Muscle & Nerve最新文献

Introduction/aims: Obesity is a well-established risk factor for carpal tunnel syndrome (CTS), but body mass index (BMI) does not distinguish adiposity from skeletal muscle mass. The role of sarcopenia in CTS has received little attention. Sarcopenia may increase nerve vulnerability to compression. We examined whether appendicular lean mass index (ALMI) and ALMI-defined sarcopenia are associated with CTS independent of BMI.

Methods: We retrospectively analyzed 193 consecutive patients aged 50 years or older who underwent carpal tunnel release by a single surgeon at a tertiary center over 4 years. Controls were 5665 age-matched participants from the 2022-2023 Korea National Health and Nutrition Examination Survey. ALMI-defined sarcopenia was compared between groups. Multivariable logistic regression was applied to examine the association between ALMI-defined sarcopenia and CTS, adjusting for BMI.

Results: Compared with controls, CTS patients exhibited a higher prevalence of sarcopenia in both men and women (p < 0.05). The association with sarcopenia was significant across most age and sex subgroups, whereas obesity was more evident in younger age groups (50-69 years). In multivariable models, sarcopenia showed a stronger association with CTS (OR 2.41, 95% CI 1.79-3.22) compared with BMI (OR 1.05, 95% CI 1.01-1.10).

Discussion: In this case-control study, both obesity and ALMI-based sarcopenia were associated with CTS, with sarcopenia showing a stronger association. These findings suggest an association between reduced muscle mass and CTS independent of BMI. Muscle mass assessment alongside BMI may help clinicians identify at-risk patients who might otherwise be overlooked by conventional obesity metrics.

Introduction/aims: Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disorder that requires complex treatment decisions and sustained disease self-management. Health literacy is essential for patient understanding of MG, yet online patient education materials (PEMs) have not been systematically studied. This study aimed to evaluate the readability of MG-related PEMs, assess the inclusion of key topics, and identify characteristics associated with more accessible and comprehensive resources.

Methods: We conducted a cross-sectional analysis of MG-related PEMs identified through Google and Bing, evaluating readability using the Flesch Reading Ease Score (FRES), Flesch-Kincaid Grade Level (FKGL), and Simple Measure of Gobbledygook (SMOG). Content analysis was conducted for inclusion of key MG topics. PEMs were categorized by organization type, target population age, and geographic location. Statistical tests included Wilcoxon signed-rank, Kruskal-Wallis, Mann-Whitney U, and Fisher's exact test.

Results: All 149 PEMs exceeded the recommended 6th-grade reading level (median FRES 41.8, FKGL 11.4, SMOG 12.9; p < 0.001). Community organization PEMs were more readable than academic PEMs (median FKGL 10.4 vs. 11.6; p = 0.02, median FRES 44.5 vs. 39.4; p = 0.01). Frequently included topics were MG definition (94%), symptoms (93%), and immunotherapy (85%), while medications to avoid (30%), myasthenic crisis (62%), and mental health (10%) were the least included. Readability varied by topic, with immunotherapy and thymectomy sections being the most complex.

Discussion: MG PEMs are written above recommended readability levels, posing barriers to comprehension. Improving readability and addressing gaps in critical topics, such as medication safety, myasthenic crisis, and mental health could enhance patient understanding and support informed decision-making.

Introduction/aims: Serum neurofilament light chain (NfL) is a promising diagnostic biomarker for differentiating amyotrophic lateral sclerosis (ALS) from clinical mimics. This study assessed the utility of integrating serum NfL into current diagnostic criteria to enhance diagnostic certainty in patients with a provisional ALS diagnosis who were confirmed as having ALS at follow-up.

Methods: We conducted a single-center, retrospective study of consecutive patients with a provisional ALS diagnosis at their initial visit at the WashU Medicine ALS Center. All underwent electrodiagnostic testing and serum NfL measurement via SIMOA using an HD-X analyzer (Quanterix). Elevated serum NfL was defined with a cutoff of 38 pg/mL.

