INTRODUCTION: Parkinson's disease (PD) is associated with cognitive decline but little is known about frontal-subcortical and posterior cortical cognitive functioning in patients with PD. The present study was designed to: (a) compare frontal and posterior cognitive functioning between patients with PD and healthy controls; (b) determine the effect of levodopa (L-dopa) on frontal-subcortical and posterior cortical cognitive functions; and (c) identify predictors of cognitive functions in patients with PD. METHODS: 50 patients diagnosed with PD from April 2016 to May 2017 at Civil Hospital, Bahawal Victoria Hospital, Bahawalpur, and Nishter Hospital Multan, Pakistan, and 50 healthy individuals from the community participated in our study. Patients had two testing sessions - first, at the time of diagnosis before taking L-dopa medication to determine baseline scores; and second, after at least three months of L-dopa medication. Participants completed the Parkinson's Disease-Cognitive Rating Scale. RESULTS: Patients with PD showed impaired performance on frontal-subcortical and posterior cortical functions in contrast with the control group. L-dopa medication had beneficial effects on frontal-subcortical and posterior cortical functioning in patients with PD. Disease duration was a significant predictor of cognitive performance in patients with PD. CONCLUSION L-dopa medication improves frontal-subcortical and posterior cortical cognitive functioning in patients with PD. Disease duration is a marker of cognitive decline in PD.

Aged ; Blood Glucose ; metabolism ; Diabetes Mellitus, Type 2 ; blood ; physiopathology ; Female ; Glycated Hemoglobin A ; metabolism ; Humans ; Male ; Middle Aged ; Neuropsychological Tests