Compound Motor Research Articles

Emphysematous Pyelonephritis: Experience of Managing 15 Consecutive Cases in a Tertiary Care Hospital of Bangladesh

Background: Carpal tunnel syndrome (CTS) is one of the most frequent entrapment neuropathies of the upper limb. CTS and diabetic polyneuropathy (DPN) are common conditions in patients with diabetes and therefore frequently occur concomitantly. Diagnosis of CTS in patients with DPN is important, as therapeutic interventions directed toward relief of CTS may be effective irrespective of diffuse neuropathy.Methods: This study was a hospital based descriptive cross sectional study done in a tertiary care hospital, Dhaka between July, 2015 and June, 2016. The initial clinical diagnosis of diabetic peripheral neuropathy was made from history and examination. It was confirmed by doing nerve conduction study. After having informed written consents, a standard preformed questionnaire was filled up for each case. Collected data were checked, verified for consistency and edited for final results. Data cleaning, validation and analysis were performed using Statistical Package for the Social Sciences (Version 20.0).Results: A total of 354 cases were finally analyzed with 153 (43.2) patients being symptomatic for CTS and among those 54 (58.7%) had electrophysiology proven CTS. It was observed that 26.0% of patients established as having DPN also had CTS. The frequency of CTS among those with symptoms was significantly higher than in asymptomatic participants. The mean age was found to be 55.99 ± 9.25 years with a range from 28 to 80 years. Majority (38.4%) of patients belonged to the age group of 51-60 years. Among all cases of electrophysiology proven CTS (92 patients), females (53.3%) numbered greater in comparison to males (46.7%). One hundred and ninety two (54.2%) patients were housewives, 57 (16.1%) were garment workers, 45 (12.7%) patients were businessmen and 60 (16.9%) patients were service holders. Study subjects with CTS had significantly higher body mass index, higher fasting blood glucose and higher HemoglobinA1c in comparison to patients without CTS. Examination of upper limb sensory nerves showed that nerve conduction velocity was significantly decreased and distal latency was found to be significantly increased in patients with CTS on median nerve examination. The mean compound motor action potential was not significantly different between patients with and without CTS.Conclusion: Symptoms and signs of CTS are mostly masked by the symptoms of DPN and patients presenting with such symptoms in the upper limbs should be evaluated for CTS as a separate entity to DPN. The finding of a frequency of CTS of 26% in subjects with diabetes with varying degrees of DPN is remarkably high. Given the high prevalence of CTS in subjects with DPN, it is recommended that therapeutic decisions be made carefully after nerve conduction study and proper diagnosis.Birdem Med J 2018; 8(3): 246-250

CONGENITAL MYASTHENIC SYNDROMES AND MYASTHENIA: P.65Muscular pathological features in Lambert-Eaton myasthenic syndrome

Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune-mediated disorder of neuromuscular transmission. Voltage-gated calcium channel antibodies (VGCC-Ab) impair calcium influx and acetylcholine release at motor nerve terminals, resulting in the failure of neuromuscular transmission. Patients present with skeletal muscle fluctuating weakness and paralysis in the clinical. Due to LEMS is often misdiagnosed as a peripheral nerve disease or a myopathy, so electromyography (EMG) and muscle biopsy are necessary. The objective of this study was to describe EMG findings and several muscle histology in LEMS. EMG, nerve conduction studies, repetitive nerve EMG showed significantly decreased mean Muscle action potentials (MUP) duration, normal motor and sensory nerve conduction. RNS showed decrease of compound motor action potential (CMAP) amplitude by at least 10% at low-frequency (2-5 Hz) and increased CMAP amplitude by more than 60% at high-frequency (20-50 Hz). Muscle biopsy showed minor evidence of denervation or marked type II fiber atrophy in the patients with longer duration of illness, whereas with shorter duration, there was scattered muscle fiber necrosis. EMG and biopsy abnormalities mimicking myopathy may often be found in patients with LEMS. Rare muscle pathological features associated with LEMS were described.

