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.

The real-life effect of catechol-O-methyltransferase inhibition on non-motor symptoms in levodopa-treated Parkinson's disease: opicapone versus entacapone.

OBJECTIVE: To evaluate the long-term, real-life effects on non-motor symptoms (NMS) of opicapone compared to entacapone in levodopa-treated people with Parkinson's disease (PwP). METHODS: A retrospective data analysis, with pre- and post-opicapone initiation data of 17 PwP with motor fluctuations compared to a comparable group of 18 PwP introduced on entacapone. The primary outcome was changes in the NMS Scale (NMSS) total score after 1-year follow-up. Secondary outcomes included changes in the NMSS domains, and Parkinson's Disease Sleep Scale (PDSS) total and item scores after the same time span. RESULTS: Groups were comparable for baseline demographics and Parkinson's-related features (p ≥ 0.314) as well as duration of follow-up (1.33 ± 0.66 years for PwP on opicapone and 1.23 ± 0.49 years for those on entacapone; p = 0.858). PwP who were introduced on opicapone showed no changes in NMSS and PDSS total scores after 1 year (p = 0.605 and p = 0.507, respectively), whereas PwP who were introduced on entacapone showed significant worsening of NMSS and PDSS total scores at follow-up (p = 0.005 and p = 0.001, respectively). In neither group changes in individual NMSS domains from baseline to follow-up were observed (p ≥ 0.288 for entacapone and p ≥ 0.816 for opicapone, respectively). In PwP on entacapone significant worsening was seen in the distressing dreams, hallucinations, and limb numbness items of the PDSS (p ≤ 0.05). CONCLUSIONS: Introduction of opicapone in real-life PwP with motor fluctuations seems to stabilise NMS burden and aspects of sleep dysfunction, in contrast to entacapone where there was a worsening of NMS burden and PDSS scores over 1 year follow-up.

Evaluation of the effect of bilateral subthalamic nucleus deep brain stimulation on fatigue in Parkinson's Disease as measured by the non-motor symptoms scale.

BACKGROUND: Fatigue is a common and disabling non-motor symptom (NMS) in Parkinson's disease (PD) patients. However, the effect of subthalamic nucleus (STN) deep brain stimulation (DBS) on fatigue has not been widely studied. OBJECTIVE: To determine the effect of STN DBS on fatigue in PD patients, measured by the Non-motor symptoms scale (NMSS). METHODS: Cross-sectional analysis of 50 patients with PD who underwent STN DBS at King's College Hospital and Salford Royal Hospital with fatigue scores (measured by question number 4 from domain 2 (sleep/fatigue) of the NMSS as the primary outcome measure. Secondary outcome measures included the PD Sleep Scale (PDSS), Scales for Outcome in PD (SCOPA)-motor examination, activities of daily living, motor complications, Hoehn and Yahr (HY) stage and changes in Levodopa Equivalent Daily Dose (LEDD). RESULTS: 50 patients with a mean follow-up period of 1.98 ± 1.36 years were studied. Significant improvement in median fatigue scores (4.00 (0.75-9.00) to 1.00 (0.00-4.50); p = .001) was observed. In addition, improvements in question 5 (sleep maintenance and fragmentation; 8.00 (4.00-12.00) to 0.00 (0.00-4.00); p < .001) and in domain 2 total score (sleep/fatigue; 20.00 (8.75-27.25) to 6.00 (0.75-16.00); p < .001) were also significant, together with improvements in NMSS total score, SCOPA scores and HY stage (p ≤ .02). Moreover, LEDD but especially dopamine agonists LEDD was significantly reduced after DBS (310.00 (0.00-480.00) to 150.00 (0.00-300.00); p < .020). CONCLUSIONS: Even though open label and not using a validated fatigue scale, this observational analysis suggest that fatigue improves significantly after STN DBS with persisting benefits at two years follow-up.

A prospective, controlled study of non-motor effects of subthalamic stimulation in Parkinson's disease: results at the 36-month follow-up.

