ABSTRACT
We evaluated prospectively 210 patients with idiopathic Parkinson's disease (PD) to determine whether cognitive deterioration and disease disability affect subject drop out. Subjects who refused to return for follow-up testing had a greater degree of bradykinesia and overall disability, more advanced disease, fewer years of education and greater depressive symptomatology. However, discriminant analysis indicated that performance on the neuropsychological measures, rather than PD severity, significantly predicted whether patients return for follow-up testing. Our findings indicate that cognitive impairment uniquely contributes to subject attrition, which may distort dementia estimates in PD.
Subject(s)
Cognition , Dementia/etiology , Parkinson Disease/complications , Parkinson Disease/psychology , Patient Dropouts/psychology , Aged , Confounding Factors, Epidemiologic , Female , Follow-Up Studies , Humans , Male , Middle Aged , Neuropsychological Tests , Parkinson Disease/physiopathology , Patient Selection , Prognosis , Prospective Studies , Severity of Illness IndexABSTRACT
It is controversial whether age of disease onset is related to cognitive decline in Parkinson's disease (PD). We administered 7 cognitive measures assessing visuospatial skills, memory, and executive functions to 222 patients with idiopathic PD and 108 normal control participants. Regression analyses demonstrated that older age of disease onset consistently predicted cognitive decline above and beyond normative aging and duration of illness. These findings suggest that older age of disease onset is a critical determinant of cognitive deterioration in PD.
