In the present study, whether subjects were experiencing the VR phenomenon known as presence was informally assessed through observing the amount of head movements or tracking, made during the session. Anecdotally the AD/HD participants appeared to engage in this behaviour more frequently during the VRDE. A greater number of head movements was interpreted as indicating a more immersive effect for the individual, however head movements were difficult to assess during the sessions, as most sessions were conducted in the dark. Although a clear method for establishing presence has yet to be determined (Hoffman, Hullfish & Houston, in press, in Rose, 1995), an unobtrusive tracking mechanism (magnetic, mechanical, infrared or gyroscopic,) registering any head motion (North, North & Coble,1996) would be a useful way to objectively assess participants' immersive experiences.

Tactile sensations during VR reportedly improves quality of the experience (Hoffman et al., 1996). Although implementation of the technology required to achieve this effect is complex, comparable effects have been noted using Mixed Reality (Milgram & Kishino, 1994; Hoffman et al., 1996). In contrast to computer generated force-feedback and tele-action, implementing tactile augmentation, such as immersing participants' hands in a container of water during a VRDE, is a cost effective alternative(Hoffman et al., 1996) and could be implemented in further studies.

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