Childhood traumatic brain injury, executive functions, and social outcomes: Toward an integrative model for research and clinical practice

Traumatic brain injury (TBI) is a leading cause of death and disability in youth under the age of 15, and therefore represents a major public health problem (Bruns & Hauser, 2003; Centers for Disease Control and Prevention, 1999). In the United States, for instance, more than 1 million children and adolescents sustain TBI annually, resulting in approximately 150,000 hospitalizations and 5,000 deaths (Kraus, 1995; Langlois, Rutland-Brown, & Thomas, 2005). Similar rates are reported in other industrialized nations (O’Connor, 2002). Injury severity is strongly related to the outcomes associated with TBI, so that moderate and severe injuries account for most of the mortality and morbidity associated with pediatric TBI, despite representing only about 15% of all cases (Kraus, 1995). As improved medical treatment has led to more frequent survival, concern has increasingly focused on the subsequent cognitive, emotional, and behavioral morbidity,especially among children with more severe injuries (Yeates, 2000), leading to signiﬁcant economic and social burden for the community. Despite the growing interest in postacute sequelae, the social outcomes of child-hood TBI remain largely uncharacterized and poorly understood. Although social competence is an important predictor of numerous other outcomes, including psychological adjustment, academic performance, and health status (Cacioppo et al., 2002; Rubin, Bukowski, & Parker, 2006), we know little about social outcomes among children with TBI. Nevertheless, because of its critical developmental implications, poor social functioning is likely to play a major role in the reductions in quality of life reported following childhood TBI (Stancin et al., 2002). Several different lines of research suggest that children with TBI are vulnerableto poor social outcomes. First, children with developmental disabilities and chronic health conditions affecting the central nervous system, such as epilepsy and cerebral palsy, are rated as less socially accepted and less socially competent than peers (Nassau & Drotar, 1997). Second, neuroimaging research has revealed an anterior-posterior gradient in the focal lesions associated with TBI. Larger and more numerous lesions are found in frontal and anterior temporal regions (Levin et al., 1989; Mendelsohn et al., 1992; Wilde et al., 2005), which are the same regions that have been implicated as the neural substrates of social information processing and the regulation of social behavior (Adolphs, 2001; Grady & Keightley, 2002). Third, the few previous studies of social outcomes in childhood TBI have shown that children with severe TBI are less skilled at social problem solving and are rated as less socially competent and lonelier than healthy children or children with injuries not involving the brain and that their poor social outcomes persist over time (Andrews, Rose, & Johnson, 1998; Bohnert, Parker, & Warschausky, 1997; Dennis, Guger, Roncadin, Barnes, & Schachar, 2001; Janusz, Kirkwood, Yeates, & Taylor, 2002; Max et al., 1998; McGuire & Rothenberg, 1986; Papero, Prigatano, Snyder, & Johnson, 1993; Yeates et al., 2004). Nevertheless, previous research on the social outcomes of childhood TBI is limitedin quantity and has not made use of state-of-the-art measures and models of social function, thereby precluding a comprehensive portrayal of social consequences following childhood TBI. Now is an excellent time to consider social outcomes in children with TBI. The emerging ﬁeld of social cognitive neuroscience provides a critical perspective on the social impact of childhood TBI. Social neuroscience not only supplies research tools needed to better understand the neural substrates and social cognitive processes associated with social functioning, but also provides a foundation for a multilevel, integrative analysis of the social difﬁculties arising from brain insults (Brothers, 1990; Cacioppo, Berntson, Sheridan, & McClintock, 2000; Moss & Damasio, 2001; Ochsner & Lieberman, 2001; Posner, Rothbart, & Gerardi-Caulton, 2001), and in particular the role of the frontal lobes and executive functions in these processes. The methods and models derived from social neuroscience will be particularlypowerful when combined with those associated with the study of social competence in developmental psychology and developmental psychopathology (Parker et al., 2006; Rubin et al., 2006). The latter approaches reﬂect a developmental perspective that can enhance the ﬁeld of social neuroscience. In short, we now have the toolsExecutive functions andand models to begin to understand how children’s abilities to identify, think about, produce, and regulate emotions; to consider other people’s perspectives, beliefs, and intentions; and to solve interpersonal problems are associated with their daily functioning in the social world. Furthermore, we can model this association in terms of developmental processes and brain pathology. The goal of this chapter is to describe the relationship between childhood TBI andsocial outcomes. The chapter begins with a description of the major elements of social development as currently conceptualized by developmental psychologists, and continues with a description of how social cognitive neuroscience informs our understanding of the neural substrates of social behavior. The chapter next summarizes developmental issues that arise in the study of social outcomes in childhood TBI. This methodological and conceptual knowledge base is then applied to childhood TBI, by showing how it affects the frontal lobes, executive functions, social information processing, and social behavior, as well as their respective linkages. It concludes with the presentation of an integrative model of social outcomes of TBI and with a discussion of future research needs and possible clinical implications.