3-Year test-retest reliability in Parkinson’s disease and healthy older adults: The Parkinson’s progression markers initiative study

= 102). All participants analyzed maintained the same cognitive status category across the assessment points. Intraclass correlation coefficients (ICCs) estimated reliability. The overall ICCs calculated across time points were as follows: Judgment of Line Orientation (PD-NC = .47, PD-AC = .50, HOA = .59); Letter-Number Sequencing (PD-NC = .64, PD-AC = .64, HOA = .65); Semantic Fluency (PD-NC = .69, PD-AC = .89, HOA = .77); Symbol Digit Modalities Test (PD-NC = .67, PD-AC = .83, HOA = .71). For the two primary components of the Hopkins Verbal Learning Test-Revised, we found the following ICCs: immediate recall (PD-NC = .46, PD-AC = .57, HOA = .58); delayed recall (PD-NC = .42, PD-AC = .57, HOA = .54). Findings from this study provide useful information for clinicians and researchers toward selecting suitable neuropsychological tests to monitor cognition at two or more time points among newly diagnosed individuals with PD and HOA.