This is a parallel, randomized, double-blinded and sham-controlled study. A total of 100 subjects will be randomly assigned to either an intervention arm: 50 participants exposed to > 99.9% oxygen at 1.5 atmosphere absolute for 60 minutes over 40 treatments or sham-treatment arm: 50 participants exposed to oxygen and pressure composition equivalent to breathing atmospheric air for 60 minutes over 40 treatments.~This study is designed to determine whether hyperbaric oxygen improves neuropsychological status and ameliorates symptoms in adults with persistent post-concussive symptoms (PPCS) following mild traumatic brain injury. It recruits from either military or civilian population; uses a validated screening tool - Repeatable battery for the assessment of neuropsychological status (RBANS)- used in dementia and other forms of brain injury not used hitherto, in previous randomized control trial that investigated the effectiveness of hyperbaric oxygen in the management of PPCS. It also includes a concssuon biomarker, as an objective secondary endpoint.~The study is based on repeated measure design. The study will describe and track changes in the outcomes of interest over time, and examine associations between measures within each participant and across certain participant characteristics.
Persistent post-concussive symptoms (PPCS) are a source of significant burden among a subset of patients with concussion with prevalence rates previously reported between 11 - 82% based on timing of assessment, diagnostic criteria, or population under study.~Examples of persistent post-concussion symptoms include balance problems, headaches, fatigue, poor concentration, forgetfulness, anxiety, irritability, and sleep disturbance. Few proposed therapies have proved successful in the management of persistent post-concussion symptoms following mild traumatic brain injury.~The investigators will explore hyperbaric oxygen administered in a randomized sham-controlled clinical trial as an effective and tolerable treatment in improving neuropsychological status among adult patients with persistent post-concussive symptoms.~The overall hypothesis to be evaluated is that hyperbaric oxygen improves neuropsychological status and a serum concussion biomarker associated with PPCS.