## 4 Results and Discussion
These results may find practical application in the diagnosis of PTSD, and the channel weight construction approach may be useful in combination with other machine learning methods. A study of veterans with PTSD syndrome confirmed our results about diagnostic F3-F4 channels [19]. The insights from this analysis have the potential to dramatically change the diagnosis of PTSD in patients. There are several ways that EEG evaluation could complement existing tools. One possibility is to use EEG screening as an initial tool to evaluate the possibility of PTSD. This could be conducted as part of general medical screening among those who may have undergone trauma. Another opportunity is to use EEG measures at an initial stage of PTSD diagnosis. Especially for patients who self-report symptoms, or those who have completed a questionnaire on their own, EEG evaluation is a cost-effective and unbiased step in the process. This allows reserving in-depth interviews for those patients where the severity of PTSD is present. Even for patients who have been diagnosed with PTSD, \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline
**Channel** & **Subject** & **H1** & **H2** & **H3** & **H4** & **H5** & **H6** & **P1** & **P2** & **P3** & **P4** & **P5** & **P6** \\ \hline \multirow{4}{*}{**F4**} & **Weights** & 0.129 & 0.126 & 0.027 & 0.053 & 0.012 & 0.026 & 0.004 & 0.012 & 0.005 & 0.003 & 0.011 & 0.099 \\ \cline{2-11}  & **Group Average** & \multicolumn{6}{c}{0.06267 (S.D. = 0.04019)} & \multicolumn{6}{c}{0.02248 (S.D. = 0.01554)} \\ \cline{2-11}  & **Group Difference** & \multicolumn{6}{c}{0.04019 (\(p\)-value = 0.02597)} \\ \hline \multirow{4}{*}{**F8**} & **Weights** & 0.086 & 0.131 & 0.023 & 0.104 & 0.036 & 0.020 & 0.008 & 0.002 & 0.022 & 0.005 & 0.005 & 0.014 \\ \cline{2-11}  & **Group Average** & \multicolumn{6}{c}{0.06678 (S.D. = 0.01916)} & \multicolumn{6}{c}{0.00949 (S.D. = 0.00303)} \\ \cline{2-11}  & **Group Difference** & \multicolumn{6}{c}{0.05729 (\(p\)-value = 0.00433)} \\ \hline \multirow{4}{*}{**Pz**} & **Weights** & 0.080 & 0.041 & 0.061 & 0.014 & 0.030 & 0.013 & 0.021 & 0.013 & 0.003 & 0.005 & 0.001 & 0.004 \\ \cline{2-11}  & **Group Average** & \multicolumn{6}{c}{0.03999 (S.D. = 0.0109)} & \multicolumn{6}{c}{0.00776 (S.D. = 0.00305)} \\ \cline{2-11}  & **Group Difference** & \multicolumn{6}{c}{0.03223 (\(p\)-value = 0.00866)} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Individual-level SVM channel weights from clustering and \(p\)-values for three significant channels by Mann–Whitney U test. EEG evaluation, using the method proposed here, provides an unbiased evaluation on the occurrence of PTSD. Conceptualization, P.N., E.S., S.T., B.M., B.R. ; methodology, V.N., M.P., P.N., B.R. ; software, M.P., B.M. ; validation, P.N., E.S., B.M., B.R. ; formal analysis, M.P., T.W., P.N., B.R. ; investigation, P.N., E.S., B.M., B.R. ; resources, P.N., B.M., B.R. ; data curation, M.P., B.R. ; writing--original draft preparation, M.P., T.W. ; writing--review and editing, P.N., E.S., S.T., B.M., B.R. ; visualization, M.P., T.W., S.T. ; supervision, P.N., E.S., B.M. ; project administration, B.R. ; funding acquisition, E.S. ; All authors have read and agreed to the published version of the manuscript. This research received no external funding. Data are contained within the article. This paper and the research behind it would not have been possible without the exceptional support of [PERSON] who passed away on Friday, 13 August 2021. He provided the EEG data for our projects accessed on 1 February 2016. [[https://www.laureateinstitute.org/in-memoriam.html](https://www.laureateinstitute.org/in-memoriam.html)]([https://www.laureateinstitute.org/in-memoriam.html](https://www.laureateinstitute.org/in-memoriam.html)). The authors declare no conflict of interest.