Muscle & Nerve

Background: Facioscapulohumeral muscular dystrophy (FSHD) is a common hereditary neuromuscular disorder. The Russian FSHD Patient Registry was established in 2019 following the development of a PCR-based method for genetic confirmation of the diagnosis. Results: The registry included 470 participants (51% male). Genetic confirmation was obtained for 76% (n=356), the remainder were included based on clinical and anamnestic data. Clinical assessment forms and patient-reported questionnaires were analyzed for 310 and 142 patients, respectively. D4Z4 repeat unit (RU) distribution showed patterns consistent with European cohorts, with a predominance of patients with 3 RUs. A moderate inverse correlation was found between RUs number and clinical severity scales. Periscapular weakness was the most common onset manifestation (46.8%), followed by facial weakness (31.6%) which was often unnoticed by patients. The mean age in the Russian cohort was 37.8 years (range 0-97), indicating a younger cohort compared to international data. A delta-adjusted cluster analysis (n=215) identified three distinct trajectories: a classic phenotype with onset before age 14 and early involvement of various muscle groups (n=177), and two clusters characterized by either facial or periscapular onset with slow progression. Conclusion: The Russian FSHD registry provides a comprehensive characterization of a large national cohort, revealing a predominance of patients with 3 D4Z4 repeats and a younger demographic profile compared to international data. Cluster analysis identified three heterogeneous disease trajectories, offering a framework for improved patient stratification.

Dystonia treatment evaluation in cerebral palsy (CP) is limited by the lack of clinician-assessed scales linking dystonia severity to functional impact. We asked 7 pediatric movement disorder specialists to review videos of 27 children with CP while performing an upper extremity task and while walking. Experts rated arm and leg dystonia severity using the Global Dystonia Severity Rating Scale (GDRS) and task-specific functional impact on a five-point scale adapted from the Dyskinetic Cerebral Palsy Functional Impact Scale. Arm GDRS scores correlated with functional impact on the upper extremity task (linear regression R^2=0.48, p=0.0005). Leg GDRS scores correlated with gait impact (R^2=0.43, p=0.001). A four-point increase in total GDRS corresponded to a one-point worsening in combined functional impact. By demonstrating how expert-rated limb dystonia severity correlates with task-specific functional impact in children with CP, these results could help clinically identify functionally-meaningful differences in dystonia severity.

ObjectivesEpidural spinal cord stimulation (SCS) is an emerging therapy for motor rehabilitation following spinal cord injury (SCI) and other motor disorders. Conventionally, SCS leads are placed along the dorsal spinal cord (SCSD), where stimulation activates large diameter afferent fibers, which indirectly activate motoneurons through reflex pathways. This leads to broad activation of flexor and extensor muscles and limited fine-tuned control of motor output. Targeting the ventral spinal cord (SCSV) may enable more direct activation of motoneuron pools, potentially improving the specificity of muscle activation; however, there is currently no established method to place leads ventrally. To address this, we evaluated the feasibility of four modified percutaneous implantation techniques to target the ventrolateral thoracolumbar spinal cord. Materials and methodsPercutaneous SCSV implantation was performed in three human cadaver torso specimens under fluoroscopic guidance. The following approaches were evaluated: sacral hiatus, transforaminal, interlaminar contralateral, and interlaminar ipsilateral. The leads in the latter 3 approaches were inserted between L1 and L5. Eighteen implants were attempted, with nine leads retained for analysis. Lead and electrode position were assessed using computed tomography (CT) with three-dimensional reconstruction, along with anatomical dissection to verify lead and electrode placement within the epidural space. ResultsSuccessful ventral epidural lead placement was achieved using all four implantation approaches. The sacral hiatus (16/16 electrodes) and transforaminal (8/8 electrodes) approaches resulted in exclusively ventrolateral placement. The interlaminar contralateral approach led to 27/32 electrodes positioned ventrolaterally and 5/32 dorsally. The interlaminar ipsilateral implantation approach led to 14/32 electrodes positioned ventrolaterally and 18/32 positioned ventromedially. ConclusionsThese findings demonstrate that ventral epidural SCS lead placement can be achieved using modified percutaneous implant techniques. The four approaches outlined here provide a clinically feasible pathway to SCSV and establishes a foundation for future clinical studies investigating SCSV for motor rehabilitation following SCI.

