Wearing-off in Parkinson's disease: neuropsychological differences between on and off periods

Background: Levodopa-associated motor fluctuations are common complications observed in Parkinson's disease (PD) patients. Although nonmotor fluctuations are a significant cause of morbidity, they frequently are not properly identified. Few studies have characterized the nonmotor emotional fluctuations and their relation to motor fluctuations. Aims: The objective of the present study is to analyze the occurrence of fluctuations in anxiety and depression symptoms, as well as in cognitive function (memory, language, executive function, and attention), and their relation to motor fluctuations in PD patients presenting wearing-off phenomenon. Methods: Twenty-four patients were assessed during the wearing on-off periods. The State-Trait Anxiety Inventory (STAI-State) and Beck Depression Inventory (BDI) were used to assess anxiety and depression, respectively, and the Wisconsin Card Sorting Test (WCST), Stroop Test, Rey Auditory Verbal Learning Test (RAVLT), Weschler Memory Scale - digits (WMS) and Controlled Oral Word Association (COWA) for assessing executive functions, verbal memory, attention and work memory and verbal fluency, respectively. Results: Patients presented higher depression and anxiety scores in the wearing-off period (P<0.05). Differences were also found in the semantic verbal fluency (P=0.017) and executive function (P=0.008) tests performance. Conclusions: Nonmotor symptoms such as anxiety and depression, verbal fluency, and executive function performance are influenced by motor fluctuations.