Annals of Clinical and Translational Neurology

Background: Hereditary spastic paraplegia (HSP) comprises a heterogeneous group of neurodegenerative disorders characterized by progressive lower-extremity weakness and spasticity, with or without additional neurological symptoms. Objectives: To characterize the molecular genetic spectrum, inheritance patterns, molecular finding rate, and clinical characteristics of HSP within a multicenter Canadian cohort. Methods: We investigated 671 patients from 423 families who met clinical criteria for HSP identified through the Canadian HSP (CanHSP) registry from 7 medical centers across Canada. Patients were evaluated using known HSP and HSP mimic gene panels, whereas unsolved and more recent patients underwent whole-exome sequencing (WES). 435 individuals underwent gene-panel testing and 485 underwent WES. Copy-number variants (CNVs) were assessed using ExomeDepth, and candidate CNVs using multiplex ligation-dependent probe amplification (MLPA). Results: Molecular findings were identified in 426 of 671 individuals (63.5%): 351 (52.3%) had HSP-associated findings, 70 (10.4%) HSP-mimicking disorders, and five (0.7%) other molecular findings; 245 (36.5%) remained unresolved. Candidate variants were found in 80 relevant genes, 36 of which were HSP-associated genes. The most frequently implicated genes were SPAST (22.5%), SPG7 (5.7%), ATL1 (5.2%), SPG11 (3.6%), and SPG8 (3.3%). Phenotypically, SPAST, ATL1, and SPG8 w[zg1.1]ere predominantly associated with pure HSP, whereas SPG7 and SPG11 more often showed complicated phenotypes, with prominent cerebellar involvement in SPG7 and cognitive and developmental features in SPG11. Conclusion: Patients in CanHSP present with genetic and phenotypic heterogeneity. Reanalysis and complementary approaches, including whole-genome, RNA, and long-read sequencing, may increase diagnostic yield.

Progressive multiple sclerosis (PMS) lacks blood-based biomarkers of the neurodegenerative processes driving disability. We measured synaptopodin, a postsynaptic protein, in neuronal-enriched extracellular vesicles (NEVs) across two independent cohorts: the SPRINT-MS trial (n=184) and a real-world validation cohort (n=268). A one SD increase in baseline synaptopodin was associated with ~32% lower risk of confirmed disability progression in PMS (p=0.011), with the strongest effect in secondary PMS (SPMS) (~57% lower odds, p=0.019). This SPMS association was replicated in the validation cohort (~60% lower odds, p=0.009). Higher baseline synaptopodin was associated with future slower whole-brain atrophy and preserved microstructural integrity across MRI metrics (p=0.007-0.013). Longitudinal changes in NEV synaptopodin were associated with disability worsening (p=0.007) and paralleled MRI microstructural changes. NEV synaptopodin, but not NfL, was associated with confirmed disability progression in PMS participants with both biomarkers measured (HR 0.71 vs 1.12, p=0.007 vs 0.22 for NEV synaptopodin and NfL, respectively) and SPMS (HR 0.58 vs 1.10, p=0.003 vs 0.50). Adding synaptopodin, but not NfL, to a base model improved discrimination for disability progression in SPMS in both cohorts (e.g. validation AUC 0.755 to 0.838, p=0.005). These findings identify NEV synaptopodin as a prognostic and longitudinal, blood biomarker of synaptic integrity in PMS, particularly SPMS, complementing NfL.

