Language skills in Parkinson's disease: state of the art.

This review aims to examine the state of the art regarding changes in language abilities in Parkinson's disease (PD), with a focus on different linguistic domains. To this end, the language alterations are organized into sections (phonetic and phonology, morphology, syntax, semantic and lexicon, and pragmatics) that correspond to each linguistic domain and are complemented by considerations for future research. Linguistic changes can emerge early in the course of PD, even when verbal abilities are not yet significantly compromised. As the disease progresses, individuals with PD commonly exhibit executive dysfunction, visuospatial difficulties, and memory impairment. Communication deficits extend beyond speech and voice, and are directly impacted by linguistic functions. Given the progressive nature of PD, the study of language provides valuable insights into the impact of neurodegeneration on communication, an area often overshadowed by the predominant focus on motor speech disorders, such as dysarthria.