Influence of Static Magnetic Field Stimulation on the Accuracy of Tachystoscopically Presented Line Bisection

Round 1

Reviewer 1 Report

• The manuscript presents an interesting application of a novel non-invasive neurostimulation intervention so provides broad interest.

Comments:

• The data appears to be non-parametric but parametric statistics are applied (ie ANOVA). 
• Further details on the sham v real stimulation would be useful. Are there noise or sensory differences associated with the real stimulation that could impact on blinding?  References to previous literature on sham stimulation for this form of stimulation would be useful.

In the abstract:

tSMS should be described in full at the first mention (L24)

L25-L26, the ordering should be changed here with the task described before the procedure.

L29-30, the brackets could be removed, further details are in the methods

In the abstract and when first described in the main manuscript, C6 and C4 need to defined in reference to the 10-20 system. 

Other

L148, typo: trial not trail.

L162, typo: Contraly = Contarily?

Author Response

Q1.

The data appears to be non-parametric but parametric statistics are applied (ie ANOVA). 

A1.

We added a sentence, “The normal distribution was confirmed using the Kolmogorov–Sminov test” (Methods P5, Lines 155 to 156).

Q2.

Further details on the sham v real stimulation would be useful. Are there noise or sensory differences associated with the real stimulation that could impact on blinding?  References to previous literature on sham stimulation for this form of stimulation would be useful.

A2.

Thank you for your helpful advice. We added a sentence about what you have pointed (Methods P3, Lines 122 to 124).

Q3.

In the abstract:

tSMS should be described in full at the first mention (L24)

L25-L26, the ordering should be changed here with the task described before the procedure.

L29-30, the brackets could be removed, further details are in the methods

In the abstract and when first described in the main manuscript, C6 and C4 need to defined in reference to the 10-20 system. 

A3.

We have modified the abstract according to your suggestion (P1, Lines 25 to 37). We decided to keep the brackets for readability and clarity.

Q4

L162, typo: Contraｌy = Contarily?

A4.

We would like to apologize for our careless mistake. We have changed “Contraly” to “In contrast” (Results P5, Line 165)

Author Response File: Author Response.docx

Reviewer 2 Report

In this Manuscript (MS), titled "Influence of static magnetic field stimulation on the accuracy of tachystoscopically presented line bisection", has been proposed a non-invasive modulation of visual spatial cognition by the application of transcranial static magnetic field stimulation (tSMS) over the parietal association cortex or temporal lobe in 16 healthy humans participants. Performance of the tSMS intervention has been examined before immediately after, and 10 min after the intervention. The main results reported by the authors of the MS is that the transient inhibition of right temporal lobe, induced by tSMS, improves the visual spatial cognition tested by a line's length judgment task. Sham stimulation has been also reported.

Overall, I the research question has been well conducted and the sham condition is really welcomed in this kind of studies. The MS is well written as well, even if, some typos need to be corrected troughout the MS such as in line 256 “[…] tSMS over applied over C6 […]”.

My main concerns are:
1) Results reported in Figure4: seem that one of the volunteer is an outlier and should be removed since its performance is very low respect to the others. Group level statistics need to be re-run without the value of this volunteer.
2) The group level analysis report a clear difference between before vs. post tSMS. However, the post 10 (ie test 10 minute after tSMS seems to reach the baseline (ie the test befor the tSMS intervention). So, if just after 10 minute intervention we are not able to observe the effects of the intervention itself how we can implement that intervention in clinical conditions?
3) Conclusion should report also the non clear results discussed in the discussion section highlighting the weaknesses of the work.

Author Response

Q1.
Results reported in Figure4: seem that one of the volunteer is an outlier and should be removed since its performance is very low respect to the others. Group level statistics need to be re-run without the value of this volunteer.

A1.

Indeed, as you pointed out, one of the subjects showing right bias was judged to be an outlier in some sections.

However, there is also an idea that statistical outliers should not be excluded from the data if they are not physiologically deviant. When statistical processing was re-performed without this subject, the intervention effect remained significant. Therefore, we would like you to accept the results we have presented and the discussion based on them.Q2.

The group level analysis report a clear difference between before vs. post tSMS. However, the post 10 (ie test 10 minute after tSMS seems to reach the baseline (ie the test befor the tSMS intervention). So, if just after 10 minute intervention we are not able to observe the effects of the intervention itself how we can implement that intervention in clinical conditions?

A2.

Thank you for your constructive suggestion. We added sentences discussing this point (Discussion P9, Lines 307 to 316).Q3.

Conclusion should report also the non clear results discussed in the discussion section highlighting the weaknesses of the work.

A3.

Thank you for your helpful advice. We added a sentence as you pointed (Conclusions P9, Lines 321 to 322).

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Suggested modifications have been made

Author Response

According to Reviewer #1 advice, we presented the statistical results without an outlier in the text as well as in a supplementary material. Please confirm.

Author Response File: Author Response.docx

Reviewer 2 Report

Q1.
Results reported in Figure4: seem that one of the volunteers is an outlier and should be removed since its performance is very low concerning the others. Group level statistics need to be re-run without the value of this volunteer.

A1.

Indeed, as you pointed out, one of the subjects showing right bias was judged to be an outlier in some sections.

However, there is also an idea that statistical outliers should not be excluded from the data if they are not physiologically deviant. When statistical processing was re-performed without this subject, the intervention effect remained significant. Therefore, we would like you to accept the results we have presented and the discussion based on them.

Q1.1 If the effects remain significant, please, use the data without the outlier. If the editor agrees to publish the data as they are, I strongly suggest to the editor that the authors should show the results without the outlier in the appendix or supplementary materials.

Author Response

L203-206

According to your advice, we presented the statistical results without an outlier in the text as well as in a supplementary material. Please confirm.

Author Response File: Author Response.docx