Journal of the International Neuropsychological Society (2011), 17, 219–229. Copyright E INS. Published by Cambridge University Press, 2010. doi:10.1017/S135561771000144X Effects of ‘‘Diagnosis Threat’’ on Cognitive and Affective Functioning Long After Mild Head Injury Lana J. Ozen, AND Myra A. Fernandes Department of Psychology, University of Waterloo, Waterloo, Ontario, Canada (RECEIVED July 10, 2010; FINAL REVISION October 29, 2010; ACCEPTED October 29, 2010) Abstract Persistent cognitive complaints are common following a mild head injury (MHI), but deficits are rarely detected on neuropsychological tests. Our objective was to examine the effect of symptom expectation on self-report and cognitive performance measures in MHI individuals. Prior research suggests that when MHI participants are informed they may experience cognitive difficulties, they perform worse on neuropsychological tests compared to MHI participants who are uninformed. In this study, undergraduate students with and without a prior MHI were either informed that the study’s purpose was to investigate the effects of MHI on cognitive functioning (‘‘diagnosis threat’’ condition) or merely informed that their cognitive functioning was being examined, with no mention of status (‘‘neutral’’ condition). ‘‘Diagnosis threat’’ MHIs self-reported more attention failures compared to ‘‘diagnosis threat’’ controls and ‘‘neutral’’ MHIs, and more memory failures compared to ‘‘diagnosis threat’’ controls. In the ‘‘neutral’’ condition, MHIs reported higher anxiety levels compared to controls and compared to ‘‘diagnosis threat’’ MHIs. Regardless of condition, MHIs performed worse on only one neuropsychological test of attention span. ‘‘Diagnosis threat’’ may contribute to the prevalence and persistence of cognitive complaints made by MHI individuals found in the literature, but may not have as strong of an effect on neuropsychological measures. (JINS, 2011, 17, 219–229) Keywords: Brain injuries, Mild concussion, Neuropsychological test, Attentions, Memory, Affects Approximately 90% of all brain injuries are classified as mild, with an estimate of 1.5 million non-institutionalized new mild to moderate cases each year in the United States (Sosin, Sniezek, & Thurman, 1996). The high prevalence of mild head injuries (MHI) largely contributes to the economic burden of all head injuries, accounting for an estimated 44% of the 56 billion dollar cost annually in the United States (Thurman, 2001). Neuropsychological assessments are one contributor to the overall cost, and are often necessary to investigate residual and persistent symptoms (cognitive, physical, and/or affective) reported by 14.5% (Rutherford, Merrett, & McDonald, 1979) to 50% (Edna & Cappelen, 1987; Middleboe, Andersen, Birket-Smith, & Friis, 1992) of individuals who have sustained a MHI in their past. Pro- spective controlled studies show that MHI participants report a significantly higher frequency of concentration difficulties (Ponsford et al., 2000), periods of confusion (Vanderploeg, Curtiss, Luis, & Salazar, 2007), and memory problems (Vanderploeg et al., 2007; Vanderploeg, Belanger, & Curtiss, 2009) at least 3 months, up to several years, following their injury compared to non-head-injured controls. Despite these persistent attention and memory complaints, standard neuropsychological tests do not consistently detect deficits in cognitive functioning. Prospective controlled studies have reported residual neuropsychological deficits (at least 3 months post-injury) in various aspects of attention (Chan, 2002; Potter, Jory, Bassett, Barrett, & Mychalkiw, 2002; Solbakk, Reinvang, Neilsen, & Sundet, 1999; Vanderploeg, Curtiss, & Belanger, 2005) and information processing speed (Bernstein, 2002; Potter et al., 2002); although the majority fail to detect significant long-term neuropsychological impairments (for meta-analyses, see Belanger, Curtiss, Demery, Lebowitz, & Vanderploeg, 2005; Binder, Rohling, & Larrabee, 1997; Vanderploeg et al., 2005). Moreover, when lingering problems are detected, they are frequently confounded by extraneous variables, such as pre-existing factors (Vanderploeg et al., 2007), co-morbid psychosocial factors (Chan, 2002; Dischinger, Ryb, Kuferea, & Auman, 2009; Fann, Uomoto, & Katon, 2001; Rapoport, McCullagh, Shammi, & Feinstein, 2005; Stulemeijer, Vos, Bleijenberg, & Van der Werf, 2007), and litigation (for review, see Belanger et al., 2005; Binder & Rohling, 1996; Tsanadis, Montoya, Hanks, Millis, & Fichtenberg, 2008). Correspondence and reprint requests to: Lana Ozen, Department of Psychology, 200 University Ave. W., University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada. E-mail: lozen@uwaterloo.ca 219