Screening for Problematic Internet Use May Help Identify Impulse Control Disorders in Parkinson's Disease.

BACKGROUND: Impulse control disorders in Parkinson's disease (PD) represent emerging problems with potentially devastating consequences. The standard screening methods for impulse control disorders are clinically imperfect. Although it is rarely reported, many patients utilize the Internet to fulfill their compulsive behaviors because of its easy accessibility. We designed a study to test the hypothesis that an active screening for excessive Internet use and Internet addiction might improve the sensitivity of identification of impulse control disorders. METHODS: The standard screening method included the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease and the modified Minnesota Impulsive Disorders Interview. In the second round, the Problematic Internet Use Questionnaire was also assessed for detecting excessive Internet use. RESULTS: While the standard approach identified 19 patients out of 106 (17.9%) with any type of impulse control disorders, screening for the problematic Internet use detected 29 patients with impulse control disorders (27.4%) having significantly better efficacy over the standard method (p = 0.004, the McNemar test). CONCLUSIONS: Our study suggests that the screening for problematic Internet use by the Problematic Internet Use Questionnaire is an effective, feasible, and easy-to-use add-on method for identifying PD patients with impulse control disorders more efficiently and probably at earlier stages.

Minimal clinically important difference for the historic parts of the Unified Dyskinesia Rating Scale.

BACKGROUND: Motor complications represent an important clinical problem in the treatment of Parkinson's disease (PD). The Motor Complications Part of the Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale (MDS-UPDRS Part IV) and the Unified Dyskinesia Rating Scale (UDysRS) are among the most reliable instruments to evaluate these problems. The minimal clinically important difference thresholds are the smallest changes in the outcome measures that are clinically meaningful. AIMS: The aim of our study was to calculate the minimal clinically important difference thresholds for the MDS-UPDRS Part IV and the historic parts of the UDysRS. METHODS: A total of 1044 paired investigations of 436 patients were analyzed. Changes in the respective outcome measures (MDS-UPDRS Part IV, UDysRS Parts I and II) were compared to the Patient-rated Global Impression of Improvement scores (anchors). Subsequently, we applied receiver-operating characteristic analysis to ascertain the MCID thresholds with optimal sensitivity and specificity. RESULTS: Any improvement greater than 2.1 points or any worsening greater than 1.8 points on UDysRS Part I represents a minimal, yet clinically meaningful change. In reference to UDysRS Part II, the smallest changes considered clinically relevant are 1.8 and 1.7 points for improvement and deterioration, respectively. The thresholds for the MDS-UPDRS Part IV are 0.9 points for improvement and 0.8 points for worsening. CONCLUSIONS: Our estimates may allow the judgment of the clinical relevance of numeric changes in the dyskinesia scales.

Comparing Sensitivity and Specificity of Addenbrooke's Cognitive Examination-I, III and Mini-Addenbrooke's Cognitive Examination in Parkinson's Disease.

BACKGROUND: Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by numerous motor and nonmotor symptoms. Neurocognitive disorders (NCD) are one of the most troublesome problems and their diagnosis is often challenging. METHODS: We compared the sensitivity and specificity of several versions of Addenbrooke Cognitive Examination (ACE, ACE-III, and Mini-ACE) on 552 subjects with PD. Normal cognition, mild and major NCD were judged in accordance with the respective criteria of the Diagnostic and Statistical Manual of Mental Disorders 5th edition. Subsequently, we applied the receiver operation characteristic (ROC) analysis in comparison of different education levels. RESULTS: For subjects with education level 0-8 and 9-12 years, the ACE-III had the best discriminating capabilities for mild NCD (cut-off scores: 83.5 and 85.5 points, respectively), while Mini-ACE was the best for subjects having education > 12 years (cut-off score: 25.5 points). For detecting major NCD, ACE-III had the best diagnostic accuracy in all levels of education (cut-off scores: 70.5, 77.5, and 78.5 points for subjects having education level 0-8, 9-12, and >12 years, respectively). CONCLUSION: ACE-III and its nested version, the Mini-ACE, had the best screening abilities for detecting mild and major NCD in PD.

Are the MDS-UPDRS-Based Composite Scores Clinically Applicable?

