Testing a Single-Case Experimental Design to Study Dynamic Light Exposure in People with Dementia Living at Home

Round 1

Reviewer 1 Report

Dear authors,

The topic and the content are important and novel. I found it suitable for the journal. However, the following items have to be studied before being published;

-In Table 2, at 07:30 pm, the CCT is suggested to be 2500K, but in the manuscript, it is stated to be 2000K. Which one is valid?

-It is advised to add Figures /drawings and/or 3D drawings of the experimental set-up in order to clarify the experimental process. More technical information (wall color-reflectances, daylight penetration, window size etc) about the interiors is important to discuss the outcomes of the study.

-2.6.4 Ethics is not a sub-topic, it shall be given and explained at the beginning of the manuscript.

-In the Discussion part, it is suggested to refer to the references and to compare the outcomes of the study with the literature.

-It is advised to add the spectral power distribution charts of the light sources to the manuscript, so the effect of wavelength can be discussed.

Warm regards,

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

It is an interesting study on the dynamic lighting exposure in people with dementia living at home. However, the design of this experiment is not sufficient to support the statements and conclusions that have been made. While I appreciate the effort of the authors, I have recommended that this paper be rejected based principally on a flawed methodology.

In real life or field studies, many variables easily lead the experiment to be compounded. So the compared variables of the experiment in them should be clear and the data collection consistent. With 10 subjects, the pilot study may be more suitable than the randomization tests. The lightings in the kitchen, in the living room and in the bedroom should be the same. The differences of the light luminaires and the heights may effects on the results. The meanings or necessities of the phase A and B should be stated to have proper ranges over six months. In Table 3, the shown reasons seem vague through the collected data.

I encourage the authors to strongly consider my questions, comments, and concerns and hope that my intent to be constructive is obvious.

 

26     In Abstract, any recommendations and lessons learned should be stated.

121    What kinds of supports are needed to have a benefit of technological systems?

125    The full spelling of the SCED should be stated here rather than in the line 160 since it is first shown.

143-154 The content may be described in the Methods section.

166-167 Where is the 2)?

176-194 The completed data of four phases were from 10 participants. It should be stated from the beginning of the paragraph. It is bewildered to have the continued change of the subjects from 13 to 11 and 10. Then why the number of the participants in Table 3, 4 and 5 is 12? These cause the suspicion of the data.

212-213 For the home settings of the participants, the positions and sizes of the windows in east west south north direction should have been measured in the rooms with the dynamic lightings at least. The effect of the daylilght and the size of the space may effect on the data of the dynamic lighting. Also the exposure time of the lighting should be estimated. If the participants spend many hours in other room or the bathroom, the data may lose some of the meanings.

238-241, 275-279 We cannot compare the data under the different lightings and the fixtures. People are influenced by the appearance as well as the lighting itself.

354 What is the hypothesis to reject the null hypothesis?

362 The validation of the equation is needed from approved references. Moreover, it should have been discussed to be applied for the experiment in the separated paragraph of the introduction.

 

Comments for author File: Comments.docx

Author Response

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Reviewer 3 Report

The overall presentation of the article is very good. The introduction provides relevant information but is perhaps a bit too long. The methodology is accessible to the uninitiated on light exposure. The choice of design is well justified. The results are clearly presented and the conclusions to each result presented provide a good synthesis. Lessons learned can be used to evaluate other interventions such as psychosocial interventions

Three pieces of information remain unclear after several readings: 
- Do the 3 installed systems work by themselves or are people free to turn the lights on and off? 

- A justification of the choice of the progression of the light intensity in part 2.4 would be interesting. I understand that the intensity follows the circadian rhythm but does this bring a possible bias in the results? 

- It is mentioned that participants have objectified sleep disorders with the NPI. It is a pity that there is no information in the result section on possible changes in this measure in addition to the qualitative elements of the user feedback.

 

Author Response

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Author Response File: Author Response.docx