Muscle & Nerve最新文献

Introduction/aims: Cervical spinal cord injury (SCI) significantly impairs upper limb function, affecting patients' quality of life. Nerve transfer surgery can restore arm and hand function, but its success depends on the health of infralesional lower motor neurons (LMNs). LMN abnormalities are prevalent in muscles targeted for nerve transfer, particularly those innervated by the posterior interosseous nerve (PIN) and radial nerve, essential for wrist extension and hand opening. This study evaluates the health of infralesional LMNs in cervical SCI using multipoint stimulation motor unit number estimation (MPS-MUNE). We assessed motor unit counts in the C7-innervated anconeus and the predominantly C8-innervated extensor indicis (EI) to determine their viability as targets for nerve transfer surgery.

Methods: We conducted a prospective, two-center cohort study using MPS-MUNE to evaluate 15 individuals with cervical SCI (26 limbs) and 17 healthy controls.

Results: Compound muscle action potential (CMAP) and MUNE values were significantly lower in SCI patients compared to controls (EI CMAP: 2.0 mV ± 1.57, EI MUNE: 33 ± 30.5; anconeus CMAP: 2.7 mV ± 1.9, anconeus MUNE: 39 ± 50.6 versus controls: EI CMAP: 6.6 mV ± 1.0, EI MUNE: 137 ± 33.9; anconeus CMAP: 6.6 mV ± 1.3, anconeus MUNE: 146 ± 42.3). Test-retest reliability for EI and anconeus were 0.84 (CI: 0.45-0.95) and 0.78 (CI: 0.36-0.93), respectively.

Discussion: Significant LMN loss was observed after cervical SCI. MPS-MUNE shows potential for evaluating LMN health, highlighting its importance for assessing nerve transfer targets and planning interventions.

Myopathies are heterogeneous in their etiology, muscle group involvement, clinical manifestation, and progression. Deficits in myopathy may include muscle weakness, atrophy, stiffness, myalgia, and extra-muscular manifestations. Consequently, these deficits could lead to impaired musculoskeletal function, inadequate engagement in daily activities and reduced participation in social activities. Exercise has been viewed as a potentially efficacious intervention to halt the loss of muscle function and to improve secondary symptoms that result from muscle loss, such as pain and fatigue. The purpose of this review is to discuss research findings within the last 10 years that examine effects of exercise interventions in many types of myopathies in humans. In general, most studies were small scale, and they varied with respect to exercise type, intensity, and outcome measures. Despite the different pathologies, various exercise subtypes of aerobic/endurance or strength/resistance training are generally beneficial and may improve muscle strength and functional outcomes. Exercise therapies are generally safe and well tolerated. Exercise prescription should be part of routine neuromuscular care for patients with myopathy, and ideally with input from a multidisciplinary team, with a focus on providing individualized exercise regimens. Further work is needed to define the optimal intensity and type of exercise to result in the best functional outcomes for persons with myopathy, as well as the effects of combining exercise and novel disease modifying therapies.

Introduction/aims: The deltoid muscle demonstrates sensitivity in detecting abnormal decrement on repetitive nerve stimulation in cases of myasthenia gravis and congenital myasthenic syndromes. However, single-fiber electromyography (concentric needle jitter) normative data is currently lacking, which this study aims to address.

Methods: Jitter, measured by the mean consecutive difference (MCD), was assessed in the voluntarily activated deltoid muscle of 32 healthy adults (16 men and 16 women) with no known or suspected neuromuscular disease. For each subject, the mean MCD of 20 pairs was calculated. The overall jitter reference value was the mean MCD across all subjects, while the 18th highest MCD among them defined the individual jitter reference value (outliers).

Results: The average age of the male subjects was 42 years (ranging from 21 to 61), while the average age for females was 46 years (ranging from 32 to 65). The mean MCD values were 21.15 ± 3.42 μs for men and 19.50 ± 2.34 μs for women. For individual assessments, the 18th highest MCD was recorded as 27.84 ± 4.68 μs for men and 25.42 ± 3.19 μs for women.

Discussion: The proposed reference values for normal mean MCD are < 28 μs for men and < 26 μs for women. The normal outlier limits are < 38 μs for men and < 32 μs for women. No previously reported values for the deltoid muscle are available for comparison.