Comparative effects of implanted electrodes with differing contact patterns on peripheral nerve regeneration and functional recovery

Electrical stimulation could enhance nerve regeneration and functional recovery. The objective of this study was to evaluate the regenerative effects of implanted electrodes with different contacts in resected sciatic nerve. Sciatic nerve resection and microsurgical repair models were established and randomly divided into four groups (point contact, 1/4 circle contact; whole-circle contact; no electrodes as control). Electrical stimulation was performed and electrophysiological, morphological and histological exams (of the sciatic nerve and muscle) were conducted at 4 and 10 weeks post-implantation. Point and 1/4 circle contact groups showed significantly higher scores in the sciatic functional index (SFI), increased amplitude of compound muscle action potential (AMP) and motor nerve conduction velocity (MNCV) compared to the control group at both 4 and 10 weeks post-implantation. Point and 1/4 circle contact morphologically promoted sciatic nerve regeneration and reduced muscular atrophy with less mechanical injury to the nerve trunk observed compared with the whole-circle contact group at both 4 and 10 weeks post-implantation. Electrodes with point and 1/4 circle contacts represented an alternatively portable and effective method of electrical stimulation to facilitate injured sciatic nerve regeneration and reduce subsequent muscular atrophy, which might offer a promising approach for treating peripheral nerve injuries.

Increased Single-Fiber Jitter Level Is Associated With Reduction in Motor Function With Aging

Age-associated skeletal muscle weakness is a major contributing factor to an increased late life mortality and morbidity, but its neurobiology is poorly understood. Previously, we provided histological evidence of dying-back axonal degeneration of motor neurons and denervation of neuromuscular junctions in age-associated muscle weakness. Given this, we aimed to evaluate the relation between impaired neuromuscular transmission and various aspects of age-associated muscle weakness. We compared two electrophysiological measures, single-fiber jitter and compound motor action potential in mice of different age groups, and correlated them with various physical performance measures, such as grip strength, standing and walking time, and treadmill performance. Consistent with our previous histological data, single-fiber jitter, a measure of neuromuscular junction transmission, was significantly increased in older animals, whereas compound motor action potential shows no difference between young and old age groups. Neither jitter nor compound motor action potential correlated with any of physical performance measures, except for jitter and standing activity. Impaired neuromuscular transmission-represented as increase in single-fiber electromyography jitter level-reflects decline in motor function with aging.

The impact of physical exercise on neuromuscular function in Myasthenia gravis patients: A single-subject design study.

There is a need for tailored exercise recommendations to patients with Myasthenia gravis (MG). A few pilot studies have recently shown that physical exercise in accordance with general recommendations to healthy adults can be applied safely to patients with mild MG symptoms. How physical exercise affects muscle parameters and risk factors for lifestyle diseases in patients with MG is, however, only poorly known. We evaluated functional skeletal muscle parameters in 11 MG patients, before and after conducting a 12-week supervised physical therapy regimen of aerobic and resistance strength training. After the training program, parameters of the rectus femoris muscle improved: compound motor action potential (from 4.5 ± 2.6 to 5.3 ± 2.8 mV, P = .016), isometric muscle force (from 25.2 ± 4.4 to 30.2 ± 3.8 kg; P = .014), and ultrasound muscle thickness (from 19.6 ± 5.6 to 23.0 ± 3.9 mm, P = .0098) all increased. Further, physical performance based measures improved, including the 30-Second Chair Stand Test (median change +2, P = .0039) as well as the clinical MG composite score [from 3 (2–5) to 2 (0–4), P = .043]. No improvement in muscle function was observed in the biceps brachii muscle. These findings indicate that MG patients can improve their muscular functions by incorporating aerobic and resistance strength training, especially in proximal leg muscles. This is important knowledge when physical therapy is considered for this patient group, for whom no guidelines on physical exercise currently exist.

Platelet-rich plasma versus corticosteroid injections for carpal tunnel syndrome: Clinical and electrophysiological study

Aim of the workTo evaluate the effectiveness of platelet rich plasma (PRP) injections in carpal tunnel syndrome (CTS) in comparison to corticosteroids clinically and electrophysiologically. Patients and methodsThe study included 36 patients with idiopathic mild to moderate CTS divided into two groups: group I received PRP and group II received corticosteroid injections into the carpal tunnel. Nerve conduction studies were carried out, visual analogue scale (VAS) and the Boston Carpal Tunnel Questionnaire (BCTQ) were administered to patients of both groups immediately before treatment, one and three months after treatment. ResultsThe mean age (36.6 ± 8.8 years vs 38.5 ± 8 years), disease durations (19 ± 11 months vs 14 ± 9 months) and genders were comparable. PRP injection was significantly better than corticosteroids injection as regard VAS, symptom severity scale (SSS), functional status scale (FSS) of BCTQ as well as the distal sensory latency after one and three months of injection. There was no significant difference between both groups in other assessed parameters including distal motor latency, amplitude of compound muscle action potential, motor and sensory conduction velocities of the median nerve. There was a significant correlation between VAS and distal sensory and motor latency of the median nerve in both groups before, 1 and 3 months after injection. ConclusionsSingle local injection of the PRP proved to be an effective treatment choice for CTS. PRP therapy seemed to be superior to steroid, showing more improvement clinically as regard the pain and function and electrophysiologically as regard the distal sensory latency throughout the follow-up period.

