Association between REM sleep behaviour disorder and impulse control disorder in patients with Parkinson's disease

White matter changes in drug-naïve Parkinson's disease patients with impulse control & probable REM sleep behavior disorders

BACKGROUND

According to epidemiological studies, Parkinson's disease (PD) patients with probable REM sleep behavior disorder (pRBD) are more prone to develop impulse control disorders (ICDs), which is shown to be present in drug-naïve PD patients, and vice versa.

OBJECTIVES

To investigate white-matter integrity differences, with and without comorbid pRBD and ICDs.

METHODS

149 de-novo PD patients and 30 age- and gender-matched controls from the Parkinson's Progression Markers Initiative were studied. PD subjects were categorized into four groups with and without these comorbidities. We investigated the white matter integrity differences between these groups.

RESULTS

PDs with only ICDs manifested greater fractional anisotropy (FA) and lower mean diffusivity (MD) in ipsilateral cerebellar connections when compared to controls and to Parkinson's with both comorbid disorders. In contrast, significantly lower FA and higher MD in the ipsilateral fornix-stria-terminalis was observed in PDs with only pRBD compared to controls and to PDs without either comorbid disorder. Also, PDs with only pRBD manifested greater FA in contralateral putamen when compared to controls.

CONCLUSIONS

Our results suggest the presence of an underlying neural network in PDs with ICDs, particularly involving cerebellar connections, which makes the subjects susceptible to pRBD. Lower white-matter integrity in the fornix of PDs with only pRBD suggests a neuropathological pathway specific to sleep behavior disorder, independent of impulse control disorders. Greater white-matter integrity observed in PDs without comorbid ICDs, regardless of their comorbid pRBD status, might reflect compensatory mechanisms. Targeted therapies for this particular neuropathology may help prevent these comorbidities.

Association between REM sleep behavior disorder and impulsive-compulsive behaviors in Parkinson's disease: a systematic review and meta-analysis of observational studies

BACKGROUND

Both REM sleep behavior disorder (RBD) and impulsive-compulsive behaviors (ICBs) are well-recognized non-motor features in patients with Parkinson's disease (PD). Studies have given contradictory results about the potential association between RBD and ICBs.

METHODS

PubMed, Embase (via Ovid), and the Cochrane Central Registry of Controlled Trials (CENTRAL) databases were systematically searched till August 20, 2019 to identify studies that explored the possible correlation between RBD and ICBs in patients with PD. Two authors independently screened records, extracted data and evaluated quality of included studies. Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated by employing a random or fixed-effects model. We performed subgroup and sensitivity analyses, and we assessed potential publication bias.

RESULTS

A total of 134 references were screened and 10 studies involving 2781 PD patients were included. Overall, RBD was associated with a more than twofold higher risk of developing ICBs (OR 2.12, 95% CI 1.43-3.14, I² = 56.7%, P < 0.01). Similar results were obtained in sensitivity analyses and in meta-analyses of subgroups stratified based on multivariable adjustment and methods for diagnosing RBD and ICBs. No significant risk of publication bias was found.

CONCLUSION

RBD in PD is confirmed to be a risk factor for ICBs. Clinicians should be aware of this association to help them improve patient management.

Impulse control disorders in Parkinson's: Sleep disorders and nondopaminergic associations

OBJECTIVES

Impulse control disorders (ICDs) are common among patients with Parkinson's disease (PD). Risk factors identified for developing ICDs include young age, family history, and impulsive personality traits. However, the association of these potentially disabling disorders with nondopaminergic drugs and sleep disorders has been understudied. Our objective was to examine the association between ICDs and nondopaminergic medications and sleep disorders.

METHODS

We conducted an observational study of 53 patients with PD from the National Institute of Neurology and Neurosurgery. ICDs were diagnosed using the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease Rating Scale (QUIP-RS). Patients underwent polysomnography screening to diagnose the presence of sleep disorders. We documented the presence of dopaminergic and nondopaminergic medications, including monoamine oxidase type B inhibitors (MAOBIs), antidepressants, sleep inductors, and antipsychotics.

RESULTS

ICDs were reported in 18.9% of the patients (n = 10), and sleep disorders were diagnosed in 81.1% of patients (n = 43). 32.1% of the patients were on antidepressants, 17% on MAOBIs, 15.1% on sleep inductors, and 1.9% on antipsychotics. We observed that QUIP-RS A-D subscore depended on the presence of antidepressants (p = .03) and sleep inductors (p = .02). Sleep disorders were not associated with the total QUIP-RS score (p = .93) or QUIP-RS A-D subscore (p = .81).

CONCLUSION

Antidepressants and sleep inductors were significant predictors for individual QUIP-RS items and subscores. Our results suggest that nondopaminergic drugs commonly used for PD may be associated with impulse control disorders. We did not identify a relationship between ICDs and polysomnography-confirmed sleep disorders in patients with PD. Larger and longitudinal studies are needed to confirm our results.