Background: Spinal cord injury (SCI) is associated with widespread reorganisation of cortical sensorimotor circuits. Persistent complications such as spasticity and neuropathic pain suggest that homeostatic plasticity, which normally helps stabilise and constrain activity-dependent changes in sensorimotor circuits, may be disrupted after SCI. Homeostatic plasticity can be probed using repeated blocks of transcranial direct current stimulation (tDCS); in healthy individuals, two closely spaced excitatory blocks typically leads to an inhibitory response, reflected as a reduction in corticomotor excitability. Objective: To determine whether individuals with SCI show reduced homeostatic suppression of corticospinal excitability in response to repeated anodal tDCS, compared with healthy controls. Methods: Twenty adults with thoracic or below SCI and 20 healthy controls completed three counterbalanced sessions. Each session comprised two 10-minute blocks of 2 mA tDCS separated by 5 minutes, with the second block always being anodal tDCS over left primary motor cortex. The first block was either anodal, cathodal, or sham tDCS, yielding 3 condition types: anodal-anodal, cathodal-anodal, and sham-anodal. To assess corticomotor excitability, transcranial magnetic stimulation-evoked motor evoked potentials (MEPs) were elicited at baseline, after priming, and every 5 minutes for 60 minutes after the second block. The primary outcome was percent change in MEP amplitude from baseline. Results: In the anodal-anodal condition, the SCI group showed greater facilitation than controls over 0-30 minutes (estimate = 83.09, 95% CI 49.75 to 116.43, p < 0.001), suggestive of a weaker homeostatic response. The cathodal-anodal condition led to a significant overall facilitatory effect with no between-group difference, while the sham-anodal condition showed no change in MEP amplitude relative to baseline. Within the SCI group, exploratory subgroup analysis suggests that those with neuropathic pain and a traumatic injury showed greater facilitation in the anodal-anodal condition than those without these features, indicative of a weaker homeostatic response. Conclusions: SCI is associated with impairment in the homeostatic regulation of corticomotor excitability following repeated excitatory brain stimulation. Disrupted plasticity stabilisation may be relevant to persistent symptoms such as neuropathic pain.

As therapeutic options emerge for hereditary spastic paraplegias (HSP), clinical trials require outcome measures that reflect disease aspects most important to patients. Patient priorities in HSP remain poorly defined. This study aimed to develop a regulatory-compliant framework of patient-prioritised health domains to evaluate treatment response in clinical trials. Patient-reported data on health impacts were collected via two multinational, multilingual online surveys conducted sequentially, including 616 and 504 patients across the clinical and genetic spectrum of HSP. Using a staged approach, we examined prevalence, relevance, and severity, focusing on health impacts that were (i) common (ii) sensitive to disease progression, (iii) highly relevant to patients, and (iv) showed strong severity-relevance correlation. Patient representatives contributed centrally to study design and prioritisation. Our patient-focused analysis yielded five highly prevalent and relevant core health domains: mobility, lower body function, autonomic dysregulation, pain, and psychosocial aspects. Ambulation and lower body function ranked highest across all disease stages. Among non-motor impacts, reduced ability to work, bladder incontinence, and fatigue were most relevant. In mild disease stages, reduced walking distance, reduced walking speed, and the urgency to empty the bladder were the most frequent and most relevant health impact. This work provides the most comprehensive patient-reported and disease stage specific profiling of HSP health impacts to date. It lays the necessary groundwork for developing patient-focused outcome tools capable of capturing treatment effects in future trials.

