Interference Pattern Analysis Research Articles

Application of time-varying analysis to diagnostic needle electromyography

Quantification in clinical, diagnostic electromyography (EMG) currently includes motor unit action potential (MUAP) analysis and interference pattern analysis. Early efforts to examine the frequency/power spectra of the interference pattern showed modest value but the technique was not developed further. This paper re-examines spectral analysis, extending it into the time-varying domain, which has never been studied in diagnostic needle EMG. Time–frequency and time-scale analysis employing wavelet and non-wavelet techniques were applied to short trains of MUAPs. The results show that time-varying analysis produces clear visual representations of the energy content of individual MUAPs within an interference pattern. The time frequency representations allow easy, qualitative distinction between normal and neurogenic MUAPs. Furthermore, the quantified MUAP energy correlates well with the current morphological standard and the quantification process is substantially faster. Time-varying analysis links classical power spectral analysis in the realm of interference patterns with quantitative MUAP analysis. In addition to morphological classification, MUAPs might also be classified by energy content, which more closely reflects the physical and physiological consequences of neuromuscular pathology on the motor unit.

The utility of EMG interference pattern analysis in botulinum toxin treatment of torticollis: A randomised, controlled and blinded study

Objective The significance of electromyography (EMG) guidance in botulinum toxin (BT) treatment has been much debated. The aim of this study was to evaluate if EMG guidance in the treatment of torticollis in BT-naive patients had a better outcome than treatment after clinical evaluation alone. Methods Twenty-six patients with torticollis were included and treated for 1 year in this prospective, blinded study. Quantitative EMG was performed simultaneously in the four most frequently affected muscles: the sternocleidomastoid muscles and the posterior neck muscles on both sides. EMGs were analysed for turns per second. Clinical ratings were performed by an experienced neurologist (A). Injections were given by another neurologist (B), who was blinded to the ratings. In group 1, the results of the EMG were available to the treating neurologist B, whereas in group 2, neurologist B was blinded. In group 1, treatment with BT was given when turns per second were higher than 100. Results In patients treated guided by EMG, clinical outcome, evaluated by objective ratings, was better than in patients treated based on clinical judgement alone ( p = 0.05). In group 2, 105 muscles were treated with BT. Of these, 37 did not show dystonic EMG activity. Conclusions Treatment with BT guided by EMG results in better clinical outcome than treatment without EMG and reduces the amount of BT used. Significance EMG guidance by interference pattern analysis may optimise BT treatment in torticollis by a more precise injection and may reduce side effects and the risk of development of antibodies to BT.

Effects of monopolar and bipolar electrode configurations on surface EMG spike analysis

This study compared the effects of monopolar and bipolar electrode configurations on interference pattern analysis of the surface electromyographic (sEMG). Twenty-four college-aged male participants performed isometric actions of the elbow flexors at 40, 60, 80, and 100 percent of maximal voluntary contraction (MVC). Separate (Ag/AgCl) electrodes were used for both configurations. There were five measures associated with “spike shape” analysis: mean spike amplitude (MSA), mean spike frequency (MSF), mean spike slope (MSS), mean spike duration (MSD) and mean number of peaks per spike (MNPPS). A load-cell and wrist-cuff assembly was used to record isometric elbow flexion forces. Both electrode configurations resulted in the same trends force changes in spike shape measures across force levels: there was a linear increase in MSA, MSS, and a quadratic decrease in MSF and the MNPPS ( p's < 0.05). The MSD underwent a quadratic increase ( p < 0.05). The spike shape measures had greater mean magnitudes and exhibited greater rates of changes across force levels for the monopolar electrode configuration ( p's < 0.05). The monopolar electrode configuration was therefore more sensitive to changes in muscle activity with increases in isometric force. This is an important consideration because the rate at which muscle electrical activity develops into a full interference pattern is an important qualitative and quantitative diagnostic measure.

