Non-motor predictors of 36-month quality of life after subthalamic stimulation in Parkinson disease

Stratifying quality of life outcome in subthalamic stimulation for Parkinson's disease

BACKGROUND

Subthalamic nucleus deep brain stimulation (STN-DBS) for Parkinson's disease (PD) improves quality of life (QoL), motor and non-motor symptoms (NMS). However, in previous studies, 43%-49% of patients did not experience clinically relevant postoperative QoL improvement. To inform individualised prediction of postoperative QoL improvement, we developed a stratification analysis of QoL outcomes based on preoperative non-motor total burden, severity of motor progression and motor response in levodopa challenge tests.

METHODS

This was a prospective, open-label, multicentre, international study with a 6-month follow-up. A distribution-based threshold identified 'QoL responders' in the PDQuestionnaire-8 Summary Index (PDQ-8 SI). After baseline stratification based on the NMS Scale, Hoehn and Yahr Scale and levodopa response assessed with the Unified PD Rating Scale-III, we compared postoperative QoL response between these strata. To assess the clinical usefulness and statistical feasibility of stratifications, we compared cumulative distribution function curves, respectively PDQ-8 within-stratum variation.

RESULTS

All main outcomes improved postoperatively. Based on the 8.1 points threshold for clinically meaningful PDQ-8 SI improvement, only 80/161 patients were classified as 'QoL responders'. The absolute risk reductions for QoL non-response among respective non-motor, motor progression and levodopa response strata were 23%, 8% and 3%, respectively. Only non-motor stratification reduced PDQ-8 within-stratum variation compared with the overall cohort.

CONCLUSIONS

Non-motor stratification, but not motor progression or levodopa response stratification, is clinically useful and statistically feasible for personalised preoperative prediction of postoperative QoL outcome of STN-DBS for PD. Our findings highlight that non-motor assessments are necessary components of a case-based, holistic approach of DBS indication evaluations geared towards optimising postoperative QoL outcomes.

TRIAL REGISTRATION NUMBER

GermanClinicalTrialsRegister: #6735.

Predictors of short-term anxiety outcome in subthalamic stimulation for Parkinson's disease

The effects of subthalamic nucleus deep brain stimulation (STN-DBS) on anxiety in Parkinson's disease (PD) are understudied. We identified clinical predictors of STN-DBS effects on anxiety in this study. In this prospective, open-label, multicentre study, we assessed patients with anxiety undergoing STN-DBS for PD preoperatively and at 6-month follow-up postoperatively. We assessed the Hospital Anxiety and Depression Scale (HADS-anxiety and depression subscales), Unified PD Rating Scale-motor examination, Scales for Outcomes in PD-motor (SCOPA-M)-activities of daily living (ADL) and -motor complications, Non-Motor Symptom Scale (NMSS), PDQuestionnaire-8 (PDQ-8), and levodopa-equivalent daily dose. We tested changes at follow-up with Wilcoxon signed-rank test and corrected for multiple comparisons (Bonferroni method). We identified patients with a clinically relevant anxiety improvement of anxiety based on a designated threshold of ½ standard deviation of baseline HADS-anxiety. Moreover, we investigated predictors of HADS-anxiety changes with correlations and linear regressions. We included 50 patients with clinically relevant baseline anxiety (i.e., HADS-anxiety ≥ 8) aged 63.1 years ± 8.3 with 10.4 years ± 4.5 PD duration. HADS-anxiety improved significantly at 6-month follow-up as 80% of our cohort experienced clinically relevant anxiety improvement. In predictor analyses, worse baseline SCOPA-ADL and NMSS-urinary domain were associated with greater HADS-anxiety improvements. HADS-anxiety and PDQ-8 changes correlated moderately. Worse preoperative ADL and urinary symptoms predicted favourable postoperative anxiety outcome, which in turn was directly proportionate to greater QoL improvement. This study highlights the importance of detailed anxiety assessments alongside other non-motor and motor symptoms when advising and monitoring patients undergoing STN-DBS for PD.

Microstructure predicts non-motor outcomes following deep brain stimulation in Parkinson's disease

Deep brain stimulation of the subthalamic nucleus (STN-DBS) effectively treats motor and non-motor symptoms in advanced Parkinson's disease (PD). As considerable interindividual variability of outcomes exists, neuroimaging-based biomarkers, including microstructural metrics, have been proposed to anticipate treatment response. In this prospective open-label study, we sought to detect microstructural properties of brain areas associated with short-term non-motor outcomes following STN-DBS. Thirty-seven PD patients underwent diffusion MRI and clinical assessments at preoperative baseline and 6-month follow-up. Whole brain voxel-wise analysis assessed associations between microstructural metrics and non-motor outcomes. Intact microstructure within specific areas, including the right insular cortex, right putamen, right cingulum, and bilateral corticospinal tract were associated with greater postoperative improvement of non-motor symptom burden. Furthermore, microstructural properties of distinct brain regions were associated with postoperative changes in sleep, attention/memory, urinary symptoms, and apathy. In conclusion, diffusion MRI could support preoperative patient counselling by identifying patients with above- or below-average non-motor responses.

