PONE-D-20-04189

The efficacy of dance for improving motor impairments, non-motor symptoms, and quality of life in Parkinson’s disease: A systematic review and meta-analysis

PLOS ONE

Dear Ms Carapellotti,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process, detailed below.

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Antony Bayer

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Review: “The efficacy of dance for improving motor impairments, non-motor symptoms, and quality of life in Parkinson’s disease: A systematic review and meta-analysis.”

Summary of study

This manuscript presents a systematic review and meta-analysis of studies investigating the potential motor and non-motor benefits of dance for people with Parkinson’s disease (PD). The aims were to evaluate the evidence for the efficacy of dance in improving the above outcomes for people with PD, to assess the methodological quality of studies, and to identify future research directions.

While there are several recent reviews and meta-analyses on this topic, this is a fast-growing area of research and the present review considers a number of more recent studies in addition to the previous evidence.

The review focuses on randomised controlled trials, with 15 studies found to be eligible for inclusion, 8 of which were also included in a meta-analysis. The analysis indicated that dance can improve motor impairment in individuals with mild to moderate PD, but further research is needed to elucidate non-motor effects. The authors offer a number of suggestions for future research in this area, including multi-centre trials, investigation of underlying mechanisms, and effects in different groups of PD patients (advanced and young onset).

This is a clearly written, well-structured review of the current literature on dance for PD, which provides an update following previous reviews and meta-analyses on this topic.

Introduction

The authors refer to a number of existing systematic reviews and meta-analyses on dance for PD. They may also wish to note the following references:

Lotzke, D., Ostermann, T., Bussing, A., 2015. Argentine tango in Parkinson disease – a systematic review and meta-analysis. BMC Neurol. 15. https://doi.org/10.1186/s12883-015-0484-0.

Aguiar, L.P.C., Da Rocha, P.A., Morris, M., 2016. Therapeutic dancing for Parkinson’s disease. Int. J. Gerontol. 10, 64–70. https://doi.org/10.1016/j.ijge.2016.02.002.

Methods

Lines 138 and 154: Please correct “Cochran” to “Cochrane”.

Line 161: “In trials where two types of dance were compared to another active control or no intervention, the means and SDs of the two dance groups’ change scores were pooled” – could the authors please explain why this approach was taken, instead of separately examining the effects for each dance style?

Results

The authors do not consistently note the dance styles concerned when discussing findings (e.g., lines 401, 410) – it would be helpful to include this throughout.

Within the qualitative synthesis section, quality of life and activities of daily living are reported under the heading of “Non-motor symptoms” – it would be more appropriate to discuss these under separate headings as they can be impacted by a range of different symptoms.

Line 211: The authors note that only one study involved a programme led by a dance therapist – this is very interesting and it would be good to know what this is in contrast to; i.e., what was the training/background of the instructors leading the other programmes?

Table 1: The column “Analysis Method” is unclear – what does yes/no refer to here?

Line 252: “Six trials …controlled for medication during the course of the intervention” – please clarify in what way medication was controlled.

Line 333: Please correct “Kunkle” to “Kunkel” (also elsewhere in the manuscript).

Discussion

The discussion is comprehensive and highlights limitations in the existing literature, as well as providing suggestions for future research, such as the need to clarify underlying mechanisms of the benefits of dance in PD (e.g., which elements of dance might target which symptoms). However, it is quite a lengthy discussion and in parts repeats information that is also presented in the results – the authors could consider condensing some of this detail.

Line 644: This is a little unclear – do the authors mean “…reduced walking speed has been identified…”?

Line 662: The discussion of “mental imagery” is introduced in the section on motor outcomes – this would be better discussed in the non-motor section, where it is already considered in more detail.

Lines 687-692: The authors discuss the use of imagery within dance and the potential of dance to improve mental imagery skills. Please see the recent review by Bek et al. below, which discusses action representation mechanisms (motor imagery and action observation) in relation to dance for PD.

Bek, J., Arakaki, A., Lawrence, A., Sullivan, M., Ganapathy, G., Poliakoff, E., 2020. Dance and Parkinson’s: A review and exploration of the role of cognitive representations of action. Neuroscience and Biobehavioral Reviews. 109. DOI: 10.1016/j.neubiorev.2019.12.023

Lines 701-703: Please clarify that the study cited here focuses on PD.

Lines 732-734: The UPDRS-II scale (motor experiences of daily living) would be more appropriately discussed within the motor outcomes section rather than the QoL section where it is currently reported.

Conclusions and future directions

Line 817: “non-motor symptoms like cognition and depression” – this needs rephrasing as “cognition” is not a symptom.

Line 843: “…how this compares to other comparable interventions…” – this should be rephrased.

Reviewer #2: Overall the paper was difficult to follow given that there were multiple end-points reviewed in both the meta-analysis and the qualitative summary. From overall review of the paper the overwhelming impression was that whilst there are a number of RCT’s identifying the impact of dance on motor and non-motor symptoms in PD the trials are highly heterogenous in terms of the type of dance intervention (tango/ foxtrot etc.), the intensity of intervention (eg. Total number of hours per week), duration of intervention, methodology (eg. Dance versus usual care or dance versus alternative intervention) and in outcome measures. In addition, most studies were of small sample size and some underpowered.

I felt the authors were able to illustrate the level of bias across studies well with the use of figures 2 and 3. The authors also provided a complementary narrative of bias. There was a good description of dropout rates and reasons for dropouts from trials.

