A recent Neurology digest,
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Study Type: Prospective, population-based cohort study

Key Question: Does epilepsy cause progressive brain atrophy beyond normal ageing, and does this vary by epilepsy phenotype, when studied in a community-based (non-tertiary) population?

Key Findings:

• People with epilepsy showed modestly accelerated global grey matter loss vs controls (2.7 vs 2.4 mL/year; p=0.01) over 3.5 years.
• Vulnerable cortical regions showed markedly accelerated thinning (5.3 vs 3.4 μm/year; p<0.001).
• Acceleration was linked to focal epilepsy, MRI-identifiable lesions, and ongoing seizures, whereas generalized epilepsy and seizure freedom showed stable trajectories.

Clinical Relevance: These population-based data—free from tertiary-centre ascertainment bias—support early seizure control and lesion identification as priorities to limit progressive structural brain damage, relevant to NHS epilepsy pathway design and prognostic counselling.

Limitations: Only two imaging time points (3.5 years apart) limit assessment of longer-term or non-linear atrophy trajectories.

Study Type: Cross-sectional cohort study (neuroimaging)

Key Question: Does Tourette syndrome (TS) involve structural cortical and white matter differences, and are these related to symptom severity, comorbidities, or medication use?

Key Findings:

• TS participants (n=151) vs controls (n=113) showed significant cortical thinning in precentral/postcentral gyri, inferior/middle frontal gyri, and inferior parietal lobule, with corresponding white matter surface displacement in overlapping regions.
• Findings persisted after adjusting for IQ, comorbidities, and medication; no moderation by age or sex.
• ADHD severity correlated with additional frontoparietal thinning; OCD and tic severity showed no significant associations.

Clinical Relevance: These structural changes appear to be trait-like neurodevelopmental markers rather than state-dependent effects of tics, supporting cortico-striato-thalamo-cortical circuitry as a potential target for future TS interventions relevant to UK paediatric and adult neurology/neuropsychiatry services.

Limitations: Cross-sectional design precludes causal or longitudinal inference about developmental trajectory.

Study Type: Translational research combining a single human case report with a controlled crossover animal study (murine model).

Key Question: Can ketamine reduce cataplexy in narcolepsy type 1 when standard monoaminergic/GABAergic therapies are ineffective or not tolerated?

Key Findings:

• A 34-year-old man with treatment-intolerant narcolepsy type 1 showed marked, sustained reduction in cataplexy with morning intranasal ketamine, recurring on discontinuation.
• In orexin knockout mice, ketamine reduced time spent in cataplexy by 76% versus vehicle (p = 0.008), with no disruption to overall sleep architecture.

Clinical Relevance: These early findings suggest ketamine, a repurposed and already NHS-available agent, may offer a novel anticataplectic option for patients failing or intolerant of current therapies, supporting consideration for future clinical trials.

Limitations: Human evidence is limited to a single case, precluding generalisability pending controlled clinical trials.

Study Type: Longitudinal cohort study

Key Question: How does neurological impairment (measured by SARA) progress in adults with ataxia-telangiectasia, and does this differ by AT subtype or genotype?

Key Findings:

• Mean SARA progression was 0.38 points/year across the cohort (n=82).
• Classic AT patients had substantially higher baseline severity (~8–9 points higher SARA) than variant AT, but annual progression rates converged in adulthood (0.33 vs 0.41 points/year).
• This convergence included 15 patients with the antisense oligonucleotide-targetable c.5763-1050A>G variant.

Clinical Relevance: These data support more accurate prognostic counselling and inform outcome measure selection and trial design for emerging mutation-specific therapies (e.g., ASO treatments) relevant to UK AT specialist services.

Limitations: SARA may underestimate progression in advanced disease and non-cerebellar domains, limiting sensitivity as an outcome measure.

Study Type: Longitudinal cohort study

Key Question: Does type 2 diabetes drive region-specific cortical thinning in cognitively unimpaired older adults, independent of Alzheimer's and vascular pathology, and does this explain diabetes-related cognitive decline?