No evidence for an association of voxel-based morphometry with short-term non-motor outcomes in deep brain stimulation for Parkinson's disease

Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an established therapy in advanced Parkinson's disease (PD). Motor and non-motor outcomes, however, show considerable inter-individual variability. Preoperative morphometry-based metrics have recently received increasing attention to explain treatment effects. As evidence for the prediction of non-motor outcomes is limited, we sought to investigate the association between metrics of voxel-based morphometry and short-term non-motor outcomes following STN-DBS in this prospective open-label study. Forty-nine PD patients underwent structural MRI and a comprehensive clinical assessment at preoperative baseline and 6-month follow-up. Voxel-based morphometry was used to assess associations between cerebral volume and non-motor outcomes corrected for multiple comparisons using a permutation-based approach. We replicated existing results associating volume loss of the superior frontal cortex with subpar motor outcomes. Overall non-motor burden, however, was not significantly associated with morphometric features, limiting its use as a marker to inform patient selection and holistic preoperative counselling.

Advanced therapies in Parkinson's disease: an individualized approach to their indication

Device aided therapies (DAT) comprising the intrajejunal administration of levodopa/carbidopa intestinal gel (LCIG) and levodopa/carbidopa/entacapone intestinal gel (LECIG), the continuous subcutaneous application of foslevodopa/foscarbidopa or apomorphine infusion (CSAI) and deep brain stimulation (DBS) are used to treat Parkinson's disease with insufficient symptom alleviation under intensified pharmacotherapy. These DAT significantly differ in their efficacy profiles, indication, invasiveness, contraindications, and potential side effects. Usually, the evaluation of all these procedures is conducted simultaneously at the same point in time. However, as disease progression and symptom burden is extremely heterogeneous, clinical experience shows that patients reach the individual milestones for a certain therapy at different points in their disease course. Therefore, advocating for an individualized therapy evaluation for each DAT, requiring an ongoing evaluation. This necessitates that, during each consultation, the current symptomatology should be analyzed, and the potential suitability for a DAT be assessed. This work represents a critical interdisciplinary appraisal of these therapies in terms of their individual profiles and compares these DAT regarding contraindications, periprocedural considerations as well as their efficacy regarding motor- and non-motor deficits, supporting a personalized approach.

Analyses of the clinical factors and freezing of gait in association with the quality-of-life indexes in Parkinson's disease subjects with and without STN-DBS therapy

INTRODUCTION

In this research, paying particular attention to freezıng of gait (FOG), we aimed to investigate the associations between the clinical features and quality of lilfe (QOL) indexes comparatively in our PD subjects with and without STN-DBS therapy.

METHODS

All consecutive PD subjects with and without STN-DBS who applied to our movement disorders outpatient clinics between January/2022 and September/2022; and accepted to participate in the study were enrolled. The demographic data and clinical features were noted. Besides, the MDS-UPDRS, the FOG Questionnaire (FOGQ) and the Parkinson's Disease Questionnaire (PDQ-39) have also been performed on all individuals.

RESULTS

Overall, 105 patients with PD participated in this study (34 patients with STN-DBS, 71 patients without STN-DBS). No difference was found in the PDQ-39 scores between patients with and without STN-DBS. The correlation analyses between the PQQ-39 scores and the clinical parameters revealed significant moderate correlations with the FOGQ score and low correlations with MDS-UPDRS scores. The analyses repeated in either patient group showed that there were no correlations between the MDS-UPDRS scores and PDQ-39 indexes in the DBS group. Besides, the correlations between the PDQ-39 scores and the FOG scores were more prominent in patients without DBS therapy.

CONCLUSION

FOG was found to be associated with worse QOL status in both patients with and without STN-DBS therapy. However, the correlations analyses in either group showed that FOG was a more significant determinant in the QOL indexes in patients without DBS. Future studies evaluating the impact of other clinical features such as falls and gait impairment in QOL of patients with STN-DBS may provide contributions to the current evidence.

Preoperative motor deficits and depressive symptoms predict quality of life in patients with Parkinson's disease at different time points after surgery for subthalamic stimulation: a retrospective study

BACKGROUND

While subthalamic nucleus deep brain stimulation (STN-DBS) improves the quality of life (QoL) of patients with Parkinson's disease (PD), the clinical parameters that predict this improvement remain debated. This retrospective study explored whether preoperative motor, cognitive, and affective parameters predict QoL or its components at 6 and 12 months after STN-DBS surgery.

