Measurement of Adult Human Brain Responses to Breath-Holding by Multi-Distance Hyperspectral Near-Infrared Spectroscopy
Round 1
Reviewer 1 Report
This paper presents a measurement study on human brain response to breath hold by multi distance hNirs. Even though this paper shows some average and standard deviation, its publication should be considered with some additional information and repeated independent experiments, which make it more convincing that the method would actually work with reproducible results. The paper should include statistical analysis to verify the results and has many typos and spacing words.
- In the figure of SO2 of Figure 4, there is a change for BH at 1 cm and 3 cm, but no change at 4 cm. A reasonable explanation is needed for this result.
- It seems that the time courses of HbO2 look similar in all channels except at 4 cm. In Table 1, the case of 3 cm looks quite different compared to the case of 4 cm. Please, explain the reason.
- At the results of 1 cm, 3 cm, and 4 cm in Table 1, the difference between peak and dip in the case of 1 cm is relatively large, and the difference tends to decrease as it goes to 3 cm and 4 cm. It may be related detection intensity. Please explain this point. Because the difference between peak and dip in 4 cm is very small, it is necessary to explain this. Also mention how to distinguish whether the peak and dip in 4 cm are simply noise or caused by changes in the brain due to BH.
- In page 2, line 57, the experimental setup is explained. Three different spectrometers are used. Is there any specific reasons? Different spectrometers can effect on the different sensitivity detection. Did you consider this difference while calculating the hemodynamics?
- In page 2, line 74, you mention that the source lights are symmetrically injected to increase the total light power. Even if it is placed symmetrically, homological environment could be different on both sides. In this case, any issues?
- In page 3, you use terminology 'rCCO', this term should be introduced with detail and kind story in introduction. What kinds of factors are related to the change of rCCO?
- In this paper, you found that optimal waveband for the detection of cerebral responses to BH in adults is 700-900 nm. What is any difference between adults and young children?
Author Response
We are very thankful to the respected Reviewer for the careful study of our manuscript and for extremely helpful comments, which helped us to improve our paper by performing additional data analysis and introducing significant changes into the text, figures, and tables.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors describe brain responses to breath hold by using a multi-distance broadband NIRS system. The manuscript requires improvement and further analysis. Moreover the novelty of the method(s) does not really come through the whole work. This aspect raises a major concern on the suitability for publication of this particular manuscript.
Comments for author File: Comments.pdf
Author Response
We are very thankful to the respected Reviewer for the careful study of our manuscript and for extremely helpful comments, which helped us to improve our paper by performing additional data analysis and introducing significant changes into the text, figures, and tables.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Thanks for the authors' detailed responses to the reviewer's comments and revision to the manuscript. They have addressed pretty much all of my questions/concerns.
Reviewer 2 Report
Dear authors, thanks for the submission of your reviewed manuscript and to have addressed the comments accordingly.
I believe the manuscript can be accepted with a minor issue to fix:
formatting text from line 303 on (page 8 to 12).
Author Response
We are thankful to the respected Reviewer for studying our manuscript. We have corrected the formatting error from line 303.