BACKGROUND: The International Parkinson and Movement Disorder Society-sponsored UPDRS (MDS-UPDRS) is a powerful clinical outcome measure. OBJECTIVES: To evaluate the feasibility of various MDS-UPDRS-based composite scores and determine their minimal clinically important difference threshold values. METHODS: Overall, 1,113 paired investigations of 452 patients were reviewed implementing three different techniques simultaneously. RESULTS: Based on the ordinal regression modeling, the MDS-UPDRS II+III, MDS-UPDRS I+II+III, and the total score of MDS-UPDRS are clinically applicable outcome measures. Any improvement greater than 4.9 points or any worsening more than 4.2 points on MDS-UPDRS II+III represent a minimal, yet clinically meaningful, change. In reference to MDS-UPDRS I+II+III, the smallest changes considered clinically relevant were 6.7 and 5.2 points for improvement and deterioration, respectively. The thresholds for the total score of MDS-UPDRS were 7.1 points for improvement and 6.3 points for worsening. CONCLUSIONS: Our findings support the application of various MDS-UPDRS-based composite scores. © 2018 International Parkinson and Movement Disorder Society.

Prevalence of Anxiety among Hungarian Subjects with Parkinson's Disease.

Although anxiety is one of the most frequent symptoms of Parkinson's disease (PD), only a few clinical tools can efficiently and reliably detect its presence. The aim of the present study was to validate the Hungarian patient-rated version of Parkinson Anxiety Scale (PAS). A total of 190 PD patients were enrolled into the clinimetric validation phase of the study and another 590 participated in the cross-sectional screening phase. The presence of anxiety disorder was diagnosed based on the Diagnostic and Statistical Manual of Mental Disorders criteria. The cutoff value for PAS which best discriminated the presence of anxiety from the absence was 12.5 points (sensitivity of 88.6%, specificity of 79.9). The area under the curve was 0.847 whereas the ROC analysis yielded the statistical significance level (p < 0.001). The optimal threshold values for mild (Hoehn and Yahr Stage, HYS 1 and 2), moderate (HYS 3), and severe (HYS 4 and 5) disease stages were 10.5, 12.5, and 13.5 points, respectively. Based on the general threshold anxiety occurred in 35.8% of the patients (persistent anxiety: 29.2%, episodic anxiety: 20.7%, and avoidant anxiety disorder: 16.8%). We demonstrate that the PAS is a valid, highly reliable, and sensitive tool for assessing anxiety.

How Efficient Is Subthalamic Deep Brain Stimulation in Reducing Dyskinesia in Parkinson's Disease?

BACKGROUND: Dyskinesia is among the most troublesome symptoms of advanced Parkinson's disease (PD). The recently developed Unified Dyskinesia Rating Scale (UDysRS) can simultaneously measure several subjective and objective aspects of dyskinesia, irrespective of the other motor symptoms of PD. Despite the advantages of deep brain stimulation (DBS), previous studies on DBS have not used the UDysRS yet. METHODS: In this prospective study, 71 consecutive patients undergoing DBS implantation were enrolled. Patients were examined twice: 1 week prior to the DBS implantation (baseline) and 12 months postoperatively. The severity of PD-related symptoms was assessed by the Movement Disorders Society Unified PD Rating Scale (MDS-UPDRS). The presence and severity of dyskinesia were specifically measured by the UDysRS and patient diaries. RESULTS: At baseline, all 71 patients had dyskinesia, but 1 year after DBS implantation, 25 patients were dyskinesia-free, and an additional 19 had only mild dyskinesia. The total score on the UDysRS decreased from 38.0 ± 17.8 to 10.8 ± 13.0 (p < 0.001). Besides this, all parts of the UDysRS showed significant improvement after STN DBS treatment, and the magnitude of these changes had a large effect size. The total score of MDS-UPDRS improved from 76.5 ± 24.3 to 60.4 ± 21.4 points (p < 0.001). CONCLUSIONS: Based on our results, UDysRS can reliably detect improvements in dyskinesia after DBS implantation.

Changes in Quality of Life in Parkinson's Disease: How Large Must They Be to Be Relevant?