METHODS

QoL was assessed with the Parkinson's Disease Questionnaire-39 (PDQ-39) before (baseline), at 6 months (N = 90) and 12 months (N = 63) after STN-DBS surgery. Changes in the PDQ-39 and its subdomains were analysed with Wilcoxon signed-rank tests. In total, seven motor, cognitive, and affective parameters recorded at baseline were used in multiple linear regressions to predict QoL and its subdomains.

RESULTS

QoL had improved significantly at six months post STN-DBS surgery. After 12 months, this effect remained significant but was less pronounced. At both time points, significant improvements in mobility, activities of daily living, stigma, and bodily discomfort were present. Correlation and linear regression analyses showed that preoperative QoL status and changes in QoL at 6 and 12 months after surgery were driven by preoperative dopaminergic medication, as well as motor (UPDRS-III medOFF and PIGD-subscore medOFF) and affective (HADS anxiety and depression) symptoms. In contrast, preoperative cognitive performance did not predict QoL at any time point.

CONCLUSION

Data show that preoperative motor and affective symptoms drive both QoL baseline status and changes in QoL after STN-DBS surgery. Thus, these clinical parameters need to be assessed appropriately to provide comprehensive presurgical advice to patients suffering from PD.

Preoperative Attention/Memory Problem Affects the Quality of Life of Parkinson's Disease Patients after Deep Brain Stimulation: A Cohort Study

Objectives

The aim of this study was to investigate the impact of nonmotor symptoms (NMS) on the quality of life (QoL) outcome after subthalamic nucleus deep brain stimulation (STN-DBS) at the 1-year follow-up.

Methods

Ninety-three patients diagnosed with Parkinson's disease (PD), who underwent subthalamic nucleus deep brain stimulation (STN-DBS) between April 2020 and August 2021, were included in this study. Demographic information was gathered through a self-designed questionnaire. The severity of both motor and non-motor symptoms, along with the quality of life (QoL), was assessed using the Unified Parkinson's Disease Rating Scale-III (UPDRS-III), Nonmotor Symptoms Scale (NMSS), and 8-item Parkinson's Disease Questionnaire (PDQ-8), respectively.

Results

Significant differences were observed in the UPDRS-III score, NMSS summary index (SI), and subscores of six domains (sleep/fatigue, mood/cognition, perceptual problems/hallucinations, attention/memory, urinary, and sexual function) between the baseline and the 6- and 12-month follow-ups. The correlation analysis revealed positive correlations between the preoperative NMSS SI and subscores of seven domains (cardiovascular, sleep/fatigue, mood/cognition, perceptual problems/hallucinations, attention/memory, gastrointestinal, and urinary) and ΔPDQ-8. Moreover, the preoperative PDQ-8 SI (β = 0.869, P < 0.001) and the preoperative attention/memory subscore (β = -0.154, P = 0.026) were predictive of the postsurgery improvement in quality of life (QoL).

Conclusion

Deep brain stimulation (DBS) led to an improvement in the patients' nonmotor symptoms (NMS) at the 1-year follow-up, along with a correlation observed between NMS and the patients' quality of life (QoL). Notably, the severity of preoperative attention/memory problems emerged as the most significant predictor of NMS influencing the QoL outcome after STN-DBS at the 1-year follow-up.

Subthalamic nucleus deep brain stimulation in primary Meige syndrome: motor and non-motor outcomes

BACKGROUND AND PURPOSE

Deep brain stimulation (DBS) has emerged as a promising treatment for movement disorders. This prospective study aims to evaluate the effects of bilateral subthalamic nucleus DBS (STN-DBS) on motor and non-motor symptoms in patients with primary Meige syndrome.

METHODS

Thirty patients who underwent bilateral STN-DBS between April 2017 and June 2020 were included. Standardized and validated scales were utilized to assess the severity of dystonia, health-related quality of life, sleep, cognitive function and mental status at baseline and at 1 year and 3 years after neurostimulation.

RESULTS

The Burke-Fahn-Marsden Dystonia Rating Scale movement scores showed a mean improvement of 63.0% and 66.8% at 1 year and 3 years, respectively, after neurostimulation. Similarly, the Burke-Fahn-Marsden Dystonia Rating Scale disability scores improved by 60.8% and 63.3% at the same time points. Postoperative quality of life demonstrated a significant and sustained improvement throughout the follow-up period. However, cognitive function, mental status, sleep quality and other neuropsychological functions did not change after 3 years of neurostimulation. Eight adverse events occurred in six patients, but no deaths or permanent sequelae were reported.