Results: The study included 43 patients with a provisional ALS diagnosis (29 men [67.4%]; median age, 63 years [range, 36-80 years]). At follow-up, 27/43 (62.8%) patients progressed to definite ALS. Serum NfL was elevated in 34/43 (79.1%) of the total cohort and 24/27 (88.9%) of those who progressed to definite ALS. Integrating serum NfL with Gold Coast Criteria (GCC) was associated with a tenfold increase in the odds of identifying patients likely to progress to definite ALS (OR 10 [1.39, 71.87], p = 0.02).

Discussion: Our results suggest that serum NfL is a robust complement to current ALS diagnostic criteria and shows potential to improve early identification and diagnostic certainty of patients likely to progress to definite ALS. Integrating serum NfL with GCC provided the strongest predictive model. These findings warrant larger multicenter, prospective studies to confirm results.

Introduction/aims: Current therapeutic management of juvenile myasthenia gravis (JMG) predominantly relies on conventional immunosuppressive therapies and expert consensus extrapolated from adult data, creating a critical gap in high-quality, pediatric-specific clinical evidence. The aim of this study was to assess the efficacy and safety of efgartigimod in the pediatric population.

Methods: This multicenter retrospective study enrolled JMG patients (under 18 years), from 12 Chinese centers, who received at least one dose of efgartigimod. Efgartigimod was administered as weekly intravenous infusions. Study visits included W0 (baseline: pretreatment) and W1-W4 (weekly posttreatment follow-ups). Efficacy was assessed via MG-related Activities of Daily Living (MG-ADL) score, Quantitative Myasthenia Gravis (QMG) score, and the MG Composite (MGC) scale.

Results: Seventeen JMG patients (3 males, 14 females) with a median disease duration of 23 months were included. At W0, 88.2% of patients were classified as Myasthenia Gravis Foundation of America (MGFA) class II-V and were anti-acetylcholine receptor (anti-AchR) antibody positive. After efgartigimod treatment, clinically meaningful improvement (CMI) was observed in 70.6% (W1), 73% (W2), and 91.7% (W4); 66.7% achieved minimal symptom expression by W4. MG-ADL and QMG scores decreased by 30% and 30.1% (W1) and by 87.6% and 71.8% (W4) compared to W0. No treatment-related adverse events occurred.

Discussion: Our study suggests efgartigimod is an effective therapeutic option for JMG, with favorable efficacy and safety profiles. Further studies are necessary to validate the efficacy and safety of efgartigimod in the pediatric population.

Introduction/aims: Myasthenia gravis (MG) is associated with thymic neoplasms. However, an increased prevalence of extrathymic neoplasms has also been reported. This study aimed to evaluate the rates of malignancy in MG patients while accounting for risk factors such as disease characteristics and immunomodulatory treatments.

Methods: We conducted a case-control study using the Clalit Health Services database, applying a machine learning (ML) algorithm to minimize diagnosis misclassification. We included MG patients aged 18 years and older, with a sex- and age-matched control group in a 1:3 ratio. We compared the prevalence and hazard ratios of extrathymic neoplasms between the groups.

Results: A total of 1558 patients with a high probability of MG, according to our ML model, were included in the cohort, alongside a control group of 4674 individuals. MG patients had a higher prevalence of malignancy prior to MG diagnosis, with an odds ratio of 1.95 (95% CI, 1.65-2.08), and a higher incidence of malignancy after MG diagnosis, with a hazard ratio of 1.56 (95% CI, 1.38-1.77). The most prevalent extrathymic neoplasms after MG diagnosis were respiratory, intrathoracic, skin (specifically non-melanoma), urinary tract, soft tissue, and myelodysplastic syndrome. Risk factors for malignancy included age, male sex, and thymoma. Immunosuppressive treatment did not increase the risk of malignancy.

