Lexical-semantic search related to side of onset and putamen volume in Parkinson’s disease

•Controls and PD groups and were compared on a qualitative measure of verbal fluency.•Right symptom-onset PD subjects produced words of an earlier age of acquisition (AoA).•AoA of responses showed a positive correlation with putamen volume in this group.•Controls showed a negative correlation with AoA of responses and caudate volume.•Findings supported a role for the striatum in the access of the lexical-semantic system. Parkinson's disease (PD) is characterized by dopaminergic cell loss and reduced striatal volume. Prior studies have demonstrated striatal involvement in access to lexical-semantic knowledge and damage to this structure may be evident in the lexical properties of responses. Semantic fluency task responses from early stage, non-demented PD participants with right (PD-R) or left (PD-L) lateralizing symptoms were compared to matched controls on lexical properties (word frequency, age of acquisition) and correlated with striatal volumes segmented from T1-weighted brain MR images. PD-R participants produced semantic fluency responses of a lower age of acquisition than PD-L and control participants (p