Theme 8 Clinical Imaging and Electrophysiology
Bibliographic record
Abstract
Background: Mutations in the C9Orf72 gene are responsible for many cases of familial ALS and FTD.Recent studies suggest that C9Orf72-related pathology may be partly linked to a neurodevelopmental disorder.This raises questions about the underlying pathogenic mechanisms and the identification of reliable biomarkers of degeneration for clinical trials.Objective of this study was to describe longitudinal cervical spinal cord (SC) pathology using MRI in a cohort of asymptomatic C9Orf72 first-degree relative subjects.Methods: 72 asymptomatic individuals were enrolled in a prospective study of first-degree relatives of ALS and FTD patients carrying the C9orf72 mutation.40 (C9þ) were carriers and 32 non carriers (C9À).Each subject underwent a 3T cervical SC MRI.Quantitative measures of GM and WM atrophy and DTI parameters were evaluated at baseline, after 18 and after 36 months.Results: At baseline, significant WM atrophy was detected in C9þ subjects older than 40 years of age (p-value <0.05) without associated changes in GM.At 18 and 36-month follow-up, no modification was observed both in WM and GM.Progressive significant fractional anisotropy (FA) reduction in the cortico-spinal tract was observed over the three time points in the C9þ group (p ¼ 0.04).Discussion: Cervical SC imaging of C9orf72 hexanucleotide carriers reveals age-related WM atrophy, which remains stable over time, and no GM atrophy.Pyramidal tract FA reduction is observed in C9þ subjects compared to C9À subjects and shows significant progression in follow-up scans.Stable WM atrophy might indicate a neurodevelopmental condition, which would explain the lack of progression over time, while the relation to increasing age of the subjects is similar to the one described in the general population.In contrast, changes in FA over time could be an early marker of progressive degeneration.Further studies with larger populations, including symptomatic C9þ subjects, are needed to confirm this hypothesis.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.076 | 0.049 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".