Journal of Neurology

Background: Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP), established biomarkers of neuroaxonal injury and astroglial pathology, are frequently only assessed in blood, which limits conclusions regarding their origin. Bi-compartmental analyses of CSF and serum may help differentiate central or peripheral origin of biomarker elevation. Moreover, studies on NfL and GFAP in distinct neuroinfectious disease (NID) phenotypes are limited. Methods: This retrospective monocentric study analyzed CSF and serum from patients with (meningo-)encephalitis/myelitis (TI+; n=48), meningitis (TI-; n=80), (cranial) nerve palsies/polyradiculitis (PND; n=61), and 113 non-neuroinflammatory/non-neurodegenerative controls. A bi-compartmental model using scatter plots and simple linear regression was applied to assess the origin of blood biomarker levels and discriminate between central and peripheral pathology. Results: CSF and serum NfL and GFAP z-scores were significantly higher in TI+ compared with TI- (CSF-GFAP p<0.001/sGFAP p=0.0083; CSF-NfL p=0.003/sNfL p=0.0004). TI+ and PND differed only in GFAP levels, which were higher in TI+ (CSF-GFAP p=0.0049/sGFAP p=0.003). Bi-compartmental analysis revealed simultaneous elevation of CSF and serum NfL in TI+, indicating predominantly central origin, whereas PND demonstrated a shift toward higher sNfL levels suggesting peripheral origin. Higher clinical severity (modified Rankin Scale 3-5) was associated with elevated serum and CSF GFAP and NfL (sGFAP p=0.012/sNfL p=0.002; CSF-GFAP p<0.0001/CSF-NfL p=0.0001), which also predicted unfavorable outcome at discharge (sGFAP p=0.006/sNfL p=0.004; CSF-GFAP p=0.003/CSF-NfL p=0.012). Conclusions: NfL and GFAP were associated with brain/myelon involvement in NID, predominantly reflecting central pathology. Despite strong CSF-serum correlations, bi-compartmental approaches provide additional insight into biomarker origin and disease compartment.

CLN3 disease is an inherited neurodegenerative disease, typically with childhood onset, and characterized by vision loss, seizures, cognitive decline, and difficulties. The CLN3 Staging System (CLN3SS) characterizes disease progression. Our aim was to assess differences in cognitive test scores in relation to CLN3SS among individuals with CLN3 disease. We evaluated the relationship between cognitive test performance and the CLN3SS in individuals with genetically confirmed CLN3 disease. Participants completed tasks of verbal reasoning, vocabulary knowledge, attention, fund of information, and ability to recite the alphabet. One-way ANOVA testing assessed differences in mean cognitive test score among CLN3SS score groups, and Chi-square testing was used to compare the proportion in each CLN3SS group that could recite the alphabet. Data were evaluated from a sample of 85 individuals with a total 245 CLN3SS assessments conducted within 6 months of their cognitive testing, A significant decrease in test scores was found between CLN3SS Stages 1 (vision loss present) and 2 (vision loss and seizures present) for each of the cognitive tests. The proportion of participants able to recite the alphabet also decreased from Stage 1 to Stage 2 (X2=12.1, p<.01). Cognitive ability declines with advanced disease severity in CLN3 disease, though motor disability in Stage 3 likely contributes to difficulty participating in cognitive assessment at this later disease stage. Understanding the relationship between cognition and CLN3 disease stage may help guide decision making, i.e., determining who could or should undergo cognitive assessment for clinical care or for group stratification in disease modifying clinical trials.

Abstract Objectives: Amyotrophic lateral sclerosis (ALS) is a clinically heterogeneous neurodegenerative disease requiring reliable biomarkers to improve patient stratification and trial design. While serum neurofilament light chain (sNfL) reflects neuroaxonal stress and disease aggressiveness, troponin T (TnT) may capture complementary aspects of neuromuscular involvement. We assessed the associations of TnT and sNfL with D50-derived measures of disease aggressiveness (D50) and disease accumulation (rD50) in ALS. Material and Methods: In this retrospective observation, TnT and sNfL levels from ALS patients in two independent German cohorts were analyzed using the D50 disease progression model; discovery cohort (Essen, n =433) and validation cohort (Bonn, n =185). Results: In both cohorts TnT demonstrated a robust correlation with rD50-defined phases across all aggressiveness subgroups (p<0.001). There was no consistent pattern regarding sNfL and the rD50 phases. sNfL concentrations demonstrated a significant and inverse correlation with D50 applied for all disease aggressiveness subgroups (p<0.001). Correlations of TnT levels with D50 disease aggressiveness groups were generally less strong and inconsistent between the two cohorts. In the discovery cohort only low aggressiveness subgroups correlated significantly (p<0.001), intermediate aggressiveness subgroups showed only a weak correlation (p<0.05) with TnT levels. High disease aggressiveness subgroups showed no significant correlation with TnT. Conclusion: In application of the D50 disease progression model, TnT was strongly associated with disease accumulation (rD50) across all disease phases, independent of disease aggressiveness (D50), whereas sNfL robustly reflected disease aggressiveness but not overall disease burden. These complementary biomarker profiles highlight the value of an integrated approach for refined disease stratification in ALS. Combining TnT and sNfL may enhance clinical decision-making, improve monitoring of disease progression and treatment response, and support optimized clinical trial design.