Introduction: Adults with spinal cord injury (SCI) often experience reduced or lost sensation and movement, impairing the ability of the brain to locate paralyzed body parts, which, in turn, compromises sensorimotor recovery. This disruption of the internal body map of the brain, or mental body representations (MBR), also contributes to neuropathic pain in about 69% of adults with SCI. Medications for neuropathic pain are often ineffective and can cause adverse reactions. Our previous pilot clinical trial showed that Cognitive Multisensory Rehabilitation (CMR), a physical therapy that restores MBR, produced significant, lasting reductions in neuropathic pain, improved sensorimotor function, and enhanced brain function. Building on these results, we examined whether 8 weeks of CMR or adaptive fitness (1) improved sensorimotor function and reduced pain; (2) greater brain activity and connectivity related to sensorimotor function and MBR in adults with SCI. Methods: Sixteen participants (52+/-8 years old, 13+/-10 years post-SCI) were randomized to 8 weeks of CMR or adaptive fitness (45 min, 3x/week). Ten participants had neuropathic pain of 3/10 or greater. Pain and sensorimotor function were assessed at baseline, post-intervention, and 3-month follow-up using the Numeric Pain Rating Scale (NPRS), ASIA Impairment Scale (AIS), and Neuromuscular Recovery Scale (NRS). Functional MRI included resting-state and 4 tasks: imagining feeling the left leg, imagining moving the left leg, whole-body movement imagery, and a sensation task. Results: After CMR, participants improved on AIS with large effect sizes (touch: d=1.54; pinprick: d=1.83; lower limb motor function: d=1.32), while adaptive fitness had small/moderate effects (touch: d=0.49; pinprick: d=0.53; lower limb motor function: d=0.74). CMR also showed larger effect sizes for NRS (core: d=2.19; upper limb: d=0.69; lower limb: d=0.74) than fitness (core: d=0.73; upper limb: d=0.34; lower limb: d=0.00). Benefits persisted at follow-up. Highest neuropathic pain intensity reduced post-CMR and at 3-month follow-up (d=0.48; d=0.63). Pain increased slightly after fitness (n=6; d=-0.19; d=-0.41). CMR increased brain connectivity and activation during the leg imagery task. Increased activation during whole-body imagery was greater after CMR than fitness. Discussion: These preliminary results support the potential of CMR to improve function and reduce neuropathic pain in adults with SCI, warranting larger confirmatory trials. Clinicaltrial.gov: NCT05167032

BackgroundPeri-synaptic astrocyte processes (PAPs) play a fundamental role in synapse formation and function. Central afferent synapse loss and astrocyte dysfunction greatly impede sensory-motor circuitry in spinal muscular atrophy (SMA) disease progression, however mechanisms underpinning tripartite synapse dysfunction remains to be fully elucidated. The aims of this study were to further define PAP and motor neuron synaptic defects in human SMA disease pathology and implement a therapeutic intervention strategy to improve motor neuron function. MethodsWe derived astrocyte monocultures and motor neuron astrocyte co-cultures from healthy and SMA patient induced pluripotent stem cell (iPSC) lines to assess intrinsic astrocyte filopodia defects and phenotypes occurring at the synapse-PAP interface, respectively, using cell surface capture mass spectrometry proteomics, confocal and super resolution microscopy, synaptogliosome isolation, and electrophysiology. ResultsSMA astrocytes demonstrated intrinsic filopodia actin defects featuring low abundance of actin-associated cell surface N-glycoproteins, and decreased filopodia density and CDC42-GTP levels after actin remodeling stimulation. This phenotype is likely driven by the significant reduction of CD44 and phosphorylated ezrin, radixin and moesin ERM proteins (pERM) within SMA astrocyte filopodia. The dual combination of SMN1 gene therapy and forskolin treatment, an adenylyl cyclase activator leading to increased cyclic adenosine monophosphate (cAMP) levels and actin signaling pathway stimulation, led to extensive branching and increased filopodia density of SMA astrocytes during actin remodeling. SMA patient-derived motor neuron and astrocyte co-cultures, particularly samples derived from male patient iPSC lines, demonstrated a significant decrease in synapse number, actin-associated pre-synaptic neurotransmitter release protein, synapsin I (SYN1), and PAP-associated expression of pERM and glutamate transporter, EAAT1. Our astrocyte-targeted SMN1 augmentation and forskolin treatment paradigm restored SYN1 protein levels within the SMA synaptogliosome, resulting in significant increases in motor neuron synapse formation and function, but did not fully restore PAP-associated proteins levels at the synapse. ConclusionsSMA astrocytes demonstrate intrinsic actin-associated defects within filopodia, which correlates with decreased pERM levels at tripartite motor neuron synapses. We also define a SMN- and cAMP-targeted treatment paradigm that significantly increases pre-synaptic neurotransmitter release protein levels to improved SMA motor neuron synapse formation and function. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=117 SRC="FIGDIR/small/714618v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@1257ab8org.highwire.dtl.DTLVardef@19c0010org.highwire.dtl.DTLVardef@c84552org.highwire.dtl.DTLVardef@3f1e62_HPS_FORMAT_FIGEXP M_FIG C_FIG