СOMPARATIVE CHARACTERISTIC OF NERVE CONDUCTION STUDIES AT CHRONIC INFLAMMATORY DEMYELINATING POLYNEUROPATHY AND HEREDITARY MOTORSENSORY NEUROPATHY TYPE 1

Results of the carried-out comparative analysis of nerve conduction studies indicators of 78 patients with demyelinating polyneuropathy (40 patients with the chronic inflammatory demyelinating polyneuropathy (CIDP) and 38 with hereditary motor and sensory neuropathy (NMSN) of type 1). It is revealed that nerve conduction studies characteristics of CIDP and NMSN of type 1 have similar lines in connection with the similar mechanism of a pathogeny - demyelination. The distinctive characteristic is uniformity of distribution of demyelinationat NMSN of type 1 in the form of uniform reduction of motor nerve conduction velocity (NCV) and compound motor action potential in the majority of the lesion peripheral nerves of extremities and high correlation dependence of indicators of NCV on tibialis on a longitudinal axis and with NCV on n.medialis and amplitude indicators at stimulation of n.medialis at patients with NMSN of type 1; patients with CIDP have a high variability and a symmetry of defeat with existence of conduction blocks and high correlation communication of amplitude indicators at stimulation of n.tibialis in distal and proximal departments.

An in Vivo Mouse Model to Investigate the Effect of Local Anesthetic Nanomedicines on Axonal Conduction and Excitability.

Peripheral nerve blocks (PNBs) using local anesthetic (LA) are superior to systemic analgesia for management of post-operative pain. An insufficiently short PNB duration following single-shot LA can be optimized by development of extended release formulations among which liposomes have been shown to be the least toxic. In vivo rodent models for PNB have focused primarily on assessing behavioral responses following LA. In a previous study in human volunteers, we found that it is feasible to monitor the effect of LA in vivo by combining conventional conduction studies with nerve excitability studies. Here, we aimed to develop a mouse model where the same neurophysiological techniques can be used to investigate liposomal formulations of LA in vivo. To challenge the validity of the model, we tested the motor PNB following an unilamellar liposomal formulation, filled with the intermediate-duration LA lidocaine. Experiments were carried out in adult transgenic mice with fluorescent axons and with fluorescent tagged liposomes to allow in vivo imaging by probe-based confocal laser endomicroscopy. Recovery of conduction following LA injection at the ankle was monitored by stimulation of the tibial nerve fibers at the sciatic notch and recording of the plantar compound motor action potential (CMAP). We detected a delayed recovery in CMAP amplitude following liposomal lidocaine, without detrimental systemic effects. Furthermore, CMAP threshold-tracking studies of the distal tibial nerve showed that the increased rheobase was associated with a sequence of excitability changes similar to those found following non-encapsulated lidocaine PNB in humans, further supporting the translational value of the model.

Compound Motor Action Potential Measures Acute Changes in Laryngeal Innervation.

Vocal fold paralysis is caused by injury to the recurrent laryngeal nerve (RLN). Current clinical measures of laryngeal innervation are often nonquantitative. Compound motor action potentials (CMAP) measure motor innervation. The goal of this study was to determine whether CMAP can quantify laryngeal innervation following acute nerve injury. Animal study. Twelve canine hemilaryngeal preparations were used. The RLN was serially stimulated with increasing intensities until the nerve was maximally stimulated. The CMAP amplitude was measured for each intensity stimulation and correlated. Next, the RLN was incompletely transected, and the reduction in CMAP amplitude was correlated to the percentage of transected axons. The percentage of transected axons was determined using horseradish peroxidase (HRP) staining. Combining all hemilaryngeal preparations, the submaximal stimulation of the RLN linearly correlated with the resultant CMAP amplitude (r = 0.83; 95% CI, 0.76-0.88). Following partial RLN transection, the percentage of remaining axons linearly correlated with the CMAP amplitude (r = 0.87; 95% CI, 0.34-0.98). CMAP amplitude is a quantitative measure that may correlate with the degree of vocal fold innervation in canines. Following RLN injury, CMAP may help clinicians quantify the number of intact axons, assess the likelihood of recovery, and counsel patients on their prognosis.

