Neuropsychological assessment has a long history in the United States military and has played an essential role in ensuring the mental health and operational readiness of service members since World War I (Kennedy, Boake, & Moore, 2010). Over the years, mental health clinicians in the military have developed paper-and-pencil assessment instruments, which have evolved in terms of psychometric rigor and clinical utility, but not in terms of technological sophistication. Since the advent of modern digital computing technology, considerable research has been devoted to the development of computer-automated neuropsychological assessment applications (Kane & Kay, 1992; Reeves, Winter, Bleiberg, & Kane, 2007), a trend that is likely to continue in the future. While many comparatively antiquated paper-and-pencil-based test instruments are still routinely used, it is arguably only a matter of time until they are supplanted by more technologically advanced alternatives. It is important to note, however, that questions have been raised about the ecological validity of many commonly used traditional neuropsychological tests, whether paper-and-pencil-based or computerized (Alderman, Burgess, Knight, & Henman, 2003; Burgess et al., 2006; Chaytor & Schmitter- Edgecombe, 2003; Chaytor, Schmitter-Edgecombe, & Burr, 2006; Parsons, 2016a; Sbordone, 2008). In the context of neuropsychological testing, ecological validity generally refers to the extent to which test performance corresponds to real-world performance in everyday life (Sbordone, 1996). In order to develop neuropsychological test instruments with greater ecological validity, investigators have increasingly turned to virtual reality (VR) technologies as a means to assess real-world performance via true-to-life simulated environments (Campbell et al., 2009; Negut, Matu, Sava, & Davis, 2016; Parsons, 2015a, 2015b, 2016a). Bilder (2011) described three historical and theoretical formulations of neuropsychology. First, clinical neuropsychologists focused on lesion localization and relied on interpretation without extensive normative data. Next, clinical neuropsychologists were affected by technological advances in neuroimaging and as a result focused on characterizing cognitive strengths and weaknesses rather than on differential diagnosis.
Ecological Validity in Virtual Reality-Based Neuropsychological Assessment