CONCLUSIONS

Bilateral STN-DBS is a safe and effective alternative treatment for primary Meige syndrome, leading to improvements in motor function and quality of life. Nevertheless, it did not yield significant amelioration in cognitive, mental, sleep status and other neuropsychological functions after 3 years of neurostimulation.

Neurostimulation for Advanced Parkinson Disease and Quality of Life at 5 Years: A Nonrandomized Controlled Trial

Importance

Deep brain stimulation of the subthalamic nucleus (STN-DBS) improves quality of life (QOL) in patients with advanced Parkinson disease (PD). However, controlled studies with more than 3 years of follow-up are lacking.

Objective

To investigate the long-term effects of STN-DBS on QOL compared with standard-of-care medication (MED).

Design, Setting, and Participants

In this prospective, observational, quasi-experimental, longitudinal nonrandomized controlled trial, 183 patients were screened for eligibility and 167 were enrolled from March 1, 2011, to May 31, 2017, at 3 European university centers. Propensity score matching for demographic and clinical characteristics was applied to 108 patients with PD (62 in the STN-DBS group and 46 in the MED group), resulting in a well-balanced, matched subcohort of 25 patients per group. Data analysis was performed from September 2022 to January 2023.

Exposure

Treatment for PD of STN-DBS or MED.

Main Outcomes and Measures

Assessments included Parkinson's Disease Questionnaire 8 (PDQ-8), Unified PD Rating Scale-motor examination, Scales for Outcomes in PD-activities of daily living (ADL) and motor complications, and levodopa-equivalent daily dose. Within-group longitudinal outcome changes, between-group differences, and correlations of change scores were analyzed.

Results

The study population in the analysis included 108 patients (mean [SD] age, 63.7 [8.3] years; 66 [61.1%] male). At 5-year follow-up, PDQ-8 and ADL worsened only in the MED group (PDQ-8 change, -10.9; 95% CI, -19.0 to -2.7; P = .01; ADL change: -2.0; 95% CI, -3.1 to -0.8; P = .002), whereas both outcomes remained stable in the STN-DBS group (PDQ-8 change, -4.3; 95% CI, -13.2 to 4.7; P = .34; ADL change, -0.8; 95% CI, -2.5 to 1.0; P = .38). Changes in PDQ-8 and ADL correlated moderately (rs = .40, P = .008). Furthermore, STN-DBS outcomes were favorable for motor complications (median difference in change scores between STN-DBS and MED, -2.0; 95% CI, -4.0 to -1.0; P = .003), mobility (-1.0; 95% CI, -2.0 to 0; P = .03), and levodopa-equivalent daily dose reduction (-821.4; 95% CI, -1111.9 to -530.8; P < .001).

Conclusions and Relevance

This study provides evidence of differences in QOL outcomes at 5-year follow-up between STN-DBS (stable) and MED (worsened), mainly driven by the favorable effect of STN-DBS on mobility (class IIb evidence). The association between changes in QOL and ADL, but not motor impairment or complications, highlights the relative importance of ADL outcomes for long-term DBS assessments.

Trial Registration

German ClinicalTrials Registry: DRKS00006735.

The Role of Levodopa Challenge in Predicting the Outcome of Subthalamic Deep Brain Stimulation

Background

Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an effective and evidence-based treatment for idiopathic Parkinson's disease (iPD). A minority of patients does not sufficiently benefit from STN-DBS.

Objective

The predictive validity of the levodopa challenge for individual patients is analyzed.

Methods

Data from patients assessed with a preoperative Levodopa-test and a follow-up examination (mean ± standard deviation: 9.15 months ±3.39) from Kiel (n = 253), Berlin (n = 78) and Toronto (n = 98) were studied. Insufficient DBS outcome was defined as an overall UPDRS-III reduction <33% compared to UPDRS-III in med-off at baseline or alternatively if the minimal clinically important improvement of 5 points was not reached. Single UPDRS-items and sub-scores were dichotomized. Following exploratory analysis, we trained supervised regression- and classification models for outcome prediction.

Results

Data analysis confirmed significant correlation between the absolute UPDRS-III reduction during Levodopa challenge and after stimulation. But individual improvement was inaccurately predicted with a large range of up to 30 UPDRS III points. Further analysis identified preoperative UPDRS-III/med-off-scores and preoperative Levodopa-improvement as most influential factors. The models for UPDRS-III and sub-scores improvement achieved comparably low accuracy.