Effectiveness of Lavendula stoechas essential oil in treatment of mild to moderate carpal tunnel syndrome: A randomized controlled clinical trial

In this study, we investigated the effectiveness of topical Lavender (Lavendula stoechas) essential oil on pain intensity, isometric pinch strength, specific parameters of electro-diagnosis study (EDS), symptom severity and functional status of patients with mild to moderate carpal tunnel syndrome (CTS). Forty-eight patients with mild to moderate CTS were enrolled in this randomized placebo-controlled trial. Group A was treated with night wrist splint and topical Lavender oil ointment. Group B was treated with night wrist splint and a placebo ointment. Patients were evaluated at baseline and after 40 days of intervention with Boston CTS questionnaire (BCTQ), Visual Analog Scale (VAS) for pain, pinch grip strength (PGS), power grip (PG), median compound motor action potential latency (MCMAPL) and median sensory nerve action potential latency (MSNAPL). At the end of the study period, both groups improved significantly in terms of BCTQ, VAS, isometric pinch powers, and EDS parameters. However, group A showed significantly greater improvements in BCTQ (mean difference: 0.39 ± 0.31 VS. 0.6 ± 0.35; P = 0.03), VAS (3.37 ± 1.86 VS. 1.33 ± 2.07; P = 0.001), and PGS (0.73 ± 0.63 VS. 0.27 ± 0.54; P = 0.01) than group B. No significant differences in PG, MCMAPL and MSNAPL were seen between the two groups. This study was the first trial of topical Lavender oil used in patients with CTS. The results of this study suggested that splinting therapy combined with topical Lavender oil is more effective than splinting and placebo in treatment of mild to moderate CTS.

Factors that affect ambulation in Charcot–Marie–Tooth patients

Charcot–Marie–Tooth (CMT) disease is the most common inherited peripheral neuropathy. Limited information on imaging in neuromuscular conditions is available and further less in Hispanic patients. Sonographic examination has been used to describe the pathology of the nerves in patients with CMT. The purpose of this study is to describe imaging of the nerves and muscles that affect ambulation using sonographic and evaluate their association with walking speed. Twenty-one patients previously diagnosed with a demyelinating form of CMT via genetic testing and/or electrodiagnostic study with family history of CMT were evaluated. Ultrasound (US) measurements of the common peroneal nerve (CPN), cross-sectional area (CSA) and anterior tibialis muscle (ATM) depth were performed. CPN compound motor action potential (CMAP) amplitude recording at the ATM was recorded. Later a 10-meter walk test and a Stair Climb test were performed. US evaluation showed significant increase in median and CPN CSA average when compared to reference data. Although not statistically significance there was a positive association between CMAP amplitude recording at the ATM and ATM depth in axial plane or size and ambulation velocity w/o AFO. This could be related to the fact that CPN with less pathology nerve conduction should be able to adequately supply the ATM, therefore better amplitude is obtained and less muscle atrophy is found. The negative association was found between CPN CSA and ambulation velocity w/o AFO not statistically significant. As the CPN increases in size, ambulation dysfunction is further observed in this population. To our knowledge no prior study has described the CPN and ATM with US, which are important components for ambulation in CMT. US is a sensitive and relatively accessible tools for evaluating this population. Future correlation of US findings and functional test is a potential field of research for future projects.