OBJECTIVE: To examine 36-month effects of bilateral subthalamic nucleus deep brain stimulation (STN-DBS) on non-motor symptoms (NMS) compared with standard-of-care medical treatment (MED) in Parkinson's disease (PD). METHODS: Here we report the 36-month follow-up of a prospective, observational, controlled, international multicentre study of the NILS cohort. Assessments included NMSScale (NMSS), PDQuestionnaire-8 (PDQ-8), Scales for Outcomes in PD (SCOPA)-motor examination, -activities of daily living, and -complications, and levodopa equivalent daily dose (LEDD). Propensity score matching resulted in a pseudo-randomised sub-cohort balancing baseline demographic and clinical characteristics between the STN-DBS and MED groups. Within-group longitudinal outcome changes were analysed using Wilcoxon signed-rank and between-group differences of change scores with Mann-Whitney U test. Strength of clinical responses was quantified with Cohen's effect size. In addition, bivariate correlations of change scores were explored. RESULTS: Propensity score matching applied on the cohort of 151 patients (STN-DBS n=67, MED n=84) resulted in a well-balanced sub-cohort including 38 patients per group. After 36 months, STN-DBS significantly improved NMSS, PDQ-8, SCOPA-motor examination and -complications and reduced LEDD. Significant between-group differences, all favouring STN-DBS, were found for NMSS, SCOPA-motor complications, LEDD (large effects), motor examination and PDQ-8 (moderate effects). Furthermore, significant differences were found for the sleep/fatigue, urinary (large effects) and miscellaneous NMSS domains (moderate effects). NMSS total and PDQ-8 change scores correlated significantly. CONCLUSIONS: This study provides Class IIb evidence for beneficial effects of STN-DBS on NMS at 36-month follow-up which also correlated with quality of life improvements. This highlights the importance of NMS for DBS outcomes assessments.

Factor Analysis and Clustering of the Movement Disorder Society-Non-Motor Rating Scale.

BACKGROUND: The primary validation of the Movement Disorder Society Non-Motor Rating Scale was recently published, but 2 important structural analyses were not included. The objective of this study was to examine the structural characteristics of the Movement Disorder Society Non-Motor Rating Scale by factor and cluster analyses. METHODS: Data came from the validation study, an international multicenter cross-sectional study of 402 Parkinson's disease patients. Demographic and clinical data, the Movement Disorder Society Non-Motor Rating Scale, and Hoehn and Yahr staging were used. Exploratory and confirmatory factor analysis and nonhierarchical cluster analysis were performed. RESULTS: The exploratory factor analysis showed that all 13 domains of the Movement Disorder Society Non-Motor Rating Scale, except 1, and the Non-Motor Fluctuations subscale performed as unidimensional (variance explained: 0.36, sleep and wakefulness; -0.82, orthostatic hypotension). The confirmatory factor analysis could be carried out in 9 domains and showed that 6 of them and the Non-Motor Fluctuations subscale adjusted to the model satisfactorily according to the root mean square error of approximation. Furthermore, all domains had comparative fit index values >0.95, except depression and pain (both, 0.94) and sleep and wakefulness (0.90). The Non-Motor Fluctuations subscale showed satisfactory root mean square error of approximation (0.07), but a low comparative fit index value (0.91). A 5-cluster solution, correctly classifying 96% of the cases, was found. CONCLUSIONS: Overall, most subscales of the Movement Disorder Society Non-Motor Rating Scale are unidimensional, and although each subscale is distinct in terms of content covered, factors and clusters that are of clinical relevance are discernible and contribute to our understanding of possible nonmotor subtypes in Parkinson's disease. © 2020 International Parkinson and Movement Disorder Society.

The movement disorder society nonmotor rating scale: Initial validation study.

