The relationship between Impulse Control Disorders and cognitive dysfunctions in Parkinson's Disease: A meta-analysis

- Impulse Control Disorders in PD are associated with reduced set-shifting and altered decision making.
- A relationship between Impulse Control Disorders and reduced abstraction ability/concept formation was found in PD.
- Impulse Control Disorders are associated with altered visuospatial/constructional abilities in PD.
- The effect was moderate for set-shifting and decision making, small for abstraction, updating and visuospatial abilities.

Impulse Control Disorders (ICD) are associated with impairment in cognitive flexibility and cortical inhibition. In Parkinson's Disease (PD) the relationship between ICD and cognitive dysfunctions is still unclear: some studies found different cognitive profiles between Parkinsonians with and without ICD, whereas others did not. Moreover, findings from studies on ICD in PD are conflicting on which cognitive function is altered. A meta-analysis of 34 studies was performed to shed light on relationship between ICD and cognitive dysfunctions and to reveal the cognitive function compromised in Parkinsonians with ICD. Data were analysed in global cognitive functioning, memory, executive functions, attention/working memory, language, and visuospatial functions. Significant relationship between ICD and dysfunction of abstraction ability/concept formation, set-shifting, visuospatial/constructional abilities and decision-making was found. These findings suggested that people affected by PD with specific frontal dysfunctions are more vulnerable to develop ICD when they take antiparkinsonian drug. Evaluation of specific cognitive functions in routine clinical practice might help to detect those people with PD susceptible to ICD before treating them with antiparkinsonian drugs.