ABSTRACT Dopaminergic therapy can improve motor functioning in Parkinson’s disease (PD), but its effect on spoken discourse is poorly understood. This study addressed whether discourse produced during a one-minute monologue would be affected by medication withdrawal. We performed a detailed analysis of semistructured speech samples in 38 patients with PD, including measures of efficiency, syntactic complexity, cohesion (i.e., lexical and grammatical ties between sentences), and coherence (i.e., semantic relationship between the utterances and the topic, or between utterances). We found that patients produced more efficient and coherent monlogues when on versus off medication. As discourse relies heavily on cognitive processes such as working memory, these findings are consistent with research showing improved working memory and executive processes with dopaminegic medication.
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