Objective: To explore the longitudinal association between global cognition and i) global motor, ii) tremor, and iii) non-tremor motor severity and progression.

Background: Impaired voluntary movement is a hallmark symptom of Parkinson’s disease (PD), frequently overlapping with non-tremor motor characteristics. Cognitive control over movement and action selection is required to successfully initiate voluntary movements. In PD, dysfunctional voluntary movements are associated with abnormal prefrontal activity and loss of volume, as well as impaired information transfer between fronto-striatal circuits1. In contrast, tremor is associated with cerebellar-driven dysfunction2. Whilst previous evidence has demonstrated cross-sectional associations between global cognition and non-tremor motor impairment, the longitudinal associations remain unclear.

Method: As part of the OxQUIP study, PD patients (N=110) were tested using cognitive (Montreal Cognitive Assessment [MoCA]) and motor (MDS-UPDRS-III) clinical assessments every three months for seven visits. Tremor and non-tremor subscores were derived from corresponding MDS-UPDRS-III items. Separate linear mixed-effects models were used to explore the longitudinal effects of MoCA on i) total MDS-UPDRS-III, ii) tremor and iii) non-tremor scores.

Results: Linear mixed-effects models showed progression in total MDS-UPDRS-III scores (p=.002) and non-tremor motor subscores (p<0.001). The trajectory of global (p=0.005) and non-tremor (p=0.001) motor decline was influenced by MoCA with lower MoCA scores being associated with greater decline. Tremor performance did not progress across visits (p=0.895) and was not influenced by global cognition (p=0.818).

Conclusion: Longitudinal analyses can uniquely illuminate the complex relationship between global cognition and motor function in PD. This is evidenced by the association between poorer global cognition and greater non-tremor motor decline. This work has important implications for improving precision medicine techniques and prognostic predictions of motor impairment for PD patients. Future work should focus on how specific cognitive impairment (e.g., executive function) can contribute to motor function in PD.  

Part of these results will be presented at the Experimental Psychology Society Meeting (Lancaster, UK, April 2025).

References: 1. Alexander, G. E., DeLong, M. R., & Strick, P. L. (1986). Parallel organization of functionally segregated circuits linking basal ganglia and cortex. Annual review of neuroscience, 9(1), 357-381.
2. Zhong,Y., Liu, H., Liu, G., Zhao, L., Dai, C., Liang, Y., … & Chen, L. (2022). A review on pathology, mechanism, and therapy for cerebellum and tremor in Parkinson’s disease. npj Parkinson’s Disease, 8(1), 82.

« Back to 2025 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/global-cognition-influences-non-tremor-motor-decline-in-parkinsons-disease/