Objective: To systematically evaluate the efficacy and safety of Deep Brain Stimulation (DBS) for the management of disabling tremor in patients with Multiple Sclerosis (MS) by synthesizing data from available clinical studies. Methods: This systematic review and meta analysis followed PRISMA 2020 guidelines and was registered with PROSPERO (CRD420261347426). A comprehensive search of PubMed, Scopus, Web of Science, and Embase was performed from database inception until December 2025 with no time or language limitation. A pre-post meta analysis design was used to estimate the pooled effect size using the Standardized Mean Change (SMC) between baseline and follow up tremor severity. Because most included studies were single arm cohorts and clinical heterogeneity was anticipated, a random effects model using the Restricted Maximum Likelihood (REML) estimator with the Hartung-Knapp adjustment was applied. Safety outcomes including hardware complications and postoperative infections were pooled using random effects meta analysis of proportions. Results: Thirteen studies including 131 patients met the eligibility criteria. Eight studies with adequate outcome data were included in the pooled efficacy analysis. DBS was associated with a significant reduction in tremor severity with an overall pooled SMC of 1.42 (95% CI 1.07 to 1.77). Statistical heterogeneity was minimal (I2 = 0.0%, p = 0.6300), although this finding should be interpreted cautiously given the limited number of studies and clinical variability in surgical targets, most commonly the ventral intermediate nucleus (VIM), and follow up duration ranging from months to more than 20 years. The pooled incidence of postoperative infection was approximately 7% with substantial heterogeneity across studies (I2 = 74.1%). The most frequently reported adverse events were stimulation related effects such as dysarthria and disequilibrium, which were generally reversible after adjustment of stimulation parameters. Overall methodological quality of included studies was predominantly moderate. Conclusion: Deep brain stimulation may provide meaningful tremor reduction in selected patients with disabling and medication refractory MS tremor, with a large pooled treatment effect (SMC = 1.42). Although complications such as postoperative infection (approximately 7%) and transient stimulation related adverse effects can occur, these events appear manageable in most cases. However, the current evidence base remains limited by small sample sizes, heterogeneous study designs, and variability in surgical targets and outcome reporting. Larger prospective studies with standardized tremor outcome measures and consistent reporting of safety outcomes are needed to better define the long term efficacy and optimal clinical role of DBS in patients with MS related tremor.

BackgroundTranscranial Magnetic Stimulation (TMS) studies identify the Resting Motor Threshold (RMT) to calibrate stimulation intensity. However, this procedure is time-consuming and subject to variability. We developed an automated procedure to improve the efficiency and standardization of RMT determination. New methodWe developed an algorithm that measures MEP amplitudes and automatically adjusts stimulation intensity to determine the RMT. Experiment 1 compared this automated method with the manual procedure in terms of reliability and equivalence. Experiment 2 developed a "Fast" automated process, assessing it against both the manual and initial automated procedures. ResultsAcross both experiments the automated approach demonstrated excellent test-retest reliability and strong agreement with the manual method (Intraclass Correlation Coefficients [&ge;]0.95), giving estimates of RMT statistically equivalent to those of manual measurements within {+/-}3% MSO, with the majority of comparisons within {+/-}2% MSO. Experiment 2 optimized the procedure, allowing empirical determination of the RMT in an average of <3 minutes with only 33-34 pulses. Comparison with existing methods RMT-Finder provides a reliable and time-efficient alternative to manual approaches. To the best of our knowledge RMT-Finder presents the first closed-loop feedback approach to identify the RMT without manual intervention. This procedure can improve standardization and reproducibility in TMS studies. ConclusionsAutomating RMT assessment allows rapid and highly reproducible assessment of this standard TMS measurement, making it viable for inclusion in routine clinical applications that require standardized procedures.

Muscle-specific kinase (MuSK) is a pivotal player in forming and maintaining healthy neuromuscular junctions (NMJ). In MuSK myasthenia gravis (MG), autoantibodies targeting MuSK disrupt its function, impairing neuromuscular transmission and causing fatigable skeletal muscle weakness. MuSK autoantibodies predominantly belong to the IgG4 subclass, which bind in a monovalent fashion due to Fab-arm exchange, although autoantibodies of other subclasses also exist. Polyclonal autoreactive IgG from patients may therefore harbor a variety of monovalent and bivalent MuSK antibodies with potentially distinct effects on MuSK signaling. To further unravel the pathomechanisms underlying MuSK MG, we have investigated how MuSK antibody-binding affects MuSK functioning with a diverse panel of (patient-derived) monoclonal MuSK antibodies. Our findings reveal that the valency of antibody-binding influences binding kinetics to MuSK, inhibition of agrin-induced MuSK activation, Dok7 binding to MuSK and NMJ gene expression. Monovalent binding to the frizzled domain of MuSK did not inhibit agrin-induced MuSK activation, while monovalent binding to the Ig-like domain 1 does. Moreover, the kinetics of Dok7 degradation induced by bivalent MuSK antibodies appear to depend on binding-epitope of MuSK. Surprisingly, none of the clones tested (both bivalent and monovalent) increased MuSK internalization. Taken together, the cumulative pathogenic effect of polyclonal MuSK antibodies in individual MuSK MG patients thus likely depends on autoantibody titer, affinity and the unique composition of MuSK autoantibodies varying in epitope and valency. This research enriches our understanding of the intricate interactions between antibodies and MuSK in MuSK MG and offers potential insights into novel therapeutic strategies using MuSK antibodies.