ObjectiveThe current International League Against Epilepsy (ILAE) guidelines for Lennox-Gastaut syndrome (LGS) mandate the presence of generalized paroxysmal fast activity (GPFA) on EEG. However, GPFA is not necessarily restricted to LGS and has been described in, among others, idiopathic generalized epilepsies. A clear definition for GPFA is currently lacking, hampering research into its utility as a diagnostic or treatment biomarker. Here, we assessed expert agreement in the interpretation of GPFA to explore feasibility of a consensus-based definition. MethodsWe internationally distributed a two-part survey on GPFA to EEG experts. First, participants completed thirteen questions gauging their preferred clinical and EEG criteria for GPFA, including duration, frequency, amplitude and topography. Second, participants classified the presence versus absence of GPFA in eleven EEG clips, while blinded to clinical context, from patients with LGS, other epilepsies, and physiological variants. Results162 respondents, predominantly from North America and Europe, completed the survey. 87% considered GPFA to also occur in epilepsies other than LGS. Considerable heterogeneity was present on defining duration, spectral frequency, amplitude and topographic distribution of GPFA. Particularly poor agreement was seen for lower limits of duration and frequency, with no single response option receiving a majority consensus (36% and 30% agreement, respectively). Similarly, the degree of agreement on interpretations was highly variable across real-world EEG clips. SignificanceMarked discrepancies exist in the EEG identification and clinical interpretation of GPFA, undermining its utility as a potential biomarker in research and clinical trials of LGS and other epilepsies. The findings also highlight the need to establish a consensus-based and eventually evidence-informed definition to formally operationalize the clinical and EEG criteria for GPFA. Key pointsO_LIGeneralized paroxysmal fast activity (GPFA) is variably defined in the literature, limiting its utility as a diagnostic or treatment biomarker C_LIO_LIIn this international survey (n = 162 respondents, 25 countries) we found limited agreement on GPFAs defining features and on interpretation of fast activity on EEG clips C_LIO_LI87% of respondents considered GPFA to occur in epilepsies other than Lennox-Gastaut syndrome C_LIO_LIPending further elucidation of the pathophysiology underlying GPFA or its computational characterization (i.e., to inform a biologically-or evidence-based definition), we underscore the need for an interim consensus-based definition C_LI

Background and objectives: Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is the most common monogenic cerebral small vessel disease. Though neuropsychiatric symptoms (NPS) of CADASIL profoundly impact function and quality of life, these symptoms remain understudied. This analysis characterizes the prevalence, severity, and profile of NPS among individuals with CADASIL-causing NOTCH3 variants and non-carrier biological family controls in the United States CADASIL Consortium (USCC). Methods: This cross-sectional analysis used multimodal baseline data from 12 enrollment sites across the country. Statistical analyses used nonparametric tests and regression models to compare clinical and neuropsychiatric outcomes across CADASIL risk tiers and controls, adjusting for age, sex, race, and education where appropriate. The primary outcome measure was the Neuropsychiatric Inventory Questionnaire (NPI-Q), an informant-reported measure which assesses 12 categories of NPS. NPI-Q item severity and distress were evaluated for individuals with confirmed cysteine-altering NOTCH3 variants and compared with controls. Results: Four hundred fifty-nine USCC participants were included in the analytic cohort: 343 cases [256 high-risk (HR); 63 medium-risk (MR); 24 low-risk (LR)]; and 116 controls. Among participants with available NPI-Q data, at least one neuropsychiatric symptom was reported by 72.6% (n = 228/314) of cases compared with 53.2% (n = 58/109) of controls. Reported symptoms were more common among CADASIL cases than controls, occurring in 75.0%, 71.2%, and 72.7% of participants in the LR, MR, and HR groups, respectively, compared with 53.2% of controls. Compared with controls, participants in the MR group and HR group had higher NPI-Q severity scores. HR participants also had higher NPI-Q distress scores than controls. Discussion: Our findings support the notion that NPS are an important clinical manifestation of CADASIL. Beyond previously reported symptoms, additional neuropsychiatric manifestations were identified. Given the higher burden and variability in the neuropsychiatric presentation of CADASIL, the relationships among neuropsychiatric, neurological, and patient-reported outcomes merit further investigation. The NPS profile may enhance the evaluation of the safety and efficacy of different treatments to target these symptoms for CADASIL patients. Trial Registration Information: The study is registered at ClinicalTrials.gov (NCT05677880, 12/12/2022).

