Impaired reach-to-grasp integration identifies cerebral visual impairment (CVI) in children and adults
Bibliographic record
Abstract
Abstract Aim Cerebral Visual Impairment (CVI), an underdiagnosed cause of childhood visual impairment, presents heterogeneous symptoms involving varying degrees of dorsal and ventral stream dysfunction. We investigated whether impaired reach-to-grasp integration occurs in CVI as a potential marker of dorsal stream dysfunction. Method People with CVI (children aged 7-17, n = 16; adults aged 18-25, n = 6) and control participants (children, n = 14; adults, n = 10) reached with their left hand to grasp plastic blocks with and without a blindfold. Reach-to-grasp timing and hand shaping measures were assessed using frame-by-frame video analysis. Results Even when they could see the block, people with CVI displayed prolonged grasp relative to reach durations, more static hand shaping during the reach, and increased reliance on non-visual hand shaping strategies after block contact to secure final grasp. The three measures were incorporated into a single composite Reach-to-Grasp Integration (RGI) score that distinguished people with CVI from controls. Interpretation Temporal, sensory, and functional dissociation of the reach and grasp occurs in CVI, consistent with dorsal stream dysfunction, and is captured by the RGI score. The RGI score could form the basis for CVI behavioural screening tools beyond standard visual assessments. What this paper adds People with CVI display impaired visually-guided integration of the reach and grasp, consistent with dorsal stream dysfunction. People with CVI use static preplanned hand shapes during visually-guided reaching. People with CVI rely on non-visual hand shaping strategies after target contact to facilitate grasping. The composite Reach-to-Grasp Integration (RGI) score distinguishes CVI from control children and adults.
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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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
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".