BACKGROUND: Minimal clinically important difference (MCID) is the smallest change in an outcome, which a patient identifies as meaningful. Although the 2 most frequently applied Parkinson's disease (PD) "quality of life" questionnaires (the PDQ-39 and PDQ-8) provide encouragingly similar results, their MCID thresholds appear to be vastly different. Our aim was to calculate the MCID estimates for both PDQ-39 and PDQ-8 Summary Indices (PDQ-39-SI and PDQ-8-SI) by the utilization of both anchor- and distribution-based techniques. METHODS: Nine hundred eighty-five paired investigations of 365 patients were included. Three different techniques were used simultaneously to calculate the MCID values. RESULTS: First, we replicated the previously published results demonstrating how both PDQ-39-SI and PDQ-8-SI provide similar values and respond in a similar way to changes. Subsequently, we calculated the MCID thresholds. The most optimal estimates for MCID thresholds for PDQ-39-SI were -4.72 and +4.22 for detecting minimal clinically important improvement and worsening. For PDQ-8-SI, these estimates were -5.94 and +4.91 points for detecting minimal clinically important improvement and worsening respectively. CONCLUSIONS: Our study is the first one that directly compared the MCID estimates for both PDQ-39-SI and PDQ-8-SI on a large pool of patients including all disease severity stages. These MICD estimates varied across PD severity.

Minimal clinically important differences for the experiences of daily living parts of movement disorder society-sponsored unified Parkinson's disease rating scale.

BACKGROUND: The minimal clinically important difference is the smallest change of scores clinically meaningful to patients. OBJECTIVES: We aimed to calculate these threshold values in association with the International Parkinson and Movement Disorder Society UPDRS (MDS-UPDRS) Parts I and II and to evaluate the feasibility of the composite score of Part I and II (MDS-UPDRS I+II) as an outcome. METHODS: Nine hundred eighty-five paired investigations of 365 patients were reviewed, implementing three different techniques simultaneously. RESULTS: Based on the ordinal regression modeling, the MDS-UPDRS I+II score is an applicable outcome measure. Any improvement greater than 2.64 points or any worsening more than 2.45 points on MDS-UPDRS Part I represent a minimal, yet clinically meaningful change. In reference to Part II, the smallest changes considered clinically relevant were 3.05 and 2.51 points for improvement and deterioration, respectively. The thresholds for MDS-UPDRS I+II were 5.73 points for improvement and 4.70 points for worsening. CONCLUSIONS: Our minimal clinically important difference thresholds can be utilized in clinical practice in judging clinical relevance. © 2016 International Parkinson and Movement Disorder Society.

Levodopa/carbidopa intestinal gel can improve both motor and non-motor experiences of daily living in Parkinson's disease: An open-label study.

BACKGROUND: Levodopa/carbidopa intestinal gel therapy (LCIG) can efficiently improve several motor and non-motor symptoms of advanced Parkinson's disease (PD). The recently developed Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale (MDS-UPDRS) improved the original UPDRS making it a more robust tool to evaluate therapeutic changes. However, previous studies have not used the MDS-UPDRS and the Unified Dyskinesia Rating Scale (UDysRS) to assess the efficacy of LCIG. OBJECTIVES: Our aim was to determine if the MDS-UPDRS and UDysRS could detect improvement in the experiences of daily living following 1-year LCIG treatment. METHODS: In this prospective, multicenter, open-label study, 34 consecutive patients undergoing LCIG treatment were enrolled. Patients were examined twice: prior to LCIG initiation and 12 months later. Impact of PD-related symptoms and dyskinesia was assessed by the MDS-UPDRS and UDysRS. RESULTS: Non-motor Experiences of Daily Living part of MDS-UPDRS improved from 20 (median, interquartile-range, IQR:14-23) to 16 points (median, IQR:12-20, p = 0.044) and the Motor Experiences of Daily Living ameliorated from 24 (median, IQR:20-29) to 18 points (median, IQR:13-25, p = 0.025). Health-related quality of life, measured by PDQ-39, also improved from 35.4 (median, IQR:26.9-50.3) to 27.0 (median, IQR:21.3-31.4) points (p = 0.003). The total score of UDysRS decreased from 47 (median, IQR:36-54) to 34 (median, IQR:21-45) points (p = 0.003). CONCLUSIONS: As far as the authors are aware of, our paper is the first to evaluate the impact of LCIG on dyskinesia by the means of UDysRS. Changes in MDS-UPDRS and UDysRS confirm that LCIG treatment can efficiently improve experiences of daily living in advanced PD.

Independent validation of the Quality of Life in Essential Tremor Questionnaire (QUEST).