BACKGROUND: The Movement Disorder Society-sponsored Nonmotor Rating Scale is an update of the existing Parkinson's disease Nonmotor Symptoms Scale modified to address some limitations in Nonmotor Symptoms Scale scoring, structure, and symptom coverage. METHODS: PD patients were recruited from movement disorder centers in an international, multicenter study. The Movement Disorder Society Nonmotor Rating Scale, consisting of 13 domains plus a subscale for nonmotor fluctuations, was rater administered, along with the Nonmotor Symptoms Scale and other clinical assessments. Standard reliability and validity testing were conducted. RESULTS: Four hundred and two PD patients were recruited (mean age ± standard deviation, 67.42 ± 9.96 years; mean age at PD onset ± standard deviation, 59.27 ± 10.67 years; median Hoehn and Yahr stage 2 (interquartile range 2-3). Data quality was satisfactory for all Movement Disorder Society Nonmotor Rating Scale domains except sexual (6.7% missing data). There were no floor or ceiling effects for the Movement Disorder Society Nonmotor Rating Scale and nonmotor fluctuations total score; domains had no ceiling effects, but some floor effects (13.5%-83.5%). The Movement Disorder Society Nonmotor Rating Scale and nonmotor fluctuations total score internal consistency were acceptable (average Cronbach's alpha, 0.66 and 0.84, respectively); interrater reliability was excellent (intraclass correlation coefficient, >0.95); for test-retest reliability, the intraclass correlation coefficient was 0.84 for the Movement Disorder Society Nonmotor Rating Scale and 0.70 for Movement Disorder Society nonmotor fluctuations total score, and precision was excellent for the Movement Disorder Society Nonmotor Rating Scale (standard error of measurement, 25.30) and fair for nonmotor fluctuations (standard error of measurement, 7.06). Correlations between Movement Disorder Society Nonmotor Rating Scale score and the corresponding Nonmotor Symptoms Scale and Movement Disorder Society UPDRS scores were high. There were no significant sex or age effects. The Movement Disorder Society Nonmotor Rating Scale score increased with increasing PD duration, disease severity, and PD medication dose (all P < 0.001). CONCLUSIONS: The Movement Disorder Society Nonmotor Rating Scale is a valid measure for measuring the burden of a wide range of Nonmotor Rating Scale scores, including nonmotor fluctuations, in PD patients. © 2019 International Parkinson and Movement Disorder Society.

Non-motor outcomes depend on location of neurostimulation in Parkinson's disease.

Deep brain stimulation of the subthalamic nucleus is an effective and established therapy for patients with advanced Parkinson's disease improving quality of life, motor symptoms and non-motor symptoms. However, there is a considerable degree of interindividual variability for these outcomes, likely due to variability in electrode placement and stimulation settings. Here, we present probabilistic mapping data from a prospective, open-label, multicentre, international study to investigate the influence of the location of subthalamic nucleus deep brain stimulation on non-motor symptoms in patients with Parkinson's disease. A total of 91 Parkinson's disease patients undergoing bilateral deep brain stimulation of the subthalamic nucleus were included, and we investigated NMSScale, NMSQuestionnaire, Scales for Outcomes in Parkinson's disease-motor examination, -activities of daily living, and -motor complications, and Parkinson's disease Questionnaire-8 preoperatively and at 6-month follow-up after surgery. Leads were localized in standard space using the Lead-DBS toolbox and individual volumes of tissue activated were calculated based on clinical stimulation settings. Probabilistic stimulation maps and non-parametric permutation statistics were applied to identify voxels with significant above or below average improvement for each scale and analysed using the DISTAL atlas. All outcomes improved significantly at follow-up. Significant spatial distribution patterns of neurostimulation were observed for NMSScale total score and its mood/apathy and attention/memory domains. For both domains, voxels associated with below average improvement were mainly located dorsal to the subthalamic nucleus. In contrast, above average improvement for mood/apathy was observed in the ventral border region of the subthalamic nucleus and in its sensorimotor subregion and for attention/memory in the associative subregion. A trend was observed for NMSScale sleep domain showing voxels with above average improvement located ventral to the subthalamic nucleus. Our study provides evidence that the interindividual variability of mood/apathy, attention/memory, and sleep outcomes after subthalamic nucleus deep brain stimulation depends on the location of neurostimulation. This study highlights the importance of holistic assessments of motor and non-motor aspects of Parkinson's disease to tailor surgical targeting and stimulation parameter settings to patients' personal profiles.

Drooling in Parkinson's Disease: Prevalence and Progression from the Non-motor International Longitudinal Study.

Sialorrhoea in Parkinson's disease (PD) is an often neglected yet key non-motor symptom with impact on patient quality of life. However, previous studies have shown a broad range of prevalence figures. To assess prevalence of drooling in PD and its relationship to quality of life, we performed a retrospective analysis of 728 consecutive PD patients who had a baseline and follow-up assessment as part of the Non-motor International Longitudinal Study (NILS), and for whom drooling presence and severity were available, assessed through the Non-Motor Symptoms Scale (NMSS). In addition, we analysed the prevalence of associated dysphagia through self-reported outcomes. Quality of life was assessed through the PDQ-8 scale. Baseline (disease duration 5.6 years) prevalence of drooling was 37.2% (score ≥ 1 NMSS question 19), and after 3.27 ± 1.74 years follow-up, this was 40.1% (p = 0.17). The prevalence of drooling increased with age (p < 0.001). The severity of drooling, however, did not change (p = 0.12). While in 456 patients without drooling at baseline, only 16% (n = 73) had dysphagia (question 20 of the NMSS), in those with drooling this was 34.3% (p < 0.001). At follow-up, the number of patients with dysphagia had increased, 20.4% with no drooling had dysphagia, and 43.6% with drooling had dysphagia. Both at baseline and follow-up, drooling severity was significantly positively associated with quality of life (PDQ-8; r = 0.199; p < 0.001). In moderately advanced PD patients, subjective drooling occurs in over one-third of patients and was significantly associated with decreased quality of life. Dysphagia occurred significantly more often in patients with drooling.