Duchenne Muscular Dystrophy (DMD) is a debilitating degenerative condition with complex musculoskeletal and cognitive symptoms. The protein responsible, dystrophin, is expressed in both muscle tissue and within the central nervous system (CNS) where it localizes to inhibitory synapses. Recent work has shown that dystrophin loss in skeletal muscle leads to abnormalities in endocannabinoid signaling, particularly related to Cannabinoid Receptor Type 1 (CB1R) signaling pathways. CB1Rs are highly expressed throughout the CNS, and have been implicated in short- and long-term plasticity mechanisms. Despite this curious overlap, no work examines how dystrophin loss impacts CB1R signaling in the CNS, a mechanism that may contribute to the diverse neurological pathologies seen in DMD patients. To address this, we used a combination of immunofluorescent labeling and ex vivo electrophysiology to examine CB1R signaling at three classes of synapses within the cerebellum. Utilizing DMDmdx mice, a mouse model of DMD, we find that loss of dystrophin significantly impairs CB1R signaling specifically at parallel fiber-Purkinje Cell synapses, a key location for cerebellar learning. We also find that endocannabinoid-mediated long-term depression at these synapses is absent. Loss of endocannabinoid signaling and synaptic plasticity may contribute to cerebellar dysfunction and motor control symptoms in DMD. These data suggest that dystrophin loss may have previously undescribed consequences for CNS function, and that modulation of endocannabinoid signaling may be a therapeutic strategy for symptom management. Significance StatementDuchenne Muscular Dystrophy (DMD) is a degenerative condition with severe CNS deficits in addition to the well-known muscle weakening. However, no effective treatments currently exist for CNS-related aspects of this disease. Given that endocannabinoid signaling is altered in dystrophic muscle and the importance of endocannabinoid signaling in CNS function, we examined endocannabinoid signaling in the cerebellum of DMDmdx mice, a model of DMD. Utilizing immunolabeling and ex vivo electrophysiology, we find a significant decrease in CB1R expression and functionality specifically at parallel fiber synapses, resulting in reduced or abolished short- and long-term synaptic plasticity. These findings demonstrate that changes in endocannabinoid function contribute to CNS deficits in DMD and open the door to new potential therapeutic targets for treatment.

Walking impairments in Parkinsons disease (PD), including reduced speed, cadence, and stride length, and increased variability, impair mobility and raise fall risk. Conventional treatments may fail to address these deficits, underscoring the need for complementary non-invasive alternatives. This study examined whether combining rhythmic auditory cueing with transcranial direct current stimulation (tDCS) over the supplementary motor area (SMA), a critical region for internally-generated movement, would enhance gait performance in PD. Thirty-three participants with PD and thirty-two healthy controls completed two sessions (anodal vs. sham tDCS) with gait assessed during stimulation, immediately after stimulation, and 15 minutes after stimulation under two auditory conditions: walking in silence and walking to music paced 10% faster than baseline cadence. Spatiotemporal, variability, and stability gait parameters were analyzed using linear mixed-effects models. Rhythmic auditory cueing significantly increased cadence and speed during, immediately after, and especially 15 minutes after stimulation, suggesting sustained effects of rhythmic entrainment. Anodal tDCS produced faster cadence, as well as lower stride time variability and stride width, particularly in individuals with PD. Although both music and anodal tDCS affected gait, no interaction was observed, indicating independent effects. Individuals with PD had greater gait variability overall, and adjusted temporal gait parameters less to music than healthy controls did. Anodal stimulation reduced walking variability in PD, reducing the group differences observed under sham conditions. These findings suggest that rhythmic cueing and SMA stimulation target complementary mechanisms, highlighting the promise of combined tDCS-music interventions for gait rehabilitation in PD.