Assessment of the early effects of botulinum toxin type A intramuscular injection on extensor digitorum brevis muscle in healthy adults

In our clinical experience, some patients indicate that their spasticity improves on the day of botulinum injection. Previous studies have indicated that compound motor action potentials (CMAPs) show a decrease as early as 2 days post-injection. However, no studies have assessed if neurophysiological changes take effect earlier than 48 hours post-injection. Fifteen healthy control subjects (10 F; mean age 41 ± 11 years) participated in this randomized double-blind study. We injected 10 units each of onabotulinumtoxinA and incobotulinumtoxinA in the extensor digitorum brevis (EDB) muscle, one in each foot. We performed serial CMAP assessments using nerve conduction study of the peroneal nerves at following time intervals after botulinum injection - 24 hours and 6 days post-injection. We used an ANOVA with repeated measures separately for each type of toxin. The mean EDB amplitudes differed statistically significantly between the tested time points in both the incobotulinumtoxinA group [F(2, 28) = 157.329, P < 0.0001] and onabotulinumtoxinA group [F(2, 28) = 66.464, P < 0.0001]. Post-hoc tests using the Bonferroni correction revealed that each type of toxin resulted in a statistically significant decrease in the EDB amplitude from pre-injection time point to 24 hours and 6 days post-injection ( P < 0.0001). In the incobotulinumtoxinA group (34% reduction at 24 hours and 68% reduction at 6 days), and onabotulinumtoxinA group (31% reduction at 24 hours and 61% reduction at 6 days). We conclude that both types of toxins tested in this study exert a significant decrease in EDB CMAP amplitude at 24 hours post-injection.

Quick, safe, and effective maneuver to prevent phrenic nerve injury during cryoballoon ablation of atrial fibrillation.

Phrenic nerve (PN) injury is a typical complication of cryoballoon ablation (CBA) of pulmonary veins. The PN function is monitored by palpating the abdomen during PN pacing, and freezing is prematurely terminated when a reduction in the diaphragm movement is recognized. This study aimed to investigate the efficacy and safety of a "pull-back" maneuver to prevent PN injury. A total of 284 patients were included, and the PN function was monitored by recording the diaphragmatic compound motor action potentials (CMAP) during the cryoballoon applications for pulmonary vein (PV) isolation. When the CMAP amplitude was reduced by more than 30% compared to the control, the "pull-back" maneuver (PBM) was undertaken to prevent PN injury. The average CMAP amplitude significantly decreased from 0.81 ± 0.04 to 0.31 ± 0.21 (p < 0.01) mV during the cryoballoon applications of PVs in 92 PVs. The PBM was employed in all cases, and the average CMAP amplitude recovered to 0.87 ± 0.31mV (p < 0.01) in 79 out of 92 PVs (85.9%), accomplishing the CBA. Cryofreezing had to be prematurely terminated due to failure of the PBM in 13 out of 92 cases (14.1%). The PBM was an effective maneuver to prevent PN injury by creating a distance between the PN and location of the cryoballoon. No adverse events were provoked by this procedure.

Chronic kidney disease and peripheral nerve function in the Health, Aging and Body Composition Study.

Chronic kidney disease (CKD) is associated with poor mobility. Peripheral nerve function alterations play a significant role in low mobility. We tested the hypothesis that early CKD is associated with altered sensory, motor and autonomic nerve function. Participants in the Health, Aging and Body Composition cohort who had kidney function measures in Year 3 (1999-2000) and nerve function measurements at Year 4 (2000-01) were analyzed (n = 2290). Sensory (vibration threshold, monofilament insensitivity to light and standard touch), motor [compound motor action potentials (CMAPs), nerve conduction velocities (NCVs)] and autonomic (heart rate response and recovery after a 400-m walk test) nerve function as well as participant characteristics were compared across cystatin C- and creatinine-based estimated glomerular filtration rate categorized as ≤60 (CKD) or >60 mL/min/1.73 m2 (non-CKD). The association between CKD and nerve function was examined with logistic regression adjusted for covariates. Participants with CKD (n = 476) were older (77 ± 3 versus 75 ± 3 years; P < 0.05) and had a higher prevalence of diabetes (20.6% versus 13.1%; P < 0.001). CKD was associated with higher odds for vibration detection threshold {odds ratio [OR] 1.7 [95% confidence interval (CI) 1.1-2.7]} and light touch insensitivity [OR 1.4 (95% CI 1.1-1.7)]. CMAPs and NCVs were not significantly different between CKD and non-CKD patients. In adjusted analyses, participants with CKD had higher odds of an abnormal heart rate response [OR 1.6 (95% CI 1.1-2.2)] and poor heart rate recovery [OR 1.5 (95% CI 1.1-2.0)]. CKD is associated with changes in sensory and autonomic nerve function, even after adjustment for demographics and comorbidities, including diabetes. Longitudinal studies in CKD are needed to determine the contribution of nerve impairments to clinically important outcomes.

