Clinical implications of early caudate dysfunction in Parkinson’s disease

Abstract

Objective Although not typical of Parkinson’s disease (PD), caudate dopaminergic dysfunction can occur in early stages of the disease. However, its frequency and longitudinal implications in large cohorts of recently diagnosed patients remain to be established. We investigated the occurrence of caudate dopaminergic dysfunction in the very early phases of PD (<2 years from diagnosis) using123I-FP-CIT single photon emission CT and determined whether it was associated with the presence or subsequent development of cognitive impairment, depression, sleep and gait problems. Methods Patients with PD and healthy controls were identified from the Parkinson’s Progression Markers Initiative (PPMI) database. We defined a clinically significant caudate dysfunction as123I-FP-CIT binding <0.001) and depression (p<0.001), and worse cognitive (p<0.001), depression (<0.05) and gait (<0.001) ratings. Significant caudate involvement was observed in 83.9% of the population after 4 years (unilateral 22.5%, bilateral 61.4%). Conclusions Early significant caudate dopaminergic denervation was found in half of the cases in the PPMI series. Baseline bilateral caudate involvement was associated with increased risk of developing cognitive impairment, depression and gait problems over the next 4 years.