Abstract Background Understanding the phenotypic spectrum of disease-associated genes is essential for accurate diagnosis and targeted therapy. FRMPD4 (FERM and PDZ Domain Containing 4) has previously been associated with intellectual disability and epilepsy. However, its potential role in non-syndromic hearing loss has not been explored. Methods We performed genetic analysis in two unrelated families presenting with non-syndromic sensorineural hearing loss, identifying maternally inherited missense variants in FRMPD4. Clinical phenotyping included audiological assessment and evaluation for neurodevelopmental involvement. Cross-species expression analyses were conducted in Drosophila, zebrafish, and mouse. Functional characterization included quantitative evaluation of sound-evoked responses in Drosophila nicht gut hoerend (ngh) mutants, assessment of neuronal development and acoustic startle responses in zebrafish loss of function models, and morphological cochlear analyses with auditory brainstem response measurements in knockout mice. Results Three affected males from two unrelated families presented with prelingual, bilaterally symmetrical sensorineural hearing loss, with confirmed congenital onset in one individual and no evidence of neurodevelopmental abnormalities. Cross-species analyses demonstrated evolutionarily conserved expression of FRMPD4 in auditory structures. In Drosophila, quantitative analysis of sound-evoked responses in ngh mutants revealed impaired auditory function. Zebrafish loss of function models exhibited reduced neuronal populations in the otic vesicle and posterior lateral line, abnormal neuromast development, and diminished acoustic startle responses. In mice, Frmpd4 knockout resulted in high-frequency hearing loss and cochlear abnormalities consistent with the human phenotype. Conclusions Our findings expand the phenotypic spectrum of FRMPD4 to include non-syndromic sensorineural hearing loss and establish its evolutionarily conserved role in auditory function. These results have direct implications for genetic diagnosis and variant interpretation in patients with hearing loss.

BackgroundSpinal cord injury (SCI) triggers persistent neuroinflammation, gliosis, neuronal loss, and demyelination, leading to motor deficits and neuropathic pain. Botulinum neurotoxin type A (BoNT/A) has shown anti-inflammatory and neuroprotective effects in acute SCI, but its potential in the chronic phase remains unclear. This study investigates whether combining BoNT/A with electrical muscle stimulation (EMS) enhances recovery in chronic SCI. MethodsAdult mice with severe thoracic SCI (paraplegic) underwent EMS (30 min/day for 10 non-consecutive days starting 3 days post-injury) or no stimulation. Fifteen days after SCI, animals received a single intrathecal injection of BoNT/A (15 pg/5 L) or saline. Functional recovery was assessed up to 60 days as well as in moderate and mild SCI mice, neuropathic pain onset and maintenance were evaluated. Spinal cord tissue was analysed for astrocytic and microglial morphology, neuronal and oligodendroglia survival, myelin protein expression, and in vitro effects on oligodendrocyte precursor cells (OPCs). The phenotype of hindlimb muscles was evaluated through morphological and gene expression analyses. ResultsEMS was able to counteract muscle atrophy and fibrosis, and when combined with BoNT/A, also denervation. Moreover, the combination restored hindlimb motor function in chronic SCI, whereas BoNT/A or EMS alone were ineffective. Neuropathic pain, a common comorbidity associated with SCI, was mitigated by BoNT/A treatment even when administered in the chronic phase. BoNT/A reduced astrocytic hypertrophy and excitatory synapse association and was associated with a morphology-based redistribution of microglial profiles toward a resting-like classification, decreased apoptosis, and increased neuronal and oligodendroglia survival. Myelin basic protein expression was significantly elevated in vivo. In vitro, BoNT/A promoted OPC differentiation into myelinating oligodendrocytes, increased process complexity, and upregulated Myelin basic protein, galactocerebroside C, proteolipid protein, and myelin oligodendrocyte glycoprotein under both proliferative and differentiating conditions. Cleaved SNAP25 colocalization with OPC confirmed direct BoNT/A internalization and activity. ConclusionsBoNT/A exerts multi-cellular neuroprotective actions in chronic SCI, supporting neuronal and oligodendroglia survival, reducing neuroinflammation, enhancing remyelination and the combination with EMS promotes substantial recovery of muscle homeostasis within a permissive microenvironment shaped by early stimulation. Its efficacy depends on a permissive microenvironment achieved through EMS. These results provide strong rationale for the clinical evaluation of BoNT/A as a therapeutic strategy for chronic SCI.

