Assessing visuospatial abilities related to visual scanning in cerebral visual impairment using the star cancellation...

Visuospatial processing dysfunctions are common in individuals with cerebral visual impairment (CVI) and can have a significant impact on how they perceive and interact with their surrounding environment. To gain further insight into the nature of these deficits, we assessed visual scanning performance in individuals with CVI compared to neurotypically developed controls. In this exploratory story, 16 individuals with CVI (mean age = 19.56 years ± 5.59 SD; mean verbal IQ = 94.85 ± 21.84) and 19 control participants (mean age = 21.37 years ± 5.21 SD; mean verbal IQ = 123.79 ± 12.59) completed the Star Cancellation Test (SCT). Gaze behavior was also recorded using wearable eye tracking (Tobii Pro Glasses 3; 100 Hz sampling rate) during naturalistic and standardized administration of the assessment. Controlling for age and verbal IQ level, we found that while test accuracy was not significantly lower in CVI participants, they took significantly longer to complete the task compared to controls. CVI participants also tended to spend more time verifying their work and had lower cancellation efficiency (a composite performance index incorporating accuracy and completion time). Regarding gaze metrics, CVI subjects had longer total fixation durations and higher fixation counts, as well as greater total saccade amplitudes (scan path length) and saccade counts. However, group differences were not significant when comparing normalized gaze metrics (i.e., average fixation duration and average saccade amplitude). The observed differences in behavioral performance and gaze metrics in CVI are consistent with a profile of less efficient and more effortful visual scanning and search. The use of standardized assessments combined with wearable eye tracking can provide further insight into the nature of visuospatial processing dysfunctions in this population.