To assess overall cognitive performance and executive functioning of nondemented Parkinson disease (PD) patients, and the influence of variables such as depression and education on cognition.
Cognitive dysfunction in PD is common even in early stages. Different variables have been identified as potential risk factors for cognitive decline in PD. Some of these variables, such as depression and educational level, are complexly interrelated.
Eighty-two (male:female 52:30) subjects underwent clinical assessment which included the Unified Parkinson's Disease Rating Scale, Schwab-England Scale, Hoehn-Yahr Scale, Beck Depression Inventory, the Frontal Assessment Battery (FAB), and the Mini-Mental State Examination (MMSE).
Patients with higher education, younger age, and who had a younger age at disease onset performed better on both the FAB and MMSE. Severity of disease correlated with worse cognitive performance. Performance on the FAB, but not the MMSE, worsened with increased severity of depressive symptoms. When patients were divided into groups with lower (≤4 y of schooling) and higher (≥5 y of schooling) education, the FAB and Beck Depression Inventory correlated negatively only in the group with lower educational level.
Patients with PD present with cognitive impairment even when nondemented. Depression may exacerbate executive dysfunction, especially in subjects with lower educational level.
Department of Internal Medicine, Neurology Unit, University Hospital, School of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, Brazil
This work was partially funded by grants from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundação de Amparo à Pesquisa do Estado de Minas Gerais (Fapemig), Brazil.
Reprints: Antônio Lúcio Teixeira, MD, PhD, Department of Internal Medicine, School of Medicine, Federal University of Minas Gerais (UFMG), Avenida Alfredo Balena, 190, Santa Efigênia, Belo Horizonte, Minas Gerais, Brazil 30130-100 (e-mail: firstname.lastname@example.org).
Received for publication October 13, 2008
accepted April 19, 2009