BACKGROUND AND PURPOSE: Quality of Life in Essential Tremor Questionnaire (QUEST) was specially developed for essential tremor population to measure the health-related quality of life. Besides the development of the Hungarian version, we performed an independent testing of the scale adding further information on its clinimetric properties. METHODS: In this study 133 ET patients treated at University of Pécs, Hungary, were enrolled. Besides QUEST, we assessed Patient's Global Impression-Severity (PGI-S) and Fahn-Tolosa-Marin Tremor Rating Scales. After the independent validation in accordance to the Classic Theory of Tests, we evaluated cut-off values for detecting clinically meaningful ET-related disabilities based on receiver operating characteristics analysis. RESULTS: Cronbach's a was 0.897. QUEST demonstrated high convergent validity with PGI and divergent validity with disease-duration, positive family history, need for deep brain stimulation surgery, and the presence of depression and anxiety. Presence of moderate ET-related disabilities was identified by scores > 11.25 points on QUEST-SI (sensitivity: 77.4%, specificity: 83.3%); whereas scores > 20.35 points indicated severe ET-related disabilities (sensitivity: 83.3%, specificity: 59.1%). CONCLUSION: We demonstrated that the fundamental clinimetric properties of the QUEST are satisfactory.

Impact of Sex on the Nonmotor Symptoms and the Health-Related Quality of Life in Parkinson's Disease.

Background. Female Parkinson's disease (PD) patients seem to experience not only more severe motor complications and postural instability but also more pronounced depression, anxiety, pain, and sleep disturbances. Objective. The aim of the present study was to evaluate the role of sex as a possible independent predictor of HRQoL in PD. Methods. In this cross-sectional study, 621 consecutive patients treated at the University of Pécs were enrolled. Severity of PD symptoms was assessed by MDS-UPDRS, UDysRS, Non-Motor Symptoms Scale, PDSS-2, Hamilton Anxiety Scale, Montgomery-Asberg Depression Rating Scale, Lille Apathy Rating Scale, and Addenbrooke Cognitive Examination. HRQoL was assessed by PDQ-39 and EQ-5D. Multiple regression analysis was performed to estimate the PDQ-39 and EQ-5D index values based on various clinical factors. Results. Although females received significantly lower dosage of levodopa, they had significantly more disabling dyskinesia and worse postural instability. Anxiety, pain, sleep disturbances, and orthostatic symptoms were more frequent among females while sexual dysfunction, apathy, and daytime sleepiness were more severe among males. Women had worse HRQoL than men (EQ-5D index value: 0.620 ± 0.240 versus 0.663 ± 0.229, p = 0.025, and PDQ-39 SI: 27.1 ± 17.0 versus 23.5 ± 15.9, p = 0.010). Based on multiple regression analysis, sex was an independent predictor for HRQoL in PD. Conclusions. Based on our results, female sex is an independent predictor for having worse HRQoL in PD.

High-Frequency Repetitive Transcranial Magnetic Stimulation Can Improve Depression in Parkinson's Disease: A Randomized, Double-Blind, Placebo-Controlled Study.

BACKGROUND: A recent evidence-based guideline demonstrated that bilateral repetitive transcranial magnetic stimulation (rTMS) over the motor cortex (M1) can improve motor symptoms of Parkinson's disease (PD). We conducted a randomized, double-blind, placebo-controlled study to evaluate the impact of bilateral M1 rTMS on depression in PD. METHODS: Forty-six patients with PD and mild-to-moderate depression were randomly assigned to active (n = 23) and sham (n = 23) rTMS. Two patients in the sham group did not complete the protocol because of reasons unrelated to the study. High-frequency rTMS was applied over the primary motor cortex bilaterally for 10 days. An investigator blinded to the treatment performed three video-taped examinations on each patient: before stimulation (baseline), and 1 day (short-term effect) and 30 days after the treatment session ended (long-term effect). The primary end point was the changes in depression, while secondary end points included health-related quality of life scales and Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS). RESULTS: In the actively treated group, not only did the severity of depression improve (from 17 to 7 points, Montgomery-Åsberg Depression Rating Scale, median values, p < 0.001), but also the health-related quality of life (from 25.4 to 16.9 points, PDQ-39 summary index, median values, p < 0.001). Besides, we could also demonstrate an improvement in MDS-UPDRS Motor Examination (from 26 to 20 points, median values, p < 0.05). In the sham-treated group, none of the examined tests and scales improved significantly after treatment. CONCLUSIONS: Our results demonstrate the beneficial effects of high-frequency bilateral M1 rTMS on depression and health-related quality of life in PD. However, this effect of rTMS should also be confirmed in patients with severe depression by further clinical trials.

