Data-Driven Subtypes of Multiple System Atrophy and Their Implications for Prognosis.

Background: While multiple system atrophy (MSA) presents with high heterogeneous motor and nonmotor symptoms, the associations between clinical phenotypes and prognosis are unclear. Objective: We aimed to evaluate clinical phenotypes of MSA using data-driven approach and measure the impact of phenotypes on survival and bedbound status. Methods: 193 MSA patients were recruited from Xuanwu Hospital Capital Medical University, whose history, motor and non-motor symptoms were examined using cluster analysis. Ninety-five participants were followed-up via telephone after a mean of 31.87 months. We employed Kaplan- Meier analysis to examine survival and performed Cox and logistic regression analyses to identify factors associated with survival and bedbound status. Results: We identified four clinical profiles of MSA: cerebellar symptom-dominant, sleep and mood disorder-dominant, rigid akinetic-dominant, and malignant diffuse. The overall median survival was 7.75 years (95% CI 7.19-8.31). After adjusting for years from symptom onset to diagnosis, age and sex, patients in the malignant diffuse and rigid akinetic-dominant clusters had greater risk of death than sleep and mood disorder-dominant cluster. Furthermore, patients in the malignant diffuse and rigid akinetic-dominant clusters had higher risk of being bedbound than cerebellar symptom-dominant cluster. Conclusions: The malignant diffuse and sleep and mood disorder-dominant were identified besides the two classical subtypes, parkinsonism, and cerebellar symptom-variant. Patients with rigid-akinetic motor profiles have a worse prognosis than cerebellar symptom-dominant profiles in general. Diffuse symptoms, especially postural instability, and cognitive alterations at diagnosis, indicate rapid functional loss and disease progression. The different profiles and prognoses might indicate varied underlying pathological mechanisms.

Multiple system atrophy (MSA) is a complex disease that can affect both movement and non-movement functions of patients. However, we do not know much about how these different symptoms relate to how the patient's health might change over time. In this study, we looked at 193 MSA patients to learn more about if the patients can be distinguished into different subgroups at diagnosis and if the subgroups might be associated with their survival and ability to move in the future. We found four main subgroups of patients: group 1 characterized by the dysfunction of cerebellum (a part of the brain), group 2 characterized by sleep and mood problems, group 3 characterized by rigidity and slow movements, and group 4 with diffuse symptoms mentioned above. After tracking 95 patients for nearly 32 months, we found that those characterized by rigidity and slow movements, and those with diffuse symptoms had a higher chance of dying compared to those characterized by sleep and mood problems. Group 3 and 4 also had a higher chance of becoming unable to move out of bed. This suggests that patients with severe symptoms of rigidity and slowness at diagnosis tend to have a worse outlook than those without. And if multiple MSA symptoms are found when the patient is diagnosed, especially trouble with thinking, are also signs that the disease is getting worse quickly. By understanding these disease patterns, we can better tailor treatments and provide better support for people with MSA.

Quantitative susceptibility mapping of subcortical iron deposition in Parkinson disease and multiple system atrophy: clinical correlations and diagnostic implications.

Background: Parkinson disease (PD) and multiple system atrophy (MSA) are neurodegenerative disorders characterized by the accumulation of alpha-synuclein. Distinguishing between these conditions remains a significant challenge. This study thus employed quantitative susceptibility mapping (QSM) to evaluate subcortical iron deposition and its clinical implications in patients with PD or MSA and a group of healthy controls (HCs). Methods: The study included 26 patients with MSA, 40 patients with PD, and 35 HCs. We used magnetic resonance imaging (MRI)-based QSM to measure iron accumulation in the substantia nigra pars compacta (SNc), substantia nigra pars reticulata (SNr), and globus pallidus internus (GPi). We assessed differences between groups, examined correlations with clinical scores, and conducted receiver operating characteristic (ROC) curve analysis. Results: Compared to those with PD, patients with MSA showed more severe motor and nonmotor impairment. QSM analysis indicated a significant increase in iron levels in the SNc, SNr, and GPi regions in patient groups compared to HCs. In patients with MSA, a notable positive correlation was found between SNc QSM values and Non-Motor Symptoms Scale scores (r=0.4; P=0.043). In patients with PD, a positive association was observed between iron levels in the SNc and Unified Parkinson's Disease Rating Scale Part III (UPDRS-III) (r=0.395; P=0.012) and Hamilton Depression Rating Scale scores (r=0.313; P=0.049). Furthermore, iron content in the GPi inversely correlated with rapid-eye movement sleep behavior disorder questionnaire-Hong Kong scores (r=-0.342; P=0.031). The SNr region demonstrated the best ability to discriminate between MSA and PD with an area under the curve (AUC) of 0.67, followed by the GPi (AUC =0.64) and SNc (AUC =0.57). Conclusions: QSM effectively quantified subcortical iron deposition in the PD, MSA, and HC groups. The correlations found between iron levels and clinical manifestations provide insights into the pathophysiological processes of these disorders, highlighting the potential of QSM as a diagnostic tool for differentiation.

