Symmetric and Profound Monoaminergic Degeneration in Parkinson's Disease with Premotor REM Sleep Behavior Disorder

Background

Rapid eye movement sleep behavior disorder (RBD) may precede or follow motor symptoms in Parkinson's disease (PD). While over 70% of idiopathic RBD cases phenoconvert within a decade, a small subset develops PD after a more extended period or remains nonconverted. These heterogeneous manifestations of RBD in PD prompt subtype investigations. Premotor RBD may signify "body-first" PD with bottom-up, symmetric synucleinopathy propagation.

Objective

Explore brainstem and nigrostriatal monoaminergic degeneration pattern differences based on premotor RBD presence and duration in de novo PD patients.

Methods

In a cross-sectional analysis of de novo PD patients (n = 150) undergoing FP-CIT PET and RBD Single-Question Screen, the cohort was categorized into groups with and without premotor RBD (PDRBD +/-), with further classification of PDRBD + based on a 10-year duration of premotor RBD. Analysis of FP-CIT binding in the striatum and pons, striatal asymmetry, and striatum-to-pons ratios compared patterns of nigrostriatal and brainstem monoaminergic degeneration.

Results

PDRBD + exhibited more severe and symmetrical striatal dopaminergic denervation compared to PDRBD-, with the difference in severity accentuated in the least-affected hemisphere. The PDRBD +<10Y subgroup displayed the most prominent striatal symmetry, supporting a more homogeneous "body-first" subtype. Pontine uptakes remained lower in PDRBD + even after adjusting for striatal uptake, suggesting early degeneration of pontine monoaminergic nuclei.

Conclusions

Premotor RBD in PD is associated with severe, symmetrical nigrostriatal and brainstem monoaminergic degeneration, especially in cases with PD onset within 10 years of RBD. This supports the concept of a "widespread, bottom-up" pathophysiological mechanism associated with premotor RBD in PD.

Opicapone to Treat Early Wearing-off in Parkinson's Disease Patients: The Korean ADOPTION Trial

BACKGROUND

Increasing levodopa (L-dopa)/dopa decarboxylase inhibitor (DDCI) daily dose or adding a catechol-O-methyltransferase (COMT) inhibitor to levodopa/DDCI therapy are strategies used to manage wearing-off symptoms in Parkinson's disease (PD) patients.

OBJECTIVES

To evaluate the COMT inhibitor opicapone versus an additional dose of levodopa to treat early wearing-off in PD patients.

METHODS

ADOPTION was a randomized, parallel-group, open-label, Phase 4 study conducted in Korea. At baseline, eligible patients were randomized (1:1) to opicapone 50 mg (n = 87) or L-dopa 100 mg (n = 81) (added to current L-dopa/DDCI therapy) for 4 weeks. The main efficacy endpoint was change from baseline to end of study in absolute off time. Other endpoints included changes in on time, in Movement Disorder Society-Unified Parkinson's Disease Rating Scale and 8-item PD Questionnaire scores, and the Clinical and Patient Global Impression of Improvement/Change.

RESULTS

The adjusted mean in absolute off time was significantly greater for opicapone 50 mg than for L-dopa 100 mg (-62.1 vs. -16.7 minutes; P = 0.0015). Opicapone-treated patients also reported a greater reduction in the percentage of off time (P = 0.0015), a greater increase in absolute on time (P = 0.0338) and a greater increase in the percentage of on time (P = 0.0015). There were no significant differences in other secondary endpoints. The L-dopa equivalent daily dose was significantly higher in the opicapone group (750.9 vs. 690.0 mg; P = 0.0247), when a 0.5 conversion factor is applied.

CONCLUSIONS

Opicapone 50 mg was more effective than an additional 100 mg L-dopa dose at decreasing off time in patients with PD and early wearing-off.

The prevalence of non-troublesome dyskinesia in Parkinson's disease

INTRODUCTION

Levodopa-induced dyskinesia is a common complication of long-term treatment of Parkinson's disease (PD), but its impact on daily activities is somewhat controversial. This study investigated the prevalence and severity of dyskinesia, particularly non-troublesome dyskinesia, to provide insights into its significance for long-term PD management.

METHODS

We reviewed electronic medical records of 2571 PD patients, who had been followed up at Seoul National University Hospital and were seen between January 2016 and June 2017. Dyskinesia severity had been assessed during follow-up and was recorded with the highest score by considering its impact on functioning (0 = no dyskinesia, 1 = minimal with patient unaware, 2 = mild disability, 3 = moderate disability, 4 = severe disability).

RESULTS

The prevalence of dyskinesia increased progressively with longer PD duration; 8.2% in the group with disease duration of 0-5 years, 40.7% for 6-10 years, 66.0% for 11-15 years, 74.6% for 16-20 years, and 83.2% for 21 years or more. The prevalence of dyskinesia scores ≥2 also increased with disease duration, with rates of 6.3% for 0-5 years, 31.9% for 6-10 years, 54.8% for 11-15 years, 62.9% for 16-20 years and 73.7% for 21 or more years.

CONCLUSION

Despite the increasing prevalence and severity of dyskinesia with longer PD duration, the study found that less than non-troublesome dyskinesia remained at approximately 26.3% even after more than 21 years of disease duration. These findings suggest that dyskinesia may not be troublesome for many PD patients even in long-term.

Transitioning from Subtyping to Precision Medicine in Parkinson's Disease: A Purpose-Driven Approach

The International Parkinson and Movement Disorder Society (MDS) created a task force (TF) to provide a critical overview of the Parkinson's disease (PD) subtyping field and develop a guidance on future research in PD subtypes. Based on a literature review, we previously concluded that PD subtyping requires an ultimate alignment with principles of precision medicine, and consequently novel approaches were needed to describe heterogeneity at the individual patient level. In this manuscript, we present a novel purpose-driven framework for subtype research as a guidance to clinicians and researchers when proposing to develop, evaluate, or use PD subtypes. Using a formal consensus methodology, we determined that the key purposes of PD subtyping are: (1) to predict disease progression, for both the development of therapies (use in clinical trials) and prognosis counseling, (2) to predict response to treatments, and (3) to identify therapeutic targets for disease modification. For each purpose, we describe the desired product and the research required for its development. Given the current state of knowledge and data resources, we see purpose-driven subtyping as a pragmatic and necessary step on the way to precision medicine. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Large-Scale Screening: Phenotypic and Mutational Spectrum in Isolated and Combined Dystonia Genes

BACKGROUND

Pathogenic variants in several genes have been linked to genetic forms of isolated or combined dystonia. The phenotypic and genetic spectrum and the frequency of pathogenic variants in these genes have not yet been fully elucidated, neither in patients with dystonia nor with other, sometimes co-occurring movement disorders such as Parkinson's disease (PD).

OBJECTIVES

To screen >2000 patients with dystonia or PD for rare variants in known dystonia-causing genes.

METHODS

We screened 1207 dystonia patients from Germany (DysTract consortium), Spain, and South Korea, and 1036 PD patients from Germany for pathogenic variants using a next-generation sequencing gene panel. The impact on DNA methylation of KMT2B variants was evaluated by analyzing the gene's characteristic episignature.

RESULTS

We identified 171 carriers (109 with dystonia [9.0%]; 62 with PD [6.0%]) of 131 rare variants (minor allele frequency <0.005). A total of 52 patients (48 dystonia [4.0%]; four PD [0.4%, all with GCH1 variants]) carried 33 different (likely) pathogenic variants, of which 17 were not previously reported. Pathogenic biallelic variants in PRKRA were not found. Episignature analysis of 48 KMT2B variants revealed that only two of these should be considered (likely) pathogenic.

