age 7 to 13 years. Journal of the American Academy of Child and Adolescent Psychiatry, 27, 5-59. Gillberg, I. C., Gillberg, C., & Groth, J. (1989). Children with preschool minor neurodevelopmental disorders. V: Neurodevelopmental profiles at age 13. De- velopmental Medicine and Child Neurology, 31, 14-24. Hechtman, L. (1999). Predictors of long-term outcome in children with atten- tion- deficit/hyperactivity disorder. Pediat- ric Clinics of North America, 46(5), 1039-1052. Hellgren, L., Gillberg, C., Gillberg, I. C., & Enerskog, I. (1993). Children with Deficits in Attention, Motor control and Perception (DAMP) almost grown up. General health at age 16 years. Developmental Medicine and Child Neurology, 35, 881-892. Hellgren, L., Gillberg, C., Gillberg, I.C. (1994). Children with Deficits in Attention, Motor control, and Perception (DAMP) al- most grown up: The contribution of vari- ous background factors to outcome at age 16 years. European Child & Adolescent Psy- chiatry, 3, 1-15. Rasmussen, P., Gillberg, C., Waldenstrom, E., & Svenson, B. (1983). Perceptual, motor and attentional deficits in 7-year-old chil- dren: Neurological and neurodevelopmental aspects. Developmental Medicine and Child Neurology, 25, 315-333. Rutter, M., Graham, P., & Yule, W. (1970). A Neuropsychiatric Study in Childhood. S.I.M.P. William Heinemann Medical Books Ltd, London. Spitzer, R. L., Williams, J. B., Gibbon, M., & First, M. B. (1992). The Structured Clinical Interview for DSM-III-R (SCID). I: History, rationale, and description. Archives of Gen- eral Psychiatry, 49, 24-629. Virtual Reality (VR) technology is in- creasingly recognized as a useful tool for the study, assessment, and rehabilita- tion of cognitive processes and func- tional abilities (Rizzo, 1994; Pugnetti et al., 1995; Rizzo & Buckwalter, 1997; Rose, Attree, Brooks & Johnson, 1998). The capacity of VR to create dynamic in- teractive immersive 3-D stimulus envi- ronments, in which all behavioral responding can be recorded, offers as- sessment and rehabilitation options not available with traditional neuro- psychological methods. In this regard, a growing number of laboratories are de- veloping research programs investigat- ing the use of Virtual Environments (VEs) for these purposes; controlled studies reporting encouraging results are now beginning to emerge (Rizzo, Buckwalter, & van der Zaag, 2001). This work has the potential to advance scien- tific study of normal cognitive and be- havioral processes, and to improve our capacity to understand and treat impair- ments in these areas typically found in clinical populations. Relevant to these efforts, this article will briefly define “virtual reality,” and present a rationale for the application of VR technology for the assessment and possible rehabilita- tion of attention processes. We will then present background on our develop- ment of a VE targeting attention pro- cesses referred to as the “Virtual Classroom,” now evaluated to assess children with ADHD. WHAT IS VIRTUAL REALITY? Virtual reality has been generally de- fined as “a way for humans to visual- ize, manipulate, and interact with computers and extremely complex data” (Aukstakalnis & Blatner, 1992). While this general definition is useful, more specifically, VR can be viewed as an advanced form of human-computer interface allowing the user to “interact” with and become “immersed” within a computer-generated environment in a naturalistic fashion. By analogy, this means that, much like an aircraft simu- lator serves to test and train piloting ability, computer-generated virtual en- vironments (VEs) can be created to as- sess and rehabilitate cognitive and functional abilities. Whereas a flight simulation system provides an interac- tive sensory illusion of a real flight, VR can provide interactive scenarios de- signed to target client needs via expo- sure to simulated “real world” and/or analog tasks. Interaction in three dimensions (3D) is a key characteristic distinguishing a VR experience from watching a movie. The believability of the virtual experi- ence (or “sense of presence”) occurs by employing such specialized technol- ogy as head-mounted displays (HMDs), tracking systems, earphones, The ADHD Report  9 A Virtual Reality Environment for the Assessment of ADHD Albert A Rizzo, Ph.D., Todd Bowerly, M.A., J. Galen Buckwalter, Ph.D., Lori Humphrey, Ph.D., Ulrich Neumann, Ph.D., Laehyun Kim, M.A., Jarrell Pair, Ph.D., Andre van Rooyen, Ph.D., and Clint Chua, M.A.