Discussion: MG patients have a higher prevalence of both solid and hematologic neoplasms compared to non-myasthenic controls, regardless of immunosuppressive treatment. This supports the notion that malignancy is related to MG disease itself rather than external factors.

Introduction/aims: There are no established biomarkers of upper motor neuron degeneration to aid in the diagnosis of motor neuron disease (MND). This study examines the diagnostic value of the motor band sign as a marker of upper motor neuron degeneration and its relationship to clinical findings in MND.

Methods: Records of consecutive patients who underwent 7T magnetic resonance imaging (MRI) between October 2021 and April 2025 for evaluation of MND or other neurologic indications were retrospectively reviewed. Clinical variables and plasma neurofilament light chain (pNfL) levels were recorded. An upper motor neuron score (Mayo UMNS) was derived from reflex scores. Blinded MRI review assessed the degree of susceptibility-weighted imaging (SWI) hypointensity in the hand, foot, and bulbar motor cortex regions.

Results: An MBS was observed in 100 of 117 (85.5%) MND patients and in 16 (15.5%) patients with non-MND diagnoses, corresponding to a sensitivity of 85.5% (78.0%-90.7%) and 84.5% (76.2%-90.2%) specificity. The MBS in 78 MND patients (70.9%) preferentially involved the middle and deep cortical layers, giving a trilaminar appearance, while only one non-MND patient had this finding. Mayo UMNS (β = 0.89, p < 0.001), pNfL (β = 0.63, p = 0.033), and age at evaluation (β = 0.68, p = 0.027) were independently associated with the summed SWI score.

Discussion: The 7T MRI MBS is a sensitive and specific marker for MND that complements established clinical evaluation. Using 7T, a trilaminar appearance of the motor cortex, reflecting known histopathological changes, can be visualized and may be specific to MND.

Introduction/aims: Identifying factors associated with short-term relapse is essential for tailoring maintenance treatment on a case-by-case basis in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). We sought to determine whether changes in demyelinating electrophysiological features during treatment could predict relapse after treatment discontinuation in a cohort of CIDP patients.

Methods: We conducted a retrospective study of patients with CIDP treated with intravenous immunoglobulin (IVIg), all of whom had a first nerve conduction study (NCS) at treatment initiation or during treatment, while the disease was in a stable phase, followed by a second study at the time of treatment discontinuation. Demyelinating features and the degree of axonal loss were determined during each NCS and compared between the two examinations.

Results: Thirty-one consecutive IVIg-responsive CIDP patients were included, with a mean age of 59.1 ± 14.6 years. Twenty (65%) were males. Sixteen patients (52%) relapsed after a mean of 6 months. Most patients demonstrated a reduced total number and type of demyelinating features between the two assessments, but overall, these changes were not different between the relapse and relapse-free groups. Similarly, axonal loss at our first assessment and the progression of axonal loss between our two assessments were not different in the relapse group compared to the relapse-free group.

Discussion: In our population of IVIg responsive CIDP patients, we were unable to demonstrate the predictive value of follow-up nerve conduction studies alone for the risk of relapse. Looking at other biomarkers alone or in combination with NCS is necessary.

Introduction/aims: The Berrettini anastomosis (BA) is a sensory communication between the ulnar and median nerves in the palm. Although well described in anatomical studies, it has been less frequently evaluated electrophysiologically. We aimed to determine the frequency and electrophysiological characteristics of BA in healthy Japanese adults.

Methods: Bilateral sensory nerve conduction studies were performed in 32 healthy volunteers (64 hands). Sensory nerve action potentials (SNAPs) were recorded from median-innervated digits during ulnar nerve stimulation and from ulnar-innervated digits during median nerve stimulation. BA was classified as Type 1 (ulnar-to-median) or Type 2 (median-to-ulnar). To exclude unintended median nerve activation due to current spread, thumb recordings were obtained during screening for Type 1. The BA index was calculated as the ratio of the SNAP amplitude recorded from the middle finger (D3) to that recorded from the ring finger (D4) during ulnar stimulation.