EuroInf 2: Subthalamic stimulation, apomorphine, and levodopa infusion in Parkinson's disease.

OBJECTIVE: Real-life observational report of clinical efficacy of bilateral subthalamic stimulation (STN-DBS), apomorphine (APO), and intrajejunal levodopa infusion (IJLI) on quality of life, motor, and nonmotor symptoms (NMS) in Parkinson's disease (PD). METHODS: In this prospective, multicenter, international, real-life cohort observation study of 173 PD patients undergoing STN-DBS (n = 101), IJLI (n = 33), or APO (n = 39) were followed-up using PDQuestionnaire-8, NMSScale (NMSS), Unified PD Rating Scale (UPDRS)-III, UPDRS-IV, and levodopa equivalent daily dose (LEDD) before and 6 months after intervention. Outcome changes were analyzed with Wilcoxon signed-rank or paired t test when parametric tests were applicable. Multiple comparisons were corrected (multiple treatments/scales). Effect strengths were quantified with relative changes, effect size, and number needed to treat. Analyses were computed before and after propensity score matching, balancing demographic and clinical characteristics. RESULTS: In all groups, PDQuestionnaire-8, UPDRS-IV, and NMSS total scores improved significantly at follow-up. Levodopa equivalent daily dose was significantly reduced after STN-DBS. Explorative NMSS domain analyses resulted in distinct profiles: STN-DBS improved urinary/sexual functions, mood/cognition, sleep/fatigue, and the miscellaneous domain. IJLI improved the 3 latter domains and gastrointestinal symptoms. APO improved mood/cognition, perceptual problems/hallucinations, attention/memory, and the miscellaneous domain. Overall, STN-DBS and IJLI seemed favorable for NMSS total score, and APO favorable for neuropsychological/neuropsychiatric NMS and PDQuestionnaire-8 outcome. CONCLUSIONS: This is the first comparison of quality of life, nonmotor. and motor outcomes in PD patients undergoing STN-DBS, IJLI, and APO in a real-life cohort. Distinct effect profiles were identified for each treatment option. Our results highlight the importance of holistic nonmotor and motor symptoms assessments to personalize treatment choices. © 2019 International Parkinson and Movement Disorder Society.

Quality of life outcome after subthalamic stimulation in Parkinson's disease depends on age.

OBJECTIVE: The purpose of this study was to investigate how quality of life outcome after bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinson's disease (PD) depends on age. METHODS: In this prospective, open-label, multicenter study including 120 PD patients undergoing bilateral STN-DBS, we investigated the PDQuestionnaire-8 (PDQ-8), Unified PD Rating Scale-III, Scales for Outcomes in PD-motor examination, complications, activities of daily living, and levodopa equivalent daily dose preoperatively and at 5 months follow-up. Significant changes at follow-up were analyzed with Wilcoxon signed-rank test and Bonferroni correction for multiple comparisons. To explore the influence of age post hoc, the patients were classified into 3 age groups (≤59, 60-69, ≥70 years). Intragroup changes were analyzed with Wilcoxon signed-rank and intergroup differences with Kruskal-Wallis tests. The strength of clinical responses was evaluated using effect size. RESULTS: The PDQuestionnaire-8, Scales for Outcomes in PD-motor complications, activities of daily living, and levodopa equivalent daily dose significantly improved in the overall cohort and all age groups with no significant intergroup differences. However, PDQuestionnaire-8 effect sizes for age groups ≤59, 60 to 69, and ≥70 years, respectively, were strong, moderate, and small. Furthermore, PDQuestionnaire-8 domain analyses revealed that all domains except cognition and emotional well-being significantly improved in patients aged ≤59 years, whereas only communication, activities of daily living, and stigma improved in patients aged 60-69 years, and activities of daily living and stigma in patients aged ≥70 years. CONCLUSIONS: Although quality of life, motor complications, and activities of daily living significantly improved in all age groups after bilateral STN-DBS, the beneficial effect on overall quality of life was more pronounced and affected a wider range of quality of life domains in younger patients. © 2017 International Parkinson and Movement Disorder Society.

