Use of the Complex Task Performance Assessment as a Performance-Based Measure of Functional Cognition in People With Parkinson’s Disease

PURPOSE: The purpose of this study was to determine how Parkinson’s disease (PD) affects performance on the Complex Task Performance Assessment (CTPA) and the association of CTPA performance with other indicators of executive function (EF) in people with PD. Executive dysfunction in people with PD without dementia is well characterized from neuropsychological tests. However, PD’s impact on functional cognition, or the integration of cognitive processes in the context of everyday activities, is unclear. The CTPA is a performance-based assessment that simulates cognitively complex clerical work and may provide insight into functional cognition among people with PD.

METHOD: This study had a cross-sectional, observational design. Participants with PD were recruited through the Washington University School of Medicine (WUSM) Movement Disorders Center, and their spouses or significant others were convenience sampled as control participants. Additional control participants were recruited through the WUSM Research Participant Registry and flyers. PD participants were diagnosed with typical idiopathic PD and classified at Hoehn and Yahr Stage I–III. Exclusion criteria included dementia or cognitive impairment (per physician report or score ≤25 on the Montreal Cognitive Assessment [MoCA]), neurological condition other than PD, current psychiatric symptoms or history of psychosis, inability to comprehend visual and auditory instructions, non-English-speaking, and other conditions that would interfere with testing. Additional exclusion criteria for the control group included a first-degree family member with PD.

Volunteers with mild to moderate PD without dementia (n = 20) and age-matched control participants (n = 19) completed measures of depression (Beck Depression Inventory) and everyday EF (Dysexecutive Questionnaire, Behavioral Rating Inventory of Executive Function Adult Version) through a web-based survey. Then participants completed the MoCA, the National Institutes of Health Toolbox cognitive function battery, and the CTPA in an in-person testing session. Descriptive statistics were calculated for all variables. Because of the small sample and nonnormal distributions of CTPA data, nonparametric analyses were used: Mann–Whitney U tests and chi-square tests were used to evaluate group differences, and Spearman rank order correlations were used to evaluate relationships between the CTPA and EF measures. All tests were two-tailed, and p < .05 was considered significant.

RESULTS: No group differences were found in CTPA scores (p ≥ .14); however, the PD group took longer to complete the CTPA than the control group (p = .008). In the PD group, CTPA total inefficiencies correlated with cognitive flexibility performance (r _s = –0.52, p = .02) and reported everyday shifting and task monitoring (r _s ≥ 0.45, p < .05), such that less efficient CTPA performance was associated with poorer performance and self-reports on these measures.

CONCLUSION: Despite similar accuracy, PD participants took longer completing the CTPA than control participants. Correlational analysis suggests that inefficient CTPA performance may be attributed to decreased cognitive flexibility and attentional control in people with PD. Use of performance-based assessments like the CTPA may increase our understanding of the effect of PD on functional cognition and may help identify those at risk for activity limitations and the nature of those limitations. Our results suggest that even in the absence of obvious cognitive decline, deficits in attentional control may negatively affect the efficiency with which people with PD can perform cognitively demanding activities. This information is important for practice because it can guide the selection or development of interventions to address functional cognition to increase participation and quality of life for the PD population.

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