AUTHOR=Martini Alice , Dal Lago Denise , Edelstyn Nicola M. J. , Grange James A. , Tamburin Stefano 

TITLE=Impulse Control Disorder in Parkinson's Disease: A Meta-Analysis of Cognitive, Affective, and Motivational Correlates

JOURNAL=Frontiers in Neurology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2018.00654

DOI=10.3389/fneur.2018.00654

ISSN=1664-2295

ABSTRACT=<p><bold>Background:</bold> In Parkinson's disease (PD), impulse control disorders (ICDs) develop as side-effect of dopaminergic replacement therapy (DRT). Cognitive, affective, and motivational correlates of ICD in medicated PD patients are debated. Here, we systematically reviewed and meta-analyzed the evidence for an association between ICD in PD and cognitive, affective, and motivational abnormalities.</p><p><bold>Methods:</bold> A systematic review and meta-analysis was performed on PubMed, Science Direct, ISI Web of Science, Cochrane, EBSCO for studies published between 1-1-2000 and 8-3-2017 comparing cognitive, affective, and motivational measures in PD patients with ICD (ICD+) vs. those without ICD (ICD–). Exclusion criteria were conditions other than PD, substance and/or alcohol abuse, dementia, drug naïve patients, cognition assessed by self-report tools. Standardized mean difference (SMD) was used, and random-effect model applied.</p><p><bold>Results:</bold> 10,200 studies were screened (title, abstract), 79 full-texts were assessed, and 25 were included (ICD+: 625 patients; ICD–: 938). Compared to ICD–, ICD+ showed worse performance reward-related decision-making (0.42 [0.02, 0.82], <italic>p</italic> = 0.04) and set-shifting tasks (SMD = −0.49 [95% CI −0.78, −0.21], <italic>p</italic> = 0.0008). ICD in PD was also related to higher self-reported rate of depression (0.35 [0.16, 0.54], <italic>p</italic> = 0.0004), anxiety (0.43 [0.18, 0.68], <italic>p</italic> = 0.0007), anhedonia (0.26 [0.01, 0.50], <italic>p</italic> = 0.04), and impulsivity (0.79 [0.50, 1.09], <italic>p</italic> &lt; 0.00001). Heterogeneity was low to moderate, except for depression (<italic>I</italic><sup>2</sup> = 61%) and anxiety (<italic>I</italic><sup>2</sup> = 58%).</p><p><bold>Conclusions:</bold> ICD in PD is associated with worse set-shifting and reward-related decision-making, and increased depression, anxiety, anhedonia, and impulsivity. This is an important area for further studies as ICDs have negative impact on the quality of life of patients and their caregivers.</p>