T45. Effects of fampridine administration on central motor conduction failure in multiple sclerosis patients

Fampridine is a slow-release potassium channel blocker that ameliorates the impaired conduction in CNS demyelinated axons. In multiple sclerosis (MS) patients, wide fluctuations in fatigue perception make difficult to assess the highly variable clinical response to treatment. Previous study reported that central motor conduction time (CMCT) improvement may predict fampridine response. Nevertheless, more than conduction slowdown, central motor conduction failure (CMCF), i.e. conduction block and axonal damage, reflects walking impairment in MS patients. Decrease of Motor Evoked Potentials (MEP) area, much more than amplitude, may detect CMCF. Serial MEP area recordings and analysis, according to a protocol that reduces MEP area random variability, may detect CMCF variation. We evaluated the effects of fampridine on CMCT and CMCF by serial recordings of MEPs from several proximal and distal muscle districts of lower limbs in a MS patients cohort and we correlated the obtained data with clinical outcome. In 10 MS patients, MEPs to TMS by double-cone coil and maximal Compound Motor Action Potentials (CMAPs) to High Voltage Electrical Stimulation of lumbosacral roots were recorded from Vastus Medialis and Lateralis, Tibialis Anterior, Peroneus Longus and Flexor Hallucis Brevis of both limbs (T1) according to the published method (Di Sapio et al., 2014). Stimulation and recorded sites were marked. In 3 patients the test was repeated after one week (T1b), as control. After 14 days of fampridine treatment, before stopping therapy (T2), the procedure was repeated, strictly maintaining the same stimulation and recording sites and stimulation intensities. The 25-foot walking test (25FWT), 6-min walking test (6’-WT), the Fatigue Score Scale (FSS) and the Modified Fatigue Inventory Scale (MFIS) were administered at each time point. In each patient CMCT, MEP area and MEP Area/CMAP area ratios (ARs) were compared, and if appropriate their variability normalized according to Troni et al. (2016). Patients were classified as neurophysiological responders when 2 or more area/latency indexes significantly improved, remaining the others stable. Moreover, pooled data from the whole cohort in different time-points were compared using T test (Wilcoxon). CMCT, MEP area and AR did not change significantly in patients not receiving fampridine. After fampridine administration 3 patients were classified as responders; the same patients reported fatigue reduction and showed significant improvement in FSS score and 25FWT, while MFIS and 6’WT improved only in 1 patient. By analysing pooled data obtained from responders only, a significant reduction of CMCT (p = 0.0057) and increase in MEP area (p = 0.0014) and AR (p = 0.048) were noted. The CMCF evaluation, together with CMCT, both made more sensitive by adopting multiple recording sites, correlate with self-reported and clinical outcome of fampridine treatment and may help to clarify doubt cases.

S164. A novel technique of axillary nerve motor conduction study

Introduction Axillary nerve involvement can commonly occur as part of the brachial plexus lesion. In traumatic pathology, the decision to surgically repair the plexus is based on the amplitude of compound muscle action potential. Our aim is to describe a novel technique for axillary nerve motor conduction studies and provide normative data of compound muscle action potential. Methods The active electrode was positioned over the most prominent portion of the middle deltoid, approximately 5–7 cm distal to the acromion. The reference electrode was positioned over the acromion. The ground electrode was placed between the active and the reference electrodes. Supra-maximal stimulation was at the Erb’s point. Routine motor conduction study filters were used to record the CMAP. Study was performed using commercially available ambu stick on electrodes. The recording were performed using Synergy or Viking EMG system. Data was collected from all consecutive patients with axillary nerve palsy referred for suspected brachial plexopathy. The study was performed bilaterally in all patients and the NCS from the asymptomatic side are used to establish the normal values. Patients with bilateral plexus lesion and generalised weakness caused due to peripheral nervous system pathology are excluded from the study. Active electrode was positioned over the most prominent portion of the middle deltoid, approximately 5–7 cm distal to the acromion. Reference electrode was positioned over the acromion. Ground electrode was placed between the active and the reference electrodes. Supramaximal stimulation was at the Erb’s point. Onset-to-peak compound motor action potential (CMAP) and onset latency (OL) were obtained. Statistical analysis was performed using SPSS. Comparison of age sex as a variable factor was done to CMAP and On-set Latency. Results A total of 163 participants (59.5% male) were examined. The ages ranged from 18 to 84 years (mean 50.0 ± 15.8 years). Comparisons between males and females showed no statistically significant differences regarding age (49.6 ± 16.2 versus 50.5 ± 15.4 respectively, p = 0.742). However, males showed significantly higher CMAP in comparison to females (12.8 ± 3.6 versus 11.3 ± 3.5 mV, p = 0.001) and significantly prolonged OL (3.3 ± 0.9 versus 2.8 ± 0.5 ms, p = 0.001). There was a significant positive correlation between the subjects’ age and the OL (Spearman’s rho 0.311, p Conclusion To our knowledge this is the largest study to-date providing normative data and new easy to perform technique of axillary motor conduction study.

