Archimedes Spiral Looping in Functional and Essential Tremor
Bibliographic record
Abstract
Functional tremor (FT) is the most common functional movement disorder, but diagnosis can be challenging. Archimedes spiral drawings are a useful bedside tool, and looping, also known as the "stretch slinky" sign, has been described as a feature of FT. However, the prevalence of looping in FT and its occurrence in essential tremor (ET) are unclear. This retrospective study examined Archimedes spirals from 22 FT and 28 ET patients. Looping (≥1) was observed in 45.5% of FT spirals and 60.7% of ET spirals, with no significant difference in loop counts between groups (Mann-Whitney U test). A loop-count threshold of ≥7 had the highest positive predictive value for FT (PPV 0.75) and high specificity (0.96), but poor sensitivity (0.14). Receiver operating characteristic analysis yielded an AUC of 0.46. Looping in Archimedes spirals occurs in both FT and ET, and loop counts alone show poor discriminative ability. A loop count ≥7, although insensitive, is highly specific for FT and may provide supportive evidence in the full clinical context.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".