Impulse Control Disorders and Levodopa-Induced Dyskinesias in Parkinson's Disease: Pulsatile versus Continuous Dopaminergic Stimulation

Background: Dopaminergic medications in Parkinson's disease (PD) are usually associated with the development of both levodopa-induced dyskinesias (LID) and impulse control and repetitive behavior disorders (ICRB). Objective: To assess the prevalence and the severity of ICRB in a cohort of moderate and advanced PD patients and to investigate the potential interplay between ICRB, LID and dopaminergic therapies. Methods: 117 PD patients were consecutively recruited. LID were assessed by using the Rush Dyskinesia Rating Scale (RDRS). ICRB were tested by means of Questionnaire for Impulsive Compulsive Disorders in Parkinson's Disease Rating Scale (QUIP-RS). Results: 55 patients were affected by LID. Among them, 37 were treated only by oral therapy, OT (LID/OT), while 18 were on treatment with jejunal levodopa infusion, JLI (LID/JLI). 62 patients were not affected by LID (NLID) and all of them were on therapy only with oral drugs. The overall prevalence of clinically significant ICRB was 34% (95% CI = 26% to 43%) and the mean value (+/- SD) of QUIP-RS total score was 5.4 +/- 8.5. Prevalence of clinically significant ICRB, as well as severity of ICRB, was higher in patients with LID compared to NLID patients (p = 0.016 and p < 0.001, respectively). When considering LID/JLI, LID/OT and NLID groups, QUIP-RS total score was significantly higher in LID/OT patients compared to LID/JLI (10.4 +/- 11.8 vs. 4.9 +/- 6.0, p = 0.019) and NLID (10.4 +/- 11.8 vs. 2.5 +/- 4.8, p < 0.001) groups. Conclusion: PD patients with LID show ICRB more frequently and more severely than patients without LID. Among LID patients, those treated by JLI showed a lower severity of ICRB than those on OT, suggesting a potential protective effect of JLI on ICRB.