Noncredible performance in mild traumatic brain injury

According to the Centers for Disease Control and Prevention approximately 1.4 million Americans suffer some form of Traumatic Brain Injury (TBI) each year (Centers for Disease Control & Prevention, 1999; Langlois, Rutland-Brown, & Thomas, 2004). Such injuries occur by falling (28%), involvement in motor vehicle accidents (MVA) (20%), being struck by or against objects (including vehicles) (19%), and physical assault (11%) (Langlois et al.). As of the millennium's closing in the USA, TBI resulted in approximately 50,000 deaths, 235,000 hospitalizations, and 1.1 million emergency room visits per annum. As a result of TBI, at least 5.3 million Americans currently need long-term assistance performing activities of daily living (Thurman, Alverson, Dunn, Guerrero, & Sniezek, 1999), often requiring substantial community, financial, and governmental resources. For instance, estimates of direct medical costs and other indirect costs (e.g., loss of work productivity, etc.) total well over $60 billion in the United States annually (Finkelstein, Corso, & Miller, 2006). Mild TBI (MTBI) accounts for 80% of all TBI cases (Sohlberg & Mateer, 2001) and has also been dubbed the signature wound of the war on terrorism in military personnel (Association of the United States Army, 2008). There is a reported high rate of MTBI in Operation Enduring Freedom/Operation Iraqi Freedom veterans, ranging from 12 to 15% (Hoge et al., 2008; Schneiderman, Braver, & Kang, 2008). However, the number of individuals who suffer a MTBI and fail to present to an emergency medical department or do not identify themselves on the battlefield remains unknown and understudied.