Key Findings:

• Diabetic participants (n=305/1298) showed faster cortical thinning over ~3 years in seven frontal, parietal, and occipital regions (β -0.046 to -0.060, corrected P<0.017), unaffected by adjustment for amyloid-PET, tau-PET, white matter hyperintensities, or APOE ε4.
• Higher baseline HbA1c predicted faster thinning in diabetes-vulnerable regions (corrected P<0.032), independent of later HbA1c changes.
• Diabetes was associated with faster processing speed decline (β=-0.022, P=0.033); regional cortical thinning mediated ~13% of this effect (indirect β=-0.034, P=0.019).

Clinical Relevance: Suggests diabetes-related neurodegeneration is a distinct, chronic-hyperglycaemia-driven pathway rather than a downstream effect of amyloid/vascular disease, supporting early and sustained glycaemic optimisation in diabetic patients seen in memory and diabetes clinics to potentially limit cognitive decline.

Limitations: Observational design precludes causal inference, and short-term HbA1c changes may not capture cumulative glycaemic exposure relevant to neurodegeneration.

Study Type: Genetic case study plus trio-based whole-exome sequencing cohort study

Key Question: Do rare de novo variants in chromatin-remodelling genes contribute to the pathogenesis of sporadic Chiari 1 malformation (CM1)?

Key Findings:

• A heterozygous loss-of-function CHD3 variant segregated with familial CM1 and syringomyelia across generations.
• In 1,585 proband–parent trios, de novo protein-altering variants were significantly enriched in CHD genes (CHD1, CHD3, CHD4, CHD8) versus 1,798 sibling controls (protein-damaging: P=1.3×10⁻⁹; predicted loss-of-function: P=8.6×10⁻⁵).
• Variants clustered in functional ATPase/helicase/chromodomain regions; affected probands often had comorbid neurodevelopmental delay, with gene expression enriched in Purkinje cells and inhibitory neurons during midgestational cerebellar development.

Clinical Relevance: These findings support a genetic basis for a subset of sporadic CM1 and suggest exome sequencing could aid diagnostic workup, prognostication, and family counselling in NHS paediatric neurosurgery/neurology clinics, particularly when neurodevelopmental features coexist.

Limitations: The study is observational/associative, limiting causal inference, and functional validation of individual variants' effects on cerebellar development is lacking.

Study Type: Preclinical animal model study (juvenile mouse model)

Key Question: Does prior viral-mimetic (TLR3) activation increase haemorrhagic transformation after arterial ischaemic stroke in juvenile mice, and can this be mitigated by targeting neutrophil elastase?

Key Findings:

• Poly-IC priming 3 days before transient MCAO altered brain microvascular gene expression and primed endothelial/inflammatory responses, leading to increased neutrophil infiltration, neutrophil elastase activation, and NETosis, with marked haemorrhagic transformation.
• Poly-IC also produced long-term vascular network changes post-stroke.
• Neutrophil elastase inhibition at MCAO onset significantly reduced haemorrhagic transformation and overall injury, attenuating peripheral inflammatory activation and altering neutrophil-monocyte interactions.

Clinical Relevance: This provides the first mechanistic model linking common childhood viral infection to arteriopathy-driven stroke severity, offering a novel therapeutic target (neutrophil elastase inhibition) relevant to paediatric stroke services in the NHS where infection-associated arteriopathy is a recognised but poorly understood risk factor.

Limitations: Findings are from a murine model and require validation in human paediatric stroke populations before clinical translation.

Study Type: Genetic case-control study with neuropathological and biochemical analysis

Key Question: Does an AGG repeat expansion in BIN1 contribute to the pathogenesis of multiple system atrophy (MSA)?

Key Findings:

• An AGG repeat expansion (>80 repeats) in BIN1 intron 1 was significantly enriched in pathologically confirmed MSA versus brain controls (13.4% vs 0%; OR infinite, 95% CI 2.1–∞, P=0.003); this did not reach significance in clinically diagnosed MSA versus blood controls (4.5% vs 2.4%, P=0.16).
• BIN1-positive glial cytoplasmic inclusions were more frequent in brains with the repeat expansion.
• Insoluble BIN1 aggregation was increased in MSA brains regardless of repeat status, suggesting a broader role for BIN1 dysfunction in disease pathology.

Clinical Relevance: This is the first identified genetic risk factor linked to MSA pathology, offering a potential molecular target for diagnostics and future disease-modifying therapies relevant to UK neurodegeneration research and biobanking efforts.

Limitations: Small numbers with repeat expansions and lack of significance in the larger clinically diagnosed cohort limit generalisability and causal inference.