and the bulbar muscles to reach a possible diagnosis. History, clinical findings and electrophysiological correlation often help to differentiate these atypical motor neuron disorders. Correct diagnosis is needed for further evaluation and prognosis. In this case series five (5) cases have described who are referred from outpatient department to neurophysiology laboratory for electrodiagnostic (EDX) correlations.Journal of National Institute of Neurosciences Bangladesh, 2017;3(1): 57-61

87. Electromyographic findings in patients with late-onset pompe disease (LOPD)

Glycogen storage disease II (GSD II), also known as Pompe disease is an autosomal recessive disorder caused by mutations in the GAA gene encoding the enzyme acid alpha-glucosidase. Two different clinical forms have been described: infantile (IOPD) and late-onset (LOPD). Aim of the study is to evaluate EMG findings, in particular distal muscle involvement, in a cohort of LOPD patients. 15 LOPD patients (9 Male–6 Female) underwent to ENG and EMG evaluation looking at spontaneous activity, MUP analysis recruitment. EMG evidenced the presence of myotonic discharges (MD) in paraspinal muscles in 6 patients and in distal limb muscles in 1 patient. Fibrillation potentials occurred in all muscles where MD were found. Short duration, MUPs were found in the paraspinal (6/12), proximal (6/12) and distal limb muscles (5/12). Our results confirm that myopathic EMG pattern is usually observed in proximal muscles, but we also find a similar pattern in distal muscles revealing a subclinical involvement. Moreover, myotonic discharges and denervation activity are present in both paraspinal and distal muscles. We can conclude that it is useful to extend the EMG study also to distal muscles even if not clinically compromised.

Transected sciatic nerve repair by diode laser protein soldering

Background and ObjectiveDespite advances in microsurgical techniques, repair of peripheral nerve injuries (PNI) is still a major challenge in regenerative medicine. The standard treatment for PNI includes suturing and anasthomosis of the transected nerve. The objective of this study was to compare neurorraphy (nerve repair) using standard suturingto diode laser protein soldering on the functional recovery of transected sciatic nerves. Study Design/Materials and MethodsThirty adult male Fischer-344 Wistar rats were randomly assigned to 3 groups: 1. The control group, no repair, 2. the standard of care suture group, and 3. The laser/protein solder group. For all three groups, the sciatic nerve was transected and the repair was done immediately. For the suture repair group, 10.0 prolene suture was used and for the laser/protein solder group a diode laser (500mW output power) in combination with bovine serum albumen and indocyanine green dye was used. Behavioral assessment by sciatic functional index was done on all rats biweekly. At 12weeks post-surgery, EMG recordings were done on all the rats and the rats were euthanized for histological evaluation of the sciatic nerves. The one-way ANOVA test was used for statistical analysis. ResultsThe average time required to perform the surgery was significantly shorter for the laser-assisted nerve repair group compared to the suture group. The EMG evaluation revealed no difference between the two groups. Based on the sciatic function index the laser group was significantly better than the suture group after 12weeks (p<0.05). Histopathologic evaluation indicated that the epineurium recovery was better in the laser group (p<0.05). There was no difference in the inflammation between the suture and laser groups. ConclusionBased on this evidence, laser/protein nerve soldering is a more efficient and efficacious method for repair of nerve injury compared to neurorraphy using standard suturing methods.

Neurogenic Dysphagia in Brainstem Disorders and EMG Evaluation

Neurogenic Dysphagia in Brainstem Disorders and EMG Evaluation

47. Quantitative EMG (qEMG)

Routine EMG studies are based on subjective, ordinal data representing the motor unit action potential (MUAP) electrical activity expressed in qualitative terms that do not have always physiologic bases and it’s very dependent on the examiner experience. Quantitative Electromyography (qEMG) on the other hand evaluates cardinal data and allows to make numerical and statistical comparisons in terms of physical units and it’s more objective. qEMG can detect earlier changes in the morphology of the motor units and help better to understand the natures pathologic changes occurring in neuromuscular disorders. Using a trigger and delay line 20 MUAPS can be obtained and analyzed either manually or automatically. The MUAP direct parameters like amplitude, duration, and number of phases are measured in order to distinguish normal from abnormal, and between neuropathic and myopathic disorders. Evaluating the presence of outliers MUAPs improves the sensitivity. Duration is the parameter that better represents the number of fibers and the spatial distribution of the motor units but determination of its onset and termination is difficult. For this reason, some derivate parameters had been developed. qEMG although takes extra time, improves the sensitivity of the EMG evaluation, but special care is required to correct automatic marking errors.

ID 230 – Adult onset acid maltase deficiency – EMG aids diagnosis in Intensive Care Unit

A 25 year old man was admitted to Intensive Care Unit with the clinical problems of worsening shortness of breath and a history of progressive proximal limb weakness and bilateral ptosis. He was found to have marked type II respiratory failure and significant proximal weakness both the upper and lower limbs and also marked extra-ocular muscle weakness. Arterial Blood Gas Analysis was consistent with type II respiratory failure. Muscle enzymes – CK levels were elevated -1174 U. Acetyl Choline Receptor antibodies – Negative. Neurophysiological Studies – Normal nerve conduction studies; EMG evaluation demonstrated marked myopathic abnormalities in proximal and distal muscles in lower as well as upper limbs. Some muscles showed frequent pseudo-myotonic discharges. The clinical presentation of progressive muscle weakness and Type II respiratory failure along with EMG features raised the possibility of adult onset Acid Maltase deficiency. Muscle biopsy demonstrated accumulation of glycogen within membrane bound vacuoles consistent with adult onset Acid Maltase Deficiency (Pompe’s disease of adult onset). Awareness of clinical and neurophysiological features of Acid Maltase Deficiency aid the diagnosis of this disorder, particularly in the context of evaluation of respiratory failure cases in an Intensive Care Unit.