Nonmotor symptoms evolution during 24 months of bilateral subthalamic stimulation in Parkinson's disease.

BACKGROUND: The objective of this study was to investigate 24-month of effects of bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) on nonmotor symptoms in Parkinson's disease (PD). METHODS: In this prospective, observational, multicenter, international study including 67 PD patients undergoing bilateral STN-DBS, we examined the Non-motor Symptom Scale, Non-Motor Symptoms Questionnaire, Parkinson's Disease Questionnaire-8, Scales for Outcomes in Parkinson's Disease-motor examination, -activities of daily living, and -complications, and levodopa-equivalent daily dose preoperatively and at 5 and 24-month of follow-up. After checking distribution normality, longitudinal outcome changes were investigated with Friedman tests or repeated-measures analysis of variance and Bonferroni correction for multiple comparisons using multiple tests. Post hoc, Wilcoxon signed rank t tests were computed to compare visits. The strength of clinical responses was analyzed using effect size. Explorative Spearman correlations of change scores from baseline to 24-month follow-up were calculated for all outcomes. RESULTS: The Non-motor Symptom Scale and all other outcome parameters significantly improved from baseline to the 5-month follow-up. From 5 to 24-month, partial decrements in these gains were found. Nonetheless, comparing baseline with 24-month follow-up, significant improvements were observed for the Non-motor Symptom Scale (small effect), Scales for Outcomes in PD-motor examination showed a moderate effect, and Scales for Outcomes in Parkinson's Disease-complications and levodopa-equivalent daily dose showed large effects. Non-motor Symptom Scale change scores from baseline to 24-month follow-up correlated significantly with Parkinson's Disease Questionnaire-8, Scales for Outcomes in Parkinson's Disease-activities of daily living, and -motor complications change scores. CONCLUSIONS: This study provides evidence of beneficial effects of bilateral STN-DBS on nonmotor symptoms at 24-month follow-up. The extent of nonmotor symptom improvement was directly proportionate to improvements in quality of life, activities of daily living, and motor complications. This study underlines the importance of nonmotor symptoms for holistic assessments of DBS outcomes. © 2018 International Parkinson and Movement Disorder Society.

Subthalamic Stimulation Improves Quality of Life of Patients Aged 61 Years or Older With Short Duration of Parkinson's Disease.

OBJECTIVE: The optimal timing of subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinson's disease (PD) is a topic of ongoing debate. In patients with short disease duration an improvement of quality of life (QoL) has been demonstrated for patients aged younger than 61 years. However, this has not been systematically investigated in older patients yet. We hypothesized that patients aged 61 years or older experience a significant QoL improvement after STN-DBS with no difference in effect sizes for groups of patients with short and longer disease duration. MATERIALS AND METHODS: From four centers (Cologne, London, Manchester, Venice) we identified "older patients" aged 61 years or older with short (≤8 years) or longer disease duration and compared QoL, motor impairment, complications, medication requirements, and Mini-Mental State Examination (MMSE) on baseline and five months after surgery. RESULTS: Mean age/disease duration in 21 subjects with shorter disease duration were 65.5/6.3 years compared to 66.8/14.6 in 33 subjects with longer disease duration. The short disease duration group was affected by less baseline motor complications (p = 0.002). QoL in the short/longer disease duration group improved by 35/20% (p = 0.010/p = 0.006), motor complications by 40/44% (p = 0.018/p < 0.001), and medication requirements by 51/49% (both p < 0.001). MMSE remained unchanged in both groups. CONCLUSION: Patients aged 61 years or older benefited from STN-DBS regardless of short (≤8 years) or longer (>8 years) disease duration. Our results contribute to the debate about DBS selection criteria and timing and call for prospective confirmation in a larger cohort.

EuroInf: a multicenter comparative observational study of apomorphine and levodopa infusion in Parkinson's disease.

