A recent Neurology digest,
as sent to subscribers

Study Type: Case-control study with meta-analysis of two independent cohorts (peripheral blood DNA methylation)

Key Question: Is biological ageing, measured by the GrimAge2 epigenetic clock, accelerated in frontotemporal dementia (FTD), and what drives it?

Key Findings:

• Pooled analysis (415 patients, 223 controls) showed greater GrimAge2 age acceleration in FTD (β = 1.17, 95% CI 0.46–1.88, p = 0.001), adjusted for sex, cell composition and smoking.
• Component analyses showed higher smoking-related methylation, inflammatory markers (TIMP-1, CRP) and HbA1c in FTD.
• Adjusting for smoking-related methylation attenuated the effect by ~48% (β = 0.62, 95% CI −0.01–1.24, p = 0.053).

Clinical Relevance: Suggests systemic inflammatory, metabolic and behavioural/lifestyle factors may contribute to FTD biology, though the findings are exploratory and not yet applicable to NHS clinical practice.

Limitations: Cross-sectional design cannot establish causality or direction, and smoking-related methylation may reflect disease-related behavioural change rather than pre-morbid exposure.

Study Type: Case series with functional validation (clinical, histological, transcriptomic, and in vitro reporter assay data)

Key Question: Does the non-coding CAPN3 3'UTR variant c.*534T>C cause calpainopathy in individuals with persistent hyperCKemia and a single identified coding CAPN3 variant?

Key Findings:

• 13 individuals from 11 unrelated families carried c.*534T>C in trans with a known heterozygous CAPN3 variant. Presentation was persistent hyperCKemia, commonly with proximal weakness and myalgia.
• Muscle western blot showed absent or markedly reduced calpain-3, and RNAseq confirmed reduced CAPN3 transcript levels.
• In silico analysis predicted a novel RBFOX1 binding site; luciferase assays supported a regulatory effect on expression (quantitative data not given in abstract).

Clinical Relevance: Patients with LGMD/hyperCKemia and only one identified CAPN3 variant may warrant 3'UTR analysis, which could resolve some UK "unsolved" cases currently left without a diagnosis.

Limitations: Small, selected cohort without a control comparison, and the abstract does not report whether the RBFOX1 mechanism was confirmed beyond reporter assays.

Study Type: Cross-sectional observational study (single-centre, consecutive patients, 24-hour home ambulatory BP monitoring)

Key Question: Are ambulatory hypertensive episodes associated with quality of life, orthostatic symptoms and motor severity in Parkinson's disease with neurogenic versus non-neurogenic orthostatic hypotension?

Key Findings:

• 59 patients (30 neurogenic OH, 29 non-neurogenic OH). In neurogenic OH, more hypertensive episodes were associated with better PDQ-39 SI, lower orthostatic symptom burden and lower motor impairment scores.
• These associations were absent or reversed in non-neurogenic OH, and were stronger during daytime than night-time.
• Results were consistent across sensitivity analyses. Abstract does not report effect sizes or confidence intervals.

Clinical Relevance: Daytime hypertensive episodes in neurogenic OH may partly reflect compensatory or treatment-related BP rises rather than purely harm, which could inform BP target-setting when treating OH in PD.

Limitations: Small sample and cross-sectional design preclude causal inference, and treatment effects (e.g. pressor agents) and reverse causation (better function enabling more activity-related BP rises) cannot be excluded.

Study Type: Preclinical experimental study (mouse model) with comparative human preterm cerebellar tissue analysis.

Key Question: How do maternal immune activation (MIA) and neonatal hypoxia, alone and in sequence, differentially remodel cerebellar development and behaviour?

Key Findings:

• Hypoxia impaired granule cell maturation and excitatory afferents to Purkinje cells, producing impaired motor execution and stereotyped, sensory-disengaged social behaviour.
• MIA expanded the granule cell progenitor layer and reduced Purkinje cell dendritic complexity, preserving social preference but altering the kinematics of social investigation.
• MIA followed by hypoxia produced a distinct phenotype: granule cell proliferative arrest, progressive mitochondrial dysfunction and hyper-interactive social behaviour. Outcomes depended on insult identity and sequence.

Clinical Relevance: Findings suggest heterogeneous perinatal exposure histories may underlie variable motor and socio-cognitive outcomes in preterm survivors, potentially informing stratification and future neuroprotective strategies in UK neonatal follow-up.

Limitations: Mouse model findings with limited human tissue comparison; the abstract gives no effect sizes, sample sizes or statistics, and clinical translation is untested.

Study Type: Single-centre retrospective/longitudinal cohort study (memory clinic; n = 259).

