The role of the dopaminergic system in mood, motivation and cognition in Parkinson's disease: a double blind randomized placebo-controlled experimental challenge with pramipexole and methylphenidate.

In Parkinson's disease (PD) reduced dopaminergic activity in the mesocorticolimbic pathway is implied in the pathophysiology of several non-motor symptoms related to mood, motivation and cognition. Insight in the pathophysiology of these syndromes may pave the way for more rational treatments. In a double-blind, randomized, placebo controlled, crossover design with three arms, we studied the effects of a direct dopaminergic challenge with the dopamine 2 receptor agonist pramipexole, an indirect challenge with the dopamine reuptake inhibitor methylphenidate, and placebo on measures of mood, motivation and cognition in 23 agonist-naïve PD patients and 23 healthy controls.

Neuropsychological correlates of apathy in mild cognitive impairment and Alzheimer's disease: the role of executive functioning.

Background: Apathy is a common and important behavioral syndrome in various neuropsychiatric diseases, such as mild cognitive impairment (MCI) and Alzheimer's disease (AD). So far, only few studies have compared the neuropsychological correlates of apathy in patients with MCI and dementia. The aim of the current study was to examine the association between apathy and neuropsychological functioning in patients with MCI and AD.

Validation of diagnostic criteria for apathy in Parkinson's disease.

Background: Apathy is a common neuropsychiatric syndrome in Parkinson's Disease (PD) that affects quality of life. Research into apathy has been hampered by a lack of broadly accepted diagnostic criteria. Recently, diagnostic criteria for apathy in neuropsychiatric disorders have been proposed, which to date have not been validated in PD.

Pharmacological treatment of apathy in neurodegenerative diseases: a systematic review.

Objective: To evaluate the efficacy of pharmacological treatment of apathy in patients with neurodegenerative diseases.

Methods: Systematic review of studies assessing the effects of pharmacological treatment on apathy in neurodegenerative diseases.

Results: Thirty-five studies were included: 2 meta-analyses, 13 randomized controlled trials (RCTs), 14 open-label studies, 5 case series, and 1 single case study.