Electrophysiological characteristics of motor units and muscle fibers in trained and untrained young male subjects

We hypothesized that the amplitudes of compound muscle action potentials (CMAPs) and interference pattern analysis (IPA) would be larger in trained subjects compared with untrained subjects, possibly due to hypertrophy of muscle fibers and/or increased central drive. Moreover, we hypothesized that the untrained muscle is less excitable compared with the trained muscle. An electromyographic (EMG) needle electrode was used to record the IPA at maximal voluntary effort. The CMAP was obtained by stimulating the musculocutaneous nerve and recording the brachial biceps muscle using surface electrodes. CMAPs were obtained by direct muscle stimulation (DMS) with two stainless-steel subdermal electrodes placed subcutaneously in the distal third of the muscle. Amplitudes of CMAP and IPA were significantly larger in trained subjects compared with untrained subjects. We found no differences between trained and untrained subjects in IPA power spectrum and turns per second or amplitude of the CMAPs obtained by DMS. Muscle fiber hypertrophy and/or altered central drive may account for our results, but there was no indication of changes in muscle fiber excitability.

Quantitative laryngeal electromyography: Turns and amplitude analysis

Laryngeal electromyography (LEMG) is primarily a qualitative examination, with no standardized approach to interpretation. The objectives of our study were to establish quantitative norms for motor unit recruitment in controls and to compare with interference pattern analysis in patients with unilateral vocal fold paralysis (VFP). Retrospective case-control study We performed LEMG of the thyroarytenoid-lateral cricoarytenoid muscle complex (TA-LCA) in 21 controls and 16 patients with unilateral VFP. Our standardized protocol used a concentric needle electrode with subjects performing variable force TA-LCA contraction. To quantify the interference pattern density, we measured turns and mean amplitude per turn for ≥10 epochs (each 500 milliseconds). Logarithmic regression analysis between amplitude and turns was used to calculate slope and intercept. Standard deviation was calculated to further define the confidence interval, enabling generation of a linear-scale graphical "cloud" of activity containing ≥90% of data points for controls and patients. Median age of controls and patients was similar (50.7 vs. 48.5 years). In controls, TA-LCA amplitude with variable contraction ranged from 145-1112 μV, and regression analysis comparing mean amplitude per turn to root-mean-square amplitude demonstrated high correlation (R = 0.82). In controls performing variable contraction, median turns per second was significantly higher compared to patients (450 vs. 290, P = .002). We first present interference pattern analysis in the TA-LCA in healthy adults and patients with unilateral VFP. Our findings indicate that motor unit recruitment can be quantitatively measured within the TA-LCA. Additionally, patients with unilateral VFP had significantly reduced turns when compared with controls.

Change in urethral sphincter neuromuscular function during pregnancy persists after delivery

The purpose of this study was to assess the effect of pregnancy and first vaginal delivery on urethral striated sphincter neuromuscular function. Quantitative electromyographic (EMG) interference pattern analysis of the urethral sphincter of 23 nulligravidas and 31 third trimester primigravidas allowed comparison of mean motor unit parameters before term vaginal delivery and postpartum. Mean electromyographic interference pattern parameters in the primigravidas were significantly lower than nulligravidas even antepartum, with decreased turns, lower amplitude, and less activity. The only significant change at 6 months' postpartum was further decline in number of turns resulting in a further decrease in turns:amplitude. All other electromyographic abnormalities persisted at 6 months' postpartum and remained abnormal compared to the nulligravidas. Urethral sphincter neuromuscular function changed significantly during pregnancy and these changes persisted postpartum. Lack of recovery 6 months' postpartum suggests a physiologic impact of pregnancy itself on future risk of urinary incontinence.

Physician-writers in the age of blogging

Muscle atrophy, fiber-type shifting, reduced contractility, metabolic alterations, capillarization defect, and mitochondrial modifications are important adaptations in COPD. Skelatal muscle dysfunction is one of the most devastating systemic manifestations of COPD which eventually leads to increase in morbidity and mortality. In this study we aimed to demonstrate the effects of COPD on both muscles and nerves in neurologically normal patients with different degrees of airflow limitations, using current electrophysiological methods.Electrophysiological examinations were performed using a Keypoint EMG machine with subjects lying supine on a bed at a room temperature. Tests were nerve conduction studies, motor unit potential (MUP) analysis, interference pattern (IP) analysis and macro EMG (mEMG) analysis on the right side in the upper and lower extremities. Multi-motor unit potential (m-MUP) analysis and interference pattern (IP) analysis revealed some changes in biceps brachii (BB) and tibialis anterior (TA) muscles, but macro EMG (mEMG) analysis was similar except for increased fiber density at TA muscles in COPD patients. Increased ulnar and sural sensory latency, decreased ulnar sensory velocity, and increased ulnar motor latency values were found in COPD. There was increased motor unit potential (MUP) turn and phase values in BB muscles and increased MUP turn and decreased MUP duration, area, area/amplitude ratio and size index values in TA muscles in COPD patients. As a conclusion, in COPD more nerve conduction abnormalities and more MUP abnormalities which reflected muscle fiber diameter changes were observed by the use of electrophysiological methods including multi MUP - IP analysis and mEMG analysis.