Key Question: Does serum β-synuclein, a synaptic marker, predict dementia conversion, cognitive decline and mortality independently of CSF Aβ42/Aβ40 and pTau181 in non-demented memory clinic patients?

Key Findings:

• Serum β-synuclein was raised in CSF-defined Alzheimer's disease (d = 0.69 vs controls) but not in A-T1+ "PASSED" individuals. Per SD increase: dementia conversion HR 1.40 (95% CI 1.11–1.77), mortality HR 1.33 (1.07–1.65), MMSE decline −0.20 points/year.
• Adjusting for CSF biomarkers attenuated conversion and mortality associations by ≤13%. The cognitive decline association was largely attenuated by pTau181 (58.5%; P = 0.186).
• Higher β-synuclein was associated with lower bilateral temporal lobe volumes (hippocampi, entorhinal cortex).

Clinical Relevance: Supports blood-based synaptic markers as prognostic adjuncts to core AD biomarkers, which may matter as UK blood biomarker pathways develop.

Limitations: Single-centre cohort without external validation, and findings varied with how pTau181 was normalised (Aβ40-normalised continuous vs staged).

Study Type: Prospective single-centre cohort study (n=41 clinically unresponsive patients; comparators: 22 conscious critically ill patients, 8 healthy volunteers).

Key Question: Can clinically unresponsive patients early after acute brain injury control an EEG-based, self-paced BCI, and does BCI control predict recovery?

Key Findings:

• 13/41 (32%) unresponsive patients achieved BCI control (8/41, 20%, CMD-positive), versus 41% of conscious patients and 100% of healthy volunteers. Median signal delay was 49.8 s in unresponsive patients versus 17.1 s and 15.5 s respectively.
• Recovery of consciousness by discharge: 31% with BCI control versus 4% without (OR 21.2; 95% CI 2.3–930.7). Functional independence (GOSE ≥4) at 12 months: 46% versus 7% (OR 9.9; 95% CI 1.8–81.6). No patient who was both BCI-negative and CMD-negative recovered.
• All survey respondents (n=37) supported future BCI use.

Clinical Relevance: Findings suggest bedside EEG-based assessment could improve prognostication and detect covert consciousness, relevant to UK practice where withdrawal of life-sustaining treatment decisions rely largely on behavioural assessment.

Limitations: Small single-centre sample with very wide confidence intervals, and outcome analyses are unadjusted for confounders and potentially influenced by clinicians' treatment decisions.

Study Type: Narrative review (no systematic search methodology reported in the abstract).

Key Question: What is known about how TMEM106B genetic variation influences neurodegenerative disease risk, and can this be therapeutically targeted?

Key Findings:

• TMEM106B risk and protective haplotypes modify susceptibility across FTLD-TDP, Alzheimer's disease, Parkinson's disease and LATE, and contribute to healthy ageing and neuronal reserve; the causal functional variant remains unresolved.
• Proposed mechanisms centre on variant effects on regulatory networks and protein levels, with emphasis on the aggregation-prone C-terminal fragment, endo-lysosomal function, proteolytic processing and fibril formation.
• Therapeutic strategies under discussion include modulating expression, specific functional pathways and fibril formation. Current mouse and iPSC models have recognised gaps for studying function and cleavage.

Clinical Relevance: TMEM106B is a candidate shared disease-modifying target across TDP-43 and other proteinopathies, relevant to UK genetic FTD cohorts (e.g. GRN carriers) and future stratified trials.

Limitations: As a narrative review, it offers no new data, and the abstract gives no quantitative effect sizes or clinical-stage evidence for the proposed therapies.

Study Type: Basic science / translational study: single-cell RNA sequencing of one human HD fetal brain and matched controls, supported by an HD mouse embryo allelic series and cross-comparison with published post-mortem and organoid datasets.

Key Question: Do cell type-specific transcriptional abnormalities arise in the developing HD brain and persist into adult pathology?

Key Findings:

• Neural progenitors showed the most differentially expressed genes in the human fetal LGE and cortex, and were also affected in HD mouse embryos.
• The progenitor signature comprised upregulated synaptic pathways and downregulated cell maintenance genes. It was moderately enriched in mouse LGE, and components persisted in adult post-mortem HD datasets.
• Cellular interactions attenuated these alterations, suggesting a potentially rescuable signature. Effect sizes and statistics are not reported in the abstract.

Clinical Relevance: The findings support a neurodevelopmental contribution to HD and may inform the timing and targets of future disease-modifying strategies, with relevance for UK HD services and presymptomatic gene-carrier cohorts.

Limitations: The human fetal data derive from a single HD brain, severely limiting generalisability and statistical inference, particularly given variable CAG repeat length.