CONCLUSION

This study confirms pathogenic variants in GCH1, GNAL, KMT2B, SGCE, THAP1, and TOR1A as relevant causes in dystonia and expands the mutational spectrum. Of note, likely pathogenic variants only in GCH1 were also found among PD patients. For DYT-KMT2B, the recently described episignature served as a reliable readout to determine the functional effect of newly identified variants. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Clinical correlates of pareidolias and color discrimination deficits in idiopathic REM sleep behavior disorder and Parkinson's disease

Visuoperceptual dysfunction is common in Parkinson's disease (PD) and is also reported in its prodromal phase, isolated REM sleep behavior disorder (iRBD). We aimed to investigate color discrimination ability and complex visual illusions known as pareidolias in patients with iRBD and PD compared to healthy controls, and their associating clinical factors. 46 iRBD, 43 PD, and 64 healthy controls performed the Farnsworth-Munsell 100 hue test and noise pareidolia tests. Any relationship between those two visual functions and associations with prodromal motor and non-motor manifestations were evaluated, including MDS-UPDRS part I to III, Cross-Cultural Smell Identification Test, sleep questionnaires, and comprehensive neuropsychological assessment. iRBD and PD patients both performed worse on the Farnsworth-Munsell 100 hue test and had greater number of pareidolias compared to healthy controls. No correlations were found between the extent of impaired color discrimination and pareidolia scores in either group. In iRBD patients, pareidolias were associated with frontal executive dysfunction, while impaired color discrimination was associated with visuospatial dysfunction, hyposmia, and higher MDS-UPDRS-III scores. Pareidolias in PD patients correlated with worse global cognition, whereas color discrimination deficits were associated with frontal executive dysfunction. Color discrimination deficits and pareidolias are frequent but does not correlate with each other from prodromal to clinically established stage of PD. The different pattern of clinical associates with the two visual symptoms suggests that evaluation of both color and pareidolias may aid in revealing the course of neurodegeneration in iRBD and PD patients.

Constipation is linked to accelerated cognitive and motor decline in isolated REM sleep behavior disorder

INTRODUCTION

Constipation is associated with higher clinical severity and predicts cognitive decline in Parkinson's disease (PD). Whether the non-motor marker is associated with unfavorable motor and cognitive trajectories from the prodromal stage remains unclear.

METHODS

In a longitudinal prospective cohort of subjects with isolated REM sleep behavior disorders (iRBD), subjects underwent repeated MDS-UPDRS and Mini-Mental Status Examination (MMSE) assessments. Generalized-estimating-equations (GEE) regression model was used to compare the time-dependent trajectories of MDS-UPDRS-III and MMSE scores between subjects with and without constipation at baseline.

RESULTS

Twenty-nine subjects with constipation at baseline (iRBD+constipation) and 24 without (iRBD-constipation) were followed over 4.085 ± 2.645 years. The iRBD+constipation group presented faster decline of both MDS-UPDRS-III and MMSE scores, with additional estimated annual progression of +1.242 and -0.713 points, respectively, compared to the iRBD-constipation group (time*group p < 0.05).

CONCLUSION

Constipation in isolated RBD is associated with accelerated progression of cognitive impairment and motor symptoms.

Analysis of HTT CAG repeat expansion among healthy individuals and patients with chorea in Korea

BACKGROUND

Although the epidemiology of Huntington's disease (HD) in Korea differs notably from that in Western countries, the genetic disparities between these regions remain unclear.

OBJECTIVE

To investigate the characteristics and clinical significance of cytosine-adenine-guanine (CAG) repeat size associated with HD in the Korean population.

METHODS

We analyzed the CAG repeat lengths of the HTT gene in 941 healthy individuals (1,882 alleles) and 954 patients with chorea (1,908 alleles) from two referral hospitals in Korea. We presented normative CAG repeat length data for the Korean population and computed the reduced penetrance (36-39 CAG) and intermediate allele (27-35 CAG) frequencies in the two groups. Furthermore, we investigated the relationship between intermediate alleles and chorea development using logistic regression models in individuals aged ≥55 years.

RESULTS

The mean (±standard deviation) CAG repeat length in healthy individuals was 17.5 ± 2.0, with a reduced penetrance allele frequency of 0.05 % (1/1882) and intermediate allele frequency of 0.69 % (13/1882). We identified 213 patients with genetically confirmed HD whose CAG repeat length ranged from 39 to 140, with a mean of 45.2 ± 7.9 in the longer allele. Compared with normal CAG repeat alleles, intermediate CAG repeat alleles were significantly related to a higher risk of developing chorea (age of onset range, 63-84 years) in individuals aged ≥55 years.

CONCLUSIONS

This study provides insights into the specific characteristics of CAG repeat lengths in the HTT gene in the Korean population. The reduced penetrance and intermediate allele frequencies in the Korean general population seem to be lower than those reported in Western populations. The presence of intermediate alleles may increase the risk of chorea in the Korean elderly population, which requires further large-scale investigations.

Caregiver Burden of Patients With Huntington's Disease in South Korea

OBJECTIVE

This is the first prospective cohort study of Huntington's disease (HD) in Korea. This study aimed to investigate the caregiver burden in relation to the characteristics of patients and caregivers.

METHODS

From August 2020 to February 2022, we enrolled patients with HD from 13 university hospitals in Korea. We used the 12-item Zarit Burden Interview (ZBI-12) to evaluate the caregiver burden. We evaluated the clinical associations of the ZBI-12 scores by linear regression analysis and investigated the differences between the low- and high-burden groups.

RESULTS

Sixty-five patients with HD and 45 caregivers were enrolled in this cohort study. The average age at onset of motor symptoms was 49.3 ± 12.3 years, with an average cytosine-adenine-guanine (CAG)n of 42.9 ± 4.0 (38-65). The median ZBI-12 score among our caregivers was 17.6 ± 14.2. A higher caregiver burden was associated with a more severe Shoulson-Fahn stage (p = 0.038) of the patients. A higher ZBI-12 score was also associated with lower independence scale (B = -0.154, p = 0.006) and functional capacity (B = -1.082, p = 0.002) scores of patients. The caregiving duration was longer in the high- than in the low-burden group. Caregivers' demographics, blood relation, and marital and social status did not affect the burden significantly.

CONCLUSION

HD patients' neurological status exerts an enormous impact on the caregiver burden regardless of the demographic or social status of the caregiver. This study emphasizes the need to establish an optimal support system for families dealing with HD in Korea. A future longitudinal analysis could help us understand how disease progression aggravates the caregiver burden throughout the entire disease course.

Monoaminergic Degeneration and Ocular Motor Abnormalities in De Novo Parkinson's Disease

BACKGROUND

Evaluating eye movements in Parkinson's disease (PD) provides valuable insights into the underlying pathophysiological changes.

OBJECTIVE

The aim was to investigate the relationship between monoaminergic degeneration and ocular motor abnormalities in de novo PD.

METHODS

Drug-naive PD patients who underwent N-(3-[18 F]fluoropropyl)-2-carbomethoxy-3-(4-iodophenyl) nortropane positron emission tomography scans and video-oculography at diagnosis were eligible. Measurements of saccadic accuracy, latency, and smooth pursuit gain and square wave jerk frequency were collected. Patients underwent Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) and detailed cognitive tests. We investigated the associations between ocular motor measurements and specific tracer uptake ratios (SUR) in the caudate nucleus, anterior and posterior putamen, thalamus, and dorsal raphe nuclei, along with motor and cognitive symptoms.

RESULTS

One-hundred twenty-four subjects were included in this study. Saccadic accuracy was positively associated with parkinsonian motor severity expressed as Hoehn and Yahr stages, MDS-UPDRS Part III scores, and subscores for bradykinesia and rigidity but not with tremor scores (PFDR  < 0.05). Saccadic accuracy correlated with poor performances in the Rey-Complex-Figure copy, and latency with the Digit Symbol Coding and the Montreal Cognitive Assessment scores (PFDR  < 0.05). Prolonged saccadic latency correlated with reduced thalamic SUR, whereas decreased saccadic accuracy correlated with reduced SUR in the anterior and posterior putamen (PFDR  < 0.05). Reduced smooth pursuit gain showed associations with reduced SUR in the dorsal raphe, a serotonin-predominant region, but did not correlate with parkinsonism severity scores.

CONCLUSION

Defective dopaminergic and nondopaminergic neural systems may discretely influence ocular motor function in de novo PD patients. © 2023 International Parkinson and Movement Disorder Society.

Effects of physical exercise interventions on cognitive function in Parkinson's disease: An updated systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To determine whether physical exercise interventions can improve cognitive function, including overall performance and specific domains, in patients with Parkinson's disease (PD) and to provide potential evidence on how cognitive benefits can be optimized by exercise prescriptions.

METHODS

Using PubMed, Web of Science, and Cochrane Library (from inception to August 2022), four independent reviewers screened the search results and extracted data from randomized controlled trials of physical exercise interventions in patients with PD with an outcome measure of cognitive function. Random-effects meta-analysis models were used to report standardized mean differences (SMDs) with 95 % confidence intervals (CIs).

RESULTS

Twenty-one randomized controlled trials including 761 patients with PD were eligible for inclusion. Physical exercise interventions led to significant improvements in global cognitive function (SMD = 0.69; 95 % CI = 0.31 to 1.06; P < 0.001). With respect to cognitive domains, the significant effect of exercise was found on executive function (SMD = 0.94; 95 % CI = 0.05 to 1.83; P = 0.039), but not on attention/working memory, language, memory, and visuospatial function. In moderator variable analyses, the effect on global cognition was observed in combined exercise programs (SMD = 0.79; 95 % CI = 0.46 to 1.12; P < 0.001), whereas there were no significant positive effects in aerobic exercise programs, strength exercise programs, and flexibility exercise programs. In addition, exercise interventions of light-to-moderate intensity with at least 60 min in duration, and of any frequency or period, were beneficial to the global cognitive function.

CONCLUSION

This updated systematic review and meta-analysis suggests that physical exercise interventions are effective in improving global cognitive function and, to a lesser extent, executive function in patients with PD. At least 60 min a day of combined exercise programs on as many days of the week as feasible may be recommended as the non-pharmacological therapeutic option to improve cognitive function.

Effects of high-intensity interval training and moderate-intensity continuous training on sarcopenia-related parameters in participants with Parkinson's disease: A 24-week randomized pilot trial substudy

OBJECTIVE

To evaluate the potential efficacy of two different supervised exercise regimens, namely high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT), on sarcopenia-related parameters in participants with Parkinson's disease (PD).

METHODS

We analyzed data from a randomized controlled pilot trial (CRIS identifier: KCT0007130). An aerobic exercise intervention using a cycle ergometer (40-60 min) in combination with calisthenics (5 min) was performed in three sessions/week for 24 weeks for HIIT (60% maximum aerobic power for 30-50 s with 1-min rest intervals) and MICT (50% peak oxygen consumption) groups. Changes in sarcopenia-related parameters, including appendicular skeletal muscle mass (ASM), ASM index (ASM/height2), handgrip strength, 6-min walking distance, and 30-s chair-stand test (30CST) score, were compared among the HIIT (n = 9), MICT (n = 10), and usual care (n = 11) groups.

RESULTS

The HIIT group showed greater increases in leg lean mass (p = 0.011), ASM (p = 0.035), and ASM index (p = 0.025), and greater improvements in 6-min walking distance (p = 0.024) and 30CST scores (p = 0.026) compared with the usual care group. However, among these parameters, only the 30CST score significantly improved in the MICT group compared to the usual care group (p = 0.002). Three of the four (75%) sarcopenic patients who underwent HIIT showed improved sarcopenia after the 24-week exercise intervention, whereas it did not improve in the sarcopenic patients included in the MICT (n = 2) and usual care (n = 2) groups.

CONCLUSION

This study suggests that HIIT may be superior to MICT in improving sarcopenia in patients with PD. Further large-scale investigations are required to confirm our findings.

Brain olfactory-related atrophy in isolated rapid eye movement sleep behavior disorder

OBJECTIVE

To investigate structural and functional connectivity changes in brain olfactory-related structures in a longitudinal prospective cohort of isolated REM sleep behavior disorder (iRBD) and their clinical correlations, longitudinal evolution, and predictive values for phenoconversion to overt synucleinopathies, especially Lewy body diseases.

METHODS

The cohort included polysomnography-confirmed iRBD patients and controls. Participants underwent baseline assessments including olfactory tests, neuropsychological evaluations, the Movement Disorders Society-Unified Parkinson's Disease Rating Scale, 3T brain MRI, and 18 F-FP-CIT PET scans. Voxel-based morphometry (VBM) was performed to identify regions of atrophy in iRBD, and volumes of relevant olfactory-related regions of interest (ROI) were estimated. Subgroups of patients underwent repeated volumetric MRI and resting-state functional MRI (fMRI) scans after four years.

RESULTS

A total of 51 iRBD patients were included, with 20 of them converting to synucleinopathy (mean time to conversion 3.08 years). Baseline VBM analysis revealed atrophy in the right olfactory cortex and gyrus rectus in iRBD. Subsequent ROI comparisons with controls showed atrophy in the amygdala. These olfactory-related atrophies tended to be associated with worse depression, anxiety, and urinary problems in iRBD. Amygdala 18 F-FP-CIT uptake tended to be reduced in iRBD patients with hyposmia (nonsignificant after multiple comparison correction) and correlated with urinary problems. Resting-state fMRI of 23 patients and 32 controls revealed multiple clusters with aberrant olfactory-related functional connectivity. Hypoconnectivity between the putamen and olfactory cortex was associated with mild parkinsonian signs in iRBD. Longitudinal analysis of volumetric volumetric MRI in 22 iRBD patients demonstrated four-year progression of olfactory-related atrophy. Cox regression analysis revealed that this atrophy significantly predicted phenoconversion.

INTERPRETATION

Progressive atrophy of central olfactory structures may be a potential indicator of Lewy body disease progression in iRBD.

Plasma neurofilament light-chain and phosphorylated tau as biomarkers of disease severity in Huntington's disease: Korean cohort data

OBJECTIVE

To investigate neurofilament light chain (NfL), phosphorylated tau (p-Tau) and total tau (t-Tau) as plasma markers for clinical severity in Korean Huntington's disease (HD) cohort.

METHODS

Genetically-confirmed 67 HD patients participated from 13 referral hospitals in South Korea. The subjects were evaluated with the Unified Huntington's Disease Rating Scale (UHDRS), total motor score (TMS) and total functional capacity (TFC), Mini-Mental Status Examination (K-MMSE), Montreal Cognitive Assessment (MoCA-K), and Beck's depression inventory (K-BDI). We measured plasma NfL, p-Tau and t-Tau concentrations using single-molecule array (SIMOA) assays. Stages of HD were classified based on UHDRS-TFC score and plasma markers were analyzed for correlation with clinical severity scales.

RESULTS

Plasma NfL was elevated in both 6 premanifest and 61 full manifest HD patients compared to the reference value, which increased further from premanifest to manifest HD groups. The NfL level was not significantly correlated with UHDRS TMS or TFC scores in manifest HD patients. Plasma p-Tau was also elevated in HD patients (p = 0.038). The level was the highest in stage III-V HD (n = 30) group (post-hoc p < 0.05). The p-Tau was correlated with UHDRS TFC scores (adjusted p = 0.002). Plasma t-Tau neither differed among the groups nor associated with any clinical variables.

CONCLUSIONS

This study supports plasma NfL being a biomarker for initial HD manifestation in Korean cohort, and a novel suggestion of plasma p-Tau as a potential biomarker reflecting the clinical severity in full-manifest HD.

Historical and More Common Nongenetic Movement Disorders From Asia

Nongenetic movement disorders are common throughout the world. The movement disorders encountered may vary depending on the prevalence of certain disorders across various geographical regions. In this paper, we review historical and more common nongenetic movement disorders in Asia. The underlying causes of these movement disorders are diverse and include, among others, nutritional deficiencies, toxic and metabolic causes, and cultural Latah syndrome, contributed by geographical, economic, and cultural differences across Asia. The industrial revolution in Japan and Korea has led to diseases related to environmental toxin poisoning, such as Minamata disease and β-fluoroethyl acetate-associated cerebellar degeneration, respectively, while religious dietary restriction in the Indian subcontinent has led to infantile tremor syndrome related to vitamin B12 deficiency. In this review, we identify the salient features and key contributing factors in the development of these disorders.

Nine Hereditary Movement Disorders First Described in Asia: Their History and Evolution

Clinical case studies and reporting are important to the discovery of new disorders and the advancement of medical sciences. Both clinicians and basic scientists play equally important roles leading to treatment discoveries for both cures and symptoms. In the field of movement disorders, exceptional observation of patients from clinicians is imperative, not just for phenomenology but also for the variable occurrences of these disorders, along with other signs and symptoms, throughout the day and the disease course. The Movement Disorders in Asia Task Force (TF) was formed to help enhance and promote collaboration and research on movement disorders within the region. As a start, the TF has reviewed the original studies of the movement disorders that were preliminarily described in the region. These include nine disorders that were first described in Asia: Segawa disease, PARK-Parkin, X-linked dystonia-parkinsonism, dentatorubral-pallidoluysian atrophy, Woodhouse-Sakati syndrome, benign adult familial myoclonic epilepsy, Kufor-Rakeb disease, tremulous dystonia associated with mutation of the calmodulin-binding transcription activator 2 gene, and paroxysmal kinesigenic dyskinesia. We hope that the information provided will honor the original researchers and help us learn and understand how earlier neurologists and basic scientists together discovered new disorders and made advances in the field, which impact us all to this day.

Diet quality and prodromal Parkinson's disease probability in isolated REM sleep behavior disorder

INTRODUCTION

It is reported that a diet that lowers oxidative stress reduces the prodromal Parkinson's disease (pPD) probability as well as the risk of Parkinson's disease (PD). In this study, we evaluated whether the diet quality of patients with isolated rapid eye movement (REM) sleep behavior disorder (iRBD) were associated with the pPD probability score, PD risk markers, or prodromal markers.

METHODS

Polysomnography (PSG)-confirmed iRBD patients from the Neurology Department at Seoul National University Hospital were enrolled. We calculated the pPD probability using the "Web-based Medical Calculator for Prodromal Risk in Parkinsonism" Diet quality was assessed using the Recommended Food Score (RFS).

RESULTS

We enrolled 101 patients with iRBD. The mean RFS score of patients with iRBD was 28.23 ± 9.29, which did not differ from the general population. Among patients with iRBD, the probability of pPD did not differ between the high and low RFS groups. In patients aged <70 years, although total RFS was not correlated with pPD probability (p = 0.529, Spearman rank correlation), legume consumption was negatively correlated with pPD probability (p = 0.032): furthermore, legume consumption was significantly higher in patients with fewer prodromal markers (p = 0.016).

CONCLUSION

Diet quality assessed by RFS did not differ between the general population and patients with iRBD in Korea. Further studies are needed to confirm these protective effects of legume consumption on iRBD, which may have strong implications for the prevention and management of PD.

Inability to suppress head rotation during the saccade test as a clinical biomarker for cognitive dysfunction in Parkinson's disease

BACKGROUND

There is a need for development of reliable and accessible clinical biomarker for detecting cognitive dysfunction in PD. This study aimed to investigate whether involuntary head rotation during the saccade test could serve as a potential biomarker for screening cognitive dysfunction in PD.

METHODS

A total of 27 PD patients and nine age- and sex-matched healthy controls were prospectively enrolled in this study. A custom-designed gyroscope was attached to the forehead of each participant, and a saccade test consisting of 20 trials was conducted. The entire test was recorded on video, and two movement disorder experts independently rated the degree of head rotation, blinded to the patients' clinical information. The peak angular velocity of head rotation was derived from the gyroscope data. Participants underwent Montreal Cognitive Assessment (MoCA) as the cognitive evaluation. Correlation analysis was performed to assess the relationship between head rotation and MoCA scores.

RESULTS

The mean peak angular velocity of head rotation significantly correlated with the MoCA scores (R = -0.52, p = 0.0023) including age, sex, disease duration, and education duration as cofactors. The optimal peak angular velocity thresholds for head rotation, which aligned with the manual ratings, were determined to be 5°/s and 10°/s for raters 1 and 2, respectively. The MoCA scores exhibited significant correlations with the number of head rotations, using both the 5°/s (R = -0.36, p = 0.042) and 10°/s (R = -0.49, p = 0.0048) thresholds. Furthermore, the mean angular velocity of the head demonstrated a 100% positive predictive value and specificity for the detection of cognitive impairment (MoCA < 26), based on the cut-offs of 5°/s and 10°/s.

CONCLUSION

Inability to suppress head rotation during saccades may serve as a potential clinical biomarker for screening cognitive dysfunction in PD.

Genetic Movement Disorders Commonly Seen in Asians

The increasing availability of molecular genetic testing has changed the landscape of both genetic research and clinical practice. Not only is the pace of discovery of novel disease-causing genes accelerating but also the phenotypic spectra associated with previously known genes are expanding. These advancements lead to the awareness that some genetic movement disorders may cluster in certain ethnic populations and genetic pleiotropy may result in unique clinical presentations in specific ethnic groups. Thus, the characteristics, genetics and risk factors of movement disorders may differ between populations. Recognition of a particular clinical phenotype, combined with information about the ethnic origin of patients could lead to early and correct diagnosis and assist the development of future personalized medicine for patients with these disorders. Here, the Movement Disorders in Asia Task Force sought to review genetic movement disorders that are commonly seen in Asia, including Wilson's disease, spinocerebellar ataxias (SCA) types 12, 31, and 36, Gerstmann-Sträussler-Scheinker disease, PLA2G6-related parkinsonism, adult-onset neuronal intranuclear inclusion disease (NIID), and paroxysmal kinesigenic dyskinesia. We also review common disorders seen worldwide with specific mutations or presentations that occur frequently in Asians.

Longitudinal evolution of cortical thickness signature reflecting Lewy body dementia in isolated REM sleep behavior disorder: a prospective cohort study

BACKGROUND

The isolated rapid-eye-movement sleep behavior disorder (iRBD) is a prodromal condition of Lewy body disease including Parkinson's disease and dementia with Lewy bodies (DLB). We aim to investigate the longitudinal evolution of DLB-related cortical thickness signature in a prospective iRBD cohort and evaluate the possible predictive value of the cortical signature index in predicting dementia-first phenoconversion in individuals with iRBD.

METHODS

We enrolled 22 DLB patients, 44 healthy controls, and 50 video polysomnography-proven iRBD patients. Participants underwent 3-T magnetic resonance imaging (MRI) and clinical/neuropsychological evaluations. We characterized DLB-related whole-brain cortical thickness spatial covariance pattern (DLB-pattern) using scaled subprofile model of principal components analysis that best differentiated DLB patients from age-matched controls. We analyzed clinical and neuropsychological correlates of the DLB-pattern expression scores and the mean values of the whole-brain cortical thickness in DLB and iRBD patients. With repeated MRI data during the follow-up in our prospective iRBD cohort, we investigated the longitudinal evolution of the cortical thickness signature toward Lewy body dementia. Finally, we analyzed the potential predictive value of cortical thickness signature as a biomarker of phenoconversion in iRBD cohort.

RESULTS

The DLB-pattern was characterized by thinning of the temporal, orbitofrontal, and insular cortices and relative preservation of the precentral and inferior parietal cortices. The DLB-pattern expression scores correlated with attentional and frontal executive dysfunction (Trail Making Test-A and B: R = - 0.55, P = 0.024 and R = - 0.56, P = 0.036, respectively) as well as visuospatial impairment (Rey-figure copy test: R = - 0.54, P = 0.0047). The longitudinal trajectory of DLB-pattern revealed an increasing pattern above the cut-off in the dementia-first phenoconverters (Pearson's correlation, R = 0.74, P = 6.8 × 10^-4) but no significant change in parkinsonism-first phenoconverters (R = 0.0063, P = 0.98). The mean value of the whole-brain cortical thickness predicted phenoconversion in iRBD patients with hazard ratio of 9.33 [1.16-74.12]. The increase in DLB-pattern expression score discriminated dementia-first from parkinsonism-first phenoconversions with 88.2% accuracy.

CONCLUSION

Cortical thickness signature can effectively reflect the longitudinal evolution of Lewy body dementia in the iRBD population. Replication studies would further validate the utility of this imaging marker in iRBD.

Genome-wide association study identifies a new susceptibility locus in PLA2G4C for Multiple System Atrophy

To elucidate the molecular basis of multiple system atrophy (MSA), a neurodegenerative disease, we conducted a genome-wide association study (GWAS) in a Japanese MSA case/control series followed by replication studies in Japanese, Korean, Chinese, European and North American samples. In the GWAS stage rs2303744 on chromosome 19 showed a suggestive association ( P = 6.5 × 10 ^-7 ) that was replicated in additional Japanese samples ( P = 2.9 × 10 ^-6 . OR = 1.58; 95% confidence interval, 1.30 to 1.91), and then confirmed as highly significant in a meta-analysis of East Asian population data ( P = 5.0 × 10 ^-15 . Odds ratio= 1.49; 95% CI 1.35 to 1.72). The association of rs2303744 with MSA remained significant in combined European/North American samples ( P =0.023. Odds ratio=1.14; 95% CI 1.02 to 1.28) despite allele frequencies being quite different between these populations. rs2303744 leads to an amino acid substitution in PLA2G4C that encodes the cPLA2γ lysophospholipase/transacylase. The cPLA2γ-Ile143 isoform encoded by the MSA risk allele has significantly decreased transacylase activity compared with the alternate cPLA2γ-Val143 isoform that may perturb membrane phospholipids and α-synuclein biology.

Who are the most vulnerable populations for primary care? Avoidable hospitalizations across individuals with different types of disabilities in South Korea

BACKGROUND

Individuals with disabilities have limited access to primary care, the quality of care must be examined.

OBJECTIVE

To examine avoidable hospitalizations among individuals with disabilities and determine the most vulnerable populations across types of disabilities.

METHODS

Using the Korean National Health Insurance Claims Database, we compared hypertension- and diabetes-related avoidable hospitalizations (HRAH and DRAH, respectively) across disability status and disability type based on age-sex standardized rates from 2011 to 2020 and logistic regression.

RESULTS

The gap between those with and without disabilities in age-sex standardized HRAH and DRAH increased over 10 years. Odds ratios for HRAH were higher for those with disabilities, with individuals with mental disabilities having the highest odds ratio, followed by those with intellectual/developmental disabilities, then those with physical disabilities; for DRAH, the three highest odds ratios belonged to individuals with mental, intellectual/developmental, and visual disabilities. Among those with disabilities, HRAH was higher for those with mental, intellectual/developmental, and severe physical disabilities, whereas DRAH was higher for those with mental, severe visual, and intellectual/developmental disabilities compared to those with mild physical disabilities.

CONCLUSION

This study reveals high avoidable hospitalization rates among individuals with disabilities and calls for policies supporting quality primary care and comprehensively addressing disparities.

Increased 10-Year Prevalence of Huntington's Disease in South Korea: An Analysis of Medical Expenditure Through the National Healthcare System

BACKGROUND AND PURPOSE

This study aimed to determine the updated 10-year prevalence of Huntington's disease (HD) in South Korea and the medical and economic burdens across the duration of the disease.

METHODS

Data from the National Health Insurance database during 2010-2019 were analyzed. We identified HD cases using predefined criteria. Information on age at diagnosis, sex, and common nonneurological comorbidities were collected. We analyzed individual patterns of the use of medical services and yearly medical expenditure. Incidence rates, 10-year prevalence rates, and longitudinal medical expenditure changes were assessed.

RESULTS

New patients with HD (average=152.10) were detected every year, with an annual incidence of 0.29 per 100,000. The estimated 10-year prevalence of HD was 2.2 per 100,000. The most common ages at the time of diagnosis were 50-59 years (23.3%). In 2019, 56.4% of patients with HD were followed-up at referral or general hospitals, and 32.2% were managed at long-term-care hospitals. The annual medical cost for an individual was KRW 6,569,341±895,097 (mean±SD) (mean≈USD 5,653). Medical expenditure was the highest in those aged 60-79 years, and lowest in those younger than 30 years. However, in all age groups, the annual medical expenditure was highest during the 9 years following a diagnosis.

CONCLUSIONS

This study found that the actual prevalence of HD in South Korea was higher than previously thought and that patients are in a situation with high medical expenditure that persists over time.

Effects of Exercise on Depressive Symptoms in Patients With Parkinson Disease: A Meta-analysis

BACKGROUND AND OBJECTIVE

The purpose of this study was to provide clear evidence in support of the use of exercise to improve depressive symptoms in patients with Parkinson disease (PD) and to investigate whether this effect differs by exercise type and intensity.

METHODS

Three independent reviewers searched for randomized controlled trials (RCTs) that applied exercise interventions with depressive symptoms as an outcome measure for patients with PD on PubMed and Web of Science up to February 28, 2022. Random-effects meta-analyses were performed, in which standardized mean differences (SMDs) between the effects of exercise and control interventions on depressive symptoms with 95% CIs were calculated.

RESULTS

A total of 19 RCTs including 1,302 patients with PD were eligible for meta-analysis, and we obtained 23 comparisons from the included studies for data synthesis. Physical exercise interventions showed significant effects on the reduction in depressive symptoms in patients with PD (SMD = 0.829; 95% CI = 0.516-1.142; p < 0.001). Moderator analyses on exercise type revealed significant positive effects for combined exercise interventions (SMD = 1.111; 95% CI = 0.635-1.587; p < 0.001), whereas aerobic training alone failed to show significant effects (SMD = 0.202; 95% CI = -0.045 to 0.449; p = 0.108). Both light-to-moderate intensity exercises (SMD = 0.971; 95% CI = 0.521-1.421; p < 0.001) and moderate-to-vigorous intensity exercises (SMD = 0.779; 95% CI = 0.407-1.152; p < 0.001) significantly improved depressive symptoms with a small difference between the exercise intensities.

DISCUSSION

Our results suggest that physical exercise has significant antidepressant effects in patients with PD. These effects seemed to be more closely associated with exercise type than intensity. Different types of exercise interventions may result in greater benefit and require further investigation.

Mortality of Deep Brain Stimulation and Risk Factors in Patients With Parkinson's Disease: A National Cohort Study in Korea

BACKGROUND

This study aimed to investigate 1) long-term outcomes of deep brain stimulation (DBS), such as mortality after DBS as well as the causes of death, 2) demographic and socioeconomic factors influencing mortality, and 3) comorbidities affecting mortality after DBS in patients with Parkinson's disease (PD).

METHODS

This study analyzed the National Health Insurance Service-National Health Information Database. Data on patients with PD diagnosis codes from 2002 to 2019 were extracted and analyzed. Data on the causes of death were obtained by linking the causes of death to data from Statistics Korea. The Kaplan-Meier method with the log-rank test was used for survival analysis. Multivariate Cox regression analyses were used to estimate hazard ratios (HRs) and their 95% confidence intervals. Regarding comorbidities such as PD dementia and fracture, which did not satisfy the assumption for the proportional HR, time-dependent Cox analysis with the Mantel-Byar method was used.

RESULTS

From 2005 to 2017, among 156,875 patients diagnosed with PD in Korea, 1,079 patients underwent DBS surgery, and 251 (23.3%) had died by 2019. The most common cause of death (47.1%) was PD. In the multivariate Cox regression analysis, the higher the age at diagnosis and surgery, the higher the mortality rate. The men and medical aid groups had significantly higher mortality rates. PD dementia and fracture were identified as risk factors for mortality.

CONCLUSION

Older age at diagnosis and surgery, being male, the use of medical aid, and the comorbidity of dementia and fractures were associated with a higher risk of mortality after DBS in patients with PD. Neurologists should consider these risk factors in assessing the prognosis of PD patients undergoing DBS.

The mortality of patients with Parkinson's disease with deep brain stimulation

Background

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is effective in improving motor function in patients with Parkinson's disease (PD). This study aimed to investigate mortality associated with bilateral STN DBS in patients with PD and to assess the factors associated with mortality and causes of death after DBS.

Methods

We reviewed the medical records of 257 patients with PD who underwent bilateral STN DBS at the Movement Disorder Center at Seoul National University Hospital between March 2005 and November 2018. Patients were evaluated preoperatively, at 3, 6, and 12 months after surgery and annually thereafter. The cause and date of death were obtained from interviews with caregivers or from medical certificates at the last follow-up.

Results

Of the 257 patients with PD, 48 patients (18.7%) died, with a median time of death of 11.2 years after surgery. Pneumonia was the most common cause of death. Older age of disease onset, preoperative falling score while on medication, and higher preoperative total levodopa equivalent daily dose were associated with a higher risk of mortality in time-dependent Cox regression analysis.

Conclusion

These results confirm the mortality outcome of STN DBS in patients with advanced PD.

Association of Early Weight Change With Cognitive Decline in Patients With Parkinson Disease

BACKGROUND AND OBJECTIVE

To examine whether early weight change is associated with subsequent deterioration in cognitive function, including overall performance and specific domains, in Parkinson disease (PD).

METHODS

This observational study used data from the Parkinson Progression Markers Initiative cohort. The patients underwent annual nonmotor assessments covering neuropsychiatric, sleep-related, and autonomic symptoms for up to 8 years of follow-up. Cognitive function was measured using the Montreal Cognitive Assessment (MoCA) and detailed neuropsychological testing. Linear mixed-effects models were applied to investigate the association of early weight change with longitudinal evolution of cognitive and other nonmotor symptoms.

RESULTS

A total of 358 patients with early PD were classified into weight loss (decrease of >3% body weight during the first year; n = 98), weight maintenance (within ±3%; n = 201), and weight gain (increase of >3%; n = 59) groups. The weight loss group showed a significantly faster decline in MoCA scores than the weight maintenance group (β = -0.19, 95% CI -0.28 to -0.10). With respect to specific cognitive domains, the weight loss group showed a steeper decline in sematic fluency test scores (β = -0.37, 95% CI -0.66 to -0.08) and MoCA phonemic fluency scores (β = -0.18, 95% CI -0.31 to -0.05) and, to a lesser extent, Letter-Number Sequencing scores (β = -0.07, 95% CI -0.14 to 0.01) compared with the weight maintenance group. Conversely, the weight gain group showed a slower decline in the Symbol Digit Modalities Test scores (β = 0.34, 95% CI 0.05 to 0.63), although no association was found with longitudinal changes in MoCA scores. We did not find any significant effects of weight change on the progression of other nonmotor symptoms.

DISCUSSION

Early weight loss was associated with a faster progression of decline in global cognitive function and executive function in patients with PD, whereas early weight gain was associated with a slower progression of decline in processing speed and attention. The impact of early weight change on nonmotor symptoms seemed to be specific to cognition.

Long-Term Outcomes of Bilateral Subthalamic Nucleus Deep Brain Stimulation for Patients With Parkinson's Disease: 10 Years and Beyond

BACKGROUND

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) represents an effective treatment for severe Parkinson's disease (PD), but little is known about the long-term benefit.

OBJECTIVE

To investigate the survival rate and long-term outcome of DBS.

METHODS

We investigated all 81 patients including 37 males and 44 females who underwent bilateral STN DBS from March 2005 to March 2008 at a single institution. The current survival status of the patients was investigated. Preoperative and postoperative follow-up assessments were analyzed.

RESULTS

The mean age at the time of surgery was 62 (range 27-82) years, and the median clinical follow-up duration was 145 months. Thirty-five patients (43%) died during the follow-up period. The mean duration from DBS surgery to death was 110.46 ± 40.8 (range 0-155) months. The cumulative survival rate is as follows: 98.8 ± 1.2% (1 year), 95.1 ± 2.4% (5 years), and 79.0 ± 4.5% (10 years). Of the 81 patients, 33 (40%) were ambulatory up to more than 11 years. The Unified Parkinson's Disease Rating Scale (UPDRS) score was significantly improved until 5 years after surgery although it showed a tendency to increase again after 10 years. The patient group with both electrodes located within the STN showed a higher rate of survival and maintained ambulation.

CONCLUSION

STN DBS is a safe and effective treatment for patients with advanced PD. This study based on the long-term follow-up of large patient populations can be used to elucidate the long-term fate of patients who underwent bilateral STN DBS for PD.

In vivo and autopsy validation of alpha-synuclein seeding activity using RT-QuIC assay in the gastrointestinal tract of patients with Parkinson's disease

OBJECTIVE

In the present study, real-time quaking-induced conversion (RT-QuIC) assay was used to evaluate pathologic alpha-synuclein (AS) seeding activity in formalin-fixed paraffin-embedded (FFPE) tissue from the gastrointestinal (GI) tract of Parkinson's disease (PD) patients.

METHODS

This study was conducted in two parts: Part I. a preliminary autopsy study that included four autopsy-confirmed patients with synucleinopathy (2 PD, 1 dementia with Lewy bodies [DLB], and 1 multiple system atrophy [MSA]) and two normal autopsy controls. Frozen and FFPE tissues of the brain were obtained. Part II. a clinical case-control study that included 20 clinically diagnosed PD patients and matched controls. Surgically resected FFPE tissues from the upper and lower GI tracts were used. The RT-QuIC assay was performed to evaluate pathologic seed amplification using frozen or FFPE tissues. The presence or absence of AS aggregation was confirmed by conventional phosphorylated AS (pAS) immunohistochemistry (IHC).

RESULTS

In Part I, RT-QuIC assay showed pathologic AS amplification in frozen and FFPE brain tissues of PD and DLB patients, and FFPE stomach tissue of PD patients but not in the MSA patient and controls. In Part II, pathologic seeding activity was found in 10% (2/20) of the stomach tissues of clinical PD patients but in none of the matched controls. IHC showed pAS-positive staining in 55% of patients (11/20) and 15% of controls (3/20).

CONCLUSION

The present study results showed that the RT-QuIC assay using FFPE tissue of the GI tract was inadequate as a biomarker in PD.

Long-Term Outcomes of Deep Brain Stimulation in Pantothenate Kinase-Associated Neurodegeneration-Related Dystonia

Objective

To investigate the long-term clinical outcomes of pallidal deep brain stimulation (GPi-DBS) in patients with pantothenate kinase-associated neurodegeneration (PKAN).

Methods

We reviewed the records of patients with genetically confirmed PKAN who received bilateral GPi-DBS for refractory dystonia and were clinically followed up for at least 2 years postoperatively at two centers in Korea. Pre- and postoperative Burke- Fahn-Marsden Dystonia Rating Scale motor subscale (BFMDRS-M) scores, disability subscale (BFMDRS-D) scores, and qualitative clinical information were prospectively collected. Descriptive analysis was performed for BFMDRS-M scores, BFMDRSD scores, and the orofacial, axial, and limb subscores of the BFMDRS-M at 6-12, 24-36, and 60-72 months postoperatively.

Results

Five classic-type, four atypical-type, and one unknown-type PKAN cases were identified. The mean preoperative BFMDRS-M score was 92.1 for the classic type and 38.5 for the atypical or unknown type, with a mean BFMDRS follow-up of 50.7 months and a clinical follow-up of 69.0 months. The mean improvements in BFMDRS-M score were 11.3%, 41.3%, and 30.5% at 6-12, 24-36, and 60-72 months, respectively. In four patients with full regular evaluations until 60-72 months, improvements in the orofacial, axial, and limb subscores persisted, but the disability scores worsened from 24-36 months post-operation compared to the baseline, mainly owing to the aggravation of eating and feeding disabilities.

Conclusion

The benefits of GPi-DBS on dystonia may persist for more than 5 years in PKAN. The effects on patients' subjective disability may have a shorter duration despite improvements in dystonia owing to the complex manifestations of PKAN.

Semiautomated Algorithm for the Diagnosis of Multiple System Atrophy With Predominant Parkinsonism

Objective

Putaminal iron deposition is an important feature that helps differentiate multiple system atrophy with predominant parkinsonism (MSA-p) from Parkinson’s disease (PD). Most previous studies used visual inspection or quantitative methods with manual manipulation to perform this differentiation. We investigated the value of a new semiautomated diagnostic algorithm using 3T-MR susceptibility-weighted imaging for MSA-p.

Methods

This study included 26 MSA-p, 68 PD, and 41 normal control (NC) subjects. The algorithm was developed in 2 steps: 1) determine the image containing the remarkable putaminal margin and 2) calculate the phase-shift values, which reflect the iron concentration. The next step was to identify the best differentiating conditions among several combinations. The highest phase-shift value of each subject was used to assess the most effective diagnostic set.

Results

The raw phase-shift values were present along the lateral margin of the putamen in each group. It demonstrates an anterior-to-posterior gradient that was identified most frequently in MSA-p. The average of anterior 5 phase shift values were used for normalization. The highest area under the receiver operating characteristic curve (0.874, 80.8% sensitivity, and 86.7% specificity) of MSA-p versus PD was obtained under the combination of 3 or 4 vertical pixels and one dominant side when the normalization methods were applied. In the subanalysis for the MSA-p patients with a longer disease duration, the performance of the algorithm improved.

Conclusion

This algorithm detected the putaminal lateral margin well, provided insight into the iron distribution of the putaminal rim of MSA-p, and demonstrated good performance in differentiating MSA-p from PD.

Sensitivity of Detecting Alpha-Synuclein Accumulation in the Gastrointestinal Tract and Tissue Volume Examined

Objective

This study aimed to evaluate whether a larger tissue volume increases the sensitivity of detecting alpha-synuclein (AS) pathology in the gastrointestinal (GI) tract.

Methods

Nine patients with Parkinson’s disease (PD) or idiopathic rapid eye movement sleep disorder (iRBD) who underwent GI operation and had full-depth intestinal blocks were included. All patients were selected from our previous study population. A total of 10 slides (5 serial sections from the proximal and distal blocks) per patient were analyzed.

Results

In previous studies, pathologic evaluation revealed phosphorylated AS (+) in 5/9 patients (55.6%) and in 1/5 controls (20.0%); in this extensive examination, this increased to 8/9 patients (88.9%) but remained the same in controls (20.0%). The severity and distribution of positive findings were similar between patients with iRBD and PD.

Conclusion

Examining a large tissue volume increased the sensitivity of detecting AS accumulation in the GI tract.

High preoperative gait variability is a prognostic predictor of gait and balance in Parkinson disease patients with deep brain stimulation

INTRODUCTION

The objective biomarker for prediction of gait and balance in the long-term follow-up of Parkinson's disease(PD) patients with subthalamic nucleus deep brain stimulation(STN-DBS) has not yet been elucidated. We investigated the value of pre-operative quantitative gait parameters for the prediction of long-term prognosis of gait in PD patients with DBS.

METHODS

We retrospectively collected gait videos(both medication ON/OFF states) of PD patients recorded as preoperative evaluation before STN DBS. We enrolled patients who were followed-up for more than 5 years after the surgery from 2006 to 2014. We derived objective gait parameters from video-based gait analysis algorithm. We defined the clinical milestones of frequent falling, impaired walking, and loss of autonomy based on the Unified Parkinson's disease rating scale and Hoehn and Yahr stage, which were regularly followed up to 156 months after surgery. We calculated hazard ratios(HRs) of baseline gait parameters for predicting the clinical milestones.

RESULTS

A total of 96 gait videos from 63 PD patients were analyzed. The mean follow-up duration(standard deviation) was 88.0(34.2) months after surgery. Relatively high (>mean + 1 standard deviation) variability for step length, step time and stride time (HR = 2.92[1.02-8.33], 3.91[1.38-11.11] and 7.16[2.09-24.52],respectively) in medication-ON state significantly predicted reaching any of the three clinical milestones of frequent falling, impaired walking and loss of autonomy. Gait parameters from the medication-OFF state did not predict any clinical milestone.

CONCLUSIONS

High preoperative gait variability from the medication-ON state predicts long-term outcomes for gait and balance in PD patients with STN DBS.

Development of Clinical Milestones in Parkinson’s Disease After Bilateral Subthalamic Deep Brain Stimulation

Objective

Deep brain stimulation of the subthalamic nucleus (STN-DBS) in Parkinson’s disease (PD) patients does not halt disease progression, as these patients will progress and develop disabling non-levodopa responsive symptoms. These features may act as milestones that represent the overall functionality of patients after DBS. The objective of this study was to investigate the development of clinical milestones in advanced PD patients who underwent bilateral STN-DBS.

Methods

The study evaluated PD patients who underwent STN-DBS at baseline up to their last follow-up using the Unified Parkinson’s Disease Rating Scale and Hoehn and Yahr scale. The symptoms of hallucinations, dysarthria, dysphagia, frequent falls, difficulty walking, cognitive impairment and the loss of autonomy were chosen as the clinical milestones.

Results

A total of 106 patients with a mean age of 47.21 ± 10.52 years at disease onset, a mean age of 58.72 ± 8.74 years at surgery and a mean disease duration of 11.51 ± 4.4 years before surgery were included. Initial improvement of motor symptoms was seen after the surgery with the appearance of clinical milestones over time. Using the moderately disabling criteria, 81 patients (76.41%) developed at least one clinical milestone, while 48 patients (45.28%) developed a milestone when using the severely disabling criteria.

Conclusion

STN-DBS has a limited effect on axial and nonmotor symptoms of the PD patients, in contrast to the effect on motor symptoms. These symptoms may serve as clinical milestones that can convey the status of PD patients and its impact on the patients and their caregivers. Therefore, advanced PD patients, even those treated with bilateral STN-DBS, will still require assistance and cannot live independently in the long run.

Serum Inflammatory Markers and Progression of Nonmotor Symptoms in Early Parkinson's Disease

BACKGROUND

The influence of peripheral inflammation on nonmotor symptoms (NMSs) in Parkinson's disease (PD) remains unclear.

