FIG. 1.
Overall group difference in LC CNRMTw and correlations with nonmotor symptom severity. Patients had lower mean CNRMTw in the right LC compared with age‐matched healthy volunteers, t 57.2 = −2.96 (P = 0.002) (A). The reduction in CNRMTw is visualized in group average MTw maps (B). Mean CNRMTw of the left LC correlated with othostatic change in systolic BP. No significant correlations were found for overall nonmotor symptom severity (NMSS), depressive symptoms (BDI‐II score), or apathy (LARS) following multiple comparisons correction (C). BDI‐II, Beck's Depression Inventory II; BP, blood pressure; CNR, contrast‐to‐noise ratio; CNRMTw, contrast‐to‐noise ratio of the magnetization transfer weighted signal; HC, healthy, age‐matched controls; LARS, Lille Apathy Rating Scale; LC, locus coeruleus; MT, magnetization transfer; MTw, magnetization transfer weighted signal; NMSS, Non‐Motor Symptom Scale; PD, Parkinson's disease. [Color figure can be viewed at wileyonlinelibrary.com]