The glymphatic system is the waste clearance pathway in the central nervous system. Although its dysfunction has been associated with several neurological disorders, its role in multiple sclerosis (MS) remains poorly understood. This system is thought to be particularly active during sleep, yet the relationship between sleep metrics and MRI-derived markers of glymphatic activity has been scarcely explored. In this study, we aimed to perform a multimodal magnetic resonance imaging (MRI) assessment of glymphatic function in MS and investigate its association with sleep parameters, clinical disability, disease duration and MRI-derived structural markers. The study included 22 patients (34.3{+/-}10.1 years; 16 female) with relapsing-remitting MS and 26 healthy controls (32.2{+/-}5.7 years; 18 female), all of whom underwent 3.0 Tesla MRI. Glymphatic function was assessed using diffusion tensor image analysis along the perivascular space (DTI-ALPS) index and global blood-oxygen-level-dependent (BOLD) signal-cerebrospinal fluid (CSF) coupling. In addition, sleep micro- and macrostructural features, clinical disability, disease duration, along with mean diffusivity (MD), lateral ventricular, choroid plexus volumes and lesion load were evaluated. Patients showed reduced DTI-ALPS index, though this difference became only a trend after controlling for MD. No significant group differences were observed in global BOLD signal-CSF coupling. However, in patients, the weaker coupling was associated with longer total sleep time, lower arousal index, greater disability and lateral ventricle enlargement, whereas the DTI-ALPS index showed no significant correlations with any of the measures. Together, these findings challenge the assumption that DTI-ALPS can serve as a reliable marker of glymphatic function in demyelinating diseases such as MS, where disease-related alterations in white matter microstructure can confound diffusion-based measures. In contrast, gBOLD-CSF coupling showed associations with sleep, clinical disability and structural changes in patients, despite the absence of a significant group-level difference. This finding suggests that gBOLD-CSF coupling may capture individual variability in glymphatic-related dynamics relevant to sleep and the clinical expression of MS.

Background: Aberrant basal ganglia activity is a key feature of the pathophysiology of dystonia, but evidence is predominantly based on adult cohorts. Neurophysiological signatures during development remain poorly characterised. Local field potentials (LFPs) recorded by bidirectional neurostimulators provide a direct measure of globus pallidus internus (GPi) activity. In a cross-sectional paediatric cohort, we investigated whether pallidal oscillatory, aperiodic and connectivity characteristics are associated with dystonia severity and whether these differ between genetic and acquired dystonias. Methods: We recruited 30 children and young adults (5-20 years) with medically refractory dystonia (genetic n = 10; acquired n = 20) who underwent bilateral GPi Deep Brain Stimulation (DBS) implantation. Ten minutes of pallidal LFPs were recorded using Medtronic Percept RC neurostimulators with stimulation off, before DBS activation and, where available, at 12 months. Spectral power, aperiodic exponent and interhemispheric pallidopallidal coherence were quantified across delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta (13-30 Hz), and low-gamma (30-45 Hz) frequency bands. Linear mixed-effects models were implemented to establish whether LFP markers were predictive of dystonia severity, as measured by the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS-Movement). Firths Bias-Reduced Logistic Regression assessed whether LFP markers were predictive of dystonia aetiology. Results: Spectral peaks were most consistently detected in the delta, beta, and low-gamma bands. Delta and low-gamma peak power significantly predicted dystonia severity. This association was independent of medication burden, structural GPi involvement, and dystonia aetiology. Theta and alpha peaks were detected less consistently, and their power was not associated with dystonia severity. Pallidopallidal coherence significantly predicted dystonia severity in interaction with medication load in all frequency bands. Low-gamma peak power was significantly lower in acquired than genetic dystonia, but the potentially confounding influence of dystonia severity could not be excluded. The aperiodic exponent was not associated with severity or aetiology. Conclusion: Pallidal LFP markers are associated with dystonia severity in children, with delta peak power, low-gamma peak power and pallidopallidal coherence reflecting clinically relevant features of disease expression. These findings highlight the potential of pallidal LFPs to characterise dystonia across the lifespan and motivate longitudinal studies of their developmental and clinical trajectories.

