The early course of affective and cognitive symptoms in de novo patients with Parkinson's disease

Neuropsychiatric and cognitive symptoms are common in patients with Parkinson's disease (PD) from the early stage of the disease but their course is still unclear. In this study we investigated prospectively the progression of affective and cognitive symptoms and disorders in de novo idiopathic PD patients. Twenty-four de novo drug naïve PD patients underwent a comprehensive neurological, psychopathological and neuropsychological evaluation at the first diagnostic visit (OFF), after 4-6 months when the antiparkinsonian therapy regimen was stabilized (ON-1), and at one year following the ON-1 follow-up visit (ON-2). Generalized least squares analysis revealed a significant improvement over time in the depressive mood, short and long term episodic verbal memory, visual memory, and the motor symptoms. Pairwise comparisons showed a significant change from OFF to ON-1 for all the aforementioned variables, except for short term episodic verbal memory which approached significance. A significant improvement from ON-1 to ON-2, however, was shown for short term episodic verbal memory. An ancillary analysis indicated that overall level and change in a number of cognitive variables, but not depression, was conditional upon age of onset, education, and sometime gender. In conclusion, early stage PD is not associated with affective and cognitive deterioration. On the contrary, very specific neuropsychiatric and cognitive symptoms may improve. This study provides Class III evidence that antiparkinsonian treatment commonly used in the clinical practice improves memory performance and depression severity in de novo patients with PD.