Consolidation of a Learned Skill Correlates with Dopamine SPECT Uptake in Early Parkinson's Disease

ABSTRACT

BACKGROUND AND PURPOSE: Basal ganglia play a pivotal role in procedural memory. However, the correlation between skill learning and striatal 123I-ioflupane uptake in Parkinson's disease (PD) has not been reported previously. Our objective was to determine whether visuomotor skill learning is associated with striatal 123I-ioflupane uptake in early PD. METHODS: We designed a case–control study to assess learning and consolidation of a visuomotor learning task (mirrored drawing of star-shaped figures) performed on two consecutive days by early-PD patients (disease duration 0.18) other than the score on part III of the Movement Disorders Society Unified Parkinson's Disease Rating Scale, which was higher in the PD patients (mean±SD: 15.0±10.4 vs. 1.3±1.1, p 0.5), whereas PD patients showed a lower consolidation index for the time per trial (p=0.009). Moreover, this performance was correlated with uptake in the right caudate nucleus (Spearman's rho=0.82, p=0.007) and the right striatum (Spearman's rho=0.67, p=0.049), including when multiple linear regression adjusting for the levodopa equivalent daily dose was performed (p=0.005 for the caudate nucleus and p=0.024 for the striatum). CONCLUSIONS: This study provides evidence of a correlation between procedural memory impairment and striatal dopaminergic dysfunction in early PD.