Validity of Center of Pressure Path Length Measured Using a Wii Balance Board for Fall Risk Screening in Community-Dwelling Older Adults

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for submitting your manuscript.
This study examines the validity of the Wii Balance Board as a screening tool for fall risk in community-dwelling older adults. The use of a simple and accessible device such as the Wii Balance Board has the potential to make a meaningful social contribution. However, there are several aspects that require substantial revision before the manuscript can be considered for publication.

Major comments:

• The sample size in this study was determined a priori as 60 participants; however, it appears to have been based primarily on correlation analysis. Could you clarify the rationale for selecting correlation analysis as the basis for the sample size calculation? What is the primary analysis of this study? In general, the sample size should be determined based on the primary analysis, and this point needs to be clearly justified.
• Previous studies have already examined the relationships among the Wii Balance Board, postural sway, and fall risk. In this context, the novelty of the present study appears to lie in the use of eight different testing conditions. If this is the case, the theoretical rationale and the necessity of employing these multiple conditions should be more clearly and convincingly articulated.
• The manuscript appears to overstate the clinical applicability of the Wii Balance Board. Although it is a low-cost and portable tool, its ability to accurately discriminate fall risk in clinical settings has not yet been sufficiently established. The distinction between measurement validity and clinical validity should be more clearly addressed.
• Sex differences are an important factor in balance function and fall risk. As the sample appears to include both male and female participants (n = 60), please clarify how this issue was addressed in the analysis. Consider conducting sex-stratified analyses or adjusting for sex as a covariate, if not already done.
• The primary objective of the study should be more clearly stated, and the corresponding primary analysis should be explicitly identified. Other analyses should be clearly positioned as secondary.

 

Minor comments:

• Figure 2 presents an experimental flowchart including a division into two groups; however, it is unclear whether this grouping is necessary. Since the grouping appears to be used only for statistical analysis, it may be sufficient to describe this in the statistical methods section. The current presentation may give the impression of an interventional study design, which could lead to misunderstanding.
• Is it necessary to report baseline characteristics with two decimal places? One decimal place should be sufficient.
• Please clarify the rationale for conducting separate regression analyses with different numbers of independent variables (e.g., 8, 3, and 1 variables).

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This cross-sectional study examines the validity of Wii Balance Board-derived center of pressure path length as a fall risk screening tool in 60 community-dwelling older adults . Using Pearson correlation, ROC analysis, and regression modeling, the authors compare WBB measures across eight postural conditions against the Tetrax® Fall Index and two functional tests . Results indicate moderate-to-strong validity, with the normal eyes-open condition yielding the highest discriminative accuracy. The study addresses a clinically relevant question and uses an appropriate multi-condition design. The manuscript would additionally benefit from the following aspects:

1.   The exclusion criterion 'current use of medication prescribed for anemia' is unusually specific. Clarify the pharmacological rationale.
2. Was the additional weight of the Tetrax® unit accounted for in the WBB calibration or post-hoc correction?
3. The Balancia software version (2.5) is reported but the platform and sampling parameters beyond frequency are not described.
4. In the eight-posture regression model, the coefficient for NO is negative (B = −0.376), which is theoretically inconsistent (greater COP path length should predict higher fall risk). 
5. For the eight-posture model, the WBB-derived Fall Index mean (136.32 ± 54.89) substantially exceeds the Tetrax® Fall Index scale maximum of 100 (0–100 range, line 169). Predicted values exceeding the scale boundary indicate severe model misspecification. This must be addressed and explained.
6. No cognitive screening was conducted or reported.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have addressed the issues proposed by my suggestions, and the manuscript is considered for publication now.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf