Mild cognitive impairment reverters have a favorable cognitive prognosis and cortical integrity in Parkinson's disease

Abstract

This study aimed to investigate whether reversion to cognitively normal status (CogN) is related to a favorable cognitive prognosis in Parkinson's disease with mild cognitive impairment (PD-MCI). We recruited 217 patients with PD-MCI who underwent serial neuropsychological assessments 3-5 times (mean interval, 1.84 years). Thirty-six patients reverted to CogN (reverters) during follow-up, whereas the other 181 did not (nonreverters). We assessed the risk of cognitive worsening in PD-MCI reverters, nonreverters, and patients with PD-CogN (n = 88). In addition, we performed comparative analyses of comprehensive neuroimaging studies between the PD-MCI reverter (n = 17) and nonreverter (n = 34) subgroups. PD-MCI reverters had a lower risk of dementia conversion than nonreverters. In addition, PD-MCI reverters had similar risks of cognitive worsening with patients with PD-CogN. PD-MCI reverters exhibited greater cortical thickness in the right parahippocampal gyrus and less severely decreased functional connectivity in the default mode and executive control networks relative to nonreverters. Our results suggest that PD-MCI reverters have relatively preserved structural and functional integrity and a favorable cognitive prognosis compared with nonreverters.