Introducing the Modified Cobb Angle for Measuring Cervical Spine Curvature During Swallowing
Bibliographic record
Abstract
Objective s: The C2-C7 Cobb angle is used to measure cervical spine curvature, an anatomical parameter that may be associated with swallowing difficulties in some patients. Challenges in visualizing lower cervical vertebrae on videofluoroscopic swallow study images led to the proposal of the C2-C4 modified Cobb angle (MCA) for use in swallowing research. Despite its initial promise, less than optimal reliability and validity suggested a need for improvement and further research. In this study, we aimed to explore the measurement properties of the MCA and a C2-C4 revised-MCA across key timepoints in healthy swallowing of thin liquid boluses. Methods: This exploratory analysis examined inter- and intra-rater reliability, as well as criterion validity of the C2-C4 MCA and C2-C4 revised-MCA in comparison to other measures of cervical spine curvature and head extension (C0-C2, C2-C6, and C2-C7 Cobb angles). Videofluoroscopic images from 35 healthy participants were analyzed using frames from still positioning, bolus passing the mandible, maximum pharyngeal constriction, and swallow rest. Data were analyzed using intraclass correlation coefficients (ICCs), Pearson correlations, and mixed model analysis. Results: The C2-C4 revised-MCA showed superior intra- and inter-rater reliability and moderate positive correlation with the C2-C6 Cobb angle, demonstrating criterion validity. No differences in C2-C4 revised-MCA were found across swallowing frames, or as a function of participant age, sex, or head extension. Conclusions: The findings suggest that the C2-C4 revised-MCA has stronger psychometric properties than the MCA, confirming its utility as a cervical spine curvature measurement during swallowing. Level of Evidence: 4.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".