Levator ani denervation and reinnervation 6 months after childbirth

The objective of the study was to assess the prevalence of levator ani denervation and reinnervation 6 months after the first delivery. Ninety-six primigravida women underwent quantitative electromyography of the levator ani during the third trimester and twice postpartum. A 95% confidence interval for normal function was created using interference pattern analysis. Fifty-seven who completed the study are presented in this secondary data analysis. Postpartum muscle sites outside the normal range were considered abnormal. Obstetric and demographic characteristics were assessed. Of 57 subjects, 70% had no denervation. Of the 30% with denervation at 6 weeks, 35% recovered by 6 months. Obstetric or maternal characteristics were not predictive of denervation or reinnervation, except subjects with persistent denervation tended toward lower body mass index (BMI) independent of mode of delivery. Nearly one-third of women have levator ani denervation after first delivery, but many recover by 6 months. Denervation is not clearly associated with mode of delivery, but higher maternal BMI may be protective.

Electromyographic Interference Pattern Analysis

Needle electromyography is used to investigate motor unit abnormalities, consisting of the anterior horn cell, the axon, the nerve end-plate, and the associated muscle fibers. The characteristics of the firing and recruitment patterns of motor units during voluntary contraction are identified as an interference pattern that is used clinically for the diagnosis of neuropathy and myopathy. Quantitative analysis of this interference pattern, using such factors as zero-crossing, spike count, number of turns (NT), the peak-to-peak amplitude, mean amplitude (MA), and automatic amplitude of the interference pattern envelope, is used to identify interference patterns resulting from specific pathologies. It is difficult, however, to improve the sensitivity and specificity of the analysis for the diagnosis of neuropathy and myopathy by separately analyzing the number or amplitude of the spikes involved in the interference pattern. Therefore, turn amplitude analysis has been developed, which combines the number and amplitude of the spikes. For the NT:MA ratio and peak ratio analysis (PRA), the turns are examined during a constant voluntary contraction. In contrast, for the cloud analysis, the distribution of NT and MA at various muscle strengths is plotted. Expert Quantitative Interference Pattern Analysis (EQUIP), which applies the expertise of an electromyographer, provides practical sensitivity and specificity for the clinical diagnosis of neuropathic and myopathic diseases. Understanding these various quantitative interference pattern analysis modalities will not only improve the ability of physiatrists to interpret electromyographic findings, but will also expand their knowledge of motor unit diseases.

Quantitative anal sphincter electromyography in primiparous women with anal incontinence

The purpose of this study was to determine whether evidence of denervation/reinnervation of the external anal sphincter is associated with anal incontinence symptoms immediately after delivery. After a first vaginal delivery, 42 women completed an anal incontinence questionnaire. They also underwent concentric needle electromyography of the external anal sphincter. For each subject, motor unit action potential and interference pattern parameters were determined. For the motor unit action potential, no difference was observed between patients with and without anal incontinence symptoms (t-test). For the interference pattern, the amplitude/turn was greater in subjects with fecal urgency (318 +/- 48 [SD] microV) and fecal incontinence (332 +/- 48 microV), compared with those without fecal urgency (282 +/- 38 microV) and fecal incontinence (286 +/- 41 microV; P = .02, t-test). In this group of postpartum women with mild anal incontinence symptoms, interference pattern analysis shows evidence of denervation and subsequent reinnervation.

Determining the shape of the turns–amplitude cloud during anal sphincter quantitative EMG

We aimed to compare our normative data for quantitative interference pattern (IP) analysis of the anal sphincter to previously published data. In 28 nulliparous women, we performed IP analysis during quantitative concentric needle electromyography (QEMG) of the anal sphincter. At each sampling site, a 500-ms epoch was analyzed. The data were log transformed. Linear regression lines (with 95% confidence intervals) were calculated from the log transformed variables "turns-second" and "amplitude-turn." These confidence intervals were then transformed back into the original parameters to yield scatterplots with confidence curves. The mean turns-second were 203 (SD 174). The mean amplitude (mcv)-turn was 266 (SD 87). The regression coefficients for the log-transformed variables are constant = 1.5, slope = 0.3, and resultant cloud of raw data has a convex upper boundary. These appear slightly different than previously published reports, potentially influencing the determination of normal and abnormal studies.