Results: BA was identified in 5 participants (15.6%) and 7 hands (10.9%), all classified as Type 1. BA-related SNAPs were recorded exclusively from D3 and not from the index finger (D2). The BA index ranged from 3.6% to 77.2% (median 5.7%). BA-related amplitudes were small relative to the corresponding ulnar SNAP amplitudes at D4.

Discussion: BA can be electrophysiologically detected in a subset of healthy individuals, typically as a small ulnar-to-median crossover to D3. Although amplitudes are generally limited, awareness of this normal anatomical variant may assist in careful interpretation of sensory nerve conduction findings, particularly in borderline or asymmetric cases.

Given the intimate link between muscle function and the skeleton's ability to adapt to mechanical loads, it is no surprise that individuals with neuromuscular disorders (NMDs) are at risk for low-trauma (i.e., osteoporotic) fragility fractures. In this review, we highlight the interdependent relationship between muscle and bone strength and the need to assess individuals with NMD who demonstrate muscle weakness that interferes with weight bearing and typical activities of daily living. This review also emphasizes the importance of the clinical context when evaluating the risk of bone fragility, as well as the potential to reclaim bone strength in the absence of bone-targeted therapy. Indeed, longitudinal skeletal phenotyping is key to understanding the individual's bone health trajectory and the need for progressive intensification (or de-escalation) of osteoporosis prevention and treatment. Overall, osteoporosis management has moved away from a bone mineral density (BMD)-centric approach to a fracture-focused approach, with vertebral fractures a clear indicator for bone-strengthening therapy (recognizing that they are frequently asymptomatic, necessitating periodic spine imaging for their timely identification). BMD assessments help guide the frequency of spine imaging and response to bone-targeted therapy and are best undertaken at multiple skeletal sites given the potential for "regional osteoporosis." Multidisciplinary osteoporosis prevention and treatment, including an expert in skeletal health, is the cornerstone of effective osteoporosis management. Looking forward, the field is shifting from secondary osteoporosis prevention to a more proactive, anticipatory approach in those with persistent risk factors, one that involves initiation of bone-targeted therapy prior to first-ever fractures.

Introduction/aims: Peripheral neuropathy, especially mononeuropathy multiplex, is a frequent manifestation of leprosy. Electrodiagnostic studies (EDX) usually show predominant axonal involvement. In this study, we report patients with prominent demyelinating abnormalities consistent with the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

Methods: We retrospectively reviewed the medical records of patients with leprosy who underwent EDX at Pitié-Salpêtrière University Hospital, Paris, France, between January 2014 and June 2022. We included patients exhibiting demyelinating abnormalities that fulfilled the 2021 European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) electrodiagnostic criteria for CIDP.

Results: Ten patients were included. Eight patients presented with conduction blocks (CB) and temporal dispersion (TD) outside entrapment sites, primarily localized on the median and ulnar nerves in the forearm. Eight patients demonstrated delayed or absent F-waves in nerves without segmental slowing or CB/TD. Two patients were initially diagnosed with multifocal CIDP and treated accordingly before a nerve biopsy corrected the diagnosis. Follow-up EDX after anti-leprosy treatment revealed partial improvement or complete resolution of CB/TD in six patients, with improvement in distal motor amplitudes in four patients.

Discussion: Patients with leprosy neuropathy can exhibit demyelinating abnormalities on EDX, particularly CB/TD in the forearm, which may misleadingly suggest an immune-mediated origin, such as multifocal CIDP. In patients from leprosy-endemic areas with a demyelinating neuropathy fulfilling electrodiagnostic criteria for CIDP, clinicians should perform a dermatological examination, repeat bacteriological and histological sampling, and consider performing a nerve biopsy if diagnostic doubt persists.