Conclusions

With large prediction intervals, the Levodopa challenge use for patient counseling is limited, though remains important for excluding non-responders to Levodopa. Despite these deficiencies, the current practice of patient selection is highly successful and builds not only on the Levodopa challenge. However, more specific motor tasks and further paraclinical tools for prediction need to be developed.

Non-motor effects of deep brain stimulation in Parkinson's disease motor subtypes

INTRODUCTION

Deep brain stimulation (DBS) is a well-established treatment for patients with Parkinson's disease (PD) improving quality of life, motor, and non-motor symptoms. However, non-motor effects in PD subtypes are understudied. We hypothesized that patients with 'postural instability and gait difficulty' (PIGD) experience more beneficial non-motor effects than 'tremor-dominant' patients undergoing DBS for PD.

METHODS

In this prospective, observational, international multicentre study with a 6-month follow-up, we assessed the Non-Motor Symptom Scale (NMSS) as primary and the following secondary outcomes: Unified PD Rating Scale-motor examination (UPDRS-III), Scales for Outcomes in PD (SCOPA)-activities of daily living (ADL) and -motor complications, PDQuestionnaire-8 (PDQ-8), and levodopa-equivalent daily dose (LEDD). We analysed within-group longitudinal changes with Wilcoxon signed-rank test and Benjamini-Hochberg correction for multiple comparisons. Additionally, we explored outcome between-group differences of motor subtypes with Mann-Whitney U-tests.

RESULTS

In 82 PIGD and 33 tremor-dominant patients included in this study, baseline NMSS total scores were worse in PIGD patients, both groups experienced postoperative improvements of the NMSS sleep/fatigue domain, and between-group differences in postoperative outcomes were favourable in the PIGD group for the NMSS total and miscellaneous domain scores.

CONCLUSIONS

This study provides evidence of a favourable outcome of total non-motor burden in PIGD compared to tremor-dominant patients undergoing DBS for PD. These differences of clinical efficacy on non-motor aspects should be considered when advising and monitoring patients with PD undergoing DBS.

PDQ-8: A Simplified and Effective Tool Measuring Life Quality in Progressive Supranuclear Palsy

BACKGROUND

The self-reported quality of life (QoL) should be carefully listened to in progressive supranuclear palsy (PSP) from the patient-centered perspective. However, there was still a lack of short QoL measurement tool in atypical parkinsonism.

OBJECTIVE

We aimed to test whether the short Parkinson's Disease Questionnaire-8 (PDQ-8) was effective in assessing QoL in PSP, comparing with Progressive Supranuclear Palsy Quality of Life Scale (PSP-QoL) and Parkinson's Disease Questionnaire-39 (PDQ-39).

METHODS

132 patients with clinical diagnosed PSP, including PSP-Richardson syndrome (RS) subtype (n = 71) and PSP-non-RS subtype (n = 61) were recruited for clinical evaluation including QoL assessment. The detailed QoL profiles and possibility of using PDQ-8 were systemically analyzed. The determinants to the QoL were then calculated by multivariate linear regression analysis.

RESULTS

The PSP-QoL total score summary index (SI) was 22.8 (10.1, 41.1), while the PDQ-8 and PDQ-39 total SI score were 28.1 (12.5, 46.9) and 29.5 (15.4, 49.4). Mobility, activities of daily life, cognition and communication were the main affected QoL subdomains (median SI: 40.0, 31.3, 25.0 and 25.0 respectively). PSP-RS subtype showed more severe damage physically (p<0.001) and mentally (p = 0.002) compared to other subtypes. More importantly, the strong relevance of PDQ-8 and recommended PSP QoL tools were confirmed (p<0.001). In addition, disease severity, depression and daytime sleepiness were proved to be critical determinants for QoL in PSP.

CONCLUSIONS

PDQ-8 could be an easy, reliable, and valid tool to evaluate QoL in patients with PSP. Besides motor symptoms, more attention should be paid to non-motor impairment such as depression in PSP.