Mitochondrial complex III deficiency in a case of HCV related noninflammatory myopathy

Sirs: Muscle involvement in the course of Hepatitis C Virus (HCV) infection has mainly been reported as a myositis secondary to an immunologically mediated reaction or to a direct effect of viral infection. Myositis was confirmed in these cases by the presence of perivascular infiltration of inflammatory cells in the muscle biopsy [1, 2]. However, lack of evidence for viral multiplication in muscle [3, 4] suggested a virus-triggered immune-mediated mechanism, rather than direct infection and in situ replication. On the other hand, several cases of HCV associated myopathy lacked signs of inflammation in the muscle biopsy [2, 5] suggesting other pathogenic mechanisms. A 60-year-old woman was admitted in April 2002 with a 3 year history of slowly progressive bilateral eyelid ptosis, diplopia, generalized weakness, severe distal upper limb weakness and respiratory distress after minimal exercise. Neurological examination disclosed mild neck and proximal upper limb weakness, bilateral ptosis and diplopia both in horizontal and upward gaze. Ptosis increased after sustained upward gaze. A mild impairment in the upward gaze was present mainly on the left side. Her family history was unremarkable. The patient had a post-transfusion HCV infection detected by chance ten years before the appearance of ptosis, and not treated with immunotherapy because of the benign course. Neoplastic, autoimmune, thyroidal, and rheumatologic diseases were excluded by appropriate tests. Repetitive stimulation (right ulnar nerveabductor digiti minimi muscle and facial nerve-nasalis muscle) did not show a decremental response. Acetylcholine receptor antibodies were absent. Ptosis did not improve after edrophonium chloride intravenous injection. Chest computed tomography (CT), spirometry, electrocardiography and echocardiography, brain and orbit, CT and magnetic resonance imaging were normal. Immunoglobulin G and immunoglobulin M cryoglobulins were detected (cryocrit value: 2 %). Electroneurography was completely normal. Automatic interference pattern analysis was consistent with a myopathic dysfunction. The patient had an abnormal turns/amplitude ratio demonstrated by scores below the sexand age-specific reference range in frontal muscle, left biceps brachii and quadriceps. The same muscles showed rapid recruitment of short duration and low amplitude motor unit potentials. Fibrillations and fasciculations were absent. A biopsy taken from the left deltoid muscle revealed moderate fiber atrophy, marked variation of fiber size with round or angular shape, type 2 myofiber predominance with increased nuclear centralization. Perivascular inflammation, necrosis, and ragged red fibers were absent. Mitochondrial enzyme activities showed decreased decylbenzoquinol cytochrome c reductase activity (complex III deficiency) (51.1 nmol/min mg, normal values: 70–150) while citrate synthase activity was normal (153 nmol/min mg, normal value: 80–210). Mitochondrial complex I, II IV and V activities were normal. The ultrastructural study showed increased subsarcolemmal accumulation of glycogen, and mitochondria with altered shape and concentric cristae. To verify these findings a LETTER TO THE EDITORS

