3 research outputs found
An immersive virtual reality system for ecological assessment of peripersonal and extrapersonal unilateral spatial neglect
Background
Unilateral spatial neglect (USN) is a debilitating neuropsychological syndrome that often follows brain injury, in particular a stroke affecting the right hemisphere. In current clinical practice, the assessment of neglect is based on old-fashioned paper-and-pencil and behavioral tasks, and sometimes relies on the examinerâs subjective judgment. Therefore, there is a need for more exhaustive, objective and ecological assessments of USN.
Methods
In this paper, we present two tasks in immersive virtual reality to assess peripersonal and extrapersonal USN. The tasks are designed with several levels of difficulty to increase sensitivity of the assessment. We then validate the feasibility of both assessments in a group of healthy adult participants.
Results
We report data from a study with a group of neurologically unimpaired participants (Nâ=â39). The results yield positive feedback on comfort, usability and design of the tasks. We propose new objective scores based on participantâs performance captured by head gaze and hand position information, including, for instance, time of exploration, moving time towards left/right and time-to-reach, which could be used for the evaluation of the attentional spatial bias with neurological patients. Together with the number of omissions, the new proposed parameters can result in lateralized index ratios as a measure of asymmetry in space exploration.
Conclusions
We presented two innovative assessments for USN based on immersive virtual reality, evaluating the far and the near space, using ecological tasks in multimodal, realistic environments. The proposed protocols and objective scores can help distinguish neurological patients with and without USN.</p
An immersive virtual reality tool for assessing left and right unilateral spatial neglect
The reported rate of the occurrence of unilateral spatial neglect (USN) is highly variable likely due to the lack of validity and low sensitivity of classical tools used to assess it. Virtual reality (VR) assessments try to overcome these limitations by proposing immersive and complex environments. Nevertheless, existing VRâbased tasks are mostly focused only on near space and lack analysis of psychometric properties and/or clinical validation. The present study evaluates the clinical validity and sensitivity of a new immersive VRâbased task to assess USN in the extraâpersonal space and examines the neuronal correlates of deficits of far space exploration. The task was administrated to two groups of patients with right ( N =â28) or left ( N =â11) hemispheric brain lesions, also undergoing classical paperâandâpencil assessment, as well as a group of healthy participants. Our VRâbased task detected 44% of neglect cases compared to 31% by paperâandâpencil tests in the total sample. Importantly, 30% of the patients (with right or left brain lesions) with no clear sign of USN on the paperâandâpencil tests performed outside the normal range in the VRâbased task. Voxel lesionâsymptom mapping revealed that deficits detected in VR were associated with lesions in insular and temporal cortex, part of the neural network involved in spatial processing. These results show that our immersive VRâbased task is efficient and sensitive in detecting mild to strong manifestations of USN affecting the extraâpersonal space, which may be undetected using standard tools