Mild motor symptoms including parkinsonian signs are common in old age, but their underlying neuropathology is unclear. We tested the hypothesis that cerebrovascular pathologies are related to parkinsonian signs. We studied brain autopsies from 418 deceased participants from the Religious Order Study, who underwent evaluation of parkinsonian signs with a modified version of the motor section of the Unified Parkinson's Disease Rating Scale. Brains were evaluated for macroscopic and microinfarcts and the severity of arteriolosclerosis. Regression analyses were used to examine the association of cerebrovascular pathologies with parkinsonian signs. More than 35% of cases (N=149) showed macroscopic infarcts. Almost 30% of cases without macroscopic infarcts showed pathologies not detected by conventional brain imaging: microinfarcts (N=33 [7.9%]), arteriolosclerosis (N=62 [14.8%]), or both (N=24 [5.7%]). Macroscopic infarcts, specifically multiple cortical and ≥1 subcortical macroscopic infarcts, were related to higher global parkinsonian scores. The presence of multiple and cortical microinfarcts was associated with global parkinsonian score. Arteriolosclerosis was associated with global parkinsonian score, but this effect was attenuated and no longer significant after accounting for infarcts. Each of the 3 pathologies was separately associated with parkinsonian gait (macroscopic infarcts [estimate, 0.552; SE, 0.210; P=0.009]; microinfarcts [estimate, 0.424; SE, 0.213; P=0.047]; arteriolosclerosis [estimate, 0.191; SE, 0.056; P<0.001]). Further analyses showed that subcortical macroscopic and microinfarcts were specifically associated with the severity of parkinsonian gait. Cerebrovascular pathologies, including macroscopic infarcts, microinfarcts, and arteriolosclerosis, are common in older persons and may be unrecognized common etiologies of mild parkinsonian signs, especially parkinsonian gait, in old age.