Quantitative EMG of facial muscles in myasthenia patients with MuSK antibodies

ObjectiveOur aim was to study the pathophysiological process leading to facial muscle atrophy in 13 patients with MuSK antibody positive myasthenia gravis (MuSK-MG), and to compare with findings from 12 acetylcholine receptor antibody positive myasthenia patients (AChR-MG), selected because they suffered from the same degree of disease severity and required similar treatment. MethodsMotor unit action potential (MUAP) and interference pattern analysis from orbicularis oculi (O oculi) and orbicularis oris (O oris) muscles were studied using a concentric needle electrode, and compared with findings in 20 normal subjects, 6 patients receiving botulinum toxin injections (representing a neurogenic model) and 6 patients with a muscle dystrophy (representing a myopathic model). The techniques and control data have been reported previously. ResultsThe mean MUAP durations for O oculi and O oris were significantly reduced (p<0.001) in both MG cohorts when compared with healthy subjects, and were similar to those in the myopathic control group. They were significantly different from those obtained from the neurogenic control group (p<0.001 for both O oculi and O oris). The MUAP findings in O oculi occurred independently from neuromuscular blocking on single fibre EMG (SFEMG) in the same muscle. On turns amplitude analysis (TAA), 50% of MuSK-MG patients and 42% of AChR-MG patients had a pattern in O oculi which was similar to that in the myopathic control group, and 62% of MuSK-MG patients and 50% of AChR-MG patients had a pattern in O oris that was also similar to that in the myopathic control group. The TAA findings for O oculi and O oris in both MG cohorts were different from those obtained from the neurogenic control group. ConclusionsFacial muscle atrophy in MuSK-MG patients is not neurogenic and the pathophysiological changes are akin to a myopathic process. The selected AChR-MG patients also show evidence of a similar pathophysiological process in the facial muscles albeit to a lesser degree. SignificanceWe propose that muscle atrophy in MuSK-MG is a myopathic process consisting of either muscle fibre shrinkage or loss of muscle fibres from motor units. The duration of disease and long-term steroid treatment may be further contributory factors.

P32.9 Fractal dimension of the EMG interference pattern: preliminary observations and comparisons with other measures of interference pattern analysis

P32.9 Fractal dimension of the EMG interference pattern: preliminary observations and comparisons with other measures of interference pattern analysis

Turns amplitude analysis of the orbicularis oculi and oris muscles

Objective The aim of the study was to determine whether ‘clouds’ from turns amplitude analysis obtained from the orbicularis oculi and oris muscles without force monitoring can be used to differentiate pathological processes affecting the face. Methods The interference pattern from orbicularis oculi and orbicularis oris was studied using a concentric needle electrode. Data-points from 20 normal subjects were plotted on a logarithmic scale of mean amplitude between turns versus turns/second, from which linear regression analysis defined the 95% confidence intervals. This enabled us to draw the boundaries of the normal cloud on a linear plot. Data-points from the interference pattern in two pathological cohorts, of 6 patients receiving botulinum toxin injections (representing a neurogenic model), and 6 patients with a muscle dystrophy (representing a myopathic model) were plotted against the normal cloud. These findings were compared and correlated with the mean durations obtained on motor unit action potential analysis from these same two facial muscles. Results The majority of patients receiving botulinum toxin injections into their facial muscles showed a pattern of high amplitude with low turns/s, or low amplitude with a low-to-normal range of turns/s in both facial muscles. These findings were associated with high-duration motor unit action potentials in most cases. In the myopathic group of patients 66% showed a pattern of low amplitude with low-to-normal range of turns/s in O oculi and O oris. This correlated with short-duration motor unit action potentials in both facial muscles. Conclusions We have demonstrated that turns amplitude analysis without force monitoring can be used to study the interference pattern from facial muscles and can be applied to differentiate primary neurogenic from myopathic pathological processes. Significance Turns amplitude analysis without force monitoring in the facial muscles can be used as an effective and practical method of interference pattern analysis to complement findings from conventional motor unit action potential analysis.

Extrinsic Fabry−Perot Interferometry for Noncontact Temperature Control of Nanoliter-Volume Enzymatic Reactions in Glass Microchips

Optical fiber extrinsic Fabry-Perot interferometry (EFPI) was investigated as a noncontact temperature sensor and utilized for regulating the temperature of small-volume solutions in microchips. Interference pattern analysis determined the optical path lengths (OPL) associated with reflections from various surfaces on or in the microchip, in particular, from gold sputtered on the bottom of a microchannel. Since OPL is directly proportional to refractive index, which is dependent on solution temperature, the EFPI sensor was capable of noncontact monitoring of solution temperature simply from alterations in the measured path length. Calibration of the sensor against a thermocouple was performed while heating the microchip in a noncontact manner with an IR lamp. The combination of EFPI temperature sensor, IR-mediated heating, and air cooling allowed a fully noncontact system for small-volume temperature control in microchip structures, and its utility was illustrated by optimal digestion of DNA by a temperature-dependent restriction endonuclease in 320 nL. The functionality and simplicity of the microchip EFPI temperature sensor was enhanced by replacing the prebonding sputtered gold with a tunable, chemically plated semireflective silver coating created in situ after chip fabrication. This provided an 8-fold improvement in the lowest detectable temperature change (deltaT = 0.1 degrees C), facilitated primarily by enhanced reflection from both the bottom and top surfaces of the microchannel. This approach for controlling micro- and nanoscale reactions--with heating, cooling, and temperature control being carried out in a completely noncontact fashion--provides an accurate and sensitive method for executing chemical and biochemical reactions in microchips.