Introduction: Blood neurofilament light chain (NfL) is an accessible biomarker of neuroaxonal injury across a broad range of neurological disorders, but its clinical implementation requires robust cross-platform analytical and clinical comparability. The objective of this study was to evaluate the analytical and clinical comparability of plasma NfL measurements using Simoa and Lumipulse across different neurological conditions, by assessing cross-platform agreement and the ability of both assays to distinguish neurological diseases from healthy controls. Paired CSF analyses were performed in a subset of participants to biologically anchor plasma findings to the central compartment. Methods: 383 individuals were included, comprising healthy controls and patients with neurodegenerative conditions, multiple sclerosis and stroke. Plasma NfL was measured in all participants using both Simoa and Lumipulse, with paired CSF analyses in a subset of 92 individuals The Lumipulse testing intermediate precision and between-day repeatability was assessed as by the CLSI EP15. Cross-platform agreement for plasma NfL was evaluated using correlation analyses, Passing-Bablok regression and Bland-Altman analysis. Associations between plasma/CSF NfL concentrations were assessed using Spearman's rank correlation analysis for each platform, separately. Age-adjusted cross-diagnostic differences were evaluated using permutation ANCOVA and multiple linear regression models for each platform, separately. Results: Plasma NfL measured by Simoa and Lumipulse showed strong cross-platform concordance in the whole cohort ({rho}=0.90), with similarly strong concordance observed for CSF NfL in the subset with paired samples ({rho}=0.90). Method-comparison analyses in plasma demonstrated consistent agreement between platforms, with identifiable constant and proportional bias, alongside systematically higher absolute plasma NfL values measured by Lumipulse. Within-platform analyses showed significant correlations between plasma and CSF NfL concentrations ({rho}=0.72 for Simoa; {rho}=0.78 for Lumipulse). Noteworthy, Lumipulse NfL CSF and Blood kits exhibited high precision and analytical accuracy. Across both assays, plasma NfL increased with age and was significantly elevated in patients with neurological disorders compared with healthy controls. Discussion: Simoa and Lumipulse capture a consistent biological signal in plasma across patients with neurological disorders, although their absolute NfL values differ, supporting the use of platform-specific reference ranges in clinical practice.

AIM: STXBP1-related disorder (STXBP1-RD) is a severe developmental and epileptic encephalopathy characterized by early-onset seizures and persistent cognitive and motor impairments. With disease-modifying trials emerging, a disorder-specific severity scale is needed. To address this, we adapted a validated clinician-reported measure from CDKL5 Deficiency Disorder to develop the STXBP1 Clinical Severity Assessment (S-CSA) and evaluated its psychometric properties. METHOD: The S-CSA was adapted from the CDKL5 Clinical Severity Assessment through expert consensus sessions with STXBP1 clinicians. Revisions addressed gaps in motor and vision domains, adding tremor and vision items. The measure was administered to 123 individuals with STXBP1-RD. Psychometric evaluation included confirmatory factor analysis, internal consistency, composite reliability, average variance extracted, and distinctiveness, compared with recommended thresholds. RESULTS: Analyses supported a three-domain structure (motor, communication, vision) with factor loadings >0.5 and strong internal consistency (Cronbachs alpha >0.7; composite reliability >0.88). Model fit and variance metrics met recommended standards, and domains demonstrated distinctiveness. No ceiling or floor effects were observed. Minimal skew was seen in motor (0.34) and communication (0.16) domains; positive skew in vision (2.2) was seen, identifying patients with and without cortical visual impairment. INTERPRETATION: The S-CSA demonstrates strong validity and reliability in STXBP1-RD and may show utility in clinical trials for STXBP1-RD and potentially other severe DEEs. Key Words: STXBP1-Related Disorder, Developmental and Epileptic Encephalopathies, Clinical Outcome Assessments

Ankle clonus is a sustained, involuntary, rhythmic muscle contraction frequently observed in humans with spinal cord injury (SCI). Although its pathophysiology remains incompletely understood, converging evidence suggests a role for brainstem systems in its generation. Following SCI, brainstem neuromodulatory inputs partially compensate for the loss of descending motor pathways by regulating motoneuron excitability during involuntary contractions, suggesting their involvement in the generation of clonus. To test this hypothesis, motoneuron excitability in response to Ia synaptic input was quantified using the soleus H reflex and maximal motor response (H/M ratio), and brainstem involvement was probed using the long lasting component of the cutaneous reflex (LLR) in the tibialis anterior and soleus muscles, as well as the StartReact response-an involuntary release of a movement triggered by a startling stimulus thought to engage the reticulospinal tract. We studied individuals with chronic SCI, both with and without ankle clonus, using standardized clinical tests across two days. Participants with clonus showed elevated H/M ratios, indicating increased motoneuron excitability, whereas those without clonus exhibited lower values than controls. Additionally, individuals with clonus exhibited longer LLR duration and greater LLR magnitude in both muscles, along with shorter reaction times to startle stimuli, consistent with enhanced monoaminergic and reticulospinal contributions. Notably, LLR duration was positively correlated with both StartReact response and H/M ratio. Together, these findings support a role for descending brainstem systems-particularly monoaminergic and reticulospinal pathways-in the maintenance of clonus in chronic SCI.

We investigated whether people with Parkinson's disease who are dual GBA1+LRRK2 carriers have a milder, LRRK2-like phenotype as previously reported. This was accomplished by comparing clinical features and alpha-synuclein seed amplification assay (SAA) positivity rates between dual GBA1+LRRK2-PD(n=13), GBA1-PD(n=169) and LRRK2-PD(n=175) carriers in a cross-sectional retrospective study of Parkinson's Progression Markers Initiative (PPMI) data. Our results show that GBA1+LRRK2-PD rate(83%) is closer to GBA1-PD rate(87%) rather than LRRK2-PD rate (62%mp-value>0.05). GBA1+LRRK2-PD have both non-motor and motor phenotypic similarity of GBA1-PD(p-value>0.05). This small PPMI cohort indicates that dual GBA1+LRRK2-PD carriers' SAA positivity and phenotype are aligned with GBA1-PD.

Importance: The real-world prevalence and the clinical determinants associated with cognitive impairment in diverse patients with Parkinson disease (PD) have been understudied. Objective: To determine the prevalence of cognitive impairment in a diverse PD cohort and explore associations with vascular, motor, and nonmotor factors. Design, setting and participants: Case-only analysis of diverse patients with PD recruited to the East London Parkinson disease project (July 2022 to July 2025) at the Royal London Hospital, a tertiary referral center. Of 237 patients with cognitive status defined by expert, multi-disciplinary, clinical consensus, 223 remained after excluding atypical or secondary parkinsonism, other dementias, and study withdrawal. Exposures: Observational study (no experimental intervention); exposures included vascular risk factors, motor and nonmotor clinical features. Main Outcome(s) and Measure(s): The main outcome was cognitive impairment (PDCI), defined as mild cognitive impairment (PDMCI) or dementia (PDD) by expert clinical consensus based on clinical, imaging, and cognitive screening. Results: Among 223 participants with a median disease duration of 4.0 (1.0-9.0) years, 112 (50.2%) had PDCI, including 62 (27.8%) with PDD and 50 (22.4%) with PDMCI. South Asian ethnicity was associated with PDCI in univariate analysis (OR, 2.30; 95% CI, 1.32-4.00, P = .003) and the association strengthened after adjusting for age, gender, years of education, disease duration and depression scores (OR, 3.60; 95% CI, 1.68-7.69, P < .001). PDCI was associated with increased odds of smoking (OR, 3.62; 95% CI, 1.56-8.41, P = .003) in the adjusted model. Increased odds were also associated with motor severity (Movement Disorders Society Unified Parkinson Disease Rating Scale Part III; OR per point increase 1.07; 95% CI, 1.04-1.10; P < .001), and daytime somnolence score (Epworth Sleepiness Scale; OR per point increase, 1.08; 95% CI, 1.01-1.16; P = .03). Conclusions and Relevance: In this multi-ethnic study of PD using gold-standard expert multidisciplinary consensus, cognitive impairment was common and more prevalent among South Asian individuals. Smoking, greater motor severity, and higher daytime somnolence were associated with increased odds of cognitive impairment.

