Muscle & Nerve最新文献

Introduction/aims: Despite treatment, a considerable proportion of patients with Guillain-Barré syndrome (GBS) experience poor recovery, highlighting a therapeutic need. There is a lack of evidence that treatment timing affects recovery. This study aims to investigate the effects of intravenous immunoglobulin (IVIg) timing on disability and speed of recovery in GBS.

Methods: We performed a retrospective study of 136 IVIg-treated GBS patients admitted to two Korean centers between 2010 and 2021. We analyzed the effect of time to IVIg on the GBS disability scale (GBS-DS) and the degree of improvement from nadir (∆GBS-DS) at 1, 3, 6, and 12 months, as well as the time to regain the ability to walk or run unaided. Time to IVIg was treated either as a continuous variable or categorized into 1-week intervals to explore critical time windows. Known prognostic factors, the modified Erasmus GBS Outcome Scores on admission and pre-treatment serum albumin levels were adjusted as covariates.

Results: Shorter time to IVIg was independently associated with better GBS-DS, greater ∆GBS-DS, and shorter time to walk or run unaided at all time points. The therapeutic effect of IVIg was notably diminished when administered beyond the first 2 weeks of onset.

Discussion: Our study highlights the timing of IVIg as a modifiable prognostic factor in GBS. The earlier IVIg is initiated, the better the outcomes, with the ideal time window being within the first 2 weeks. These findings underscore the importance of prompt diagnosis and early intervention to optimize recovery in GBS patients.

Introduction/aims: The hand-held dynamometer (HHD) is a reliable and portable tool for quantitatively assessing muscle strength. However, a number of variables, including the strength of the tester, the adequacy of stabilization, and the selected testing position, can affect the reliability of the device. The objective of the present study was to examine the reproducibility and inter-rater reliability of strength assessments using HHD with and without a stabilization device.

Methods: Strength assessments were conducted with and without the stabilization device by two independent raters. Healthy volunteers with no history of musculoskeletal disorders were included in the study. The strength of the shoulder flexion, scapula elevation, knee extension, and hip abduction muscle groups was evaluated using HHD. The reliability of the measurements was evaluated using intra-class correlation (ICC), standard error of measurement, and minimal detectable change.

Results: Fifty-two healthy volunteers (age 21.51 ± 2.02 years) participated in the study. The reproducibility was found to be excellent (ICC = 0.89-0.99). While reliability between the assessors was good to excellent (ICC = 0.85-0.93), reliability between assessors and device was found moderate to good (ICC = 0.48-0.78).

Discussion: The strength values obtained for all directions of movement with the stabilization device were found to be significantly higher than those obtained without fixation of the HHD. It can be concluded that the data obtained from the assessors and HHD with stabilization device are not comparable. Moreover, the utilization of a stabilization device may serve to enhance the reliability of the measurements by eliminating the rater effect.

Introduction/aims: Fat-referenced magnetic resonance imaging (MRI) has emerged as a promising volumetric technique for measuring muscular volume and fat in neuromuscular disorders, but the experience in inflammatory myopathies remains limited. Therefore, this work aimed at describing how sporadic inclusion body myositis (sIBM) manifests on standardized volumetric fat-referenced MRI muscle measurements, including within-scanner repeatability, natural progression rate, and relationship to clinical parameters.

Methods: Ten sIBM patients underwent whole-leg Dixon MRI at baseline (test-retest) and after 12 months. The lean muscle volume (LMV), muscle fat fraction (MFF), and muscle fat infiltration (MFI) of the quadriceps, hamstrings, adductors, medial gastrocnemius, and tibialis anterior were computed. Clinical assessments of IBM Functional Rating Scale (IBMFRS) and knee extension strength were also performed. The baseline test-retest MRI measurements were used to estimate the within-subject standard deviation (s_w). 12-month changes were derived for all parameters.

Results: The MRI measurements showed high repeatability in all muscles; s_w ranged from 2.7 to 18.0 mL for LMV, 0.7-1.3 percentage points (pp) for MFF, and 0.2-0.7 pp for MFI. Over 12 months, average LMV decreased by 7.4% while MFF and MFI increased by 3.8 pp and 1.8 pp, respectively. Mean IBMFRS decreased by 2.4 and mean knee extension strength decreased by 32.8 N.

Discussion: The MRI measurements showed high repeatability and 12-month changes consistent with muscle atrophy and fat replacement as well as a decrease in both muscle strength and IBMFRS. Our findings suggest that fat-referenced MRI measurements are suitable for assessing disease progression and treatment response in inflammatory myopathies.

Introduction/aims: Changes in body composition in patients with spinal muscular atrophy (SMA) can cause endocrine abnormalities that are insufficiently studied in adults. We aimed to assess the endocrine profile in a cohort of adults with SMA. Second, we compared body composition and endocrine profiles between nonambulatory and ambulatory patients and between different types of SMA.

