“…Briefly, ''Class I'' consisted of prospective randomized controlled trials (RCTs); ''Class II'' consisted of prospective cohort studies, retrospective case-control studies, or controlled clinical series; and ''Class III'' included uncontrolled clinical series or single-subject studies. Based on these criteria, six studies were rated as Class I McDonald, 2008b, 2008c;Dahlberg et al, 2007;Helffenstein and Wechsler, 1982;McDonald et al, 2008;Radice-Neumann et al, 2009), one as Class II ( Johnson and Newton, 1987), and five as Class III (Braunling-McMorrow et al, 1986;Brotherton et al, 1988;Gajar et al, 1984;Guercio et al, 2004;O'Reilly et al, 2000). In most of the studies reviewed here, participants were reported to be medically stable, and classification of injury severity was based on Glasgow Coma Scale scores or duration of post-traumatic amnesia.…”