Background: To determine the crude and age-adjusted point prevalence of motor neuron disease (MND) and its phenotypes (classical amyotrophic lateral sclerosis [ALS], primary lateral sclerosis [PLS] and progressive muscular atrophy [PMA]) using a comprehensive multi-source case ascertainment strategy. Methods: Cross-sectional population-based study with a prevalence date of 1 January 2025. Cases were identified through five complementary regional data sources and confirmed by clinical review against the revised El Escorial and Gold Coast criteria. Cases were classified by phenotype as ALS, PLS or PMA. The reference population was the population aged 15 years or older in Valencian Community (n=4,433,999). Crude prevalence was calculated per 100,000 with 95% Poisson confidence intervals; age-adjusted rates were obtained by direct standardisation to the 2013 European Standard Population. Results: A total of 374 confirmed MND cases were identified. The overall crude prevalence of MND was 8.43 per 100,000 (95% CI: 7.60-9.29) and the age-adjusted prevalence was 7.85 per 100,000 (95% CI: 7.05-8.65). By phenotype, ALS accounted for 325 cases (86.9%; crude prevalence 7.33 per 100,000), PLS for 26 (7.0%; 0.59 per 100,000) and PMA for 23 (6.1%; 0.52 per 100,000). Prevalence was consistent across provinces. Mean age was 65.9 years, the male-to-female ratio was 1.37:1, and 83.4% were receiving riluzole. Conclusions: This is the first comprehensive, multi-source population-based estimate of MND prevalence and its subtypes in the Valencian Community. The estimate is higher than the previous single-unit figure and consistent with recent European data, underscoring the value of multi-source ascertainment.

The Vanishing White Matter (VWM) Registry is a single-center database containing longitudinal survey data from >470 untreated patients with DNA- and MRI-confirmed VWM. VWM is a rare genetic disorder of the brain's white matter with an estimated live birth incidence of 1 per 100,000 and prevalence of 1.3 per 1,000,000 people in the Netherlands. The Registry represents a remarkably extensive collection of systematically gathered information on this disease, enabling crucial research into the natural history of VWM and providing a valuable resource for control arms in clinical trials. Data, initially collected on paper from 2004, have been maintained electronically since 2018, and include validated scales alongside a disease-specific customized questionnaire covering clinical, functional, and psychosocial domains. Survey packages, available in eight languages, are sent one to four times a year, depending on patient age. Built-in validity checks and review by pediatric and adult neurologists ensure data quality. The dataset is continuously updated with questionnaires expanding its scope, and structured for analysis and reuse in research on VWM.

Background. CNM-Au8, a catalytic nanocrystalline gold suspension, is proposed to support neuronal bioenergetics, but its effect on chronic lesion evolution in multiple sclerosis (MS) has not been reported. Objectives. To evaluate the effect of CNM-Au8 on chronic lesion tissue expansion (CLTE). Results. In this exploratory post hoc analysis of the VISIONARY randomised placebo-controlled trial, CLTE was quantified from serial FLAIR MRI. Fifty-five participants were included (CNM-Au8, n=40; placebo, n=15). Compared with placebo, CNM-Au8 was associated with lower lesion expansion rate (p=0.001; Cliffs =-0.58) and volume (p<0.001; Cliffs =-0.65). Conclusions. CNM-Au8 treatment was associated with substantially reduced chronic lesion tissue expansion.

Background: Pseudo-orthostatic tremor (psOT) is a rare form of tremor of the lower body, triggered by standing, at frequencies lower than 13 Hz. It is believed to be secondary to other neurological disorders in a large proportion of cases. Surface electromyography (sEMG) can identify its core characteristics and differentiate it from other similar disorders such as primary orthostatic tremor (POT) and orthostatic myoclonus (OM). Objectives: Our study aims to illustrate the clinical and neurophysiological features as well as the outcomes and final diagnoses of patients with psOT in a retrospective two-centre cohort. Methods: We retrospectively examined the available clinical and neurophysiological records of 35 consecutive patients with a diagnosis of psOT in the 2022-2026 period. Data on demographics, clinical characteristics, sEMG findings, pharmacological treatments, ancillary investigations and patient reported outcomes were collected. Results: 35 patients with psOT were identified, of which 6 (17%) displayed features consistent with a functional neurological disorder (FND). Among the 29 patients with organic psOT, 21 (72.4%) fulfilled the diagnostic criteria for essential tremor (ET), while an identifiable neurological cause was established in four (13.8%). sEMG findings differed between functional and organic psOT, with the latter often displaying features consistent with weight-bearing hyperkinesias. Conclusions: Our retrospective study suggests that psOT is most often associated with ET, while an identifiable neurological cause was found in a relatively small proportion of patients. We also describe functional psOT as a previously unrecognized clinical presentation of FND.

