Cognitive determinants of visual search in patients with Parkinson's disease

Abstract

Visual search impairments may negatively affect activities of daily living. Few studies explored the cognitive deficits that contribute to impaired visual search in Parkinson's disease (PD). The aim was to investigate the associations between visual search performance and cognitive functions in PD. Twenty patients with PD [age: 69 ± 8 yo; sex (Men/Women): 16/4] and 15 controls (age: 61 ± 11 yo; sex: 8/7) performed a visual search task where they were instructed to search for a target stimulus (road sign) among distractor stimuli (other road signs). Neuropsychological tests were also administered. Partial correlations (r or r) were analyzed to investigate associations between correct detection times (cDT) of the visual search task with cognitive variables whilst controlling for age. In patients, significant partial correlations were found between cDT and Montreal Cognitive Assessment scores (ρ = −0.65, P = 0.002), divided attention of the Useful Field Of View test (ρ = 0.60, P = 0.007), interference condition of the Stroop test ( r = −0.58, P = 0.023), Figure of Rey (ρ = −0.74, P < 0.001), errors and completion times on the Dot Cancellation test (errors: ρ=0.83, P < 0.001; completion times: r = 0.53, P = 0.018), response times on Trail Making Test-part A (ρ = 0.56, P = 0.013) and part B ( r = 0.58, P = 0.015). In controls, only one significant partial correlation was found, between cDT and completion times of dot cancellation test ( r = 0.88, P = 0.001). This study shows that visual search is affected by cognitive functions of individuals living with PD. Our findings may have implications for the assessment of cognitive functions and the development of training programs in patients with PD. Further study in PD will develop dynamic visual search task in driving conditions to better understand cognitive functions that may affect real-world activities.