Objective: The aim of this study was to investigate the relationship between cognition and other symptoms of Parkinson’s disease (PD) using computational neuropsychological tests.

Background: Computational neuropsychological testing is a flexible and precise way to evaluate cognitive function, and thus can be used to study mild and subtle cognitive changes in PD patients.

Methods: Twenty PD patients were enrolled. Their motor and non-motor symptoms were assessed during on-medication period : (1) motor function measured by UPDRS Part III; (2) olfaction by Odor Stick Identification Test for Japanese (OSIT-J); (3) color discrimination by F-M 100-hue test; (4) REM sleep behavior disorder (RBD) by REM Sleep Behavior Disorder Questionnaire (RBDQ-HK); (5) cognition by MoCA and computational neuropsychological tests, including Stroop (focusing on attention and working memory) and Task Switching (focusing on executive function). Patients responded to the computational tasks by pressing the right or left button of a game controller. Reaction time (RT) and accuracy were calculated by the computer.

Results: Patients had a mean age of 56.6±9.7 years and mean disease duration of 5.4±3.3 years. On average, motor score was 19.8±8.1; OSIT-J score was 5.4±2.2, with 85% suffering from hyposmia (score<9); color discrimination score was 79.1±45.5, with 30% suffering from decreased color discrimination (score>100); RBDQ-HK score was 27.9±18.5, with 70% having RBD (score>18); MoCA score was 26.7±1.6. Mean RT and accuracy for Srtoop was 738.9±166.3 ms and 0.95±0.05, respectively. Mean repeat RT, switch RT, repeat accuracy and switch accuracy for Task Switching were 1369.30±384.51 ms, 1421.75±393.06 ms, 0.91±0.10 and 0.89±0.10, respectively. Stroop accuracy was negatively correlated with LEDD (r=-0.502, p<0.05). And there was a potential negative correlation between LEDD and switch accuracy of Task Switching (r=-0.429, p=0.059). Repeat accuracy of Task Switching was positively correlated with MoCA score (r=0.529, p<0.05). Computational tests performance was not correlated with motor symptoms or nonmotor symptoms.

Conclusions: Hyposmia, RBD and decreased color discrimination are prevalent in PD. Higher doses of dopaminergic medication might have a negative effect on cognitive function for PD patients. computational neuropsychological tests can be a potential screening tool for cognitive impairment in PD.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/an-investigation-of-the-relationship-between-computational-neuropsychological-testing-outcomes-and-symptoms-of-parkinsons-disease/