Preoperative Facial Nerve Mapping to Plan and Guide Pediatric Facial Vascular Anomaly Resection

Facial vascular anomalies are surgical challenges due to their vascularity and facial nerve distortion. To assist facial vascular anomaly surgical treatment, presurgical percutaneous facial nerve stimulation and recording of compound motor action potentials can be used to map the facial nerve branches. During surgery, the nerve map and continuous intraoperative motor end plate potential monitoring can be used to reduce nerve injury. To investigate if preoperative facial nerve mapping (FNM) is associated with intraoperative facial nerve injury risk and safe surgical approach options compared with standard nerve integrity monitoring (NIM). This investigation was a historically controlled study at a tertiary vascular anomaly center in Seattle, Washington. Participants were 92 pediatric patients with facial vascular anomalies undergoing definitive anomaly surgery (from January 1, 1999, through January 1, 2015), with 2 years' follow-up. In retrospective review, a consecutive FNM patient cohort after 2005 (FNM group) was compared with a consecutive historical cohort (1999-2005) (NIM group). Postoperative facial nerve function and selected surgical approach. For NIM and FNM comparisons, statistical analysis calculated odds ratios of nerve injury and operative approach, and time-to-event methods analyzed operative time. The NIM group had 31 patients (median age, 3.3 years [interquartile range, 2.2-11.4 years]; 20 [65%] male), and the FNM group had 61 patients (median age, 4.4 years [interquartile range, 1.5-11.0 years]; 26 [43%] male). In both groups, lymphatic malformation resection was most common (19 of 31 [61%] in the NIM group and 32 of 61 [52%] in the FNM group), and the median anomaly volumes were similar (52.4 mL; interquartile range, 12.8-183.3 mL in the NIM group and 65.4 mL; interquartile range, 18.8-180.2 mL in the FNM group). Weakness in the facial nerve branches at 2 years after surgery was more common in the NIM group (6 of 31 [19%]) compared with the FNM group (1 of 61 [2%]) (percentage difference, 17%; 95% CI, 3%-32%). Anterograde facial nerve dissection was used more in the NIM group (27 of 31 [87%]) compared with the FNM group (28 of 61 [46%]) (percentage difference, 41%; 95% CI, 24%-58%). Treatment with retrograde dissection without identification of the main trunk of the facial nerve was performed in 21 of 61 (34%) in the FNM group compared with 0 of 31 (0%) in the NIM group. Operative time was significantly shorter in the FNM group, and patients in the FNM group were more likely to complete surgery sooner (adjusted hazard ratio, 5.36; 95% CI, 2.00-14.36). Facial nerve mapping before facial vascular anomaly surgery was associated with less intraoperative facial nerve injury and shorter operative time. Mapping enabled direct identification of individual intralesional and perilesional nerve branches, reducing the need for traditional anterograde facial nerve dissection, and allowed for safe removal of some lesions after partial nerve dissection through transoral or direct excision.

Characteristics of Phrenic Nerve Injury During Pulmonary Vein Isolation Using a 28-mm Second-Generation Cryoballoon and Short Freeze Strategy.