Lille Apathy Rating Scale and MDS-UPDRS for Screening Apathy in Parkinson's Disease.

BACKGROUND: Apathy is a syndrome characterized primarily by lack of motivation which may be associated with cognitive, affective and behavioral changes. Although the Lille Apathy Scale (LARS) has been extensively utilized in PD for detecting apathy and testing the effectiveness of specific therapeutic interventions, the highly variable cut-off values (between -11 and -22 points) ensures the applicability of the LARS degree of difficulty as a superb screening tool. OBJECTIVE: The aim of this study is to determine more reliable threshold values based on the neuropsychiatric status of patients. METHODS: Depression was assessed utilizing the Montgomery-Asberg Depression Rating Scale and neurocognitive status by Addenbrooke's Cognitive Examination. The presence of apathy was assessed by the proposed diagnostic criteria of Drijgers et al, and graded by both LARS and the 'Apathy' item of MDS-UPDRS. RESULTS: Based on multivariate regression analysis, we revealed the neurocognitive status, severity of depression, and also gender while applying dosage of dopamine agonists to determine the degree of patient apathy. Based on whether or not depression and neurocognitive disorders were indeed present, we established four different threshold values for the LARS: patients with normal cognition and without depression: -22.5; patients with normal cognition and with depression: -18.5; patients with NCD and without depression: -19.5; patients with NCD and with depression: -14.5. CONCLUSIONS: The LARS and the 'Apathy' item of MDS-UPDRS were confirmed to be potentially operational, beneficial and easy-to-assess instruments for detecting apathy syndrome in PD. However, there is no universal threshold value for the LARS suitable in all types of Parkinson's patients.

Minimal Clinically Important Difference on Parkinson's Disease Sleep Scale 2nd Version.

Background and Aims. The aim of the present study was to determine the estimates of minimal clinically important difference for Parkinson's Disease Sleep Scale 2nd version (PDSS-2) total score and dimensions. Methods. The subject population consisted of 413 PD patients. At baseline, MDS-UPDRS, Hoehn-Yahr Scale, Mattis Dementia Rating Scale, and PDSS-2 were assessed. Nine months later the PDSS-2 was reevaluated with the Patient-Reported Global Impression Improvement Scale. Both anchor-based techniques (within patients' score change method and sensitivity- and specificity-based method by receiver operating characteristic analysis) and distribution-based approaches (effect size calculations) were utilized to determine the magnitude of minimal clinically important difference. Results. According to our results, any improvements larger than -3.44 points or worsening larger than 2.07 points can represent clinically important changes for the patients. These thresholds have the effect size of 0.21 and -0.21, respectively. Conclusions. Minimal clinically important differences are the smallest change of scores that are subjectively meaningful to patients. Studies using the PDSS-2 as outcome measure should utilize the threshold of -3.44 points for detecting improvement or the threshold of 2.07 points for observing worsening.

Deep Brain Stimulation Can Preserve Working Status in Parkinson's Disease.

Objectives. Our investigation aimed at evaluating if bilateral subthalamic deep brain stimulation (DBS) could preserve working capability in Parkinson's disease (PD). Materials. We reviewed the data of 40 young (<60 year-old) PD patients who underwent DBS implantation and had at least 2 years of follow-up. Patients were categorized based on their working capability at time of surgery: "active job" group (n = 20) and "no job" group (n = 20). Baseline characteristics were comparable. Quality of life (EQ-5D) and presence of active job were evaluated preoperatively and 2 years postoperatively. Results. Although similar (approximately 50%) improvement was achieved in the severity of motor and major nonmotor symptoms in both groups, the postoperative quality of life was significantly better in the "active job" group (0.687 versus 0.587, medians, p < 0.05). Majority (80%) of "active job" group members were able to preserve their job 2 years after the operation. However, only a minimal portion (5%) of the "no job" group members was able to return to the world of active employees (p < 0.01). Conclusions. Although our study has several limitations, our results suggest that in patients with active job the appropriately "early" usage of DBS might help preserve working capability and gain higher improvement in quality of life.

[Diagnosis and therapy for neurocognitive disorders in Parkinson's disease]. / Neurokognitív zavarok diagnosztizálási és kezelési lehetoségei Parkinson-kórban.

