B. M. Brooks

Virtual Reality in Brain Damage Rehabilitation: Review

Given the high incidence of brain injury in the population, brain damage rehabilitation is still a relatively undeveloped field. Virtual reality (VR) has the potential to assist current rehabilitation techniques in addressing the impairments, disabilities, and handicaps associated with brain damage. The main focus of much of the exploratory research performed to date has been to investigate the use of VR in the assessment of cognitive abilities, but there is now a trend for more studies to encompass rehabilitation training strategies. This review describes studies that have used VR in the assessment and rehabilitation of specific disabilities resulting from brain injury, including executive dysfunction, memory impairments, spatial ability impairments, attention deficits, and unilateral visual neglect. In addition, it describes studies that have used VR to try to offset some of the handicaps that people experience after brain injury. Finally, a table is included which, although not an exhaustive list of everything that has been published, includes many more studies that are relevant to the use of VR in the assessment and rehabilitation of brain damage. The review concludes that the use of VR in brain damage rehabilitation is expanding dramatically and will become an integral part of cognitive assessment and rehabilitation in the future.

Training in virtual environments: transfer to real world tasks and equivalence to real task training

Virtual environments (VEs) are extensively used in training but there have been few rigorous scientific investigations of whether and how skills learned in a VE are transferred to the real world. This research aimed to measure and evaluate what is transferring from training a simple sensorimotor task in a VE to real world performance. In experiment 1, real world performances after virtual training, real training and no training were compared. Virtual and real training resulted in equivalent levels of post-training performance, both of which significantly exceeded task performance without training. Experiments 2 and 3 investigated whether virtual and real trained real world performances differed in their susceptibility to cognitive and motor interfering tasks (experiment 2) and in terms of spare attentional capacity to respond to stimuli and instructions which were not directly related to the task (experiment 3). The only significant difference found was that real task performance after training in a VE was less affected by concurrently performed interference tasks than was real task performance after training on the real task. This finding is discussed in terms of the cognitive load characteristics of virtual training. Virtual training therefore resulted in equivalent or even better real world performance than real training in this simple sensorimotor task, but this finding may not apply to other training tasks. Future research should be directed towards establishing a comprehensive knowledge of what is being transferred to real world performance in other tasks currently being trained in VEs and investigating the equivalence of virtual and real trained performances in these situations.

A preliminary investigation into the use of virtual environments in memory retraining after vascular brain injury: indications for future strategy?

PURPOSE In a preliminary investigation of the use of Virtual Environments (VEs) in neurorehabilitation, this study compares the effects of active and passive experience of a VE on two types of memory in vascular brain injury patients and controls. METHOD Forty-eight patients with vascular brain injury and 48 non-impaired control participants were randomly assigned to active and passive VE conditions. The active participants explored a virtual bungalow seeking a particular object; the passive participants observed, but did not control movement through the VE, also seeking the object. Afterwards, both active and passive participants completed spatial recognition and object recognition tests. RESULTS Expectedly, the patients were impaired relative to the controls but were able to perform the virtual tasks. Active participation in the VE enhanced memory for its spatial layout in both patients and controls. On object recognition, active and passive patients performed similarly, but passive controls performed better than active controls. CONCLUSIONS The findings are discussed in relation to their implications for memory rehabilitation strategies.

Allocentric Spatial Memory Activation of the Hippocampal Formation Measured With fMRI

Hippocampal activation was investigated, comparing allocentric and egocentric spatial memory. Healthy participants were immersed in a virtual reality circular arena, with pattern-rendered walls. In a viewpoint-independent task, they moved toward a pole, which was then removed. They were relocated to another position and had to move to the prior location of the pole. For viewpoint-dependent memory, the participants were not moved to a new starting point, but the patterns were rotated to prevent them from indicating the final position. Hippocampal and parahippocampal activation were found in the viewpoint-independent memory encoding phase. Viewpoint-dependent memory did not result in such activation. These results suggest differential activation of the hippocampal formation during allocentric encoding, in partial support of the spatial mapping hypothesis as applied to humans.

Probing Memory and Executive Functions with Virtual Reality: Past and Present Studies

The technology of virtual reality (VR) has been used to develop interactive programs that simulate everyday life environments, where healthy subjects and patients with central nervous system dysfunctions are asked to carry out tasks that probe incidental memory and executive functions. The results of three studies support previous claims that VR-based tests overcome several limitations of traditional paper-and-pencil tests, are at least as sensitive to target cognitive impairments, while providing a richer range of opportunities for measuring behavior. Preliminary analyses also suggest that results of VR-based memory tests are replicable across laboratories and subjects samples and that the technology is well-accepted and tolerated by both healthy and impaired subjects.

