Language impairment in Parkinson's disease

Increasingly, researchers and clinicians are beginning to unveil both cognitive and linguistic impairments in Parkinson's disease (PD), a condition characterized in the past primarily by impairment of the motoric aspects of ambulation and speech. This study describes subtle language impairment in 20 subjects with PD on a battery of measures selected to be sensitive to frontal lobe language function. Comparative performances of the PD subjects with an age, gender, and education-matched control group revealed significant performance level differences across several language variables. The PD subject group as a whole, presented with impaired naming and definitional abilities, and difficulties in interpreting ambiguity and figurative language. When the PD subjects were divided on the basis of their score on a cognitive rating scale, PD subjects with below normal cognitive status presented with deficits in naming, definition, and multi-definition abilities, as well as problems in interpreting ambiguity and figurative language, sentence construction, and semantic verbal fluency. Parkinson's disease subjects with normal cognitive status presented with difficulties in providing definitions and in sentence construction. These results are interpreted in terms of models of subcortical participation in language