Advances in Understanding the Relationship between Sleep and Attention Deficit-Hyperactivity Disorder (ADHD)
Round 1
Reviewer 1 Report
The amount of time you took in revising the article based on the reviewer's comments is noticeable. I have a clearer understanding of the flow from the initial hypotheses to the search of the literature to the conclusions that were drawn. The number cited in your text and in your Figure 1 now match up. I also believe the addition of supplementary materials to list out your abbreviations was a smart move. This will allow understanding by a broader audience.
Author Response
The amount of time you took in revising the article based on the reviewer’s comments is noticeable. I have a clearer understanding of the flow from the initial hypotheses to the search of the literature to the conclusions that were drawn. The number cited in your text and in your Figure 1 now match up. I also believe the addition of supplementary materials to list out your abbreviations was a smart move. This will allow understanding by a broader audience.
We thank the reviewer for his/her appreciations.
Reviewer 2 Report
This paper addresses and important topic: the study of sleep disturbances in children with ADHD. The authors focused only in those studies using polysomnographic recordings.
The revision seems exhaustive and systematic. Nevertheless the authors do not clearly report the results of their revision. That is, in the discussion section, the variables: age, ADHD subtypes, status of medication and comorbidities have to be included in the discussion as variables to compare the results from different authors. It is also important to analyze differences between different comorbidities (I.E. anxiety vs. conduct disorders). Instead, the authors only list these variables in the limitation paragraph of the discussion and they do not explain how these variables influence the results and differences between studies. And this has to be done not only for papers with positive results but also in those reporting negative results for different polysomnographic parameters. The mentioned variables can explain differences between authors, but the authors of this manuscript do not analyze these data.
In the discussion section
Line 266 Check the expression “comorbid subjects”
What kind comorbid disorders do you mean?
The paper will benefit from language review
Author Response
The revision seems exhaustive and systematic. Nevertheless the authors do not clearly report the results of their revision. That is, in the discussion section, the variables: age, ADHD subtypes, status of medication and comorbidities have to be included in the discussion as variables to compare the results from different authors. It is also important to analyze differences between different comorbidities (I.E. anxiety vs. conduct disorders). Instead, the authors only list these variables in the limitation paragraph of the discussion and they do not explain how these variables influence the results and differences between studies. And this has to be done not only for papers with positive results but also in those reporting negative results for different polysomnographic parameters. The mentioned variables can explain differences between authors, but the authors of this manuscript do not analyze these data.
We thank the reviewer for his/her suggestions. We agree with the reviewer on the potential impact (on sleep) of age, comorbidities, ADHD subtypes and medications effects, as reported in the limitation paragraph. We have to underline that the choice to mention these issues only in the limitation section stems from the fact that the available results do not provide a clear (if any) association between these variables and sleep patterns. Indeed, except for the “age-effect” -discussed in relation to the microstructural measures- the link between sleep alteration and the mentioned variables appears to be “random” in the reviewed studies and no specific hypothesis seems to be viable. In other words, any other comments would be speculative and could make difficult to follow the main conclusions of the manuscript. However, we highlighted that these factors represent confounding variables when they are not systematically controlled. In fact, this is not the main topic of our review and the reviewed studies according to the current selection criteria reported strong differences in combining these variables (e.g., comorbidities, subtypes or medications), not allowing to draw any compelling conclusion. In other words, further systematic-reviews and/or meta-analyses should assess it, by using article selection criteria specifically aimed to disentangle the issues. According to the request of the reviewer, we have added further comments about these variables in the revised manuscript.
In the discussion section
Line 266 Check the expression “comorbid subjects”
What kind comorbid disorders do you mean?
Clarified in the revised manuscript.
The paper will benefit from language review
According to the request of the reviewer, the paper has been further checked for typos and grammar errors by a native English speaker (the same of the first round of revisions). As detailed in the cover letter, if the editor still believe that it is necessary, we will send the manuscript for a professional proof-reading after its acceptance. Now, this request conflicts with the available time for our revision (i.e., 5 days).
Round 2
Reviewer 2 Report
I have my concerns regarding the organization of the content of different sections of the manuscript: discussion, limitations, conclusions, results and even the introduction.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The stated aim of this paper is to examine the evidence for sleep problems in ADHD using the perspective of polysomnographic (PSG) recordings. It appears as if the authors did a comprehensive review of available literature. Because of the limitations in the available evidence they go on to summarize various studies in a general way.
This paper tackles an interesting topic. But it does not deliver the goods. They want to use polysomnographic measures as a lens to evaluate the association of ADHD and sleep problems. There needs to be a clearer statement of what each of the poly measures is thought to mean. These measures need to be prioritized. The discussion and conclusions are too long for the material that is presented and makes it difficult to follow the main conclusions of the paper.
The paper is very difficult to follow for various reasons. First, the specific goals are not clearly spelled out. Why did they focus on the indices of sleep that they chose? Apparently, the results of objective and subjective reports of sleep problems are in conflict with each other.
The second reason why the paper is difficult to follow is the excessive use of abbreviations that are not clearly defined in the text. perhaps a table of these definitions would help.
The writing is very stilted and the paper needs a professional edit from an English speaker.
One example is pasted below:
Beyond the observed variability, a notable overlap has been reported in the neurocognitive deficits associated with poor sleep quality and those characterizing ADHD children/adolescents. In fact, also in healthy people sleep problems affect the ability to suppress responses and, more in general inhibitory control, enhancing the impulsivity. In other words, sleep alterations may induce 60 ADHD-like symptoms.
Here, we highlight that sleep features may have a pivotal role to better understand the ADHD 62 phenomenology. However, the relationship between sleep and ADHD is still poorly understood. We 63 reviewed the available literature of the last 15 years on the interaction between ADHD and sleep, 64 focusing on macrostructural and microstructural features of sleep in this neurodevelopmental 65 disorder.
The number of studies reported in the text does not seem to concur with the number mentioned in the PRISMA table.
Ultimately, the reader is left with a sense that they do not know what the main conclusions of the review were in fact. A re-write would be helpful.
Reviewer 2 Report
I appreciate the effort you all put in collecting the articles for this review of the connection between ADHD and sleep.
I would suggest making some edits (primarily related to grammar and sentence structure) before final publication. For example, the sentence on lines 33-35 does not flow well in English and would benefit from being re-worded. In lines 42 and 59, I would move "also" to be nearer the verb phrase (for example: "Beyond this, sleep alterations also are significantly observed..."). Delete the comma after "last 15 years" on line 78. Add a comma after "Reduced SE was reported [24], and..." in line 137 as well as after "The results are mixed, and..." in line 348. Change the comma to a period after "...as compared with HC" in line 178. There is an extra space between "learning/memory tasks" and the references in line 216.
You did a nice job of listing the limitations of the chosen studies. I am hopeful this review article is read and used as a springboard for research addressing these issues to further explore the association of sleep in children with ADHD.