Assessing stroke patients' prospective memory using virtual reality.

There is a dearth of empirical evidence about prospective memory (remembering to perform actions in the future) in stroke patients. A probable reason for this is that it is difficult to perform a realistic and controlled assessment of prospective memory ability in a rehabilitation setting. Virtual reality may provide a solution to this difficulty by allowing prospective memory to be tested in a simulation of a real-life situation whilst retaining a laboratory level of scientific control. This exploratory study assessed the performance of stroke patients and age-matched control participants on event-, time- and activity-based prospective memory retrieval tasks in a personal computer-based virtual environment. Stroke patients were severely impaired at the event- and activity-based tasks compared with age-matched controls, but only marginally impaired at the time-based task. The additional knowledge gained from this form of assessment could direct rehabilitation more effectively towards specific impairments of individual patients.

An evaluation of the efficacy of training people with learning disabilities in a virtual environment.

Purpose : To evaluate the efficacy of using a virtual kitchen for vocational training of people with learning disabilities. Method : Twenty four catering students with learning disabilities participated in the study. Half the students were currently being trained in the kitchen on which the virtual kitchen was modelled but the remaining students were unfamiliar with this kitchen. Students were first pre-tested on four food preparation tasks and identification of 12 hazards in their own training kitchens. They were subsequently trained on one food preparation task and three hazards in their own training kitchens, one food preparation task and three hazards in the virtual kitchen, and one food preparation task and three hazards in specially designed workbooks. They were then retested in their own training kitchens on all the food preparation tasks and all the hazards. Results : Virtual training was found to be as beneficial as real training and more beneficial than workbook and no training in the food preparation tasks. However, virtual, real and workbook training were found to be equally beneficial in the hazard identification task. Students who were unfamiliar with the kitchen on which the virtual kitchen was modelled benefited from virtual training to the same extent as students who were familiar with the kitchen. Conclusions : Vocational students with learning disabilities were able to use the virtual environment and were motivated to learn using this training method. Depending on the task being trained, virtual training had a more beneficial effect on real task performance than workbook training, even when the virtual kitchen was not modelled on the real training kitchen.

An exploratory investigation into the usability and usefulness of training people with learning disabilities in a virtual environment.

Purpose : Two studies sought to answer the following questions. Are people with learning disabilities capable of using a virtual environment? Are they motivated to learn using this training method? Do they show any benefit from using a virtual environment? Does any benefit transfer to improved real world performance? Method : In the first study, 30 students with learning disabilities were sequentially allocated to an active or a passive experimental group. Active participants explored a virtual bungalow searching for a toy car. Passive participants watched the exploration undertaken by the preceding active participant and searched for the toy car. All participants then performed spatial and object recognition tests of their knowledge of the virtual environment. In the second study, the errors of 45 participants on a real steadiness tester task were noted before they were randomly allocated to three groups--a real training group, a virtual training group and a no training group. After training, the participants performed a second test trial on the real steadiness tester. Results : The students were capable of using a virtual environment and were motivated to use this training method. Active exploration of a virtual environment was found to enhance their memory of the spatial layout of the bungalow but not their memory of the virtual objects. In the second study, virtual training was found to transfer to real task performance. Conclusions : These two laboratory-based studies provide answers to four important questions concerning virtual training of people with learning disabilities. Hopefully, the findings will encourage this training aid to be used more widely.

Learning and Memory in Virtual Environments: A Role in Neurorehabilitation? Questions (and Occasional Answers) from the University of East London

The virtual reality research group at the University of East London has its origins in basic neuroscience research on environmental influences on recovery of function from brain damage. Here we describe our work since incorporating within our research the use of virtual environments (VEs) in brain damage rehabilitation. We have focused on three issues relating to the development of VEs for people with impaired brain function: usability, the value of active interaction (as opposed to passive observation), and the nature of transfer of training from virtual to real environments. Our studies, which have encompassed vascular, traumatic, degenerative, and developmental brain damage, suggest that VEs have great potential in brain damage rehabilitation.

Primacy and recency in primed free association and associative cued recall.

Two experiments compared the serial positions of primed words in an implicit free association test with words recalled in a cued recall test. In both tests, weakly or strongly related word pairs were studied, and the first words of each pair formed the test cues. In the implicit test, weakly related words pairs showed primacy and extended recency effects but strongly related word pairs did not. In the explicit test, both weakly and strongly related word pairs showed primacy and extended recency effects. These functional dissociations between implicit and explicit memory tests indicate that strongly related word pairs are encoded together because they have unitized memory representations that function as integrated units without requiring any additional associative links to be made, but that an additional system or process is required to strengthen weakly related word pairs during encoding. In addition, a further additional system or process is accessed by explicit retrieval.