Research ethics approval was obtained from the Research Ethics Boards of Simon Fraser University, Fraser Health Authority, and the National Research Council of Canada. As co-investigators and co-authors, Captain (retired) Trevor Greene (TG) and his wife Debbie Greene (DG) continue as collaborators in a combined PT/functional neuroimaging longitudinal case study that began in 2010. D'Arcy et al. provided a detailed case description. In summary, TG was 41-years-old, right-handed, and university-educated when he was on tour in Afghanistan in 2006. He was leading a meeting with Shinkay village elders on March 4, 2006, to help provide access to basic needs. He and the other soldiers had removed their helmets and laid down their weapons as a gesture of respect. At this point, a 16-year-old male pulled out an axe and swung it with two hands from above his head into the top of TG's skull. The act signaled a Taliban attack.
The axe blow resulted in a severe open TBI with a deep penetrating injury along the midsagittal plane, extending from the frontal to the parietal lobes, with greater right frontal and left parietal damage relative to the sagittal suture. Primary motor, premotor, primary somatosensory, and superior parietal areas were affected. The depth of the injury extended from the cortex inferiorly to the lateral ventricle, affected anterior cingulate gyri, corpus callosum (body and genu), and surrounding white matter tissue.
Immediately afterward, TG underwent emergency care and was medevacked to Kandahar Airfield, where he was transferred to Germany for neurosurgical treatment and induced into a medical coma at the US Army Landstuhl Regional Medical Centre. TG was subsequently transported back to Vancouver General Hospital (Vancouver, BC, Canada), with an initial prognosis of permanent vegetative state. During acute care, he emerged from the coma and gradually recovered full consciousness over the following 18-months. He was then admitted to the Halvar Jonson Centre for Brain Injury Centre (Alberta, Canada) for a 14-month intensive rehabilitation program.
Since then, TG has managed severe physical movement disabilities through intensive daily rehabilitation. He has returned to his career as a journalist/writer after retiring from active duty, is a published author of several non-fiction books, speaker (including TEDx), and holds honorary doctorates along with other notable distinctions. He has actively engaged in cognitive training while managing on-going post-traumatic stress disorder (PTSD). For TG, on-going PTSD challenges include night terrors and being unable to sit with his back to a door. For a full description of TG and DG's rehabilitation journal, see their book entitled: "March Forth: An Inspiring True Story of a Canadian Soldier's Journey of Love, Hope, and Survival" (Greene and Greene,). TG's rehabilitation objectives continue to focus on recovering walking abilities along with all other related impacts. As a former elite rower, he applies intensive daily training together with mental imagery to continue to push the limits of his recovery.
The objective of the longitudinal case study has been to monitor TG's recovery using multimodal functional neuroimaging (i.e., fMRI, MEG, and EEG). In the first phase (D'Arcy et al.,), fMRI was used four times a year over 3 years (12 times total) to monitor motor activation recovery. In parallel to clinical measures of movement recovery, a significant 5-fold increase in lower limb motor activation was observed. Of note, TG also showed significantly higher mental imagery activity (imagined rowing) relative to a matched control in the same active regions. The findings demonstrated neuroplasticity-related recovery well beyond conventional limits of 6-months to 1 year (6+ years at the time of the study).
The second phase incorporated assistive device technologies following an extended plateau in rehabilitation progress (D'Arcy et al.,). Following various assistive device trial evaluations, the study phase began in 2018 with the specific goal of investigating whether non-invasive neuromodulation, when paired with continuing physical rehabilitation, could help overcome the plateau of the recovery beyond 12-years post-injury. TLNS through the PoNS  was highlighted in the book The Brain That Changes Itself (Doidge,). To evaluate whether PT + TLNS could facilitate further recovery, we collected clinical, EEG, and MEG data during a 1-year PT only plateau period (i.e., baseline) and a 14-week PT + TLNS period (i.e., treatment). In a parallel study of motor function, PT + TLNS treatment led to clinically significant motor ability improvements with corresponding significant changes in both EEG and MEG activation suggesting network-level neuroplasticity effects in motor control function (D'Arcy et al.,). The present study focuses on the associated cognitive changes.