Aims: After stroke, patients can experience an increase in their sensitivity for visual stimuli (visual hypersensitivity). They, for instance, feel overwhelmed when surrounded by bright lights or fast-moving visual stimuli. It has been proposed that these symptoms are related to atypical bottom-up sensory processing and impaired selective attention, but empirical evidence is currently lacking. The current study aimed to investigate the relationship between post-stroke visual hypersensitivity and sensory thresholds, sensory processing speed, and selective attention using computational modelling of behavioural data.
Method: During a whole/partial report task, participants (51 stroke patients, 76 orthopedic patients, and 77 neurotypical adults) had to correctly identify a single target letter that was presented alone (for 17 to 100 ms) or along a distractor (for 83ms). Based on the performance on this task the sensory threshold, sensory processing speed, and selective attention abilities of each participant were estimated within the framework of the Theory of Visual Attention.
Results: There was evidence, both on a group and individual level, for impaired selective attention and (to a lesser extent) lower sensory thresholds in patients with post-stroke visual hypersensitivity as compared to neurotypical adults, orthopedic patients, or stroke patients without post-stroke sensory hypersensitivity.
Discussion: These results provide a significant advancement in our comprehension of the underlying mechanisms of post-stroke visual hypersensitivity which can help us identify patients which are at risk for developing these symptoms, improve treatment protocols, as well as serve as a catalyst for further research.