BackgroundThe reported incidence of phrenic nerve injury (PNI) varies owing to different definitions, balloon generations, balloon size, freezing regimen, and protective maneuvers. We evaluated the incidence, predictors, and outcome of PNI during cryoballoon pulmonary vein isolation in a large population.Methods and ResultsFive hundred fifty atrial fibrillation patients underwent pulmonary vein isolation using one 28‐mm second‐generation cryoballoon and single 3‐minute freeze strategy under diaphragmatic compound motor action potential (CMAP) monitoring. A total of 34 (6.2%) patients experienced PNI during the right superior and inferior pulmonary vein ablation in 30 and 4 patients, respectively. Applications were interrupted using double‐stop techniques after 136 [104–158] second applications, and a pulmonary vein isolation was already achieved in all but one case. The baseline CMAP amplitude and timing of deflation (CMAP def) were 0.75±0.30 and 0.17±0.17 mV, respectively. Persistent atrial fibrillation, larger right superior pulmonary vein ostia, and deeper balloon positions were associated with higher incidences of PNI. The CMAP def predicted a PNI recovery delay, and the best cutoff value for predicting PNI recovery by the next day was 0.20 mV (sensitivity 57.1%, specificity 100%). Among 6 patients undergoing second procedures 8.5 (6.7–15.0) months later, the right superior pulmonary vein was durable in 3 with >120 second applications. Despite active balloon deflation, no significant pulmonary vein stenosis was observed in 15 right superior pulmonary veins evaluated 6 (5–9) months later. No patients had symptoms, and the PNI recovered 1 day and 1 month postprocedure in 21 and 4 patients, respectively.Conclusions PNI resulting from cryoballoon ablation was reversible. The double‐stop technique is safe, and immediate active deflation following a CMAP decrease appears to be essential for faster PNI recovery.

Muscle strength and size are associated with motor unit connectivity in aged mice.

In older adults, the loss of muscle strength (dynapenia) and the loss of muscle mass (sarcopenia) are important contributors to the loss of physical function. We sought to investigate dynapenia, sarcopenia, and the loss of motor unit function in aging mice. C57BL/6J mice were analyzed with cross-sectional (males: 3 vs. 27 months; males and females: 8 vs. 12 vs. 20 months) and longitudinal studies (males: 10–25 months) using in vivo electrophysiological measures of motor unit connectivity (triceps surae compound muscle action potential and motor unit number estimation), in vivo measures of plantar flexion torque, magnetic resonance imaging of hind limb muscle volume, and grip strength. Compound muscle action potential amplitude, motor unit number estimation, and plantar flexion torque were decreased at 20 months. In contrast, grip strength was reduced at 24 months. Motor unit number estimates correlated with muscle torque and hind limb muscle volume. Our results demonstrate that the loss of motor unit connectivity is an early finding in aging male and female mice and that muscle size and contractility are both associated with motor unit number.

Progressive myoclonus epilepsy without renal failure in a Chinese family with a novel mutation in SCARB2 gene and literature review

PurposeTo describe the clinical and genetic features of a Chinese progressive myoclonus epilepsy (PME) patient related with SCARB2 mutation without renal impairment and review 27 SCARB2-related PME patients from 11 countries. MethodsThe patient was a 27-year-old man with progressive action myoclonus, ataxia, epilepsy, dysarthria and absence of cognitive deterioration. Renal functional test was normal. Electroencephalography (EEG) showed progressively slowed background activity and sporadic generalized spike-and-wave discharges. Electromyography (EMG) showed slowed motor and sensory nerve conduction velocities and distal motor latency delay accompanied by normal compound motor action potential (CMAP) and amplitudes of sensory nerve action potential (SNAP). The amplitude of cortical components of brainstem auditory-evoked potential (BAEP) was normal with slightly prolonged latencies. Generalized atrophy, ventricle enlargement and white matter degeneration was observed in brain magnetic resonance imaging (MRI). Open muscle biopsy and genetic analysis were performed. Two hundred healthy individuals were set for control. Quantitative real time PCR (qPCR), western blotting and immunofluorescence were carried out to evaluate the fate of the SCARB2 mRNA and lysosomal-membrane type 2 (LIMP2) protein level. ResultsOne homozygous mutation in SCARB2 gene (c.1187 + 5G > T) was identified in the patient. Each of his parents carried a heterozygous variant. This mutation was not detected among the healthy controls and predicted to be damaging or disease causing by prediction tools. qPCR revealed a significantly lower level of SCARB2 mRNA in peripheral blood cell of the proband compared with his parents and healthy control individuals. Muscle biopsy showed mild variation in fiber size. Western blotting and immunofluorescence detected an extremely weak signal of LIMP2 protein from skeletal muscle of the proband. ConclusionIn this study, we identified a SCARB2-related PME patient with normal renal function and a novel homozygous splicing mutation. SCARB2 gene should be analyzed in patients with progressive action myoclonus, epilepsy, peripheral neuropathy, without cognitive deterioration or renal failure.