Effects of Transcutaneous Auricular Vagus Nerve Stimulation on Posttraumatic Stress Disorder Symptoms in World Trade Center Responders: A Feasibility and Acceptability Study

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

I appreciate the real world application of this device to the field and literature. It is important that we start to move some of the science outside the lab and into accessible real-world based cohorts. I also appreciate the group publishing a study with mildly positive results. While the results are positive they are not overwhelmingly so, which can be difficult to publish, but are necessary for the field and moving science forwards. IT is interesting that there is such a robust sham effect here with a 28.5% rate of 10+ point drop in CAPS-5. 

• If wording is a limitation, in line 48 thirty-two could switch to 32 as all other numbers in the abstract are written numerically not spelled out. It strikes the reader a bit odd that this one is different than all others.
• lines 76-78 read a bit off, and might benefit from rewording
• is "the health program for WTC responders" an entity - should it be capitalized ? (line 83)
• lines 87-88 seem to assume reasons why individuals are not receiving this care - do we know if it was due to lack of availability? or efficacy (as stated) or "acceptable treatment options"? Or lack of knowledge about what is available? Or concern for stigma about receiving and accepting this care? Seems there may be many other options owering the number receiving care than the two stated here. 
• line 89 switches to passive past tense after writing in present tense prior two paragraphs then switches back to present
• same in 94 "studies indicate" instead of "studies have indicated"
• lines 99-101 need citation(s)
• all references to prior work should be changed to "studies demonstrate" or "studies show" instead of "have shown" if this is written in present tense 
• lines 115-16 needs rewording "evaluated the following: acceptability, questionnaire completion, data quality... etc" or evaluated and examined... ? It has both then a list of many things, it would be better to group the verb(s) and nouns together 
• the passive tense is difficult to read, please consider revising " an exploratory aim investigated" not "was to investigate"
• line 142 higher_on is a typo
• the first 2 paragraphs of results would be better suited to the methods
• were statistics run on the demographics to determine if groups were well matched? 
• it seems that the reductions could be assessed using ANOVA even if not powered to find significant differences based on effect size. 
• how do you regard the change in CAPS-5 but not PCL-5? 
• line 338 uses "no significant association between CAPS-5 scores..." but it was previously stated statistics could not be run due to small sizes, either do not use words such as "significant" or run the statistics and report results accordingly
• How did you determine use for 50-60% of study? is this percentage of days? or weeks? or total time used? I assume this was the same as written in line 345, which seems to be number of sessions
• It would be interesting to compare participation between sham and active groups (i.e. did one group have better adherence than another), this could help demonstrate that individuals using active felt some benefit and were more driven to use device. 
• please include citations in lines 410-418
• it is touched briefly in lines 420s about the CAPS-5 clinician scores changing more than patient report scores, could be interesting to add a line if this is consistent with other studies and why it is important to have both types of metrics 
• OVerall the discussion would benefit from more citations, there are a few generalizing statements made which would be better supported with clear evidence

The paper overall needs some cleaning up but will make a strong contribution to the literature when completed. I do think more statistics could be pulled out as well to strengthen the impact of the manuscript. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for the opportunity to review this manuscript. I think it is excellent and will make a significant scholarly contribution to the literature and treatment of PTSD.

I think the manuscript is clear and excellently written. The study is sound, and the methodology and findings are good.

My only feedback is that I think it would be good to include Dr. Stephen Porges’s work. While evidence for polyvagal therapy is still developing, it is an approach that shows promise for PTSD treatment through understanding the vagus nerve and helping people learn ways to activate their ventral vagal system. Not discussing this work seems an oversight.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This pilot feasibility and acceptance study was a randomized, double-blind, sham-controlled trial comparing transcutaneous auricular vagus nerve stimulation to a sham control in 9/11 responders with PTSD. The research was well conceived and well presented. The findings found high retention and adherence rates suggesting that further trials of the effectiveness of transcutaneous auricular vagus nerve stimulation are warranted. The authors should consider the following:
1.    In the limitations section, the authors should have acknowledged that the sample was primarily male, white and non-Hispanic participants so the findings may not generalize to females or non-white participants.
2.    When discussing future research that should follow from the current feasibility study, the authors should have specifically outlined what effectiveness trial should be developed from their successful feasibility study. 
3.    The authors might consider that future trials of transcutaneous auricular vagus nerve stimulation that demonstrated improvement in mood and cognition be combined with antidepressant exposure that has been shown to be more effective for the anxiety/hyperarousal symptoms of PTSD. 

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

I read the paper very carefully and find the use of the taVNS technique very interesting.
The authors have clearly described the purpose of the scientific work and thoroughly discussed the state of the art in the most recent literature.
Transcutaneous Auricular VNS (taVNS) has emerged as a promising alternative for treating PTSD. Research indicates that the tragus, concha, and cymba concha areas of the outer ear are unique in having direct access to the vagus nerve at the skin's surface. This anatomical feature enables non-invasive approaches like taVNS, which send electrical impulses directly to the vagus nerve through the cymba concha of the ear.
The work is presented as a pilot study.
I noticed that there is no graph of the averages, nor is there a summary table of the pre-post measurements.
I believe that the work needs only a few adjustments and is an excellent candidate for publication.

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf