Erratum: Validation Study of the Official Korean Version of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale.

This corrects the article on p. 633 in vol. 16, PMID: 33029970.

Validation Study of the Official Korean Version of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale.

BACKGROUND AND PURPOSE: The Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is widely used for estimating the symptoms of Parkinson's disease. Translation and validation of the MDS-UPDRS is necessary for non-English speaking countries and regions. The aim of this study was to validate the Korean version of the MDS-UPDRS. METHODS: Altogether, 362 patients in 19 centers were recruited for this study. We translated the MDS-UPDRS to Korean using the translation-back translation method and cognitive pretesting. We performed both confirmatory and exploratory factor analyses to validate the scale. We calculated the comparative fit index (CFI) for confirmatory factor analysis, and used unweighted least squares for exploratory factor analysis. RESULTS: The CFI was higher than 0.90 for all parts of the scale. Exploratory factor analysis also showed that the Korean MDS-UPDRS has the same number of factors in each part as the English version. CONCLUSIONS: The Korean MDS-UPDRS has the same overall structure as the English MDS-UPDRS. Our translated scale can be designated as the official Korean MDS-UPDRS.

Correlation of electrode position and clinical outcomes in globus pallidus stimulation for dystonia.

BACKGROUND: The correlation between the electrode location and the clinical outcome for internal globus pallidus (GPi) deep brain stimulation (DBS) has not been fully elucidated. OBJECTIVE: The aim of this study was to determine the discrepancies between the theoretical target planned by magnetic resonance imaging (MRI) and the actual electrode location in postoperative MRI, as well as to find the correlation between the final electrode locations and the clinical outcome after GPi DBS. METHODS: Thirty-six patients who underwent GPi DBS for dystonia were included in this retrospective study. The X coordinate was defined as the lateral distance from the midline, the Y coordinate as the anterior distance from the midcommissural point, and the Z coordinate as the inferior distance from the intercommissural line. RESULTS: All coordinates showed a significant difference between theoretical and actual values for all electrode locations (p < 0.05). In particular, greater differences were exhibited for Y than for the X and Z coordinates. There was no significant difference in the accuracy of the localization of the left-side versus the right-side electrode for any coordinates. The patients whose electrodes were located within or near the posteroventral GPi showed better clinical outcomes. CONCLUSIONS: The actual electrode location was slightly more posterior to the theoretically planned target. Electrodes concentrated near the posteroventral GPi tended to yield favorable outcomes.

Pregnancy and Delivery in a Generalized Dystonia Patient Treated with Internal Globus Pallidal Deep Brain Stimulation: a Case Report.

Internal globus pallidus (GPi) deep brain stimulation (DBS) has been widely accepted as an effective treatment modality of medically refractory dystonia. However, there have been few studies regarding the safety issue of pregnancy and childbirth related with DBS. This report describes a female patient who was pregnant and delivered a baby after GPi DBS surgery. A 33-year-old female patient with acquired generalized dystonia underwent bilateral GPi DBS implantation. She obtained considerable improvement in both movement and disability after DBS implantation. Four years later, she was pregnant and the obstetricians consulted us about the safety of the delivery. At 38-weeks into pregnancy, a scheduled caesarian section was carried out under general anesthesia. After induction using thiopental and succinylcholine, intubation was done quickly, followed by DBS turn off. For hemostasis, only bipolar electrocautery was used. Before awakening from the anesthesia, DBS was turned on as the same parameters previously adjusted. After delivery, she could feed her baby by herself, because the dystonia of left upper extremity and hand was improved. Until now, she has been showing continual improvement and being good at housework, carrying for children, with no trouble in daily life. This observation indicates that the patients who underwent DBS could safely be pregnant and deliver a baby.

Clinical Heterogeneity of Atypical Pantothenate Kinase-Associated Neurodegeneration in Koreans.

OBJECTIVE: Neurodegeneration with brain iron accumulation (NBIA) represents a group of inherited movement disorders characterized by iron accumulation in the basal ganglia. Recent advances have included the identification of new causative genes and highlighted the wide phenotypic variation between and within the specific NBIA subtypes. This study aimed to investigate the current status of NBIA in Korea. METHODS: We collected genetically confirmed NBIA patients from twelve nationwide referral hospitals and from a review of the literature. We conducted a study to describe the phenotypic and genotypic characteristics of Korean adults with atypical pantothenate kinase-associated neurodegeneration (PKAN). RESULTS: Four subtypes of NBIA including PKAN (n = 30), PLA2G6-related neurodegeneration (n = 2), beta-propeller protein-associated neurodegeneration (n = 1), and aceruloplasminemia (n = 1) have been identified in the Korean population. The clinical features of fifteen adults with atypical PKAN included early focal limb dystonia, parkinsonism-predominant feature, oromandibular dystonia, and isolated freezing of gait (FOG). Patients with a higher age of onset tended to present with parkinsonism and FOG. The p.R440P and p.D378G mutations are two major mutations that represent approximately 50% of the mutated alleles. Although there were no specific genotype-phenotype correlations, most patients carrying the p.D378G mutation had a late-onset, atypical form of PKAN. CONCLUSIONS: We found considerable phenotypic heterogeneity in Korean adults with atypical PKAN. The age of onset may influence the presentation of extrapyramidal symptoms.

Long-Term Clinical Outcome of Internal Globus Pallidus Deep Brain Stimulation for Dystonia.

BACKGROUND: GPi (Internal globus pallidus) DBS (deep brain stimulation) is recognized as a safe, reliable, reversible and adjustable treatment in patients with medically refractory dystonia. OBJECTIVES: This report describes the long-term clinical outcome of 36 patients implanted with GPi DBS at the Neurosurgery Department of Seoul National University Hospital. METHODS: Nine patients with a known genetic cause, 12 patients with acquired dystonia, and 15 patients with isolated dystonia without a known genetic cause were included. When categorized by phenomenology, 29 patients had generalized, 5 patients had segmental, and 2 patients had multifocal dystonia. Patients were assessed preoperatively and at defined follow-up examinations postoperatively, using the Burke-Fahn-Marsden dystonia rating scale (BFMDRS) for movement and functional disability assessment. The mean follow-up duration was 47 months (range, 12-84). RESULTS: The mean movement scores significantly decreased from 44.88 points preoperatively to 26.45 points at 60-month follow up (N = 19, P = 0.006). The mean disability score was also decreased over time, from 11.54 points preoperatively to 8.26 points at 60-month follow up, despite no statistical significance (N = 19, P = 0.073). When analyzed the movement and disability improvement rates at 12-month follow up point, no significant difference was noted according to etiology, disease duration, age at surgery, age of onset, and phenomenology. However, the patients with DYT-1 dystonia and isolated dystonia without a known genetic cause showed marked improvement. CONCLUSIONS: GPi DBS is a safe and efficient therapeutic method for treatment of dystonia patients to improve both movement and disability. However, this study has some limitations caused by the retrospective design with small sample size in a single-center.

The Pathogenic Role of Low Range Repeats in SCA17.

INTRODUCTION: SCA17 is an autosomal dominant cerebellar ataxia with expansion of the CAG/CAA trinucleotide repeats in the TATA-binding protein (TBP) gene. SCA17 can have various clinical presentations including parkinsonism, ataxia, chorea and dystonia. SCA17 is diagnosed by detecting the expanded CAG repeats in the TBP gene; however, in the literature, pathologic repeat numbers as low as 41 overlap with normal repeat numbers. METHODS: The subjects in this study included patients with involuntary movement disorders such as cerebellar ataxia, parkinsonism, chorea and dystonia who visited Seoul National University Hospital between Jan. 2006 and Apr. 2014 and were screened for SCA17. Those who were diagnosed with other genetic diseases or nondegenerative diseases were excluded. DNA from healthy subjects who did not have a family history of parkinsonism, ataxia, psychiatric symptoms, chorea or dystonia served as the control. In total, 5242 chromosomes from 2099 patients and 522 normal controls were analyzed. RESULTS: The total number of patients included in the analysis was 2099 (parkinsonism, 1706; ataxia, 345; chorea, 37; and dystonia, 11). In the normal control, up to 44 repeats were found. In the 44 repeat group, there were 7 (0.3%) patients and 1 (0.2%) normal control. In 43 repeat group, there were 8 (0.4%) patients and 2 (0.4%) normal controls. In the 42 repeat group, there were 16 (0.8%) patients and 3 (0.6%) normal controls. In 41 repeat group, there were 48 (2.3%) patients and 8 (1.5%) normal controls. Considering the overlaps and non-significant differences in allelic frequencies between the patients and the normal controls with low-expansions, we could not determine a definitive cutoff value for the pathologic CAG repeat number of SCA17. CONCLUSION: Because the statistical analysis between the normal controls and patients with low range expansions failed to show any differences so far, we must consider that clinical cases with low range expansions could be idiopathic movement disorders showing coincidental CAG/CAA expansions. Thus, we need to reconsider the pathologic role of low range expansions (41-42). Long term follow up and comprehensive investigations using autopsy and imaging studies in patients and controls with low range expansions are necessary to determine the cutoff value for the pathologic CAG repeat number of SCA17.

Rotigotine transdermal system as add-on to oral dopamine agonist in advanced Parkinson's disease: an open-label study.

BACKGROUND: Achieving optimal symptom control with minimal side effects is a major goal in clinical practice. Dual-agent dopamine receptor agonist (DA) therapy in Parkinson's disease (PD) may represent a promising approach to treatment, as the combination of different pharmacokinetic/pharmacological profiles may result in a lesser need for high dosages and, accordingly, may be well tolerated. The objective of the current study was to investigate safety and efficacy of rotigotine transdermal system as add-on to oral DA in patients with advanced PD inadequately controlled with levodopa and low-dose oral DA. METHODS: PD0015 was an open-label, multinational study in patients with advanced-PD and sleep disturbance or early-morning motor impairment. Patients were titrated to optimal dose rotigotine (≤8 mg/24 h) over 1-4 weeks and maintained for 4-7 weeks (8-week treatment). Dosage of levodopa and oral DA (pramipexole ≤1.5 mg/day, ropinirole ≤6.0 mg/day) was stable. Primary variable was Clinical Global Impressions (CGI) item 4: side effects, assessing safety. Other variables included adverse events (AEs), Patient Global Impressions of Change (PGIC), Unified Parkinson's Disease Rating Scale (UPDRS) II and III, Parkinson's Disease Sleep Scale (PDSS-2), Pittsburgh Sleep Quality Index (PSQI), and "off" time. RESULTS: Of 90 patients who received rotigotine, 79 (88%) completed the study; 5 (6%) withdrew due to AEs. Most (83/89; 93%) had a CGI-4 score <3 indicating that rotigotine add-on therapy did not interfere with functioning; 6 (7%) experienced drug-related AEs that interfered with functioning (score ≥3). AEs occurring in ≥5% were application site pruritus (13%), dizziness (10%), orthostatic hypotension (10%), nausea (8%), dyskinesia (8%), and nasopharyngitis (6%). Numerical improvements in motor function (UPDRS III), activities of daily living (UPDRS II), sleep disturbances (PDSS-2, PSQI), and reduction in "off" time were observed. The majority (71/88; 81%) improved on PGIC. CONCLUSIONS: Addition of rotigotine transdermal system to low-dose oral DA in patients with advanced-PD was feasible and may be associated with clinical benefit. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT01723904 . Trial registration date: November 6, 2012.

Switch from oral pramipexole or ropinirole to rotigotine transdermal system in advanced Parkinson's disease: an open-label study.

OBJECTIVE: Investigate safety, feasibility and efficacy of switching therapy in patients with advanced-stage Parkinson's disease (PD) inadequately controlled with pramipexole (≤ 3.5 mg/day) or ropinirole (≤ 14 mg/day) to rotigotine transdermal system (≤ 14 mg/24 h; dose adjustments ≤ 16 mg/24 h permitted). METHODS: PD0009 (ClinicalTrials.gov: NCT01711866) was an open-label study in patients with advanced-stage PD receiving levodopa, and experiencing sleep disturbance or early-morning motor impairment. Pramipexole/ropinirole was switched to equivalent dose rotigotine overnight or in two stages. During the 4-week treatment period rotigotine dose adjustments were permitted (up to 16 mg/24 h). Primary variable: Clinical Global Impressions (CGI) item 4: side effects (assessing safety) at end of treatment. RESULTS: 79/87 (91%) patients completed the study; 2 (2%) withdrew due to adverse events (AEs). Most (84; 97%) had CGI item 4 score < 3 indicating switch did not interfere with functioning; three experienced drug-related AEs interfering with functioning (score = 3). 62% patients improved on Patient Global Impression of Change, assessing effectiveness. AEs occurring ≥ 5%: application site pruritus (10%), application site erythema (7%), dizziness (7%), dyskinesia (7%), erythema (6%), pruritus (6%). Unified Parkinson's Disease Rating Scale II and III, Parkinson's Disease Sleep Scale-2 and Pittsburgh Sleep Quality Index were unchanged. Numerical improvements in 'off' time, awakenings and nocturias were observed. CONCLUSIONS: Switch from pramipexole or ropinirole to rotigotine (up to 14 mg/24 h) was feasible and possibly associated with some benefit.

Vestibular Performance During High-Acceleration Stimuli Correlates with Clinical Decline in SCA6.

In spinocerebellar ataxia type 6 (SCA6), the vestibular dysfunction and its correlation with other clinical parameters require further exploration. We determined vestibular responses over a broad range of stimulus acceleration in 11 patients with SCA6 (six men, age range=33-72 years, mean age±SD=59±12 years) using bithermal caloric irrigations, rotary chair, and head impulse tests. Correlations were also pursued among disability scores, as measured using the International Cooperative Ataxia Rating Scale, disease duration, age at onset, cytosine-adenine-guanine (CAG) repeat length, and the gain of the vestibulo-ocular reflex (VOR). In response to relatively low-acceleration, low-frequency rotational and bithermal caloric stimuli, the VOR gains were normal or increased regardless of the severity of disease. On the other hand, with relatively high-acceleration, high-frequency head impulses, there was a relative increase in gain in the mildly affected patients and a decrease in gain in the more severely affected patients and gains were negatively correlated with the severity of disease (Spearman correlation, R=-0.927, p<0.001). Selective decrease of the vestibular responses during high-acceleration, high-frequency stimuli may be ascribed to degeneration of either the flocculus or vestibular nuclei. The performance of the VOR during high-acceleration, high-frequency head impulses may be a quantitative indicator of clinical decline in SCA6.

Whole-brain diffusion-tensor changes in parkinsonian patients with impulse control disorders.

BACKGROUND AND PURPOSE: The aim of this study was to determine the changes in diffusion-tensor images associated with medication-related impulse control disorder (ICD) in Parkinson's disease (PD) patients undergoing chronic dopamine-replacement therapy. METHODS: Nineteen PD patients, comprising 10 with ICD (PD-ICD) and 9 without ICD (PD-nonICD), and 18 age-matched healthy controls (HCs) with no cognitive or other psychiatric disorders were analyzed. All subjects underwent 3-T magnetic resonance diffusion-tensor imaging. For all PD patients, clinical data on PD duration, antiparkinsonian medication dosages, Unified Parkinson's Disease Rating Scale and Mini-Mental State Examination were collected. Whole-brain voxel-based measures of fractional anisotropy (FA) and mean diffusivity (MD) were analyzed. RESULTS: In comparison with HCs, the PD-nonICD subjects had low FA at the bilateral orbitofrontal areas. While the PD-ICD subjects exhibited no such difference, their FA was significantly elevated at the anterior corpus callosum. Analysis of FA between the two PD groups revealed that FA in the anterior corpus callosum, right internal capsule posterior limbs, right posterior cingulum, and right thalamic radiations were significantly higher (corrected p<0.05) in the PD-ICD than in the PD-nonICD patients. MD did not differ between the PD-ICD and PD-nonICD groups in any brain regions. CONCLUSIONS: The PD-ICD patients appear to have relatively preserved white-matter integrity in the regions involved in reward-related behaviors compared to PD-nonICD patients. Further investigation is required to determine whether the difference in FA between PD-ICD and PD-nonICD patients reflects microstructural differences in the pathological progression of PD or is secondary to ICD.

Comparison of sleep and other non-motor symptoms between SWEDDs patients and de novo Parkinson's disease patients.

BACKGROUND: SWEDDs (Scans Without Evidence of Dopaminergic Deficits) was defined from a series of pharmaceutical trials on Parkinson's disease (PD). Non-motor features including sleep-related problems are common even in early-stage PD patients; however, little is known about the burden of the non-motor symptoms in SWEDDs patients. METHODS: The Non-motor Symptoms Assessment Scale (NMSS), revised version of the Parkinson's Disease Sleep Scale (PDSS-2), Epworth Sleepiness Scale (ESS), and EuroQol 5-Dimension (EQ-5D) were applied to evaluate 17 SWEDDs patients and 28 de novo PD patients. The presence of clinically probable rapid eye movement sleep behavior disorder (cpRBD) was assessed using the International Classification of Sleep Disorders-Revised (ICSD-R) criteria. RESULTS: The total NMSS score for the SWEDDs group was significantly lower than for the de novo PD group (p = 0.032). The most distinct difference was in taste or smell change (p < 0.000). Prevalence of cpRBD was higher in de novo PD patients than in SWEDDs patients (p = 0.030), though no significant differences in the PDSS-2 total score (p = 0.496) or the ESS score (p = 0.517) were found. The SWEDDs patients did not significantly differ from the de novo PD patients with regard to quality of life, as measured by the EQ-5D index score (p = 0.177). CONCLUSIONS: The patients with SWEDDs have less non-motor problems than newly diagnosed untreated PD patients. Given the difficulty distinguishing between SWEDDs and early PD, identifying some of non-motor symptoms, such as RBD or olfactory impairment, could aid clinicians in their work.

Maladaptive reward-learning and impulse control disorders in patients with Parkinson's disease: a clinical overview and pathophysiology update.

Impulse control disorders (ICD) in Parkinson's disease (PD) are a disabling non-motor symptom with frequencies of 13-35% among patients receiving dopamine replacement therapy. ICD in PD is strongly associated with dopaminergic drug use, especially non-ergot dopamine agonists (DA). However, individual susceptibility and disease-related neural changes are also important contributors to the development of ICD. Discrepancies between nigrostriatal and mesolimbic dopaminergic degeneration and non-physiological administration of dopaminergic drugs may induce abnormal 'hyperstimulation' of the mesolimbic system, which alters reward-learning behaviors in PD patients. In addition, DA can make patients more impulsive during decision-making and seek risk-taking behaviors. DA intake is also related to the biased representation of rewards. Ultimately, loss of negative feedback control due to dysfunctional frontostriatal connections is necessary for the establishment of ICD in PD. The subsequent behavioral and neural changes are affected by PD treatment and disease progression; thus, proper treatment guidelines for physicians are needed to prevent the development of ICD. Future studies aimed at producing novel therapeutics to control the risk factors for ICD or treat ICD behaviors in PD are warranted. This review summarizes recent advances from epidemiological and pathophysiological studies on ICD in PD. Management principles and limitations of current therapeutics are briefly discussed.

Influence of propofol and fentanyl on deep brain stimulation of the subthalamic nucleus.

We investigated the effect of propofol and fentanyl on microelectrode recording (MER) and its clinical applicability during subthalamic nucleus (STN) deep brain stimulation (DBS) surgery. We analyzed 8 patients with Parkinson's disease, underwent bilateral STN DBS with MER. Their left sides were done under awake and then their right sides were done with a continuous infusion of propofol and fentanyl under local anesthesia. The electrode position was evaluated by preoperative MRI and postoperative CT. The clinical outcomes were assessed at six months after surgery. We isolated single unit activities from the left and the right side MERs. There was no significant difference in the mean firing rate between the left side MERs (38.7 ± 16.8 spikes/sec, n=78) and the right side MERs (35.5 ± 17.2 spikes/sec, n=66). The bursting pattern of spikes was more frequently observed in the right STN than in the left STN. All the electrode positions were within the STNs on both sides and the off-time Unified Parkinson's Disease Rating Scale part III scores at six months after surgery decreased by 67% of the preoperative level. In this study, a continuous infusion of propofol and fentanyl did not significantly interfere with the MER signals from the STN. The results of this study suggest that propofol and fentanyl can be used for STN DBS in patients with advanced Parkinson's disease improving the overall experience of the patients.

Clinical spectrum of dopa-responsive dystonia and related disorders.

Dopa-responsive dystonia (DRD) has a classic presentation of childhood or adolescent-onset dystonia, mild parkinsonism, marked diurnal fluctuations, improvement with sleep or rest, and a dramatic and sustained response to low doses of L-dopa without motor fluctuations or dyskinesias. However, there have been many papers on patients with a wide range of features, which report them as DRD mainly because they had dystonic syndromes with L-dopa responsiveness. Many mutations in the dopaminergic system have been found as molecular genetic defects. Therefore, the clinical and genetic spectra of DRD are unclear, which lead to difficulties in diagnostic work-ups and planning treatments. We propose the concept of DRD and DRD-plus to clarify the confusion in this area and to help understand the pathophysiology and clinical features, which will help in guiding diagnostic investigations and planning treatments. We critically reviewed the literature on atypical cases and discussed the limitations of the gene study.

Identifying the clusters within nonmotor manifestations in early Parkinson's disease by using unsupervised cluster analysis.

BACKGROUND: Classical and data-driven classifications of Parkinson's disease (PD) are based primarily on motor symptoms, with little attention being paid to the clustering of nonmotor manifestations. METHODS: Clinical data on demographic, motor and nonmotor features, including the Korean version of the sniffin' stick (KVSS) test results, and responses to the screening questionnaire of the nonmotor features were collected from 56 PD patients with disease onset within 3 years. Nonmotor subgroups were classified using unsupervised hierarchical cluster analysis (HCA). In addition to unsupervised HCA, we performed a cross-sectional analysis comparing the performance on the KVSS olfactory test with other nonmotor manifestations of the patients. RESULTS: Forty-nine patients (87.5%) had hyposmia based on the KVSS test. HCA suggested three nonmotor clusters for all PD patients and two nonmotor clusters in de novo PD patients, without a priori assumptions about the relatedness. In the cross-sectional analysis, dream-enactment behavior was more prevalent in patients with lower olfactory scores, implying impaired olfactory function (P = 0.029 for all PD patients; P = 0.046 for de novo PD patients). CONCLUSION: We propose the existence of different clusters of nonmotor manifestations in early PD by using unsupervised hierarchical clustering. To our knowledge, this study is the first to report the identification of nonmotor subgroups based on unsupervised HCA of multiple nonmotor manifestations in the early stage of the disease.

Alpha-synuclein repeat variants and survival in Parkinson's disease.

OBJECTIVES: To determine whether α-synuclein dinucleotide repeat (REP1) genotypes are associated with survival in Parkinson's disease (PD). METHODS: Investigators from the Genetic Epidemiology of Parkinson's Disease Consortium provided REP1 genotypes and baseline and follow-up clinical data for cases. The primary outcome was time to death. Cox proportional hazards regression models were used to assess the association of REP1 genotypes with survival. RESULTS: Twenty-one sites contributed data for 6,154 cases. There was no significant association between α-synuclein REP1 genotypes and survival in PD. However, there was a significant association between REP1 genotypes and age at onset of PD (hazard ratio: 1.06; 95% confidence interval: 1.01-1.10; P value = 0.01). CONCLUSIONS: In our large consortium study, α-synuclein REP1 genotypes were not associated with survival in PD. Further studies of α-synuclein's role in disease progression and long-term outcomes are needed.