Introduction Functional neurological disorder (FND) is a common cause of neurological disability and is associated with substantial healthcare utilisation and cost. Most available treatments target specific symptom subtypes, and prospective evidence regarding the effect of treatment on health-system costs remains limited. We evaluated the real-world clinical and economic outcomes of a transdiagnostic outpatient intervention, attention-based rehabilitation (ABR). Methods We conducted a pragmatic waitlist-controlled study in 54 consecutively referred patients with neurologist-diagnosed FND attending a specialist outpatient service. Clinical outcomes--including quality of life (Short Form-36), social and occupational participation (Work and Social Adjustment Scale), symptom severity, and mental health (Hospital Anxiety and Depression Scale)--were assessed at waitlist entry, treatment commencement, treatment completion, and 6 and 12 months post-treatment. Healthcare utilisation and costs were obtained prospectively from health-service financial records for the 6 months preceding treatment, the treatment period, and two consecutive 6-month post-treatment periods. Longitudinal clinical outcomes and healthcare costs were analysed using Bayesian mixed-effects and mixture models, respectively. Results All clinical measures remained stable or worsened during the waitlist control period. Across treatment, six of eight SF-36 domains, WSAS, employment status, and both HADS subdomains improved, with maintenance through 12 months. Patient-reported symptom improvement persisted post-treatment. Expected monthly health system costs approximately halved post-treatment, with net cost savings by approximately 50 days. Conclusion A fixed-duration, symptom-agnostic outpatient ABR programme was associated with durable improvements in functioning and quality of life, alongside substantial reductions in healthcare utilisation and cost, supporting scalable symptom-agnostic treatment models for FND.

Background: Mucopolysaccharidosis type IIIB (MPS IIIB) is a devastating neurodegenerative lysosomal storage disorder caused by alpha-N-acetylglucosaminidase (NAGLU) deficiency. There is currently no approved therapy. We report the 3-month outcomes of a novel intracerebroventricular (ICV) gene therapy in a child with MPS IIIB. Methods: In an open-label, single-center, investigator-initiated trial (ChiCTR2600121466), a single dose of RDGT-101 (2.0E14; vg of an AAV9 vector encoding human NAGLU) was administered via ICV infusion. Primary outcomes were safety and tolerability. Secondary outcomes included serum NAGLU activity, urinary heparan sulfate (HS) excretion, and neurocognitive function. Exploratory analyses included hematological parameters. Results: The patient achieved serum NAGLU activity (17.06 nmol/mL/hour) approaching that of healthy controls (17.75 {+/-} 1.37 nmol/mL/hour) by Month 3, accompanied by a 58.4% reduction in urinary HS. Clinically, previously severe hand and toe contractures resolved, allowing for full extension. Neurocognitive improvements were observed, including clear articulation, logical conversation, and sustained eye contact. Hematological analyses revealed normalized red blood cell indices and improved iron utilization. No dose-limiting toxicities, serious adverse events, or clinically significant laboratory abnormalities were observed. Conclusions: A single ICV infusion of RDGT-101 was safe and well-tolerated in this patient with MPS IIIB. Early biochemical correction was accompanied by marked improvements in somatic, neurocognitive, and hematological parameters. These findings support further investigation of ICV AAV9 gene therapy for MPS IIIB.

AO_SCPLOWBSTRACTC_SCPLOWO_ST_ABSBackgroundC_ST_ABSExcessive or unregulated iron in the brain can lead to toxicity via ferroptosis and related mechanisms. Iron accumulation in the substantia nigra (SN) occurs with Parkinsons disease (PD) progression and has been hypothesized to be an etiological mechanism. ObjectiveBased on emerging clinical observations, we tested the hypothesis that iron accumulation in the SN is a consequence of levodopa administration and is treatment-related rather than an intrinsic etiological mechanism. MethodsWe used both unilaterally lesioned 6-OHDA and unlesioned rats. We administered levodopa to rats at doses that were allometrically calculated to be similar to those used in mid-stages of PD. Iron-sensitive MRI (R2*) was used to quantify iron in the brain. Both group and intra-subject analyses were done using paired t-tests and linear mixed models. ResultsExperiment 1 used the unilateral 6-OHDA model to take advantage of the almost complete lack of dopamine neurons on the lesioned side. This permitted testing if levodopa-induced iron accumulation occurred in and/or depended on dopamine neurons. Fifteen days of levodopa treatment caused a marked increase in Fe in both the lesioned (p = 0.042) and unlesioned sides (p = 0.005), showing that iron accumulation does not depend on the presence of dopamine neurons. Based on these data, in experiment 2 unlesioned rats were administered levodopa daily for four months, and iron (R2*) values were assessed at baseline, 1, 2, and 4 months. In these normal rats, the levodopa-treated group had significantly increased Fe (R2*) in the substantia nigra compared to the vehicle group (p = 0.013). Interestingly, these effects were limited to the striatum, with no increases seen in the striatum, ventral tegmental area, or frontal cortex ConclusionLevodopa triggers processes that increase iron deposition in the substantia nigra, but this process may not depend on dopamine neurons. The underlying mechanisms and the effect on PD progression are important to elucidate and may transform how we understand PD and related neurodegenerative disorders