Objective: Myofascial pain (MP) is a leading cause of disability globally. Pain quality and severity vary widely for people with MP, making it difficult to accurately assess the spectrum of symptoms and develop appropriate treatments. We assessed potential contributors to variability in the clinical spectrum of unexplained neck/shoulder pain and associated myofascial component(s). Design: Prospective cross-sectional study of adults reporting neck/shoulder pain and pain-free individuals. Outcomes Measures: Pain intensity and interference (PEG); Symptom burden measured using patient-reported outcomes and objective measures: pain catastrophizing (PCS); PROMIS physical function (PF); sleep disturbance; anxiety (GAD-2); depression (PHQ-2); hypermobility (Beighton/Brighton); Objective measures in the medial upper trapezius: pressure pain threshold (PPT) and quantitative sensory testing (QST). Results: Of the 96 adults recruited for the study, 82 had complete records (age 32.2 +/-13.1 years, 57% women). On physical exam, 23 were assessed to be in an active group (those with spontaneous MP without provocation), 38 in a latent group (those with MP upon provocation), and 21 in a normal group (no MP in neck and shoulder). The symptom burden explained 75% of the variance in PEG in the overall sample, 85% in the active group and 92% in the normal group. PF and PCS are key predictors of PEG. Network analysis identified unique symptom clusters in the active and latent groups. Conclusions: The symptom burden explains the variability in the clinical spectrum of pain intensity and interference in unexplained neck/shoulder MP. Network analysis can further improve clinical risk stratification. These findings represent a step towards an eventual goal of developing multidisciplinary clinical guidance for managing the whole patient, rather than the current emphasis on regional pain contributors in MP.

IntroductionThe exploration of alternative strategies for neural tissue regeneration and repair is giving rise to a novel paradigm in neurosurgery: fusogenic therapy. This approach promises rapid restoration of peripheral nerve and spinal cord function by circumventing Wallerian degeneration and eliminating the delay associated with axonal regrowth. Its potential stems from the capacity of fusogens to induce axonal fusion and achieve immediate membrane sealing, complemented by their pronounced neuroprotective properties. However, experimental data on fusogens and their effects are inconsistent, often contentious, and derived using heterogeneous methodologies. MethodsWe present the first comprehensive systematic review covering nearly four decades of research on fusogens for axonal membrane repair and 26 years of their experimental and clinical application in mammalian and human models for peripheral and central nervous system restoration. The review includes a meta-analysis of fusogen efficacy following traumatic spinal cord and peripheral nerve injuries. ResultsConducted in accordance with the PRISMA 2020 flow protocol and PICO criteria, our analysis incorporates 86 sources, 20 of which were included in the meta-analysis. DiscussionIn summary, we have systematized the prevailing approaches and methods for fusogen application, delineated key contentious issues, and identified promising directions for the development of axonal fusion technology.

Twenty percent of familial amyotrophic lateral sclerosis (fALS) cases are linked to mutations in the Superoxide Dismutase 1 (SOD1) gene and accumulation of misfolded SOD1 aggregates. SOD1 misfolding from the broader ALS population without SOD1 mutations is less clear. Here, we report SOD1 seeding activity in antemortem cerebrospinal fluid (CSF) from ALS participants with and without SOD1 mutations during ALS progression. Antemortem CSF from controls, SOD1-ALS, and sporadic ALS (sALS) patients was subjected to SOD1 seed amplification real-time quaking induced conversion (RT-QuIC) assays. SOD1-ALS CSF exhibited shorter lag phase and increased ThioflavinT (ThT) fluorescence amplitude compared to healthy controls and those with spinal muscular atrophy. CSF from sALS participants, who had no mutations in SOD1 or nine other ALS risk genes, also displayed SOD1 seeding activity, indicating wild-type SOD1 is aggregate-prone in the broader ALS population. Longitudinal CSF data indicated that SOD1 seeding activity correlates with ALS progression via the ALS Functional Rating Scale Revised (ALSFRS-R) slope decline and CSF neurofilament light. Our sALS CSF cohort primarily comprised of participants less than 2 years from symptom onset, suggesting that SOD1 seeding activity is an early biomarker that may enable inclusion in clinical trials. With the FDA-approval of tofersen (Qalsody), a SOD1-lowering antisense oligonucleotide, new SOD1 diagnostic, prognostic and pharmacodynamic biomarkers may enable SOD1-targeting strategies that could benefit the broader ALS population.