Gender gap in deep brain stimulation for Parkinson's disease

Previous studies have shown less access to deep brain stimulation (DBS) for Parkinson’s disease (PD) in women compared to men raising concerns about a potential gender gap resulting from nonclinical factors or gender differences in clinical efficacy for postoperative quality of life (QoL), motor, and nonmotor symptoms (NMS) outcomes. This was a cross-sectional and a longitudinal, prospective, observational, controlled, quasi-experimental, international multicenter study. A total sample size of 505 consisted of 316 consecutively referred patients for DBS indication evaluation at the University Hospital Cologne (01/2015–09/2020) and 189 consecutively treated patients at DBS centers in the University Hospitals Cologne and Marburg, Salford’s Royal Hospital Manchester, and King’s College Hospital London. In the cross-sectional cohort, we examined gender proportions at referral, indication evaluations, and DBS surgery. In the longitudinal cohort, clinical assessments at preoperative baseline and 6-month follow-up after surgery included the PD Questionnaire-8, NMSScale, Scales for Outcomes in PD-motor scale, and levodopa-equivalent daily dose. Propensity score matching resulted in a pseudo-randomized sub-cohort balancing baseline demographic and clinical characteristics between women with PD and male controls. 316 patients were referred for DBS. 219 indication evaluations were positive (women n = 102, respectively n = 82). Women with PD were disproportionally underrepresented in referrals compared to the general PD population (relative risk [RR], 0.72; 95%CI, 0.56–0.91; P = 0.002), but more likely to be approved for DBS than men (RR, 1.17; 95%CI, 1.03–1.34; P = 0.029). Nonetheless, their total relative risk of undergoing DBS treatment was 0.74 (95%CI, 0.48–1.12) compared to men with PD. At baseline, women had longer disease duration and worse dyskinesia. Exploring QoL domains, women reported worse mobility and bodily discomfort. At follow-up, all main outcomes improved equally in both genders. Our study provides evidence of a gender gap in DBS for PD. Women and men with PD have distinct preoperative nonmotor and motor profiles. We advocate that more focus should be directed toward the implementation of gender equity as both genders benefit from DBS with equal clinical efficacy. This study provides Class II evidence of beneficial effects of DBS in women with PD compared to male controls.

Proceedings of the Ninth Annual Deep Brain Stimulation Think Tank: Advances in Cutting Edge Technologies, Artificial Intelligence, Neuromodulation, Neuroethics, Pain, Interventional Psychiatry, Epilepsy, and Traumatic Brain Injury

DBS Think Tank IX was held on August 25-27, 2021 in Orlando FL with US based participants largely in person and overseas participants joining by video conferencing technology. The DBS Think Tank was founded in 2012 and provides an open platform where clinicians, engineers and researchers (from industry and academia) can freely discuss current and emerging deep brain stimulation (DBS) technologies as well as the logistical and ethical issues facing the field. The consensus among the DBS Think Tank IX speakers was that DBS expanded in its scope and has been applied to multiple brain disorders in an effort to modulate neural circuitry. After collectively sharing our experiences, it was estimated that globally more than 230,000 DBS devices have been implanted for neurological and neuropsychiatric disorders. As such, this year's meeting was focused on advances in the following areas: neuromodulation in Europe, Asia and Australia; cutting-edge technologies, neuroethics, interventional psychiatry, adaptive DBS, neuromodulation for pain, network neuromodulation for epilepsy and neuromodulation for traumatic brain injury.

The Contribution of Subthalamic Nucleus Deep Brain Stimulation to the Improvement in Motor Functions and Quality of Life

BACKGROUND

Subthalamic nucleus deep brain stimulation (STN-DBS) effectively treats motor symptoms and quality of life (QoL) of advanced and fluctuating early Parkinson's disease. Little is known about the relation between electrode position and changes in symptom control and ultimately QoL.

OBJECTIVES

The relation between the stimulated part of the STN and clinical outcomes, including the motor score of the Unified Parkinson's Disease Rating Scale (UPDRS) and the quality-of-life questionnaire, was assessed in a subcohort of the EARLYSTIM study.

METHODS

Sixty-nine patients from the EARLYSTIM cohort who underwent DBS, with a comprehensive clinical characterization before and 24 months after surgery, were included. Intercorrelations of clinical outcome changes, correlation between the affected functional parts of the STN, and changes in clinical outcomes were investigated. We further calculated sweet spots for different clinical parameters.

RESULTS

Improvements in the UPDRS III and Parkinson's Disease Questionnaire (PDQ-39) correlated positively with the extent of the overlap with the sensorimotor STN. The sweet spots for the UPDRS III (x = 11.6, y = -13.1, z = -6.3) and the PDQ-39 differed (x = 14.8, y = -12.4, z = -4.3) ~3.8 mm.

CONCLUSIONS

The main influence of DBS on QoL is likely mediated through the sensory-motor basal ganglia loop. The PDQ sweet spot is located in a posteroventral spatial location in the STN territory. For aspects of QoL, however, there was also evidence of improvement through stimulation of the other STN subnuclei. More research is necessary to customize the DBS target to individual symptoms of each patient. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Short and Long-Term Cognitive Effects of Subthalamic Deep Brain Stimulation in Parkinson's Disease and Identification of Relevant Factors

BACKGROUND

Subthalamic nucleus deep brain stimulation (STN-DBS) successfully controls the motor symptoms of Parkinson's disease (PD) but has associated cognitive side-effects.