CACNA1A-related disorders arise from altered function of the P/Q-type calcium channel Cav2.1 and encompass a broad spectrum of neurological phenotypes, including developmental and epileptic encephalopathy, familial hemiplegic migraine type 1 and episodic ataxia type 2. Although loss-of-function and gain-of-function mechanisms have both been implicated, interpretation of rare CACNA1A missense variants remains challenging because clinical presentation is heterogeneous and many variants identified through diagnostic sequencing remain classified as variants of uncertain significance. To generate clinically interpretable functional evidence, we developed a calibrated high-throughput automated patch-clamp assay to assess the CACNA1A variants. Twenty-six curated benign/likely benign and 30 curated pathogenic/likely pathogenic missense variants were expressed in Flp-In HEK293 cells with CACNB4 and CACNA2D1. We quantified current density, {Lambda}V0.5 activation,{Lambda}V0.5 inactivation and recovery from inactivation (T0.5 RFI), and used benign controls to define parameter-specific normal ranges with {+/-}3 Z-score thresholds. This multi-parameter framework classified all benign controls as functionally normal and 29 of 30 pathogenic controls as abnormal, yielding 100% specificity and 96.7% sensitivity. Current density identified 19 pathogenic controls with loss of function, while gating and recovery from inactivation identified additional abnormal variants with preserved or partially preserved current density. The assay generated likelihood ratios of 0.033 for normal function and 25.13 for abnormal function, supporting BS3 and PS3 functional evidence, respectively. Application to 23 CACNA1A variants identified in Australian patients showed abnormal function in all four variants already classified as pathogenic or likely pathogenic. Among 19 variants of uncertain significance, 11 were functionally abnormal and nine were reclassified as likely pathogenic after integration of PS3 evidence with other ACMG/AMP criteria. These data show that CACNA1A missense variants can produce loss-of-function, gain-of-function or mixed effects, and that multi-parameter functional assessment is required for accurate interpretation. This calibrated automated patch-clamp framework provides clinically interpretable evidence for refining CACNA1A variant classification in diagnostic practice.

Objective To examine whether prospectively recorded maternal BMI in early pregnancy is associated with offspring multiple sclerosis (MS) risk, including childhood-onset and adult-onset MS. Design Nationwide population-based cohort study. Setting Swedish national health and demographic registers. Participants 1,524,863 singleton children born in Sweden from 1992 to 2007 and followed through 2025. Exposures Maternal BMI recorded at the first antenatal visit, categorised as underweight (<18.5), normal weight (18.5-24.9), overweight (25.0-29.9), and obesity ([&ge;]30.0), and also modelled continuously. Main outcome measures MS in offspring, identified as at least three ICD-10 G35 codes recorded on separate dates. Cox models estimated adjusted hazard ratios (HR) and 95% confidence intervals (CI) adjusting for confounders. Results During follow-up, 1539 offspring (0.1%) were diagnosed with MS at a median age of 24 years (interquartile range, 20-27 years). MS incidence rates by maternal BMI category were 0.37 per 10,000 person-years for both underweight, and normal weight, 0.42 for overweight, and 0.45 for obesity. Compared with normal weight women, maternal overweight and obesity were associated with higher hazards of offspring MS, with adjusted HRs of 1.20 (95% CI, 1.05 to 1.37) and 1.35 (95% CI, 1.11 to 1.64), respectively. Onset-specific analyses showed similar findings for adult-onset MS and less precise but directionally consistent estimates for paediatric-onset MS. Each 1-unit increase in maternal BMI was associated with a 3%, 4%, and 3% higher hazard of overall, paediatric-onset, and adult-onset offspring MS, respectively. Conclusions In this population-based cohort study, higher maternal BMI were associated with an increased rate of MS in offspring. The findings provide large-scale prospective evidence that maternal adiposity may be related to offspring MS risk and support further investigation of the prenatal metabolic environment in the early-life origins of MS.