Impact-induced soft-tissue vibrations associate with muscle activation in human landing movements: An accelerometry and EMG evaluation.

Previous studies have not used neurophysiological methodology to explore the damping effects on induced soft-tissue vibrations and muscle responses. This study aimed to investigate the changes in activation of the musculoskeletal system in response to soft-tissue vibrations with different applied compression conditions in a drop-jump landing task. Twelve trained male participants were instructed to perform drop-jump landings in compression shorts (CS) and regular shorts without compression (control condition, CC). Soft-tissue vibrations and EMG amplitudes of the leg within 50 ms before and after touchdown were collected synchronously. Peak acceleration of the thigh muscles was significantly lower in CS than in CC during landings from 45 or 60 cm and 30 cm heights (p < 0.05), respectively. However, the damping coefficient was higher in CS than in CC at the thigh muscles during landings from 60 cm height (p < 0.05). Significant decrease in EMG amplitude of the rectus femoris and biceps femoris muscles was also observed in CS (p < 0.05). Externally induced soft-tissue vibration damping was associated with a decrease in muscular activity of the rectus femoris and biceps femoris muscles during drop-jump landings from different heights.

Does percutaneous internal ring suturing contain risk of ilioinguinal nerve entrapment?

In this study, we aim to assess the alteration of IIN functions in children with inguinal hernias operated on using open or 'percutaneous internal ring suturing' (PIRS). This study was based on a prospective clinical trial of 60 pediatric patients. They were operated on using PIRS or conventional open hernia repair technique. Group 1 included 35 patients who were treated with PIRS technique. Group 2 included 22 patients who underwent a conventional open hernia repair. The ilioinguinal nerve stimuli in both the operational and non-operational areas were evaluated in patients with peripheral EMG for possible ilioinguinal nerve damage on the hernia side before the operation and to reevaluate ilioinguinal nerve function in the third postoperative week. In Group 1, 19 cases underwent a preoperative EMG examination and in 35 cases, EMG examination was obtained postoperatively. Pre- and postoperative EMG results were normal in all cases in Group 1 on both the operational and non-operational sides. In Group 2, 15 preoperative and 25 postoperative EMG examinations were obtained. In Group 2, only one case with a right inguinal hernia who had normal preoperative EMG results showed no IIN response in a postoperative EMG evaluation obtained in the third postoperative week, with a normal left-side response. The EMG was repeated at the three-month postoperative third mark and revealed the same result. In a six-year-old female case, there was a negative EMG response on the non-operative side both pre- and postoperatively.

An Ergonomic Study of Firefighters’ Postural Comfort Evaluation Based on EMG Method

This paper reports the ergonomic evaluation of firefighters’ postures during the firefighting procedure based on EMG method. Collecting EMG data of postures of different comfort level under the condition of the posture database has been established. Obtaining posture samples for comfort evaluation through signal denoising and feature extraction. Several classifiers are used to verify the effectiveness of EMG evaluation methodology. The conclusion is expected to provide operation instruments for firefighters as well as a reference for product design related to firefighting activities.

P442: The value of SSR recordings in the assessment of autonomic nervous dysfunction in patients with sacral-pudendal impairment

P442: The value of SSR recordings in the assessment of autonomic nervous dysfunction in patients with sacral-pudendal impairment

Pisa syndrome in Parkinson’s disease: an electrophysiological and imaging study

The pathophysiology of postural abnormalities in patients with Parkinson's disease is poorly understood. In the present study, 13 patients with Pisa syndrome (PS) underwent EMG study of paraspinal lumbar (L2-L4) and thoracic (T8-T10) muscles, and of non-paraspinal muscles. Patients also underwent a whole spine X-ray and an MRI assessment of paraspinal muscles (L1-S1). The EMG evaluation disclosed two main patterns: patients with pattern I (n = 6, hyperactivity of lumbar paraspinals ipsilateral to the trunk leaning side) or pattern II (n = 7: hyperactivity of lumbar paraspinals contralateral to the trunk leaning side. In pattern I, half the patients also had ipsilateral hyperactivity of the thoracic paraspinals, the other half had contralateral thoracic hyperactivity; in pattern II, thoracic paraspinal hyperactivity was contralateral in all patients (like the lumbar paraspinal hyperactivity). Non-paraspinal muscles were hyperactive ipsilaterally in four of six patients with pattern I and in all patients with pattern II. The MRI showed mild muscular atrophy with fatty degeneration in patients with pattern I, whereas in pattern II patients this was greater and prevalent on paraspinal lumbar muscles ipsilateral to the leaning side. The present data support the hypothesis that two main patterns of muscular activation are associated with PS. In both patterns, hyperactivity of contralateral paraspinal muscles is probably compensatory for the trunk leaning.

EMG evaluation of hip adduction exercises for soccer players: implications for exercise selection in prevention and treatment of groin injuries

IntroductionExercise programmes are used in the prevention and treatment of adductor-related groin injuries in soccer; however, there is a lack of knowledge concerning the intensity of frequently used exercises.ObjectivePrimarily to...

Combination of Physical and Acupuncture Therapy: Acupoint Stimulation Physical Therapy (ASPT)

We introduced Acupoint Stimulation Physical Therapy (ASPT) as a combination of physical and acupuncture therapy. The characteristics of ASPT were as follows. We pressed acupoints on the meridians running through the affected muscles. The magnitude and duration of acupressure stimulation were maximized to alter muscle tonus and not cause pain to the patient. We demonstrated its effects by scientific research using EMG and clinical evaluation in patients with knee contracture. In the future, we would like to develop ASPT as a novel physical therapy for all patients with disorders of muscle tonus.