OBJECTIVE

Establish the short- and long-term cognitive effects of STN-DBS in PD.

METHODS

Both the short-term and long-term effects of STN-DBS on cognition were examined through evaluation of the controlled studies that compared patients with STN-DBS to unoperated PD patients, thus controlling for illness progression. We also reviewed the literature to identify the factors that influence cognitive outcome of STN-DBS in PD.

RESULTS

The meta-analysis of the short-term cognitive effects of STN-DBS revealed moderate effect sizes for semantic and phonemic verbal fluency and small effect sizes for psychomotor speed and language, indicating greater decline in the STN-DBS operated than the unoperated patients in these cognitive domains. The longer-term STN-DBS results from controlled studies indicated rates of cognitive decline/dementia up to 32%; which are no different from the rates from the natural progression of PD. Greater executive dysfunction and poorer memory pre-operatively, older age, higher pre-operative doses of levodopa, and greater axial involvement are some of the factors associated with worse cognition after STN-DBS in PD.

CONCLUSION

This evidence can be used to inform patients and their families about the short-term and long-term risks of cognitive decline following STN-DBS surgery and aid the team in selection of suitable candidates for surgery.

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.

Multicenter Validation of Individual Preoperative Motor Outcome Prediction for Deep Brain Stimulation in Parkinson's Disease

BACKGROUND

Subthalamic nucleus deep brain stimulation (STN DBS) is an established therapy for Parkinson's disease (PD) patients suffering from motor response fluctuations despite optimal medical treatment, or severe dopaminergic side effects. Despite careful clinical selection and surgical procedures, some patients do not benefit from STN DBS. Preoperative prediction models are suggested to better predict individual motor response after STN DBS. We validate a preregistered model, DBS-PREDICT, in an external multicenter validation cohort.

METHODS

DBS-PREDICT considered eleven, solely preoperative, clinical characteristics and applied a logistic regression to differentiate between weak and strong motor responders. Weak motor response was defined as no clinically relevant improvement on the Unified Parkinson's Disease Rating Scale (UPDRS) II, III, or IV, 1 year after surgery, defined as, respectively, 3, 5, and 3 points or more. Lower UPDRS III and IV scores and higher age at disease onset contributed most to weak response predictions. Individual predictions were compared with actual clinical outcomes.

RESULTS

322 PD patients treated with STN DBS from 6 different centers were included. DBS-PREDICT differentiated between weak and strong motor responders with an area under the receiver operator curve of 0.76 and an accuracy up to 77%.

CONCLUSION

Proving generalizability and feasibility of preoperative STN DBS outcome prediction in an external multicenter cohort is an important step in creating clinical impact in DBS with data-driven tools. Future prospective studies are required to overcome several inherent practical and statistical limitations of including clinical decision support systems in DBS care.

The New Satisfaction with Life and Treatment Scale (SLTS-7) in Patients with Parkinson's Disease

BACKGROUND

The satisfaction with life and, in particular, with treatment in Parkinson's disease (PD) is understudied.

OBJECTIVE

To explore a new 7-item rating tool assessing satisfaction with life and treatment (SLTS-7) in PD.

METHODS

In this cross-sectional, multi-center study, including patients screened for advanced therapies, psychometric characteristics of the SLTS-7 were analyzed. An exploratory factor analysis identified the underlying factorial structure of the SLTS-7.

RESULTS

117 patients were included, and the data quality of the SLTS-7 was excellent (computable data 100%), and acceptability measures satisfied standard criteria. Besides the global assessment (item 1), the exploratory factor analysis produced item 2 (physical satisfaction) as an independent item and two factors among the remaining items: items 3-5 (psycho-social satisfaction), and items 6 and 7 (treatment satisfaction). Cronbach's alpha was 0.89, indicative of high internal consistency. The SLTS-7 total score correlated moderately with motor symptoms and weakly with non-motor symptoms total scores. SLTS-7 showed the highest correlations with the European Quality of Life with 5 items (EQ-5D) visual analog scale (0.43-0.58, p < 0.01), indicating a moderate convergent validity. The SLTS-7 significantly increased with higher non-motor symptoms burden levels (p = 0.002).

CONCLUSION

Life satisfaction in PD covers three specific aspects, namely physical, psycho-social, and treatment satisfaction. The new SLTS-7 is a valid, reliable, and easy-to-use tool to assess satisfaction with life and treatment in patients with PD screened for advanced therapies. Longitudinal studies analyzing the effect of advanced PD treatment on life and treatment satisfaction are warranted.