Based on the observation that in normal EEG rhythms, the low-voltage beta frequencies dominate in the anterior region while characteristic high(er)-amplitude slower rhythms manifest more posteriorly, we studied these gradients across normal subjects and patients with different monogenic epilepsies. From large data sets (long term records of 374 controls and 241 patients) we selected 60s eyes-open rest-EEG epochs to determine the spectral power of the EEG bands. To help manage the large data sets and facilitate analyses, we employed AI to preselect and assist in coding. While both preselection and coding was extensively verified and validated by the authors, which was a time-consuming effort, the AI contribution reduced the net effort of evaluating the large dataset. We developed a metric that reflects the anterior-posterior gradients of the beta rhythm and the so-called posterior dominant rhythm. Our results indicate that this simple gradient measure across 1-10 year-age groups may provide a robust quantitative biomarker of cerebral dysfunction in monogenic epilepsy. Because EEG is noninvasive, widely available, repeatable, and relatively inexpensive, such a biomarker could ultimately provide a practical means of assessing the cerebral effects of emerging targeted therapies across multiple genetic epilepsies.

Background: Secondary progressive multiple sclerosis (SPMS) is traditionally viewed as predominantly neurodegenerative, with limited inflammatory activity. However, chronic active lesions characterised by persistent rim inflammation and gradual expansion may continue to contribute to tissue injury. Objectives: To characterise chronic lesion dynamics in SPMS and determine whether chronic lesion expansion contributes to tissue damage and neurodegeneration. Thirty-one patients with SPMS underwent longitudinal MRI including T1-weighted, FLAIR and diffusion imaging. White matter lesions were manually segmented and chronic lesion tissue expansion (CLTE) was quantified as annualised percentage change. Associations between lesion expansion, mean diffusivity (MD) changes and brain atrophy were assessed using correlation, regression and mixed-effects modelling. Results: CLTE remained prominent, with a mean annual expansion rate of 7.1 +- 4.1%. Expansion substantially exceeded the contribution of newly formed lesions and occurred at rates comparable to relapsing multiple sclerosis. CLTE demonstrated moderate intra-patient clustering (ICC = 0.23). MD increased significantly within lesions during follow-up and was associated with lesion expansion. Chronic lesion expansion was also strongly associated with ventricular enlargement (partial r = 0.72, p < 0.001). Conclusions: Chronic lesion expansion persists in SPMS and represents a major source of tissue injury associated with microstructural degeneration and brain atrophy.

Identifying regional brain atrophy is critical for understanding neurodegenerative disorders. Traditionally, group comparisons rely on frequentist statistics, utilising $p$-values and point estimates that offer limited characterization of uncertainty. Bayesian methods provide an alternative by estimating effect sizes and credible intervals while incorporating prior knowledge and uncertainty. This study evaluated the feasibility of Bayesian hierarchical modelling to assess regional brain atrophy in Progressive Supranuclear Palsy (PSP) and Corticobasal Syndrome (CBS) compared to healthy controls. Participants meeting diagnostic criteria for CBS or PSP, together with healthy controls, were recruited from the Cambridge Centre for Parkinson-plus. Grey matter volume, cortical thickness, and subcortical volumes were derived using FreeSurfer for 210 cortical and 36 subcortical regions defined by the Human Brainnetome Atlas. Participants with PSP were classified into Richardson syndrome (PSP-RS), corticobasal syndrome variant (PSP-CBS), frontal variant (PSP-F), and other presentations (PSP-Other). Bayesian hierarchical ANOVA models with appropriate priors were used to estimate group differences. Regions of practical equivalence (ROPE) were calculated to assess evidence of meaningful group effects. A total of 428 people were included (113 PSP-RS, 30 PSP-CBS, 23 PSP-Other, 19 PSP-F, 81 CBS, and 162 healthy controls). For grey matter volume, there was evidence of whole brain volume loss compared to controls for all disease groups except PSP-Other, which showed evidence of no difference. For cortical thickness, there was evidence of global cortical thinning in CBS compared to controls, but for no other group. For subcortical volume all groups showed evidence of volume loss compared to controls. Patterns of regional atrophy were identified in keeping with previous literature, with the largest effect observed in the left pre-motor thalamus (30\% reduction in CBS). There was greater loss of subcortical volume in PSP-RS compared to other PSP subgroups. Bayesian hierarchical modelling provides a feasible framework for quantifying regional brain atrophy, with interpretable effect size estimates and uncertainty measures. This approach complements conventional statistical methods, particularly in the assessment of rare neurodegenerative and neuropsychiatric disorders.