Detecting and avoiding the necking deformation along polypropylene fibre axis using the fringe pattern analysis of multiple-beam microinterferometry

A fibre-drawing device attached with the system for producing multiple-beam Fizeau fringes in transmission is used to optimize the optical properties during the cold drawing of polypropylene (PP) fibres. This system is automated for interference pattern analysis. Two drawing processes for the PP fibres are applied and investigated. The first one is fast drawing in which the necking deformation is predicted and the other is the slow (step) drawing in which the necking can be avoided. The refractive index profiles ( n ∥ and n ⊥ ) of PP fibres are determined at different positions along the fibre axis during the fast and slow drawing processes. The fibre interference patterns are automatically digitized and stored in a computer storage media. The slow drawing technique for PP fibres is recommended to overcome the deformation difficulties along the fibre axis due to necking during the drawing processes. Microinterferograms in case of light vibrating parallel and perpendicular to the fibre axis are given for illustration.

Evaluation and autoalignment method of the focusing unit for a near-field optical recording system

Evaluation results and an autoalignment method for an optical head of a near-field recoding (NFR) system are presented. The focusing unit is an optical head of a NFR system and is composed of a solid immersion lens (SIL) and an objective lens (OL). Generally, the size of the focusing unit is smaller than that of the conventional optical recording head. Hence there are difficulties in assembling the small focusing unit precisely and a novel method for an effective assembly is required. We compose an evaluation system with an interferometer and evaluate some focusing unit samples aligned and assembled manually and present the obtained results. We also propose a conceptual method of autoalignment to assemble the focusing unit well by a pattern recognition using a neural network. Using the conventional optical tool, Code V, a tolerance analysis of the assembly error between the SIL and the objective lens and an interference pattern analysis for the assembly error are executed. Then, through an analysis of the simulation results, the autoalignment methodology using a neural network approach is proposed.

A Neural Network Approach Based on Interference Pattern Analysis: Application to an Autoalignment Method for the Focusing Unit of NFR System

From the viewpoint of assembly, evaluation results and an autoalignment method for the focusing unit (FU) of a near-field recording (NFR) system are proposed. Generally, the size of the focusing unit composed of the objective lens and the solid immersion lens is smaller than that of the conventional focusing unit. Hence there are difficulties in the precise assembly of the small focusing unit. We developed an evaluation system with an interferometer and evaluated some focusing unit samples, then a tolerance analysis of the assembly error between the SIL and the objective lens and an interference pattern analysis of the assembly error were carried out. A pattern recognition method using a neural network is presented with features, which were extracted from interference patterns due to errors in the FU.

Análisis del patrón de interferencia en pacientes con distrofia muscular

The conventional electromyography contribute to differentiation of myopatic and neuropatic patterns in neuromuscular disorders, however, the classical patterns related to myopatic changes can result in neurogenic components, this confusion could be due to denervation and reinervation changes involved at the different stages of those diseases. Demonstrate the importance of quantitative electromyographic techniques, as the interference pattern analysis (IPA), for a better differentiation of muscular dystrophies. IPA was done in 95 patients with 3 different muscular dystrophies: 52 Duchenne muscular dystrophy (DMD), 33 limb girdle muscular dystrophy (LGMD) and 10 myotonic muscular dystrophy (MD) individuals and in a control group of 25 individuals. The left braquial biceps and right anterior tibial muscles were evaluated; the variables analyzed were turns/seconds (t/s), amplitude/turns (a/t), ratio turns/amplitude mean and root squared mean (RSM). We found statistical significant differences in all variables in both braquial biceps and right anterior tibial muscles (p < 0.05) in DMD patients. In LGMD we only found differences in a/t in braquial biceps. In MD the differences were observed in a/t, ratio and RSM in braquial biceps, and in a/t (in anterior tibial). All the DMD patients show differences in IPA values in relation to control group, MD only in biceps, However there were not important changes in LGMD probably because the diversity and lack of homogeneity in affected muscles in this group.