Increased iron in the substantia nigra has been thought to be a mechanism potentially related to the etiology and/or progression of Parkinson's disease (PD). We hypothesized that genetic variants of HFE, a major iron regulatory gene, would influence substantia nigra iron accumulation in PD. The HFE genotype was obtained from 195 subjects (102 PD and 83 Controls) who participated in the PD biomarker program (PDBP) in central Pennsylvania, United States. For this study, carriers of two SNPs (HFE H63D and/or C282Y) were considered as variants and the others as wildtype. Susceptibility MRI metrics (QSM, R2*) were assessed at baseline, 18, and 36 months. The primary region of interest was the substantia nigra, the key pathology focus of PD. Group differences in substantia nigra QSM and R2* between HFE variants carriers and wildtype were compared between PD patients and controls at baseline and in progression over time using linear mixed-effects model. We also used interaction analyses to explore if HFE genotype impacts clinical measures of PD progression. Of the 102 PD patients, 72 were wildtype, and 30 HFE variant. Of the 83 controls, 56 were wildtype and 27 were HFE variants. There was a total of 451 data points available for analysis. Compared to wildtype patients, patients with HFE variants showed higher baseline substantia nigra QSM (p=0.006), but not higher R2* (p=0.487). Controls had no HFE-dependent differences. Longitudinally, substantia nigra QSM and R2* increased significantly over both 18- and 36-months regardless of HFE status (p's<0.05). Compared to wildtype, PD subjects with HFE variants showed an overall faster increase in R2* (p=0.004) and QSM (p=0.003) over the total 36-month epoch, and this reached the statistical significance for R2* during the first 18-months (p=0.026) and for QSM in 36-months (p=0.005). HFE status showed a significant interaction with motor scales [MDS-UPDRS II (p=0.006), III (p=0.0002)], suggesting a faster symptomatic progression in PD patients with HFE variants compared to wildtype. Although HFE genotype has been shown not to associate with the occurrence of PD, these data demonstrate for the first time that in PD patients substantia nigra iron accumulation and disease progression are affected by HFE genotype. The underlying mechanisms may be important in the progression of PD and the development of personalized treatment.

Germinal matrix-intraventricular hemorrhage (GM-IVH) is one of the most frequent and severe neurological complications in preterm infants (PT). It triggers an inflammatory response accompanied by neuronal and glial injury and may progress to post-hemorrhagic ventricular dilatation (PHVD), thereby increasing long term disability and cognitive deficits. Nevertheless, the characteristics and evolution of the associated pathology is poorly understood. To assess neuroimmune response and neuropathology induced by GM-IVH, we quantified cytokines, glial activation and neurodegeneration makers in cerebrospinal fluid collected from 12 patients with grades III/IV GM-IVH and PHVD and 5 controls neonates from the onset of pathology up to 2 months of age. Additionally, to evaluate long-term deficits and behavioral outcomes, we used standard behavioral test including Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) at 2 years of age. Interestingly, we found that while pathology markers such as ubiquitin carboxy-terminal hydrolase L1 (UCHL1), alpha II spectrin breakdown product 145 (SBDP145) and myelin basic protein (MBP) are elevated in PT, their level decline over time. Furthermore, cytokine profiling identified two divergent temporal trajectories (i.e., diminishing or sustained) that correspond with either neuronal or astrocytic markers. Specifically, diminishing cytokines including IL-6, IL-8, and IP-10 decreased with age and were correlated with neuronal markers such as SBDP145, UCH-L1, and MBP. In contrast, sustained cytokines such as IFN-{gamma}, IL-7, IL-13, and MCP-1 remained elevated or unchanged throughout the study period and were positively correlated with astrocyte reactivity marker GFAP. Notably, sustained cytokines were consistent with worse motor function and behavioral outcome. Together, longitudinal CSF analysis in PT with severe GM-IVH and PHVD identifies a cytokine profile that declines and correlates with neuronal and glial injury markers, and another that remains sustained and correlates with gliosis and adverse neurodevelopmental outcomes. These findings highlight potential CSF biomarkers associated with disease progression and long-term neurological impairment, providing a foundation for future evaluation of candidate therapeutic interventions.