Introduction/aims: Healthcare utilization and costs in myotonic dystrophy (DM) are not well understood. This study describes the burden of DM and its associated costs.

Methods: We performed a retrospective study using data from a large U.S. administrative claims database to identify commercially insured individuals with DM and compared healthcare utilization and cost with a matched cohort. Analyses were performed between the cohorts with ≥ 3 years of insured follow-up.

Results: We identified 1182 DM individuals with coverage at least 3 year prior and 3 years following an index DM diagnosis from January 1, 2009 to December 31, 2018. Compared to controls, DM individuals were 3.7 times more likely to be hospitalized (p < 0.0001), 2.4 times more likely to visit an emergency department (p < 0.0001), and had twice as many outpatient visits (p < 0.0001) in the first year post-diagnosis, with similar utilization at 2- and 3-years post-diagnosis. Annual mean costs were 3.9 times higher for health plan paid costs (p < 0.0001) and 2.6 times higher for patient-paid costs (p < 0.0001) for DM individuals than controls in the first year post-diagnosis, with similar costs at 2- and 3-years post-diagnosis. Factors associated with higher costs included the need for durable medical equipment, including gait aids or respiratory support devices.

Discussion: Individuals with DM experience significantly higher healthcare utilization and associated healthcare costs than controls of similar age, sex, race, and census region. The findings show the high clinical and economic burden of DM, highlighting the importance of improving cost-effective care delivery in this population.

Introduction/aims: Previously tested interventions to reduce pain with needle electromyography (EMG) reported limited benefit. A topical cold and vibrating device has reported benefit in interventional procedures. We aimed to evaluate the effect of this device with EMG.

Methods: This was a two-part, prospective controlled study of a cold and vibrating device. In part one, 50 patients undergoing EMG testing on the upper extremity were randomized to EMG with or without the device and reported pain scores for each muscle. In the second part, 25 patients having EMG of both upper extremities reported pain scores, one side with the device and the other without.

Results: In part one, there was no significant difference in average pain scores for patients with use of the device as compared to those without (average pain score 4.1 versus 3.7, p = 0.61). In the second part, there was no significant difference in pain scores in muscles tested with the device as compared those without (average pain score 4.3 versus 4.6, p = 0.47). In both parts, a wide range of pain scores were reported (0-10). In comparing device-to-control pain scores for each patient, 27% had a lower score, 15% had a higher score, and 58% had equal scores. There were no adverse events.

Discussion: This study did not show pain reducing benefits from a cold and vibrating device that have been described in other interventional procedures. This may relate to different study populations, wide range of pain scores and study sample size.

Introduction/aims: Postoperative myasthenic crisis (POMC), which occurs specifically after thymectomy in myasthenia gravis (MG) patients, is a serious complication with known risk factors such as prior myasthenic crisis. However, the predictive value of perioperative blood lactic acid levels (BLAL) for POMC remains unclear. This study aims to determine whether changes in perioperative BLAL can predict POMC in MG patients undergoing thymectomy.

Methods: A total of 340 patients diagnosed with MG and undergoing thymectomy at the First Affiliated Hospital of Sun Yat-sen University were enrolled (January 2008-September 2018). Multivariate logistic regression analyses were employed to discern independent factors linked with POMC.

Results: Among the patients with POMC, notable differences including higher Myasthenia Gravis Foundation of America (MGFA) stage, and history of preoperative myasthenic crisis were observed. Higher postoperative lactic acid levels and the extent of changes were more prevalent in the POMC group. The multivariate analysis unveiled history of myasthenic crisis (odds ratio, OR: 67.18), postoperative BLAL change ratio greater than 50% (OR: 2.86), the video-assisted thoracoscopic surgery (VATS) approach (OR: 4.33), and higher preoperative BLAL (OR per unit: 2.68) were associated with POMC. Both continuous and grouped lactic acid models demonstrated a good predictive capability, yielding area under the curve (AUC) values of 0.84 and 0.83, respectively. The optimal threshold for 24-h postoperative BLAL was 1.98 mmol/L.

Discussion: These findings offer valuable insights for clinical decision-making and monitoring of prognosis in managing patients with MG. Future research should explore further the underlying mechanisms linking elevated lactate levels to POMC.

