Biodynamic Lighting and Functional Disability; a Single-Case Experimental Design in Three Community Dwelling People with Dementia

Round 1

Reviewer 1 Report

Introduction

1. The introduction is structured well, progressing logically from one idea to the next. 
2. Light therapy and biodynamic lighting should have been reviewed more thoroughly. For instance, research about the effects of light therapy on any other behavior / performance / emotional state of subjects. Also, any debates in the literature about the efficacy of light therapy, and suggestions on how to resolve them.
3. English should be improved. Writing is not always "scientific" (i.e. line 60 - "umbrella term"; line 81 - not clear - an interaction doesn't suggest......).

Materials and Methods

1. line 129: Terms should be referred to consistently (i.e. IADL in the introduction vs. (I)ADL in the methods).
2. Major comment: The A-B-A-B experimental design assumes that withdrawal of the experimental manipulation withdraws the clinical effect (as in pharma studies). Here, the benefits of the experimental phase (B1)  could continue long into the placebo phase (A2) and occlude any statistical difference between the conditions.
3.   Lines 118-119: Is the randomization of phase length done once and repeated between subjects or did each subject get a difference randomization? It's not clear how is this beneficial for external validity. In such a small sample, randomization between subjects could actually harm external validity .
4.  Line 120: It's better to use the term "attuned" instead of "reset".
5. Figure 1: Should be improved. It is recommended to organise in stages (Informed consent / Pre-experimental testing/ experiment).
6. Line 161: Different dementias could have different effects on ADL. The liberal inclusion criteria (i) could enhance substantially the variance of results.
7. Lines 169-176: Criteria 6-10 should be noted as 'exclusion criteria'. There should be a differentiation between inclusion and exclusion criteria.
8. Line 177 (Table 1)- Participants are not well matched. Initial differences in age and in ADL could have different improvement trajectory, occluding statistical differences between conditions.
9. Table 1 - The rows should be better differentiated.

Results

1. Line 307-310: Results should be reported according to APA format.
2. Descriptive statistics about the BADL and IADL results should be added.
3. Figure 3 - Add reference to statistical test. Add Standard error.
4. Figure 4 - correct figure lining. Add standard error.
5. Line 333: "Participant".
6. Line 344 - This is a complete change of the course of the experiment. Not applicable. This case should be omitted.
7. It is recommended to present the same data set for all participants. 
8. Lawton & Katz figures are not clear. Graphs are superimposed one on the other in an incomprehensible way. It is better to separate the graphs, so that each figure will have several decks corresponding to the different functions.
9. Major comment - No significant findings.

Discussion

1. Line 469-471: The assumption that there was no decline in functioning was not checked statistically in this experiment. Concluding that there was no decline is problematic.
2. Line 488: Not clear. Is there a positive relationship between BADL and lighting?
3. Lines 521-525: Some spontaneous fluctuations in function is expected among patients with dementia. Without statistical evidence you cannot conclude that there is some improvement in ADL.
4. The biodynamic light treatment in the current experiment did not follow cyrcadian patterns as it should. Subjects received more "evening light" with it's spectral configuration in comparison to day light. This limitation should be also discussed in the discussion.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

I think no conclusion can be drawn from a clinical trial for dementia that includes only 3 people. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

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Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Thank You for your corrections. Most of the issues I have raised were resolved nicely in this version.

In the correction form you inserted new box plot figures. I think adding them could confuse the readers. Consider superimposing the spread on the bar graphs.

I also recommend text editing for minor grammar corrections.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

I agree with the authors that this experimental clinical trial setup is worth publishing, and I appreciate that the authors deleted all claims to an effect of lighting on effects on Alzheimer's. Such claims would require a far greater number of patients. 

Author Response

Thank you for your reaction. 

Our paper has now been professionally proofread. 

Reviewer 3 Report

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Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Round 3

Reviewer 3 Report

Thank you for clarifying the answers to the questions posed by this reviewer. This manuscript is currently considered appropriate for publication.