Predictors of short-term impulsive and compulsive behaviour after subthalamic stimulation in Parkinson disease.

Background: The effects of subthalamic stimulation (subthalamic nucleus-deep brain stimulation, STN-DBS) on impulsive and compulsive behaviours (ICB) in Parkinson's disease (PD) are understudied.
Objective: To investigate clinical predictors of STN-DBS effects on ICB.
Methods: In this prospective, open-label, multicentre study in patients with PD undergoing bilateral STN-DBS, we assessed patients preoperatively and at 6-month follow-up postoperatively. Clinical scales included the Questionnaire for Impulsive-Compulsive Disorders in PD-Rating Scale (QUIP-RS), PD Questionnaire-8, Non-Motor Symptom Scale (NMSS), Unified PD Rating Scale in addition to levodopa-equivalent daily dose total (LEDD-total) and dopamine agonists (LEDD-DA). Changes at follow-up were analysed with Wilcoxon signed-rank test and corrected for multiple comparisons (Bonferroni method). We explored predictors of QUIP-RS changes using correlations and linear regressions. Finally, we dichotomised patients into 'QUIP-RS improvement or worsening' and analysed between-group differences.
Results: We included 55 patients aged 61.7 years±8.4 with 9.8 years±4.6 PD duration. QUIP-RS cut-offs and psychiatric assessments identified patients with preoperative ICB. In patients with ICB, QUIP-RS improved significantly. However, we observed considerable interindividual variability of clinically relevant QUIP-RS outcomes as 27.3% experienced worsening and 29.1% an improvement. In post hoc analyses, higher baseline QUIP-RS and lower baseline LEDD-DA were associated with greater QUIP-RS improvements. Additionally, the 'QUIP-RS worsening' group had more severe baseline impairment in the NMSS attention/memory domain.
Conclusions: Our results show favourable ICB outcomes in patients with higher preoperative ICB severity and lower preoperative DA doses, and worse outcomes in patients with more severe baseline attention/memory deficits. These findings emphasise the need for comprehensive non-motor and motor symptoms assessments in patients undergoing STN-DBS.
Trial Registration Number: DRKS00006735.
Competing Interests: Competing interests: AS is funded by the Gusyk programme of the Medical Faculty of the University of Cologne and has received funding from the Prof. Klaus Thiemann Foundation. PL was funded by the SUCCESS-Programme of the University of Marburg, the Parkinson’s Foundation and the Stiftung zur Förderung junger Neurowissenschaftler. STJ was funded by the Prof. Klaus Thiemann Foundation. JNP-S has received travel grants from Boston Scientific. LK reports academic grants from EU Horizon 2020 and from the excellence strategy of the Technical University Dresden, Germany; habilitation funding for women from the Medical Faculty of the Technical University Dresden, Germany. MTB received speaker’s honoraria from Medtronic, Boston Scientific, Abbott (formerly St. Jude), GE Medical, UCB, Apothekerverband Köln e.V. and Bial as well as research funding from the Felgenhauer-Stiftung, Forschungspool Klinische Studien (University of Cologne), Horizon 2020 (Gondola), Medtronic (ODIS), and Boston Scientific and advisory honoraria for the IQWIG. GRF serves as an editorial board member of Cortex, Neurological Research and Practice, NeuroImage: Clinical, Zeitschrift für Neuropsychologie, and DGNeurologie; receives royalties from the publication of the books Funktionelle MRT in Psychiatrie und Neurologie, Neurologische Differentialdiagnose and SOP Neurologie; received honoraria for speaking engagements from Bayer, Desitin, Ergo DKV, Forum für medizinische Fortbildung FomF, GSK, Medica Academy Messe Düsseldorf, Medicbrain Healthcare, Novartis, Pfizer and Sportärztebund NRW. PM-M has received honoraria from Editorial Viguera and Takeda Pharmaceuticals for lecturing in courses; from Britannia for writing an article in their Parkinson’s Disease Medical Journal-Kinetic; and from the International Parkinson and Movement Disorder Society (MDS) for management of the Programme on Rating Scales. Grants from the MDS for development and validation of the MDS-NMS. KRC has received funding from Parkinson’s UK (funding ID Parkinson’s UK K-1406), NIHR, UCB and the European Union; he received honoraria from UCB, Abbott, Britannia, US Worldmeds, and Otsuka Pharmaceuticals; and acted as a consultant for AbbVie, UCB and Britannia. VV-V is a member of the advisory boards and reports consultancies for Boston Scientific. LT reports grants, personal fees and non-financial support from SAPIENS Steering Brain Stimulation, Medtronic, Boston Scientific and St. Jude Medical. DW reports no financial disclosures. HSD was funded by the EU Joint Programme – Neurodegenerative Disease Research (JPND), the Prof. Klaus Thiemann Foundation, and the Felgenhauer Foundation and has received honoraria by Boston Scientific, Medtronic and Stadapharm.
(© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.)