Subcutaneous apomorphine infusion (Apo) and intrajejunal levodopa infusion (IJLI) are two treatment options for patients with advanced Parkinson's disease (PD) and refractory motor complications, with varying cost of treatment. There are no multicenter studies comparing the effects of the two strategies. This open-label, prospective, observational, 6-month, multicenter study compared 43 patients on Apo (48.8% males, age 62.3 ± 10.6 years; disease duration: 14 ± 4.4 years; median H & Y stage 3; interquartile range [IQR]: 3-4) and 44 on IJLI (56.8% males, age 62.7 ± 9.1 years; disease duration: 16.1 ± 6.7 years; median H & Y stage 4; IQR, 3-4). Cohen's effect sizes (≥0.8 considered as large) were "large" with both therapies with respect to total motor, nonmotor, and quality-of-life scores. The Non-Motor Symptoms Scale (NMSS) with Apo showed moderate improvement, whereas sleep/fatigue, gastrointestinal, urinary, and sexual dimensions of the NMSS showed significantly higher improvement with IJLI. Seventy-five percent on IJLI improved in their quality-of-life and nonmotor symptoms (NMS), whereas in the Apo group, a similar proportion improved in quality of life, but 40% in NMS. Adverse effects included peritonitis with IJLI and skin nodules on Apo. Based on this open-label, nonrandomized, comparative study, we report that, in advanced Parkinson's patients, both IJLI and Apo infusion therapy appear to provide a robust improvement in motor symptoms, motor complications, quality-of-life, and some NMS. Controlled, randomized studies are required.

Impulse control disorders in Parkinson's disease: decreased striatal dopamine transporter levels.

OBJECTIVE: Impulse control disorders are commonly associated with dopaminergic therapy in Parkinson's disease (PD). PD patients with impulse control disorders demonstrate enhanced dopamine release to conditioned cues and a gambling task on [(11)C]raclopride positron emission tomography (PET) imaging and enhanced ventral striatal activity to reward on functional MRI. We compared PD patients with impulse control disorders and age-matched and gender-matched controls without impulse control disorders using [(123)I]FP-CIT (2ß-carbomethoxy-3ß-(4-iodophenyl)tropane) single photon emission computed tomography (SPECT), to assess striatal dopamine transporter (DAT) density. METHODS: The [(123)I]FP-CIT binding data in the striatum were compared between 15 PD patients with and 15 without impulse control disorders using independent t tests. RESULTS: Those with impulse control disorders showed significantly lower DAT binding in the right striatum with a trend in the left (right: F(1,24)=5.93, p=0.02; left: F(1,24)=3.75, p=0.07) compared to controls. CONCLUSIONS: Our findings suggest that greater dopaminergic striatal activity in PD patients with impulse control disorders may be partly related to decreased uptake and clearance of dopamine from the synaptic cleft. Whether these findings are related to state or trait effects is not known. These findings dovetail with reports of lower DAT levels secondary to the effects of methamphetamine and alcohol. Although any regulation of DAT by antiparkinsonian medication appears to be modest, PD patients with impulse control disorders may be differentially sensitive to regulatory mechanisms of DAT expression by dopaminergic medications.

Musculoskeletal pain in Parkinson's disease: Association with dopaminergic deficiency in the caudate nucleus.

BACKGROUND: Musculoskeletal (MSK) pain affects over 80% of People with Parkinson's (PD, PwP) and may, in part, be dopaminergic in origin, as dopaminergic medication often leads to its relief. METHODS: PwP who underwent striatal dopamine transporter visualization with a radiopharmaceutical DaTscan™ (123 I-Ioflupane Injection) using a single-photon emission computed tomography (SPECT) as a part of their clinical-diagnostic work up were enrolled in the "Non-motor International Longitudinal Study" (NILS; UK National Institute for Health Research Clinical Research Network Number 10084) and included in this cross-sectional analysis. The association between specific DaTscan binding ratios for each striatum, the caudate nucleus and putamen and clinical ratings for MSK pain (assessed using the King's Parkinson's Disease Pain Scale (KPPS)) were analysed. RESULTS: 53 PwP (30.2% female; age: 63.79 ± 11.31 years; disease duration (DD): 3.32 (0.31-14.41) years; Hoehn & Yahr stage (H&Y): 2 (1-4); Levodopa Equivalent Daily Dose (LEDD): 543.08 ± 308.94 mg) were assessed and included in this analysis. MSK pain was highly prevalent (71.7% of all participants, mean KPPS Item 1 score 5.34 ± 4.76) and did not correlate with the motor symptoms burden (SCOPA-Motor total score; p = 0.783) but showed a significant correlation with quality of life (PDQ-8, rs = 0.290, p = 0.035). z-scores for the caudate nucleus (Exp (B) = 0.367, 95% CI for Exp (B) 0.148-0.910, p = 0.031) and striatum (Exp (B) = 0.338, 95% CI for Exp (B) 0.123-0.931, p = 0.036), adjusted for DD, H&Y and LEDD, were significant determinants of MSK pain. CONCLUSIONS: Our findings suggest an association between MSK pain in PwP and the severity of dopaminergic deficiency in the caudate nucleus. SIGNIFICANCE: In People with Parkinson's, musculoskeletal pain does not arise simply as a direct sequel to motor symptoms-instead, it is linked to the severity of dopaminergic depletion in the caudate nucleus.

