Objective: To investigate whether proactive or reactive adaptive control are impaired in Parkinson’s disease (PD).

Background: Adaptive control in patients with PD remains understudied, with heterogenous results [1] and was assessed with task designs that do not control for the effects of contingency learning [2]. We investigate proactive and reactive control abilities of patients with PD under their usual dopaminergic medication regiment. To reduce the effect of contingency learning we constructed our task using separate inducer and diagnostic items (as recommend by Bream et al. [2]).

Method: 30 participants with PD (mean age 64.1 years, 9 female) and 30 age- and sex matched healthy control participants (mean age 59.4 years, 12 female) performed an adapted version of the numerical Stroop task, while EEG activity was recorded. Participants were instructed to identify the numerically larger number in a two number comparison. Physical size was manipulated to introduce congruency effects. To introduce adaptive control effects proportion of congruency (80:20) was manipulated in a set of inducer items. For the assessment of proactive control on the block-level and for reactive control on the item-level (large number- versus small number comparisons). Log-transformed reaction time data was analyzed in a set of unbiased (50:50) diagnostic items using general linear mixed effect models (GLMM).

Results: For proactive control a GLMM shows a significant interaction of congruency and block-level-congruency (β = -0.017, p < 0.0001). Post-hoc tests revealed that under block high-incongruent manipulation responses to incongruent items were faster than for blocks with block low-incongruent manipulations. An interaction of congruency, block-level-congruency and group was non-significant both in the inducer and the diagnostic items. With regard to reactive control an interaction of congruency and item-level-congruency crossed the threshold of significance (β = -0.009, p < 0.047) in the diagnostic items. Post-hoc tests revealed the same pattern as in the proactive control analysis. A three-way interaction involving group was also not significant. EEG data is currently analyzed and will be presented at the conference.

Conclusion: Results of our analysis provide no evidence for impairment of proactive or reactive adaptive control in participants with PD on their usual dopaminergic medication in our task design.  

References: [1] Ruitenberg, M. F., van Wouwe, N. C., Wylie, S. A., & Abrahamse, E. L. (2021). The role of dopamine in action control: insights from medication effects in Parkinson’s disease. Neuroscience & Biobehavioral Reviews, 127, 158-170.
[2] Braem, S., Bugg, J. M., Schmidt, J. R., Crump, M. J., Weissman, D. H., Notebaert, W., & Egner, T. (2019). Measuring adaptive control in conflict tasks. Trends in cognitive sciences, 23(9), 769-783.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/examining-adaptive-control-in-patients-with-parkinsons-disease/