Visuospatial Processing in Parkinson's Disease: A Computer-Based Dual-Task Study

Parkinson’s disease is a progressive disorder of the central nervous system. The primarily affected regions are the dopaminergic neurons of the substantia nigra pars compacta and the striatum, accompanied by the aggregation of misfolded alpha-synuclein (Morris et al., 2024; Zhang et al., 2026). Historically, Parkinson’s disease was known for its distinct motor symptomatology (Fang et al., 2020); in recent years, much more attention has focused on researching the disease’s non-motor symptoms. Cognitive deficits are frequently observed in patients with Parkinson’s disease, with approximately 25% of individuals being affected by them at the time of diagnosis (Barone et al., 2011). Executive functions, memory, and visuoperceptual abilities are the most affected cognitive domains (Emre, 2003). Visuospatial impairment in Parkison’s disease is recognized in literature as a feature of cognitive decline, yet it remains relatively understudied (Oliveira et al., 2025). The current study aimed to investigate visuospatial processing using a computerized dual-task paradigm. The computerized approach was compared with a standard paper-and-pencil test designed to assess visuospatial attention (Behavioral Inattention Battery), to determine whether the computer-based dual-task paradigm could detect finer-grained visuospatial deficits under different cognitive and perceptual demands. The study included a healthy control group and a group of patients with Parkinson’s disease. Both groups underwent computerized spatial testing comprising three cognitive load conditions (single, dual-visual, dual-auditory), two stimulus diameter conditions (0.3° and 0.8°), and four stimulus locations (left, right, bilateral, and no-target). The Parkinson’s disease group underwent a second level neuropsychological assessment using paper-and-pencil tests. For the Parkinson’s disease group, disease duration from diagnosis and side of onset of symptoms were also included as variables. The results yielded by the analysis showcased a high accuracy within the control group, with a clear decrease in accuracy in the dual task conditions. For the Parkinson’s disease group, there was a high level of inter-individual variability, yet the spatial performance of the sample did not yield a lateralized pattern of spatial bias. However visuospatial attention accuracy was modulated by the interaction among cognitive load, disease duration and stimulus location. The use of a computerized dual-task paradigm as a tool for assessing visuospatial deficits in individuals with Parkinson’s disease allows the detection of subtle visuospatial impairments that are sensitive to task demands and that would otherwise go undetected through standard paper-and-pencil tests.