A Psychometric Evaluation of Maximum Phonation Time and <scp> <i>S</i> / <i>Z</i> </scp> Ratio as Pragmatic Outcome Measures of Bulbar Function in Adults With Spinal Muscular Atrophy
Bibliographic record
Abstract
INTRODUCTION/AIMS: A pragmatic evaluation of bulbar function among adults with spinal muscular atrophy (awSMA) is needed, requiring the validation of a low-cost, feasible outcome measure (OM). Maximum phonation time (MPT) and S/Z ratio (S/Z) are potential low-cost OMs for bulbar function. This study aimed to evaluate the psychometric properties of MPT and S/Z among awSMA. METHODS: This single-site prospective observational study followed awSMA over 12 months. Each participant completed MPT, S/Z, and a battery of routinely used OMs at baseline and 12 months. The psychometric properties of intra-rater reliability (IRR), test-retest reliability (TRT), concurrent validity (CV), predictive validity (PV), and sensitivity to change were evaluated. RESULTS: Fifteen awSMA completed the study, with a mean age of 35.5 (SD: 16.7) and 47% male participants. MPT correlated moderately with forced vital capacity (liters) and peak cough flow, and demonstrated high IRR (0.95, 0.94) and TRT over 12 months (0.80). MPT exhibited poor sensitivity to change over 12 months (0.08, 95% CI: -0.56 to 0.71). The S/Z did not exhibit significant CV, and demonstrated only modest TRT (0.55, 95% CI: 0.06-0.83), and low sensitivity to change (0.25, 95% CI: -0.32 to 0.83). DISCUSSION: MPT is a low-cost pragmatic tool to measure bulbar function and a surrogate for respiratory function OMs among awSMA. MPT may be helpful for patients with limited access to alternative bulbar or respiratory measures or for telehealth clinical care settings. MPT's low sensitivity to change limits its clinical utility over a 12-month interval. Larger studies are necessary.
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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 | 0.010 | 0.023 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".