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  • Assessing visuospatial proc...
    Zhang, Xin; Manley, Claire E.; Micheletti, Serena; Tesic, Isidora; Bennett, Christopher R.; Fazzi, Elisa M.; Merabet, Lotfi B.

    Research in developmental disabilities, 12/2022, Letnik: 131
    Journal Article

    Cerebral visual impairment (CVI) is a brain based visual disorder associated with the maldevelopment of central visual pathways. Individuals with CVI often report difficulties finding a target of interest in cluttered and crowded visual scenes. However, it remains unknown how manipulating task demands and other environmental factors influence visual search performance in this population. We developed a novel and naturalistic virtual reality (VR) based static visual search task combined with eye tracking called the “virtual toy box” to objectively assess visual search performance in CVI. A total of 38 individuals with CVI (mean age 13.18 years ± 3.58 SD) and 53 controls with neurotypical development (mean age 15.25 years ± 5.72 SD) participated in the study. In a first experiment, study subjects were instructed to search for a preselected toy presented among a varying number of surrounding distractor toys (set size ranging from 1 to 36 items). In a second experiment, we assessed the effects of manipulating item spacing and the size of the visual area explored (field of view; FOV). Behavioral outcomes collected were success rate, reaction time, gaze error, visual search area, and off-screen percent (an index of task compliance). Compared to age-matched controls, participants with CVI showed an overall impairment with respect to all the visual search outcomes of interest. Specifically, individuals with CVI were less likely and took longer to find the target, and search patterns were less accurate and precise compared to controls. Visual search response profiles were also comparatively less efficient and were associated with a slower initial pre-search (visual orienting) response as indexed by higher slope and intercept values derived from the analysis of reaction time × set size functions. Search performance was also more negatively affected in CVI at the smallest as well as largest spacing conditions tested, while increasing FOV was associated with greater decreased gaze accuracy and precision These results are consistent with a general profile of impaired visual search abilities in CVI as well as worsening performance with increased visual task demands and an overall sensitivity to visual clutter and crowding. The observed profile of impaired visual search performance may be associated with dysfunctions related to how visual selective attention is deployed in individuals with CVI. •Higher order visual perceptual abilities are typically not assessed as part of a standard ophthalmological exam.•Visual search performance in CVI was characterized by using a novel virtual reality-based task combined with eye tracking.•Compared to age-matched controls, participants with CVI showed an overall impairment in performance on all visual search outcomes of interest.•The general profile observed in CVI was consistent with worsening performance with increased visual task demands and sensitivity to visual clutter and crowding.