Purpose: Polypharmacy is highly prevalent among critically ill patients, yet it's independent impact on intensive care unit (ICU) outcomes in sepsis remains critically unexplored. We aimed to evaluate whether pre-admission polypharmacy independently predicts ICU mortality and provides incremental prognostic value using the medication reconciliation module of the MIMIC-IV-ED linked database. Materials and Methods: We conducted a retrospective cohort study of 3,347 adults admitted to the ICU who met Sepsis-3 criteria. Pre-admission polypharmacy was categorized as none (0-4), standard (5-9), or high (>=10 medications). Multivariable logistic regression, propensity score matching, and reclassification analyses (NRI/IDI) were performed. The primary outcome was in-hospital ICU mortality. Results: High polypharmacy was present in 58.9% of patients. Crude ICU mortality increased sequentially: 18.5% (none), 26.0% (standard), and 27.5% (high; p < 0.001). After multivariable adjustment, high polypharmacy independently predicted in-hospital ICU mortality (aOR 1.45, 95% CI (1.10-1.91)), and 28-day mortality (aOR 1.47). Drug-class analysis identified statins as significantly protective (aOR 0.56), whereas RAS blockers combined with diuretics increased acute kidney injury risk (aOR 1.49). Propensity matching confirmed the primary mortality association (matched aOR 1.28). Conclusions: By utilizing the ED medication reconciliation table, this study proves high polypharmacy represents a distinct 'pharmacologic frailty', independent of acute severity. Available instantly at triage, this zero-latency metric provides significant early prognostic value (SOFA NRI = 0.24) and identifies actionable high-risk interactions (e.g., RAS blockers plus diuretics) for immediate, targeted pharmacist-led intervention upon ICU admission.

Background: Parkinson's disease (PD) is the second most common progressive neurological disorder that is pathologically characterized by the loss of dopaminergic neurons within the substantia nigra (SN). However, disease progression probably involves coordinated changes across both neuronal and glial cell populations. Although single-nucleus RNA-seq resolved cell-type-specific transcriptional profiling, differential expression and regulatory interpretation are commonly reported separately; however, they may limit the mechanistic prioritization to uncover novel therapeutic targets. Methods: Here, we performed sample-aware pseudobulk framework analysis on single-nucleus transcriptomes obtained SN of PD and control donors. Cell-type-specific differential expression for PD vs. control was identified using edgeR quasi-likelihood modeling (FDR < 0.05; |log2FC| > 0.5). Further, to quantify disease-specific remodelling, we computed one-vs-rest cell-type specificity scores in each condition and defined delta-specificity as the PD-control shift. We further prioritized the gene-set for dopaminergic neurons and microglia based on edge R significance and delta-specificity shifts, followed by upstream regulatory assessment using transcription factor enrichment and subnetwork visualization using ChEA-KG. Moreover, we used Cellchat to identify altered cell-cell communication networks to infer differences between both conditions. Results: Dopaminergic neurons demonstrated upregulation of neuronal-state remodeling transcriptional programs related gene sets in PD group, including receptor signaling and contact/guidance pathways (e.g., CHRM3, ROBO1, PLXNA4, UNC5D, EFNA5), neuronal excitability homeostatsis, RNA components, cellular traffickings and proteostasis, suggesting coordinated remodeling in surviving neuronal population. Microglia exhibited a compact PD-associated signature enriched for regulatory and activation state-related genes. TF networks analysis revealed distinct regulatory subnetwork in each population,including BNC2-centered network in microglia and an NPAS3-centered network in dopaminergic neurons with embedded ZNF804A and chromatin-associated components. Conclusions: In summary, integrating pseudobulk, delta-specificity scoring and TF-network enrichment analysis provides coherent dopaminergic and microglial programs in PD substantia nigra. This framework prioritizes cell-type-specific potential candidate mechanisms for downstream validation. The inferred regulatory networks and interactions are hypothesis generating and need orthogonal validation, such as spatial or proteomics approaches and independent cohorts.

