On 2016 Aug 29, David Keller commented:

If the investigators were not blinded, how was bias excluded from their scoring of the balance, stability and TUG tests?

The placebo, nocebo, Pygmalion and other expectation effects can be substantial in Parkinson's disease. Unblinded investigators can transmit cues regarding their own expectations to patients, thereby affecting the patients' response to therapy. In addition, unblinded investigators are affected by bias in their subjective evaluations of patient response to therapy, and even in their measurement of patient performance on relatively objective tests. What was done to minimize these sources of bias from contaminating the results of this single-blinded study? Were the clinicians who scored the BBS, TUG and LOS tests aware of the randomization status of each patient they tested?

In addition, I question whether the results reported for the LOS test in the Results section of the abstract are statistically significant. The patients assigned to exergaming scored 78.9 +/- 7.65 %, which corresponds to a Confidence Interval of [71.25 - 86.55] %, while the control patient scores of 70.6 +/- 9.37 % correspond to a confidence interval of [61.23 - 79.97] %. These two confidence intervals overlap from 71.25 % to 79.97 %, a range which includes the average score of the exergaming patients.

If a follow-up study is planned, the blinding of investigators, especially those who score the patients' test performances, would reduce bias and expectation effects. Increasing the number of subjects assigned to active treatment and to control treatment would improve the statistical significance of the results.

On 2016 Aug 29, David Keller commented:

If the investigators were not blinded, how was bias excluded from their scoring of the balance, stability and TUG tests?

The placebo, nocebo, Pygmalion and other expectation effects can be substantial in Parkinson's disease. Unblinded investigators can transmit cues regarding their own expectations to patients, thereby affecting the patients' response to therapy. In addition, unblinded investigators are affected by bias in their subjective evaluations of patient response to therapy, and even in their measurement of patient performance on relatively objective tests. What was done to minimize these sources of bias from contaminating the results of this single-blinded study? Were the clinicians who scored the BBS, TUG and LOS tests aware of the randomization status of each patient they tested?

In addition, I question whether the results reported for the LOS test in the Results section of the abstract are statistically significant. The patients assigned to exergaming scored 78.9 +/- 7.65 %, which corresponds to a Confidence Interval of [71.25 - 86.55] %, while the control patient scores of 70.6 +/- 9.37 % correspond to a confidence interval of [61.23 - 79.97] %. These two confidence intervals overlap from 71.25 % to 79.97 %, a range which includes the average score of the exergaming patients.

If a follow-up study is planned, the blinding of investigators, especially those who score the patients' test performances, would reduce bias and expectation effects. Increasing the number of subjects assigned to active treatment and to control treatment would improve the statistical significance of the results.