In the present review the recent developments in the definitions of neurocognitive disorders associated with Parkinson's disease are summarized including the possibilities for screening and treating. For a long time, the recognition of neurocognitive disorders associated in patients with Parkinson's disease was unsatisfactory due to the heterogeneity of definitions. The recently developed Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) introduced the definitions of mild and major neurocognitive disorders instead of mild cognitive impairment and dementia. The new DSM-5 definitions are clinically well applicable; therefore, the validation of the most frequent screening tests (Mini-Mental State Examination; Addenbrooke's Cognitive Examination; Montreal Cognitive Assessment; Mattis Dementia Rating Scale) is warranted. Based on a Hungarian sample of 295 patients with Parkinson's disease, the cut-off scores having the best discriminative values are highly dependent on education years (Addenbrooke's Cognitive Examination: 0-8 years of education: 82.5 points, 9-12 years of education: 83.5 points, and ≥13 years of education: 84.5 points; Mini-Mental State Examination: 26.5-27.5-28.5 points, Montreal Cognitive Assessment: 23.5-24.5-24.5 points, Mattis Dementia Rating Scale: 138.5-139.5-139.5 points, respectively).

Screening Mild and Major Neurocognitive Disorders in Parkinson's Disease.

INTRODUCTION: Among the nonmotor features of Parkinson's disease (PD), cognitive impairment is one of the most troublesome problems. New diagnostic criteria for mild and major neurocognitive disorder (NCD) in PD were established by Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5). The aim of our study was to establish the diagnostic accuracy of widely used screening tests for NCD in PD. METHODS: Within the scope of our study we evaluated the sensitivity and specificity of different neuropsychological tests (Addenbrooke's Cognitive Examination (ACE), Mattis Dementia Rating Scale (MDRS), Mini Mental State Examination (MMSE), and Montreal Cognitive Assessment (MoCA)) in 370 PD patients without depression. RESULTS: MoCA and ACE feature the finest diagnostic accuracy for detecting mild cognitive disorder in PD (DSM-5) at the cut-off scores of 23.5 and 83.5 points, respectively. The diagnostic accuracy of these tests was 0.859 (95% CI: 0.818-0.894, MoCA) and 0.820 (95% CI: 0.774-0.859, ACE). In the detection of major NCD (DSM-5), MoCA and MDRS tests exhibited the best diagnostic accuracy at the cut-off scores of 20.5 and 132.5 points, respectively. The diagnostic accuracy of these tests was 0.863 (95% CI: 0.823-0.897, MoCA) and 0.830 (95% CI: 0.785-0.869, MDRS). CONCLUSION: Our study demonstrated that the MoCA may be the most suitable test for detecting mild and major NCD in PD.

Bilateral Subthalamic Stimulation can Improve Sleep Quality in Parkinson's Disease.

BACKGROUND: Sleep problems are among the most common non-motor symptoms of Parkinson's disease (PD). The PD Sleep Scale 2nd version (PDSS-2) improved the original PDSS by adding more items on different aspects of sleep problems, making it a more robust tool to evaluate the severity of sleep disturbances. However, previous studies on deep brain stimulation (DBS) have not used the PDSS-2. OBJECTIVE: To determine if the PDSS-2 could detect improvement reliably in sleep problems after bilateral subthalamic nucleus DBS for PD. METHODS: In this prospective study, 25 consecutive patients undergoing DBS implantation were enrolled. Patients were examined twice: 1 week prior to the DBS implantation (baseline) and 12 months postoperatively. Severity of PD symptoms were assessed by the Movement Disorders Society Unified PD Rating Scale (MDS-UPDRS) and the Non-Motor Symptoms Scale (NMSS). Presence and severity of sleep disturbances were specifically measured by PDSS-2. RESULTS: Total score of MDS-UPDRS improved from 81 (median, interquartile-range: 63-103) to 55 points (median, IQR: 46-75, p <  0.001). Health-related quality of life, measured by PDQ-39, also improved from 29 (IQR: 18-40) to 15 (IQR: 9-28) points (p = 0.002). Most domains of NMSS also improved. At baseline 13 patients reported sleep problems, but 1 year after DBS implantation only 3 did (p = 0.012). Although only 6 out of 15 items showed a significant decrease after DBS implantation, the total score of PDSS-2 decreased from 24 (IQR: 17-32) to 10 (IQR: 7-18) points (P <  0.001). CONCLUSIONS: Based on our results, PDSS-2 can detect improvements in sleep quality reliably after DBS implantation.