Positive Technology Journal

Field dependency and the sense of object-presence in haptic virtual environments.

Cyberpsychol Behav. 2007 Apr;10(2):243-51

Authors: Hecht D, Reiner M

Virtual environment (VE) users often report having a sense of being present in the virtual place or a sense that the virtual object is present in their environment. This sense of presence depends on both the technological fidelity (e.g., in graphics, haptics) and the users' cognitive/ personality characteristics. This study examined the correlation between user's cognitive style on the field-dependency dimension and the level of object-presence they reported in a haptic VE. Results indicated that field-independent individuals reported higher presence ratings compared to field-dependent participants. We hypothesize that field-independents' advantage in reorganizing the perceptual field and constructing it according to their previously acquired internal knowledge enables them to cognitively reconstruct the VE experience more efficiently by selectively attending only to the relevant cues and by filling in the gap of missing information with their previous knowledge and creative imagination. This active and creative cognitive process may be behind the enhanced sense of presence. In addition, we raise a possible linkage between field dependency, the sense of presence, and simulator sickness phenomenon.

Virtual reality in stroke rehabilitation: Still more virtual than real.

Disabil Rehabil. 2007 Jul 30;29(14):1139-46

Authors: Crosbie JH, Lennon S, Basford JR, McDonough SM

Purpose. To assess the utility of virtual reality (VR) in stroke rehabilitation. Method. The Medline, Proquest, AMED, CINAHL, EMBASE and PsychInfo databases were electronically searched from inception/1980 to February 2005, using the Keywords: Virtual reality, rehabilitation, stroke, physiotherapy/physical therapy and hemiplegia. Articles that met the study's inclusion criteria were required to: (i) be published in an English language peer reviewed journal, (ii) involve the use of VR in a stroke rehabilitation setting; and (iii) report impairment and/or activity oriented outcome measures. Two assessors independently assessed each study's quality using the American Academy for Cerebral Palsy and Developmental Medicine (AACPDM) grading system. Results. Eleven papers met the inclusion criteria: Five addressed upper limb rehabilitation, three gait and balance, two cognitive interventions, and one both upper and lower limb rehabilitation. Three were judged to be AACPDM Level I/Weak, two Level III/Weak, three Level IV/Weak and three Level V quality of evidence. All articles involved before and after interventions; three randomized controlled trials obtained statistical significance, the remaining eight studies found VR-based therapy to be beneficial. None of the studies reported any significant adverse effects. Conclusion. VR is a potentially exciting and safe tool for stroke rehabilitation but its evidence base is too limited by design and power issues to permit a definitive assessment of its value. Thus, while the findings of this review are generally positive, the level of evidence is still weak to moderate, in terms of research quality. Further study in the form of rigorous controlled studies is warranted.

Influence of mirror therapy on human motor cortex.

Int J Neurosci. 2007 Jul;117(7):1039-48

Authors: Fukumura K, Sugawara K, Tanabe S, Ushiba J, Tomita Y

This article investigates whether or not mirror therapy alters the neural mechanisms in human motor cortex. Six healthy volunteers participated. The study investigated the effects of three main factors of mirror therapy (observation of hand movements in a mirror, motor imagery of an assumed affected hand, and assistance in exercising the assumed affected hand) on excitability changes in the human motor cortex to clarify the contribution of each factor. The increase in motor-evoked potential (MEP) amplitudes during motor imagery tended to be larger with a mirror than without one. Moreover, MEP amplitudes increased greatly when movements were assisted. Watching the movement of one hand in a mirror makes it easier to move the other hand in the same way. Moreover, the increase in MEP amplitudes is related to the synergic effects of afferent information and motor imagery.