Background: Diagnosing the over 700 known rare bone diseases (RBDs) is inherently challenging and often requires extensive time and multiple clinical visits. Effective treatment, particularly for RBDs with approved therapies, depends on early and precise identification of the specific RBD type. Image recognition artificial intelligence (AI) has the potential to significantly enhance diagnostic processes and improve patient outcomes. Many of these disorders cause characteristic skeletal changes, especially in the hands, and are associated with growth abnormalities. Consequently, affected children routinely undergo hand radiographs for bone age assessment, making these images a widely available yet underutilized diagnostic resource. Materials and Methods: We retrospectively compiled 5,623 multi-institutional hand radiographs from 2,471 patients with 45 different RBDs and 1,382 unaffected controls. We trained two deep learning models: a binary classifier to differentiate between RBD and non-RBD hand radiographs, and a multi-class classifier covering ten RBDs (or RBD groups), using 5-fold cross-validation. Preprocessing included masking, normalization, and data augmentation. Additionally, we applied occlusion sensitivity mapping to visualize class-specific features and evaluated the learned representations through cosine-based retrieval and UMAP projections of the feature space. Results: The affected versus unaffected classifier achieved a balanced accuracy of 85.5% on the test dataset. The ten-class classifier reached a balanced (top-1) accuracy of 76.6%, with top-3 accuracy exceeding 90%. Disorders with highly distinctive phenotypes, such as achondroplasia, achieved accuracies above 95%, whereas phenotypically overlapping disorders, such as ACAN- and SHOX-related short stature, were more frequently confused. Feature space analysis showed that validation samples clustered closely with their respective training distributions, supporting the consistency and generalizability of the learned embeddings. Conclusion: This manuscript presents a proof of principle for the development of Bone2Gene, a next-generation phenotyping (NGP) tool for the detection and differential diagnosis of RBDs, currently based on hand radiographs. Ongoing efforts focus on expanding the dataset to include additional RBDs or RBD groups in the current multi-class classifier for differential diagnosis and to further evaluate its generalizability. The Bone2Gene study is open to collaboration.

Wolfram syndrome is a rare genetic disorder characterized by antibody-negative early-onset atypical diabetes mellitus, optic nerve atrophy, sensorineural hearing loss, diabetes insipidus (arginine vasopressin deficiency), and progressive neurodegeneration, with significant variability in disease severity. We assessed the accuracy of a genotype-based severity scoring system to predict the onset of cardinal symptoms in Wolfram syndrome. This system is based on the type of WFS1 variants (in-frame or out-of-frame) and their location relative to transmembrane domains. Severity scores were assigned to 324 patients with documented onset ages for diabetes mellitus, optic atrophy, hearing loss, and diabetes insipidus. Our analysis revealed a clear correlation between severity scores and earlier onset of diabetes mellitus and optic atrophy. Patients with in-frame variants outside transmembrane domains exhibited milder symptoms, especially WFS1 c.1672C>T (p.Arg558Cys) variant, whereas those with out-of-frame variants showed the earliest onset. Severity scores 3 and 4 did not follow the expected progression, suggesting that transmembrane domain involvement in both alleles may result in greater severity. These findings suggest that this scoring system provides valuable insights into the progression of Wolfram syndrome and may guide clinical care. Further refinement may improve its utility for predicting the onset of non-diabetic symptoms.

Spinal muscular atrophy (SMA) is caused by loss of SMN protein and is increasingly recognized as a multisystem disorder involving molecular pathology beyond motor neurons. Recently, we identified NRF2-KEAP1 signaling as dysregulated in SMA mice. Because NRF2 coordinates transcriptional programs that maintain cellular redox homeostasis and adaptive stress responses, we investigated whether NRF2 signaling is similarly altered in SMA type I patient-derived fibroblasts and whether it can be pharmacologically engaged. Compared with control fibroblasts, SMA fibroblasts displayed reduced basal expression of NRF2 target proteins, including NQO1 and xCT (SLC7A11), along with decreased levels of PGC1. Omaveloxolone (OMAV), a pharmacological NRF2 activator approved for the treatment of Friedreichs ataxia, increased cell viability and upregulated NRF2 target proteins in both control and SMA fibroblasts. Notably, OMAV produced a modest increase in SMN protein abundance and PGC1 levels selectively in SMA cells. Together, these findings support diminished NRF2 pathway output as a feature of SMA fibroblasts and demonstrate that OMAV induces NRF2 target proteins in this human SMA cellular model, consistent with enhanced cytoprotective signaling. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/712434v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@1904bfeorg.highwire.dtl.DTLVardef@6d20e2org.highwire.dtl.DTLVardef@89f365org.highwire.dtl.DTLVardef@ca9638_HPS_FORMAT_FIGEXP M_FIG C_FIG