OBJECTIVE

The aim of this study was to explore whether serum inflammatory marker profiles are associated with the progression of NMSs in early PD.

METHODS

We included 45 patients with early PD and 20 healthy control subjects. Six inflammatory markers, including interleukin (IL)-1β, IL-2, IL-6, IL-10, tumor necrosis factor-α, and high-sensitivity C-reactive protein, were measured. NMSs were assessed using the Non-Motor Symptoms Scale, Montreal Cognitive Assessment, and Composite Autonomic Symptom Score-31 at baseline and after 3 years.

RESULTS

Principal component (PC) analysis showed that only PC3 scores, mainly loaded by IL-2 and IL-6, were significantly elevated in the PD group compared with the control group. Higher PC3 scores in the PD group were associated with faster progression of Non-Motor Symptoms Scale total and mood/apathy domain scores. There were no significant associations of PC scores with Montreal Cognitive Assessment and Composite Autonomic Symptom Score-31 score changes.

CONCLUSIONS

Peripheral inflammation may be related to the evolution of NMSs, particularly mood symptoms, in the early stages of PD. © 2022 International Parkinson and Movement Disorder Society.

Brain Metabolism Related to Mild Cognitive Impairment and Phenoconversion in Patients With Isolated REM Sleep Behavior Disorder

Background and Objectives

Mild cognitive impairment (MCI) in isolated REM sleep behavior disorder (iRBD) is a risk factor for subsequent neurodegeneration. We aimed to identify brain metabolism and functional connectivity changes related to MCI in patients with iRBD and the neuroimaging markers' predictive value for phenoconversion.

Methods

This is a prospective cohort study of patients with iRBD with a mean follow-up of 4.2 ± 2.6 years. At baseline, patients with iRBD and age- and sex-matched healthy controls (HCs) underwent ¹⁸F-fluorodeoxyglucose (FDG)–PET and resting-state fMRI scans and a comprehensive neuropsychological test battery. Voxel-wise group comparisons for FDG-PET data were performed using a general linear model. Seed-based connectivity maps were computed using brain regions showing significant hypometabolism associated with MCI in patients with iRBD and compared between groups. A Cox regression analysis was applied to investigate the association between brain metabolism and risk of phenoconversion.

Results

Forty patients with iRBD, including 21 with MCI (iRBD-MCI) and 19 with normal cognition (iRBD-NC), and 24 HCs were included in the study. The iRBD-MCI group revealed relative hypometabolism in the inferior parietal lobule, lateral and medial occipital, and middle and inferior temporal cortex bilaterally compared with HC and the iRBD-NC group. In seed-based connectivity analyses, the iRBD-MCI group exhibited decreased functional connectivity of the left angular gyrus with the occipital cortex. Of 40 patients with iRBD, 12 patients converted to Parkinson disease (PD) or dementia with Lewy bodies (DLB). Hypometabolism of the occipital pole (hazard ratio [95% CI] 6.652 [1.387–31.987]), medial occipital (4.450 [1.143–17.327]), and precuneus (3.635 [1.009–13.093]) was associated with higher phenoconversion rate to PD/DLB.

Discussion

MCI in iRBD is related to functional and metabolic changes in broad brain areas, particularly the occipital and parietal areas. Moreover, hypometabolism in these brain regions was a predictor of phenoconversion to PD or DLB. Evaluation of cognitive function and neuroimaging characteristics could be useful for risk stratification in patients with iRBD.

Quantitative Gait Analysis Using a Pose-Estimation Algorithm with a Single 2D-Video of Parkinson's Disease Patients

BACKGROUND

Clinician-based rating scales or questionnaires for gait in Parkinson's disease (PD) are subjective and sensor-based analysis is limited in accessibility.

OBJECTIVE

To develop an easily accessible and objective tool to evaluate gait in PD patients, we analyzed gait from a single 2-dimensional (2D) video.

METHODS

We prospectively recorded 2D videos of PD patients (n = 16) and healthy controls (n = 15) performing the timed up and go test (TUG). The gait was simultaneously evaluated with a pressure-sensor (GAITRite). We estimated the 3D position of toes and heels with a deep-learning based pose-estimation algorithm and calculated gait parameters including step length, step length variability, gait velocity and step cadence which was validated with the result from the GAITRite. We further calculated the time and steps required for turning. Then, we applied the algorithm to previously recorded and archived videos of PD patients (n = 32) performing the TUG.

RESULTS

From the validation experiment, gait parameters derived from video tracking were in excellent agreement with the parameters obtained with the GAITRite. (Intraclass correlation coefficient > 0.9). From the analysis with the archived videos, step length, gait velocity, number of steps, and the time required for turning were significantly correlated (Absolute R > 0.4, p < 0.005) with the Freezing of gait questionnaire, Unified PD Rating scale part III total score, HY stage and postural instability. Furthermore, the video-based tracking objectively measured significant improvement of step length, gait velocity, steps and the time required for turning with antiparkinsonian medication.

CONCLUSION

2D video-based tracking could objectively evaluate gait in PD patients.

Automatic Measurement of Postural Abnormalities With a Pose Estimation Algorithm in Parkinson's Disease

Objective

This study aims to develop an automated and objective tool to evaluate postural abnormalities in Parkinson’s disease (PD) patients.

Methods

We applied a deep learning-based pose-estimation algorithm to lateral photos of prospectively enrolled PD patients (n = 28). We automatically measured the anterior flexion angle (AFA) and dropped head angle (DHA), which were validated with conventional manual labeling methods.

Results

The automatically measured DHA and AFA were in excellent agreement with manual labeling methods (intraclass correlation coefficient > 0.95) with mean bias equal to or less than 3 degrees.

Conclusion

The deep learning-based pose-estimation algorithm objectively measured postural abnormalities in PD patients.

Relationship of Genotype, Phenotype, and Treatment in Dopa-Responsive Dystonia: MDSGene Review

BACKGROUND

Pathogenic variants in 5 genes (GCH1, TH, PTS, SPR, and QDPR), involved in dopamine/tetrahydrobiopterin biosynthesis or recycling, have been linked to Dopa-responsive dystonia (DRD). Diagnosis and treatment are often delayed due to high between- and within-group variability.

OBJECTIVES

Comprehensively analyzed individual genotype, phenotype, treatment response, and biochemistry information.

METHODS

734 DRD patients and 151 asymptomatic GCH1 mutation carriers were included using an MDSGene systematic literature review and an automated classification approach to distinguish between different forms of monogenic DRDs.

RESULTS

Whereas dystonia, L-Dopa responsiveness, early age at onset, and diurnal fluctuations were identified as red flags, parkinsonism without dystonia was rarely reported (11%) and combined with dystonia in only 18% of patients. While sex was equally distributed in autosomal recessive DRD, there was female predominance in autosomal dominant DYT/PARK-GCH1 patients accompanied by a lower median age at onset and more dystonia in females compared to males. Accordingly, the majority of asymptomatic heterozygous GCH1 mutation carriers (>8 years of age) were males. Multiple other subgroup-specific characteristics were identified, showing high accuracy in the automated classification approach: Seizures and microcephaly were mostly seen in DYT/PARK-PTS, autonomic symptoms appeared commonly in DYT/PARK-TH and DYT/PARK-PTS, and sleep disorders and oculogyric crises in DYT/PARK-SPR. Biochemically, homovanillic acid and 5-hydroxyindoleacetic acid in CSF were reduced in most DRDs, but neopterin and biopterin were increased only in DYT/PARK-PTS and DYT/PARK-SPR. Hyperphenylalaninemia was seen in DYT/PARK-PTS, DYT/PARK-QDPR, and rarely reported in autosomal recessive DYT/PARK-GCH1.

CONCLUSIONS

Our indicators will help to specify diagnosis and accelerate start of treatment. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.