Introduction. The cerebellum is increasingly recognized as a key contributor to cognitive reserve and network adaptation in Parkinsons disease (PD). However, how cerebellocortical and cerebellobasal ganglia connectivity reorganizes across disease duration and cognitive status remains incompletely understood. Methods. Resting state fMRI data from the Parkinsons Progression Markers Initiative were analyzed in 172 individuals with PD. We investigated cerebellobasal ganglia and cerebellocortical connectivity using ROI to ROI and seed to voxel pipelines respectively, providing novel insights into both subcortical and cortical effects. Effects of age, disease duration, cognitive status, motor symptom severity, and dopaminergic medication were assessed. Results. Across all participants, cerebellar lobule VI and vermis VI showed robust positive connectivity with the pallidum, along with high intracerebellar coupling. When controlling for dopaminergic medication, lobule V connectivity with the primary motor cortex was reduced. Age was associated with lower cerebellobasal ganglia connectivity widespread across nodes, evident across medication states. Disease duration showed region specific effects: in cognitively normal PD, longer duration corresponded to stronger lobule V and temporal cortex connectivity as well as higher Crus I and precentral gyrus connectivity than PD with cognitive dysfunction. Motor symptom severity was not related to connectivity. Conclusions. Cerebellar connectivity patterns in PD are linked to disease duration and cognitive preservation. Enhanced cerebellocortical coupling in cognitively normal PD may reflect compensatory network recruitment that diminishes with cognitive decline.

Background and Objectives Patients with peripheral neuropathies (PN) commonly exhibit balance impairment. In clinical practice, balance is typically assessed using the Rombergs test and ataxia scales, which rely on examiner interpretation, while objective biomarkers for quantifying balance remain lacking. Wearable sensors are valuable tools for objectively quantifying gait abnormalities in PN patients and may capture clinically meaningful changes over time. By integrating these parameters, artificial intelligence (AI) can assist in generating a digital score that enables easy, objective, and reproducible monitoring of patients postural balance. This study aims to generate and assess an AI-generated digital Rombergs test to quantify balance impairments in a cohort of PN patients. Methods PN patients were assessed in a longitudinal study using a wearable system composed of inertial sensors placed on the trunk and plantar pressure sensors integrated in insoles. Patients performed the Rombergs test under both eyes-open and eyes-closed conditions and were classified according to ataxia severity (mild, moderate, or severe) following the score obtained in item 1 of MICARS and SARA scales. Results We included 97 patients with PN (including autoimmune and hereditary polyneuropathies), and 117 healthy controls (HC). Significant differences in trunk sway and center of pressure (COP) were observed between groups, particularly with eyes closed. Using wearable sensor parameters, we developed an AI digital Rombergs test, which correlated with clinician-rated Rombergs test performance and distinguished patients with and without ataxia (AUC=0.632) and across different PN pathologies. Longitudinally, digital Rombergs test and iRODS showed concordant trajectories. Also, changes [&ge;]25% in the score were associated with clinical changes in ataxia severity measured by an increase in MICARS-SARA score (+1.42 points), whereas improvement was associated with a decrease (-0.20 points) in the scale. Discussion This study demonstrates that wearable sensors are useful to detect and quantify balance impairment. The AI-generated Rombergs test is an objective and reproducible tool for postural balance assessment, with robust discriminatory performance across clinical ataxia severity in PN. Scores longitudinal changes aligned with clinical severity, supporting its potential for monitoring disease progression and treatment response. Its strong association with balance measures reinforces its role as a quantitative biomarker of postural control in ataxia patients.

Introduction: Myalgic Encephalomyelitis (ME)/Chronic Fatigue Syndrome (CFS) is a debilitating condition characterised by severe fatigue and post-exertional malaise (PEM). Reported neuropsychophysiological abnormalities suggest ME/CFS is multifactorial, but current knowledge remains fragmented. This study protocol outlines a multimodal investigation designed to (1) compare neuropsychophysiological mechanisms between ME/CFS patients and healthy participants, (2) test an integrative model of ME/CFS, (3) identify neuropsychophysiological subgroups within the patient population, and (4) identify predictors of symptom response during rehabilitation. Methods and analysis: This study will enroll 115 ME/CFS patients and 55 healthy participants. Groups will be comparable in age, sex, and education level, with a larger patient sample enabling subgroup and longitudinal analyses. A cross-sectional assessment at baseline will be carried out in both groups. Patients will then be evaluated longitudinally throughout a standardized cognitive-behavioral therapy rehabilitation program delivered as routine care. Baseline measures include systemic inflammation and general health biomarkers, measures of autonomic and central nervous system function, neuroinflammation (magnetic resonance spectroscopy, [18F]DPA714 PET in a subsample), serum short-chain fatty acid levels, gut microbiota composition and function, and neuroendocrine and self-reported responses to psychosocial stress. Fatigue severity (physical and cognitive) and PEM will be assessed through validated questionnaires, ecological momentary assessment, and laboratory tasks. These will be re-evaluated during therapy, and all non-neuroimaging measures will be repeated after the rehabilitation program. Statistical analyses will comprise multivariate analysis of variance, general linear models, classification algorithms, structural equation models, least absolute shrinkage selection operator principal component regression (LASSO-PCR), cluster analysis and latent class growth analysis (LCGA).