Background: Relapsing-remitting multiple sclerosis (RRMS) often progresses to secondary-progressive MS (SPMS), but diagnosis is typically retrospective, delaying potential interventions. Existing rule-based and machine learning approaches often lack prospective validation and provide no uncertainty estimates, limiting clinical adoption. Objective: To prospectively evaluate a conformal prediction (CP)-enabled random forest model for reproducing clinician-recorded disease course labels in the Swedish Multiple Sclerosis Registry (SMSReg) and compare its classifications with the Lorscheider criteria. Methods: The CP model was trained and calibrated on SMSReg-2022 (10,787 individuals, 85,461 hospital visits) and then validated on SMSReg-2025 (15,719 individuals, 45,077 hospital visits; not included in the SMSReg-2022 training/calibration/testing datasets). Performance was assessed at the hospital visit and individual levels and compared with the Lorscheider criteria. Results: The model maintained good calibration on the prospective dataset. At the per-hospital visit-level, the model accuracies were 92% (RRMS) and 95% (SPMS). At the individual level, sensitivity was 98%, specificity 89%, and F1-score 0.75. With clinician-recorded labels as reference, the model showed higher sensitivity than the Lorscheider criteria (98% vs. 71%), more transition assignments (90% vs. 57%), and higher F1-score (0.76 vs. 0.69). Conclusion: The CP-enabled model prospectively reproduced clinician-recorded disease course labels with calibrated uncertainty, supporting harmonization and decision support.

Tissue-based assays provide broad screening for neural autoantibodies but remain vulnerable to technical and reader-dependent variability. We evaluated an integrated workflow combining automated 3,3'-diaminobenzidine tissue-based assay processing, digital whole-slide imaging, and interpretable deep learning. Model development used 2,357 retrospective serum and cerebrospinal fluid images referred from more than 80 institutions and processed in a centralized laboratory, with reference labels established by expert-consensus tissue-based assay interpretation. A prospective validation cohort included 200 images from 200 unique patients (154 positive and 46 negative; 100 serum and 100 cerebrospinal fluid). The same images were evaluated by two expert and two novice readers in a fixed-order two-round study, with unaided interpretation followed by artificial-intelligence-assisted interpretation after a washout of at least two weeks. The standalone binary classifier achieved an area under the receiver operating characteristic curve of 0.922, accuracy of 86.5%, sensitivity of 85.7%, and specificity of 89.1% in prospective validation. Pooled reader accuracy was 90.4% in the unaided round and 97.4% in the artificial-intelligence-assisted round (McNemar P < 0.001), with specificity of 82.6% and 99.5%, respectively. Novice-reader accuracy was 83.3% unaided and 96.5% with artificial-intelligence assistance (P < 0.001), approaching unaided expert accuracy of 97.5%. Among tissue-based-assay-positive cases, reader accuracy for cytoplasmic/nuclear antigen-associated versus neural surface antigen-associated staining-pattern subclassification was 88.8% unaided and 94.0% with artificial-intelligence assistance (P < 0.001). These findings support further multicentre, cross-platform evaluation of artificial-intelligence-assisted neural autoantibody tissue interpretation.