Personalised Advanced Therapies in Parkinson's Disease: The Role of Non-Motor Symptoms Profile

Device-aided therapies, including levodopa-carbidopa intestinal gel infusion, apomorphine subcutaneous infusion, and deep brain stimulation, are available in many countries for the management of the advanced stage of Parkinson’s disease (PD). Currently, selection of device-aided therapies is mainly focused on patients’ motor profile while non-motor symptoms play a role limited to being regarded as possible exclusion criteria in the decision-making process for the delivery and sustenance of a successful treatment. Differential beneficial effects on specific non-motor symptoms of the currently available device-aided therapies for PD are emerging and these could hold relevant clinical implications. In this viewpoint, we suggest that specific non-motor symptoms could be used as an additional anchor to motor symptoms and not merely as exclusion criteria to deliver bespoke and patient-specific personalised therapy for advanced PD.

Predictors of Global Non-Motor Symptoms Burden Progression in Parkinson's Disease. Results from the COPPADIS Cohort at 2-Year Follow-Up

Background and Objective: Non-motor symptoms (NMS) progress in different ways between Parkinson's disease (PD) patients. The aim of the present study was to (1) analyze the change in global NMS burden in a PD cohort after a 2-year follow-up, (2) to compare the changes with a control group, and (3) to identify predictors of global NMS burden progression in the PD group. Material and Methods: PD patients and controls, recruited from 35 centers of Spain from the COPPADIS cohort from January 2016 to November 2017, were followed-up with after 2 years. The Non-Motor Symptoms Scale (NMSS) was administered at baseline (V0) and at 24 months ± 1 month (V2). Linear regression models were used for determining predictive factors of global NMS burden progression (NMSS total score change from V0 to V2 as dependent variable). Results: After the 2-year follow-up, the mean NMS burden (NMSS total score) significantly increased in PD patients by 18.8% (from 45.08 ± 37.62 to 53.55 ± 42.28; p < 0.0001; N = 501; 60.2% males, mean age 62.59 ± 8.91) compared to no change observed in controls (from 14.74 ± 18.72 to 14.65 ± 21.82; p = 0.428; N = 122; 49.5% males, mean age 60.99 ± 8.32) (p < 0.0001). NMSS total score at baseline (β = -0.52), change from V0 to V2 in PDSS (Parkinson's Disease Sleep Scale) (β = -0.34), and change from V0 to V2 in NPI (Neuropsychiatric Inventory) (β = 0.25) provided the highest contributions to the model (adjusted R-squared 0.41; Durbin-Watson test = 1.865). Conclusions: Global NMS burden demonstrates short-term progression in PD patients but not in controls and identifies worsening sleep problems and neuropsychiatric symptoms as significant independent predictors of this NMS progression.

Long-term effect of bilateral STN-DBS on non-motor symptoms in Parkinson's disease: A four-year observational, prospective study

BACKGROUND

Several studies have shown beneficial effects of bilateral stimulation of the subthalamic nucleus (STN-DBS) on motor as well as on non-motor symptoms (NMS) up to 36 months post-surgery in advanced Parkinson's disease (PD) patients. We set to explore the long-term effect of STN-DBS on NMS in a four-year follow-up, prospective, observational study.

METHODS

Forty patients were enrolled and assessed at baseline. Twenty-eight were followed-up at 6, 12, 24, 36 and 48 months after the operation. The effect of post-operative time on NMS was analyzed by six-level repeated measures ANOVA. In a post-hoc analysis the follow-up scores were compared to baseline using a paired t-test.

RESULTS

The following scores stayed improved up to 24 months after surgery, presented as baseline/24 months, p-value (t-test): total Non-Motor Symptoms Scale score (54.0 ± 5.6/44.9 ± 5.0, p = 0.029), Hamilton Anxiety Scale (14.3 ± 1.3/11.3 ± 1.2, p = 0.019) and PDQ39 (53.4 ± 4.5/40.2 ± 2.9, p = 0.012). PD Sleep Scale 2 remained improved throughout the study (17.4 ± 2.0/12.8 ± 1.3 at 48 months, p = 0.032), while Beck Depression Inventory only at six months post-surgery (9.5 ± 1.2/6.7 ± 0.7 at 6 months, p = 0.006). Montreal Cognitive Assessment remained stable up to 24 months and then declined at 36 months (26.3 ± 0.5/25.4 ± 0.5 at 36 months, p = 0.003), Starkstein Apathy Scale deteriorated throughout the study (7.6 ± 0.7/12.7 ± 0.9 at 48 months, p = 0.006).

CONCLUSIONS

We observed beneficial effect of STN-DBS in several but not all domains of NMS at least up to 24 months post-op in advanced PD. Further long-term studies on larger cohorts of PD patients and longer follow-up need to be conducted to better understand the long-term effect of STN-DBS on NMS.