Aims: There are few long-term studies evaluating clinical outcomes and mortality among individuals with Duchenne muscular dystrophy (DMD); particularly using longitudinal health administrative claims data, reflecting populations managed in typical clinical practice. This study aimed to characterize DMD outcomes via a population-based database.

Methods: Patients with DMD, diagnosed between 01/1979 and 03/2020 at ≤ 10 years of age, were identified using the Manitoba Population Research Data Repository housed at the Manitoba Centre for Health Policy. De-identified longitudinal administrative data from 1998 to 2020 were used to retrospectively assess frequencies and age at first observation of key DMD outcomes including scoliosis, cardiovascular-related complications, severe respiratory-related morbidities, and mortality. Survival analyses using Kaplan-Meier curves were used to describe attrition and estimate probability of patients remaining observation-free by age.

Results: This study included 198 patients with median (IQR) follow-up of 9.6 (6.6-15.5) years. Corticosteroid use was observed in 26%, with a mean (SD) percentage of days covered of 31% (39%) from initiation to end of follow-up. Scoliosis observations were captured in 18% (median[IQR] age 12 [11-15] years at first observation), severe respiratory-related morbidities in 20% (14[6.5-18] years), and cardiovascular-related complications in 32% of the cohort (12.5[2-20.5] years). Mortality was observed in 14% of the cohort. Kaplan-Meier curves estimated 15% mortality by age 20 years and 20% by 25 years.

Discussion: In a population-based data set with decades of follow-up, these data provide longitudinal observations of the substantial burden of DMD, and insight into contemporary estimates of mortality and treatment patterns in Canada.

Iatrogenic nerve injuries are a significant concern for medical professionals and the patients affected. Peri-procedural nerve injuries result in functional deficits associated with pain and disability. The exact pathophysiology and etiology of peri-procedural nerve injuries are complex and often elude providers. The rates of injury to specific nerves are unclear and relate to both procedural and patient specific risk factors. Initial classification of the nerve injury into neurapraxia, axonotmesis, mixed nerve injury, or possible complete transection (neurotmesis) guides rehabilitation and management. Electrodiagnostic medical consultation at least four weeks post-injury, supplemented with nerve imaging (ultrasound and magnetic resonance imaging), can allow for accurate nerve injury classification. Supplemented with nerve imaging and detailed clinical evaluation, treatment, recovery and rehabilitation can be maximized. Recognizing nerves at risk associated with medical and surgical procedures can facilitate injury avoidance and early diagnosis. If a nerve injury is incomplete, in an optimized physiologic milieu (good glucose control, smoking cessation, etc.), there is a good potential for spontaneous (total or partial) improvement over time. Surgical referral should be considered for severe nerve injuries within 6 months, especially if there is concern for neurotmesis, and/or deteriorating nerve function. This review gives guidance for approaching peri-procedural peripheral nerve injuries, including the timing and the role of electrodiagnostic medical consultation including serial electrodiagnostic studies in management and rehabilitation.

A unifying mechanistic cause for amyotrophic lateral sclerosis (ALS) remains uncertain. Multiple pathophysiological processes appear to occur simultaneously. Cannabinoids, including delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD), cannabigerol (CBG), and others found in cannabis, and cannabis extracts (CEs), appear to have activity in these pathogenic pathways, which have led to increasing interest in cannabinoids as therapeutic agents for ALS. The use of cannabinoids as a treatment strategy is substantiated by preclinical evidence suggesting a role for the endocannabinoid system (ECS) in ALS and other neurodegenerative disorders. Preclinical data indicate that cannabis and CEs have powerful antioxidative, anti-inflammatory, and neuroprotective effects in the SOD1^G93A mouse model of ALS. The use of CEs in SOD1^G93A murine models has been shown to prolong neuronal cell survival, which leads to delayed onset of the disease state, and slows progression of the disease. Although research in humans remains limited, a few studies suggest that cannabis and CBD, in humans, provide benefits for both motor symptoms, including rigidity, cramps, and fasciculations, and non-motor symptoms including sleep quality, pain, emotional state, quality of life, and depression. There remains a need for further, well-designed clinical trials to validate further the use of an individual cannabinoid, or a combination of cannabinoids, as a disease-modifying therapy for ALS.