Validation study of the Japanese version of the King's Parkinson's Disease Pain Scale and the King's Parkinson's Disease Pain Questionnaire.

INTRODUCTION: The King's Parkinson's Disease Pain Scale (KPPS)/King's Parkinson's Disease Pain Questionnaire (KPPQ) was developed as a tool to quantitatively assess pain in patients with Parkinson's disease (PwPD). Here, we conducted a Japanese multicenter validation study to verify the reliability of KPPS/KPPQ in Japanese PwPD. METHODS: PwPD, ≥20 years, with unexplained pain were included; those with a definitive primary cause of pain other than PD were excluded. A total of 151 patients who fulfilled the criteria were analyzed, and test-retest reliability was investigated in 25 individuals. RESULTS: The 151 patients included 101 women (66.9 %); mean age 68.3 ± 9.9 years, mean disease duration 9.2 ± 5.2 years. The most frequent pain type in the KPPS classification was musculoskeletal pain (82.8 %). There was a positive correlation between KPPS total score and the Non-Motor Symptoms Scale (NMSS) total score, NMSS item 27, the Parkinson's disease sleep scale-version 2 (PDSS-2) total score, PDSS-2 item 10, the Parkinson's Disease Questionnaire-8 (PDQ-8) summary index and PDQ-8 item 7. Cronbach's alpha of KPPS was 0.626 (0.562-0.658) and the intraclass correlation coefficient of test-retest reliability was 0.740. Cronbach's alpha of KPPQ was 0.660 (0.617-0.705) and a test-retest reliability of kappa coefficient was 0.593 (0.0-1.0). CONCLUSIONS: KPPS correlated well with other scales for assessing pain. KPPS correlated well with patients' quality of life, non-motor symptoms, and sleep disturbances. The reproducibility of KPPS/KPPQ makes it suitable for continuous evaluation of the same patient. On the other hand, the internal consistency of KPPS/KPPQ is rather low.

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.

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.

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.

Motor and nonmotor complications in Parkinson's disease: an argument for continuous drug delivery?

The complications of long-term levodopa therapy for Parkinson's disease (PD) include motor fluctuations, dyskinesias, and also nonmotor fluctuations-at least equally common, but less well appreciated-in autonomic, cognitive/psychiatric, and sensory symptoms. In seeking the pathophysiologic mechanisms, the leading hypothesis is that in the parkinsonian brain, intermittent, nonphysiological stimulation of striatal dopamine receptors destabilizes an already unstable system. Accordingly, a major goal of PD treatment in recent years has been the attainment of continuous dopaminergic stimulation (CDS)-or, less theoretically (and more clinically verifiable), continuous drug delivery (CDD). Improvements in the steadiness of the plasma profiles of various dopaminergic therapies may be a signal of progress. However, improvements in plasma profile do not necessarily translate into CDS, or even into CDD to the brain. Still, it is reassuring that clinical studies of approaches to CDD have generally been positive. Head-to-head comparative trials have often failed to uncover evidence favoring such approaches over an intermittent therapy. Nevertheless, the findings among recipients of subcutaneous apomorphine infusion or intrajejunal levodopa/carbidopa intestinal gel suggest that nonmotor PD symptoms or complications may improve in tandem with motor improvement. In vivo receptor binding studies may help to determine the degree of CDS that a dopaminergic therapy can confer. This may be a necessary first step toward establishing whether CDS is, in fact, an important determinant of clinical efficacy. Certainly, the complexities of optimal PD management, and the rationale for an underlying strategy such as CDS or CDD, have not yet been thoroughly elucidated.