The reporting of level of heterogenicity (I2) with results in the meta-analysis was appropriate however in the discussion and conclusion section of the paper this was not highlighted. As a consequence, statements that commented on the fact that statistically significant results had been observed were not then qualified with a comment that this may be difficult to interpret in the context of the level of heterogenicity between trial designs. For example, [line 569] that ‘overall evidence suggest dance can have a positive impact in mild to moderate PD, with the results most strongly supporting its ability to manage motor symptom severity in comparison to usual care and improve balance more effectively than other forms of physical activity’: this is in the context of an I2 of 90% for MDS-UPDRS and 78% for balance and limits ability to make bold conclusions.

It is commented that heterogenicity values are reported but not used to exclude trials: given the number of trials that are still included despite the degree of heterogenicity this is not reflected in the discussion section when making claims about the benefits of dance in PD.

The authors have addressed their primary objective and provided narrative about insufficient data being available to draw conclusions with respect to the impact of dance on non-motor symptoms. The authors’ section on the quality of evidence is excellent in outlining trial heterogenicity and provides constructive advice to guide the design of future clinical trials in order to reduce bias and investigate relevant clinical parameters. The authors’ conclusion section is concise and insightful.

Suggestions:

As per PRISMA: Was there a review protocol which should be commented on in the methods section?

Line 138- Cochrane (spelling)

Line 148- All trials deemed to have a high risk of performance bias therefore excluded from risk of bias assessment: was it appropriate to do this given as this will affect the overall level of bias? This will undoubtedly affect the validity of results. This should also be mentioned in your conclusions.

Line 154- Cochrane (spelling)

Line 211- Only one trial led by a dance therapist: does this infer that the other trials were not led in a structured approach by a trained professional? If so a brief comment about who delivered the dance training in other trials would be appropriate.

Line 242- You have commented that ‘only’ three out of the fifteen included RCTs had statistically significant differences between groups at baseline. This is still 20% of the trials. It would be helpful to support this comment by looking at the total number of patients in these three trials and establishing how this reflects across the total number of participants across trials. I also think this should be commented on in the ‘Quality of Evidence’ section.

Line 254- Four studies instructed participants to continue with regular exercise outside of intervention. Has the level of exercise outside of intervention been quantified? If so, a comment on additional level of exercise should be made as this may augment any observed benefits from dance therapy.

Line 464- Clinical global impression of change: It should be specified if in this study the examiner was blinded to intervention and if so how this was achieved?

Line 484- You have commented that the heterogenicity values are reported but not used to exclude trials: is this appropriate given the degree of heterogenicity and the data on bias?

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Reviewer #1: No

Reviewer #2: No

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Attachments

Attachment

Submitted filename: PLOS review Feb 2020.docx

PONE-D-20-04189R1

The efficacy of dance for improving motor impairments, non-motor symptoms, and quality of life in Parkinson’s disease: A systematic review and meta-analysis

PLOS ONE

Dear Dr. Carapellotti,

Thank you for submitting your revised manuscript to PLOS ONE and for your careful attention to the previous reviewer comments. After careful consideration, we feel that it has considerable merit but would benefit from some minor changes to respond to the suggestions below. I also spotted another typo in the abstract (line 22) and perhaps the whole manuscript would benefit from a final check. Therefore it does not fully meet PLOS ONE’s publication criteria as it currently stands and we invite you to submit a revised version of the manuscript that addresses these points.​

Please submit your revised manuscript by Jul 17 2020 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

Antony Bayer

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Thank you for addressing all the points raised in the reviews - you have provided a clear and comprehensive revision and improved the overall quality of the manuscript.

Reviewer #2: The revisions to the article have overall contributed to a more measured and transparent systematic review and meta-analysis. The formatting and editing have resulted in a paper that is far less repetitive and clearer to comprehend. In addition, clarifying outcomes in relation to intervention/ dance style throughout the article has provided added clarity. The quality of evidence section provides an excellent overview of the limitations of data interpretation in view of small sample sizes, inclusion of underpowered studies, statistically significant differences in some studies baseline characteristics, the randomisation process, impact of medication and consistency of co-intervention. In addition the conclusions section provides an excellent summary and very valid recommendations for the methods future research could employ.

The authors have met both their primary and secondary objectives. The authors have also been candid in their descriptions of limitations of generalisability with reference to multiple areas of bias, inclusion of relevant heterogenicity scores, comments on the significant drop-out rate for studies and explanations provided for reasons for participant withdrawal and comments on the incomplete retrieval of identified research.

My only further suggestions are:

Line 22: spelling correction 'mon' to non-motor

Line 714: spelling correction 'met' to meta-analysis

Line 715: I think it is inaccurate to claim 'dance can have an impact on gait velocity, stride length and endurance' when the qualitative synthesis showed variable outcomes and when the meta-analysis observed no significant effect on forward or backward velocity in the dance versus no intervention arms, no effect on stride length in the dance versus no intervention arms and whilst the 6MWT favoured dance, the caveat is that the heterogenicity value for those studies was 84%. It would be more accurate to suggest that the impact of dance on gait velocity, stride length and endurance is not robust enough to draw firm conclusions and should be a focus of future research.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

The efficacy of dance for improving motor impairments, non-motor symptoms, and quality of life in Parkinson’s disease: A systematic review and meta-analysis

PONE-D-20-04189R2

Dear Dr. Carapellotti,

Thank you for your further manuscript and careful revision. We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Antony Bayer

Academic Editor

PLOS ONE

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