Alternating hemiplegia of childhood (AHC) is a rare neurodevelopmental disorder primarily caused by heterozygous de novo mutations in the ATP1A3 gene, which encodes the neuron-specific catalytic 3 subunit of the P-type Na/K-ATPase. Among these, the E815K variant is the second most frequent ATP1A3 mutation in AHC and is associated with the most severe clinical phenotypes, characterized by frequent epileptic and dystonic episodes and profound developmental impairment, making it a key target for mechanistic study. Although E815K was shown to disrupt pump function in heterologous systems and animal models, its impact on human neurons remain poorly understood. To investigate its disease-relevant pathophysiology, we generated induced pluripotent stem cells (iPSCs) from an AHC patient carrying the E815K mutation and differentiated them into mature neurons. Patient-derived neurons displayed normal differentiation and synaptogenesis, with preserved evoked synaptic transmission. However, 3-specific Na/K pump currents were nearly abolished, whereas 1 activity remained intact. This selective dysfunction was associated with a depolarized resting membrane potential, reduced input resistance, and diminished intrinsic excitability. Patient neurons generated fewer action potentials in response to depolarizing current steps, displayed altered firing patterns, and showed significantly decreased voltage-gated sodium current densities, while potassium conductance remained unaffected. Taken together, these results indicate that the ATP1A3 E815K mutation disrupts intracellular sodium homeostasis and consequently modifies the excitability of human neurons. Overall, these findings provide mechanistic insight into the molecular pathophysiology underlying this AHC variant and thereby establish a patient-derived neuronal model which serves as a platform for future drug screening approaches and therapeutic investigation.

Introduction and objectives Hydrocephalus is a common complication of aneurysmal subarachnoid haemorrhage. This is one of several standard indications for the insertion of an external ventricular drain, but there are no standard guidelines for timing of extraventricular drain discontinuation in this population. Therefore, the study aims were to examine the 1) factors associated with extraventricular drain duration in aneurysmal subarachnoid haemorrhage and 2) association between extraventricular drain duration and clinical and resource-based outcomes. Methods In this single centre retrospective cohort study, data for adult patients treated in the ICU between 2015-2023 with aneurysmal subarachnoid haemorrhage and requiring an extraventricular drain were analysed. Data were extracted from both a prospective patient registry and the electronic medical record. Linear regression modelling was used to identify the factors associated with extraventricular drain duration. Measures used to examine the association between extraventricular drain duration, and the outcomes of interest included hazard ratio, relative risk, and mean differences as appropriate for a specific outcome. Results Of the participants (n=205), 68% (n = 140) were female, mean age was 60.7 (SD 13.3) years and 71% (n = 145) had a modified Fisher score of 4. Mean extraventricular drain duration was 15.3 (SD 8.6) days. The number of days mechanically ventilated and extraventricular drain challenge by clamp trial were associated with an increased duration of extraventricular drain treatment. Increased extraventricular drain duration was associated with an increased incidence of ventriculoperitoneal shunt insertion, and an increase in ICU and hospital length of stay when extraventricular drain duration exceeded 20 days. Conclusion The factors associated with an increased duration of extraventricular drain treatment were a longer duration of mechanical ventilation. The outcomes associated with an increased duration of extraventricular drain treatment were an increased incidence of ventriculoperitoneal shunt insertion, an increased incidence of ventriculitis when extraventricular drain duration exceeded 20 days, and an increase in ICU length of stay. These study findings may inform the conduct of a larger multi-centre study to examine the factors associated with duration of treatment with extraventricular drain, and outcomes associated with extraventricular drain duration.

Introduction: Neuroinflammation is a known pathophysiologic mechanism in multiple sclerosis and a proposed mechanism in fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Positron Emission Tomography (PET) imaging of the translocator protein (TSPO) has been widely used to measure neuroinflammation, though second-generation ligands are highly sensitive to a single nucleotide polymorphism, rs6971, resulting in high, mixed, and low affinity binders. It is unknown whether this polymorphism is associated with neuroinflammatory disorders. Materials and Methods: Eighty-six total participant genotypes for TSPO binding affinity were identified through Sanger sequencing (30 fibromyalgia, 21 ME/CFS, 11 multiple sclerosis, and 24 healthy controls). Associations between patient group and genotype were assessed with Fishers Exact test. Associations between genotype and symptom severity from self-report questionnaires were assessed with Kruskal-Wallis tests. Results: In the present study individuals with fibromyalgia, (ME/CFS), or multiple sclerosis were more likely to have a mixed- or low-affinity genotypes compared to healthy controls. Presence of the low or mixed genotypes were also associated with greater self-reported fatigue severity and depressive symptoms. Discussion: These findings should be confirmed in larger samples but suggest functional consequences of rs6971 polymorphism that may be related to the pathophysiology of pain and fatigue illnesses.