Background Neuropsychiatric fluctuations in Parkinson's disease (PD) often accompany motor fluctuations, but their temporal relationship during the acute levodopa response remains unclear. Objectives To determine whether motor and neuropsychiatric responses occur synchronously during the OFF-to-ON transition. Methods Nineteen fluctuating PD patients underwent a high-resolution levodopa challenge with repeated assessments every 10 minutes for 60 minutes after levodopa administration. Motor symptoms (akinesia, rigidity) and neuropsychiatric fluctuations were quantified. Transition times (t25%-t50%-t75%-t100%) and response profiles were analyzed using correlation and clustering approaches. Results Motor and neuropsychiatric transition times were not correlated at any threshold (all FDR-corrected p>0.05; Bayes factors <1), supporting temporal dissociation. Among 18 patients with complete data, clustering revealed synchronous (6/18), neuropsychiatric-preceding (7/18), and motor-preceding (3/18) profiles. Conclusion Motor and neuropsychiatric responses to levodopa during PD fluctuations are partly independent and follow heterogeneous, patient-specific temporal profiles, supporting the search for distinct biomarkers and future individualized adaptative therapies

Background: Neurological, neuropsychiatric, and neurodevelopmental disorders cluster in ALS families, sharing a common genetic architecture with ALS. Pathogenic variants in genes associated with other neurological, neurodevelopmental, or neuropsychiatric disorders may also co-occur in ALS and modify phenotype. We have sought to determine the prevalence and clinical pattern of likely-pathogenic/pathogenic (LP/P) non-ALS neurological, neurodevelopmental, and neuropsychiatric variants, alone and in combination with ALS-gene variants, in two large ALS cohorts. Methods: Whole-genome sequencing (WGS) of 469 Irish and 774 Answer ALS people with ALS (pwALS) was analysed for ClinVar LP/P variants associated with other neurological (n = 15541), neurodevelopmental (n = 9761), and neuropsychiatric (n = 321) phenotypes. Inheritance patterns for associated genes (autosomal recessive/autosomal dominant) along with the associated phenotype were validated using OMIM. Standardised clinical data included family history, site and age of onset, El Escorial category, survival, motor decline, and cognitive and behavioural assessments. Known ALS-gene variants and C9orf72 repeat expansion status were included for each cohort. Results: Non-ALS neurological variants were identified in 47/469 (10.0%) Irish and 69/774 (8.9%) Answer ALS participants, most frequently in hereditary spastic paraplegia-associated genes (3.2% Irish; 2.8% Answer ALS). Irish neurological variant carriers showed higher frequency of respiratory onset (10.6% vs 1.2%, Fisher's exact p = 0.002, {Phi} = 0.20) and fewer premorbid behavioural symptoms (0.92 +/- 0.56 vs 3.08 +/- 0.97, Cohen's d = -0.40). Neurodevelopmental variants occurred in 12/469 (2.6%) Irish and 20/774 (2.6%) Answer ALS participants. In the Irish cohort, neurodevelopmental variant carriers had significantly shorter survival in Cox proportional hazards model (log-rank p = 0.005), corresponding to a more than two-fold increased hazard of death (HR = 2.25, 95% CI 1.26-4.00), and had significantly increased familial burden of neuropsychiatric disorders among first- and second-degree relatives (negative binomial IRR for carriers = 2.41, 95% CI: 1.12-5.18, p = 0.025). Across combined cohorts, 18 individuals (Irish n = 8; Answer ALS n = 10) carried [&ge;]2 LP/P variants spanning ALS and non-ALS genes. Conclusion: Rare LP/P variants in genes associated with other neurological and neurodevelopmental disorders occur in up to 12% of pwALS across two independent cohorts. Carriers show distinct phenotypes, shorter survival, and characteristic family history patterns. These findings suggest that extended pleiotropic and oligogenic architectures may contribute to ALS heterogeneity.