Hoehn and Yahr staging of Parkinson's disease in relation to neuropsychological measures

Abstract

Parkinson's disease (PD) is primarily considered to be a progressive degenerative motor disease associated with the degeneration of striatal dopamine neurons. However, increasing evidence has suggested progressive cognitive and psychiatric changes as well. Forty-six patients with PD, ranging in severity from Hoehn and Yahr (H-Y) score of 1:4, were recruited from a clinic specializing in PD. Various cognitive and neuropsychological measures were used to discover if there were indeed differences due to the progression of PD. As H-Y stage significantly increased, so did age and levodopa equivalency dose of medications, both independent of one another. Years of education had a significant negative relationship with H-Y score. Measures of general cognition divulged a significant decrease as H-Y score increased. Finally, as H-Y score increased, magical ideation decreased, and religious group social support increased. Mechanistically, the significant cognitive decline occurring with H-Y staging may be linked to a reduced dopaminergic function. Significant cognitive and neuropsychological changes are associated with the progression of PD and its possible relationship to Reward Deficiency Syndrome (RDS).