Cognitive Impairments and Self-Reported Sleep in Early-Stage Parkinson’s Disease with Versus without Probable REM Sleep Behavior Disorder

Round 1

Reviewer 1 Report

Thank you for giving me a chance to review the manuscript titled “Executive Control Impairments and Self-reported Sleep in Patients with Early-stage Parkinson’s Disease: Associations with Probable REM Sleep Behavior Disorder”. Overall, the manuscript is well written and potentially informative to many clinicians and researchers, but several things need to be revised to make the manuscript publishable.

 

<Primary comments>

 

Introduction

- The flow is nicely arrayed with good amount of background evidence.

 

Methods

- Well explained, but the authors may want to add few more information accordingly (Please refer to comments for Results).

 

Results

- Age is significantly different between two groups. Although the authors mentioned that this is one of the limitations in this study, it might be interesting to see whether significant difference in age affects the outcomes of the study. For this, the authors may want to find a proper statistic and conduct an additional analysis.

 

- In Table 1, for switching accuracy, are those values correct? They do not seem to be between 0 and 1.

 

- Throughout the manuscript including the study title, the authors consistently mention about “association” between RBD and multiple aspects in PD. However, no correlation analysis was conducted in this study.

 

Discussion and conclusions

- In limitation, it might be worthwhile to discuss that this study did not include the presence of comorbidities in people with PD, because most people with PD have other comorbidities beyond PD, which could affect the sleep quality. The authors may want to mention about this very briefly in discussion.

 

<Minor comments>

- In Abstract, keywords do not need to have numbers at the end.

 

- In Table 1, “2- & 3-back, RT average” does not have a unit.

 

- In Table 1, add “RT = reaction time” in the abbreviation list.

 

- Just one last suggestion. Throughout the manuscript and the study title, the authors used a term “patient”, this term contains a negative image on people with medical conditions. It could be more neutral or perhaps positive if you change the term to “individuals” with PD or “people” with PD.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

The authors present a secondary data analysis on associations between cognitive functioning and self-reported sleep in early-stage PD patients with or without probable REM sleep behavior disorder. The manuscript is rather short and to the point and I find it worth to be published.

There are two important points I would like the authors to add and change in order to make the manuscript publishable regarding the research question.

First, please provide figures such as pirate plots (yarrr package in R) in which readers can see the full distributions of the variables of interest, split for the two groups. In this way, readers do not have to rely on p-values from underpowered statistical tests (see next point) but they can make their own picture about potential group differences and the strength of evidence, which is important for this manuscript considering it's based on very small sample sizes.

Second, please do not interpret p values > .05 as indicating the absence of group differences. This is a harsh statistical mistake, particularly with such small sample sizes. Effects could exist and be substantially high without becoming significant. See e.g. Mehler, Edelsbrunner, & Matic 2019: https://www.researchgate.net/profile/Peter_Edelsbrunner/publication/334971998_Appreciating_the_Significance_of_Non-significant_Findings_in_Psychology/links/5d5d3cfc92851c37636ebf25/Appreciating-the-Significance-of-Non-significant-Findings-in-Psychology.pdf

and Lakens et al (2018): Improving inferences about null effects with Bayes factors and equivalence tests https://academic.oup.com/psychsocgerontology/advance-article/doi/10.1093/geronb/gby065/5033832

I am not content expert in this area.

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

This is a second review after revision. Thank you for a quick revision. I believe the authors properly addressed and answered the concerns previously made. I do not have any other concerns regarding the contents of the manuscript. I would recommend to accept this manuscript. Thank you.

 

Minor comment:

I found a typo in Sec. 2.3 (Cohn --> Cohen).

Author Response

Dear Reviewer,

Thank you for the positive feedback on our paper. We made sure to make the suggested typo correction that you mentioned.

With the additional time that we had to review our paper, we thoroughly went through our paper and corrected further grammatical errors we found in the text. We also thoroughly reviewed our analyses and statistics presented in the paper, tables and figures to assure that they are all accurate and correct. We are confident this draft is accurate and properly polished for publication.