Methods: The cross-sectional study included 29 SMA patients (18 [62.1%] males and 11 [37.9%] females) of median age 44 (IQR 30-51.5) years with type 2, 3, or 4. Body composition was measured by bioimpedance. Morning blood samples were drawn for glycated hemoglobin (HbA1c), lipid profile, testosterone, cortisol, and insulin-like growth factor-1 (IGF-1). Blood glucose, insulin, and beta-hydroxybutyrate (BHB) were measured during a 75 g oral glucose tolerance test. The homeostatic model assessment for insulin resistance index was calculated.

Results: In total, 75.9% of patients had increased fat mass (FM), with 51.7% having an increase despite normal body mass index. Ambulation was the most important discriminating factor of body composition. 93.1% of patients had metabolic abnormalities, including hyperglycemia, insulin resistance, and dyslipidemia. Increased BHB, a marker of ketosis, was present in more than a third of patients. Functional hypogonadism was present in half of male patients. Testosterone and IGF-1 negatively correlated with FM.

Discussion: Adult patients with SMA had abnormal body composition and highly prevalent metabolic disturbances that might increase cardiometabolic risk. Because treatments have modified the course of SMA, it is important to investigate whether these observations translate into clinically relevant outcomes.

Introduction/aims: Studies have demonstrated the potential of muscle MRIs to measure disease progression in ALS. However, the responsiveness and utility of quantitative muscle MRIs in an ALS clinical trial remain unknown. This study aimed to determine the responsiveness of quantitative muscle MRIs to measure disease progression in ALS.

Methods: Longitudinal quantitative muscle MRIs were obtained in an ALS study that delivered human neural progenitor cells to the spinal cord (NCT02943850). Participants underwent MRIs at baseline, 1, 3, 6, 9, and 12 months. MRI measures included fat fraction (ff), water T2 (T_2m), cross-sectional area (CSA), and remaining muscle area (RMA). Non-MRI measures included strength via Accurate Test of Limb Isometric Strength (ATLIS) and the ALSFRS-R. Standardized response means (SRM) were calculated at 1, 3, 6, and 12 months.

Results: Significant increases in muscle FF and decreases in CSA and RMA were seen as early as 1 month from baseline. At 6 months, the most responsive measures were muscle FF (SRM_thigh = 1.85, SRM_calf = 1.39), T_2m (SRM_thigh = 1.2, SRM_calf = 1.71), CSA (SRM_thigh = -1.58, SRM_calf = -1.14), RMA (SRM_thigh = -1.77, SRM_calf = -1.28), and strength tested via ATLIS (SRM_{knee extension} = -1.79, SRM_{knee flexion} = -1.3). The ALSFRS-R was the least responsive at 6 months (SRM = -0.85). Muscle FF and T_2m correlated with ALSFRS-R leg subscores and MRI measures demonstrated varying degrees of correlation with strength.

Discussion: High responsiveness and low variability make quantitative muscle MRI a novel and complementary outcome measure for ALS clinical trials.

Introduction/aims: MScanFit motor unit number estimation (MUNE) is the most recent MUNE method which has shown promising results in extremity muscles, but it has not been applied to bulbar muscles. Bulbar muscles are particularly important in the diagnosis of amyotrophic lateral sclerosis (ALS). This study aimed to investigate the feasibility and reliability of MScanFit MUNE in the accessory nerve and trapezius muscles.

Methods: A total of twenty healthy participants were examined twice within 1-2 weeks. We extracted the MScanFit MUNE and size parameter, and compound muscle action potential (CMAP) amplitude values. The reliability of these parameters was assessed using the intra-rater coefficient of variation (CoV), intraclass correlation coefficient (ICC), and Bland-Altman plots. We also correlated MUNE values with CMAP amplitudes using correlation coefficients.

Results: Mean MUNE values (Day 1 = 132.1 and Day 2 = 137.4), CMAP amplitudes (Day 1 = 9.71 mV and Day 2 = 10.10 mV) and size parameters did not differ between the two sessions (p > 0.05). CoV showed excellent reliability for MUNE values, size parameters, and CMAP amplitudes (CoV < 7%) whereas ICCs showed moderate reliability for MUNE values (ICC = 0.619), poor to moderate reliability for size parameters (between 0.393 and 0.689), and good reliability for CMAP amplitude (ICC = 0.864) There was no correlation between MUNE values and CMAP amplitudes.

Discussion: MScanFit MUNE is applicable and mostly reliable in the trapezius muscle. Further studies in patients are needed to investigate the sensitivity of MScanFit in this muscle in detecting motor unit loss, particularly in ALS.

Introduction/aims: Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome is a paraneoplastic syndrome due to an underlying plasma cell dyscrasia. Polyneuropathy in POEMS syndrome may present as a subacute or chronic symmetric sensorimotor polyneuropathy, with electrophysiological features suggesting demyelination. Motor conduction block (CB), which is mostly seen in chronic inflammatory demyelinating polyneuropathy (CIDP), is considered an atypical electrophysiological feature in POEMS syndrome. We examined the frequency of motor CB in POEMS syndrome.

Methods: Patients with POEMS syndrome from the database of our department who had been examined between August 2017 and December 2022 were included in this study. All of the patients' clinical and electrophysiological data were retrospectively collected and analyzed.

Results: We present the data of seven POEMS syndrome patients. Twenty-eight upper extremity motor nerve conduction studies were performed on these patients, and partial CB was detected in seven upper extremity motor nerves (25%) of six of the patients. One patient had motor CB in both the median and ulnar nerves.

Discussion: The distinction between POEMS syndrome and CIDP is important since these conditions require different treatments. Motor CB in POEMS may be more common than has been generally believed. Clinicians should consider this when evaluating patients with demyelinating polyneuropathies and be meticulous in identifying CB. Data from much larger numbers of patients are needed.

Introduction/aims: Pediatric patients with dystrophinopathies [Becker and Duchenne muscular dystrophy (BDMD)] are more likely to have neurodevelopmental and neuropsychiatric conditions. This prospective pilot study tested a novel screening questionnaire developed to identify the common behavioral (B), emotional (E), learning (L), and social (S) difficulties in BDMD.

Methods: A total of 45 caregivers of BDMD patients (ages 4-19 years) seen at the Arkansas Children's Hospital Dystrophinopathy Clinic completed the BELS questionnaire during standard clinic visits. To establish external validity, caregivers also completed four well-validated standardized questionnaires assessing overlapping symptoms [Pediatric Symptom Checklist-17 (PSC-17), Colorado Learning Difficulties Questionnaire (CLDQ), the obsessive compulsive disorder (OCD) subscale from the Revised Children's Anxiety and Depression Scale (RCADS), and Barkley Deficits in Executive Functioning Scale (BDEFS)].

Results: Caregivers reported high rates of behavioral (>60%), emotional (50%-70%), learning (50%-70%), and social (30%-50%) concerns, even though relatively few patients had clinical diagnoses related to these symptoms. Passive suicidality (i.e., thoughts of death) were also common (22.2%; 10/45 patients). The BELS questionnaire was moderately to highly correlated with total scores on the four well-validated questionnaires (p < .001), and BELS subscales showed specificity. A BELS score of 21 corresponded with the established PSC-17 cutoff.

Discussion: The BELS questionnaire shows promise as a screening questionnaire to identify neurobehavioral and neuropsychiatric symptoms common in dystrophinopathy. While BELS cannot currently be used as a standalone measure to make clinical diagnoses, identification of symptoms that warrant further follow-up may improve clinical care and quality of life.

Introduction/aims: The degree of change in neuropathic impairment and quality of life (QoL) that is clinically meaningful to patients with hereditary transthyretin amyloidosis with polyneuropathy (ATTRv-PN) is not established. This study aimed to estimate the magnitude of treatment differences that are meaningful to patients in measures of neuropathy and QoL and to determine whether eplontersen achieved a meaningful improvement versus placebo.

Methods: Data from the NEURO-TTRansform trial on patients with ATTRv-PN treated with eplontersen (n = 141) or historical placebo (n = 59) were used. Anchor-based approaches were used to estimate thresholds for meaningful differences in the modified Neuropathy Impairment Score +7 (mNIS+7) composite score, Norfolk QoL-Diabetic Neuropathy (Norfolk QoL-DN) total score, Neuropathy Symptoms and Change (NSC) total score, and modified body mass index (mBMI). Differences between the least squares means of the treatment groups were analyzed.

Results: Meaningful improvement in mNIS+7 was estimated as -4.0 points and deterioration as 1.8 points. The estimated ranges of meaningful improvement and deterioration in Norfolk QoL-DN were -12.8 to -4.0 points, and 5.9 to 14.7 points, respectively. For NSC, ranges were -2.4 to -1.3 points for meaningful improvement, and 0.6 to 5.8 points for deterioration. The estimated meaningful improvement in mBMI was 9.8 kg/m² × g/L and deterioration was -40.9 kg/m² × g/L. Improvements in each measure with eplontersen versus placebo were greater than the estimates of meaningful differences.

Discussion: Eplontersen demonstrated a clinically meaningful effect on neuropathic impairment, QoL, and nutritional status. Such estimates have implications for clinical practice and trials.