Predictors of Deep Brain Stimulation Efficacy for Impulsive and Compulsive Behavior in PD

Subthalamic nucleus-deep brain stimulation (STN-DBS) is associated with greater improvements in impulsive and compulsive behaviors (ICBs) in patients with Parkinson disease (PD) who have severe ICBs and lower dopamine agonist (DA) dosages prior to operation. Those with more severe attention/memory deficits at baseline have worse post-operative outcomes. These are the findings of a study published in the Journal of Neurology, Neurosurgery and Psychiatry.

STN-DBS is used to treat patients with advanced PD, leading to improvements in quality of life and motor and non-motor symptoms. This treatment is also known to affect symptoms like depression, anxiety, alexithymia, impulsivity and compulsivity. However, data on the effect of DBS on ICBs is contrasting and limited.

The current study objective was to identify clinical predictors of the effect of STN-DBS on ICB in patients with PD aged 61 years and older with a disease duration of about 10 years.

The prospective, open-label study included 55 patients with PD (mean age, 61.7 years; mean PD duration, 9.8 years) who underwent bilateral STN-DBS and were assessed prior to operation as well as at 6-months’ follow-up. The investigators assessed patients using the Questionnaire for Impulsive-Compulsive Disorders in PD-Rating Scale (QUIP-RS), PD Questionnaire-8, Non-Motor Symptom Scale (NMSS), and Unified PD Rating Scale. Changes to levodopa-equivalent daily dose total (LEDD-total) and dopamine agonists (LEDD-DA) were also evaluated.

The QUIP-RS cut-offs and psychiatric assessments found that 38.9% of patients had ICBs at baseline. The ICBs in the cohort included eating disorders (16.2%), hypersexuality (5.4%), excessive shopping (5.4%), and punding and hobbyism (31.4%). In patients who reported clinically relevant ICB prior to operation, there was a significant improvement in QUIP-RS total score by follow-up (30.5±10.7 vs 24.1±14.0; P =.044).

According to the researchers, there was substantial interindividual variability of clinically relevant QUIP-RS outcomes, as reflected by 27.3% of patients who experienced worsening while 29.1% experienced improvement. In the predictor analysis, significant predictive variables of greater postoperative improvements in QUIP-RS included higher baseline QUIP-RS total score (P =.008) and lower baseline LEDD-DA (P =.010).

Patients in the QUIP-RS worsening group appeared to have more severe impairment in the NMSS attention/memory domain at baseline compared with the QUIP-RS improvement group (5.1±4.4 vs 2.8±5.1, respectively; P =.043). The QUIP-RS worsening group also had higher baseline LEDD-DA (321.9mg ±139.2 vs 180.3 mg ±156.1; P =.021) and lower QUIP-RS total (12.1±13.6 vs 21.8±10.6; P =.009) score.

Study limitations included its small sample size as well as the relatively few numbers of patients who reported clinically relevant ICB at baseline.

The researchers wrote that their “study’s novel findings highlight the importance of a comprehensive assessment of patients’ motor and non-motor profiles before DBS surgery.”

Disclosure: Multiple authors declared affiliations with the pharmaceutical industry. Please refer to the original article for a full list of disclosures.

Reference

Sauerbier A, Loehrer P, Jost ST, et al. Predictors of short-term impulsive and compulsive behaviour after subthalamic stimulation in Parkinson disease. J Neurol Neurosurg Psychiatry. Published online September 11, 2021. doi:10.1136/jnnp-2021-326131