Research question
Does amplitude-modulated music change anterior–posterior standing sway once the repeated-measures design is respected and extra analyses are kept from wandering?
Condensed abstract
A source-faithful reanalysis of 334 usable 60-second trials from 28 participants, across three visual contexts and four Mozart conditions. The only confirmatory endpoint is log anterior–posterior root-mean-square center-of-pressure displacement, tested with 99,999 participant-blocked permutations. Music condition affected displacement. The 0.1 Hz amplitude-modulated versus no-music ratio was 1.129 (95% CI 1.038–1.230). The visual-by-music interaction was unsupported, and the other reported analysis families did not yield a positive result. The paper presents this as a robustness reanalysis, not an independent discovery.
Key contribution
A bias-controlled secondary analysis that keeps one confirmatory sway endpoint, blocks permutations by participant, and reports the flexible analyses that did not survive alongside the one contrast that did.
Method overview
Each participant contributes trials under three visual contexts and four music conditions. The confirmatory test is a participant-blocked restricted permutation test of log anterior–posterior root-mean-square center-of-pressure displacement, using 99,999 permutations. Nonlinear measures were multiplicity-controlled, as was a post-result spectral family. A delayed-feedback surrogate is checked for prediction and recovery, and classifiers are evaluated with participants held out.
One contrast, and the analyses that stopped
Baseline and current
The baseline stays fixed. Both figures use the same scales.
Dataset and evaluation
Data
Public force-plate recordings from Streepey and Dent (PhysioNet, 2021): 28 participants and 12 planned 60-second trials each. Vision is eyes closed, a static virtual street, or anterior–posterior virtual translation at 0.1 Hz. Music is silence, unmodified Mozart, or Mozart amplitude-modulated at 0.1 Hz or 0.25 Hz. The reanalysis uses 334 of those 336 trials.
Protocol
One confirmatory endpoint was declared: log anterior–posterior RMS displacement. Music condition was tested with participant-blocked restricted permutations. The reported follow-up contrast is the 0.1 Hz amplitude-modulated condition divided by no music. The visual-by-music interaction was tested and unsupported. Nonlinear measures, and a post-result spectral family, were multiplicity-controlled. The surrogate had to meet both predictive and recovery criteria. Classifiers were scored with participants held out.
Main results
Music condition affected displacement, F(3, 301) = 5.52, permutation p = 0.00003. The 0.1 Hz amplitude-modulated / no-music ratio was 1.129 (95% confidence interval 1.038–1.230). The visual-by-music interaction was unsupported. Multiplicity-controlled nonlinear and post-result spectral families were null. The delayed-feedback surrogate failed its predictive and recovery criteria, and participant-held-out classifiers did not exceed chance.
Baseline comparison
The music main effect is the confirmatory result. It is not accompanied by a supported visual-by-music interaction, a surviving nonlinear or spectral family, a surrogate that recovered the effect, or a classifier that beat chance. The paper does not treat the ratio as a discovery independent of the source experiment.
Limitations and failure modes
- This is a robustness reanalysis of a public dataset, not an independent experiment or a new data collection.
- The supported result is one pooled music contrast. The visual-by-music interaction was unsupported, so the ratio is not a vision-specific effect.
- Multiplicity-controlled nonlinear and spectral families were null. A delayed-feedback surrogate failed, and participant-held-out classifiers did not exceed chance.
- The interactive figure and the small check transcribe these reported statistics. They do not reanalyze the force-plate files or rerun the permutation test.
Reproducibility
A transcription check of the confirmatory ratio, its interval, and the six reported analysis-family outcomes.
Reported statistics checkedChecked locally 2026-10-24 · bundle v1.0.0
- Paper-associated code
- No public full-paper code archive is linked by this portfolio.
- Inputs for this check
- The ratio 1.129, the interval 1.038–1.230, and the family outcomes named in the abstract. No force-plate files are required.
- Prerequisites
- Python 3.10+ · standard library only · CPU · no network or large dataset download. A notebook environment is optional.
- Full study data
- PhysioNet body sway, music, and virtual-reality motion Consult the paper and dataset documentation before attempting the full study.
Run the small check
- Download and extract the complete bundle.
- Open a terminal in the extracted folder and run
python check.py. - Confirm the ratio lies inside the interval, the interval excludes 1, and the family labels match the abstract.
Includes Python, an equivalent notebook, source JSON, expected output, and SHA-256 provenance. The notebook runs from the extracted folder.
Expected output and individual files
Ratio inside the interval. Interval excludes 1. Families: music supported; interaction unsupported; nonlinear null; spectral null; surrogate failed; classifiers at chance.
What this does not establish
This check does not reanalyze the 334 usable trials, rerun 99,999 participant-blocked permutations, or fit a classifier. Passing it confirms the transcription, not an independent discovery.
These checks use the portfolio’s existing sourced records. External archive links could not be freshly rechecked during package preparation. A passing check is not a full-paper replication.
The decisions behind the method
Why this reanalysis keeps a single displacement contrast, and what the other analysis families did not support.
Read the research noteVerification sources
Cite this work
Mehrafarin Babaee, Arman Salehi, Dornaz Milani, Ashkan Heydarian (2026). Music amplitude modulation and postural sway across visual contexts: A repeated-measures secondary analysis of nonlinear dynamics and model adequacy. Journal of Low Frequency Noise, Vibration and Active Control, Article 14613484261499171. https://doi.org/10.1177/14613484261499171
BibTeX
@article{babaee2026sway,
title = {Music amplitude modulation and postural sway across visual contexts: A repeated-measures secondary analysis of nonlinear dynamics and model adequacy},
author = {Mehrafarin Babaee and Arman Salehi and Dornaz Milani and Ashkan Heydarian},
year = {2026},
doi = {10.1177/14613484261499171},
journal = {Journal of Low Frequency Noise, Vibration and Active Control},
article-number = {14613484261499171},
publisher = {SAGE Publications}
}Publication record last verified 2026-10-24.
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