MOTOR RESERVE AS A MODIFIER OF LONG-TERM PROGNOSIS IN PARKINSON’S DISEASE
- Verena Dzialas, Germany
Abstract
Aims
In Alzheimer’s disease, higher cognitive reserve has been linked to a more rapid cognitive decline from the point of diagnosis. Whether similar trajectories exist concerning motor reserve (MR) in Parkinson's disease (PD) remains unclear. Here, we investigated the longitudinal decline in motor function by considering different levels of MR.
Methods
Data of 151 PD patients (Mage=58.7±4.5) were included, for whom a baseline DaT-SPECT and longitudinal clinical information were available at the PPMI database. Based on the residuals derived from the association between DaT signal loss and UPDRS-III score, we defined a group of high (n=50, Myears_follow-up=6.2) and low (n=45, Myears_follow-up=5.4) MR. To assess the trajectories of motor decline, we performed linear mixed-effects models with SPSS26 (p<.05), comparing the decline of high and low MR group over time. The model comprised an interaction term between time and reserve groups additionally to several covariates as fixed plus subjects and time as random effects, allowing individually varying slopes and intercepts. The model was corrected by an unstructured covariance matrix.
Results
At baseline, high MR was associated with significantly lower UPDRS-III scores compared to low MR. While this difference remained over 7 years (p=.029), no difference in group-average decline rate (p=.252) was observed. However, a positive covariance (covIntercept-Slope= .082, p=.018) between intercept and slope was found indicating that individual motor decline depends on baseline symptom severity.
Conclusions
Higher initial MR may be associated with slower disease progression and generally less severe symptoms over time, which has major implications for disease prognosis and the development of interventional strategies.