Striatal and Extrastriatal Monoaminergic Disruption in Progressive Supranuclear Palsy.

BACKGROUND: As a biomarker targeting vesicular monoamine transporter 2 (VMAT2), 18F-9-fluoropropyldihydrotetrabenazine (18F-FP-DTBZ) positron emission tomography (PET) is highly accurate in diagnosing Parkinson's disease (PD) and assessing its severity. However, evidence is insufficient in patients with progressive supranuclear palsy (PSP). OBJECTIVE: We evaluated the striatal and extrastriatal monoaminergic disruption of PSP and differences in patterns between patients with PSP, PD, and healthy controls (HCs) using 18F-FP-DTBZ PET, as well as its correlations with the clinical characteristics of PSP. METHODS: We recruited 58 patients with PSP, 23 age- and duration-matched patients with PD, as well as 17 HCs. Patients were scanned using 18F-FP-DTBZ PET/computed tomography, and images were spatially normalized and analyzed based on the volume of interest. RESULTS: VMAT2 binding differed significantly in the striatum and substantia nigra among the groups (P < 0.001). A more severe disruption in the caudate was noted in the PSP group (P < 0.001) than in the PD group. However, no differences were found in the nucleus accumbens, hippocampus, amygdala, or raphe between the PD and PSP groups. Within the PSP group, striatal VMAT2 binding was significantly associated with the fall/postural stability subscore of the PSP Rating Scale, especially in the putamen. Furthermore, VMAT2 binding was correlated with Mini-Mental State Examination or Montreal Cognitive Assessment in the hippocampus. CONCLUSIONS: Caudate disruptions showed prominent differences among the groups. VAMT2 binding in the striatum and hippocampus reflects the severity of fall/postural stability and cognition, respectively. © 2024 International Parkinson and Movement Disorder Society.

18F-FP-DTBZ PET/CT detectable associations between monoaminergic depletion in the putamen with rigidity and the pallidus with tremor in Parkinson's disease.

INTRODUCTION: The motor subtypes of Parkinson's disease (PD) are widely accepted and implemented. However, the motor subtypes have been thought to represent different stages of PD recently because some patients experience tremor-dominant (TD) conversion to the non-tremor-dominant subtype, such as postural instability-gait difficulty (PIGD). In this study, we explore the monoaminergic denervation features of the striatal and extra-striatal areas in patients with different subtypes of PD with 18F-9-fluoropropyl-(+)-dihydrotetrabenazine (18F-FP-DTBZ) PET/CT. METHODS: Sixty-five patients diagnosed with PD were included and classified as TD (n = 25) and PIGD (n = 40). We evaluated the difference of monoaminergic features of each subregion of brain between motor subtypes of PD, as well as associations between these features and Parkinsonian motor symptoms. RESULTS: The striatal standardized uptake value ratios (SUVR) showed that dopaminergic disruption of patients with PIGD was more symmetrical in the posterior ventral putamen (p < 0.001) and more severe in the ipsilateral posterior dorsal putamen (p < 0.001 corrected) compared with that of patients with TD. The severity of PIGD scores was associated with striatal dopaminergic depletion, while tremor was associated with monoaminergic changes in extra-striatal areas, including pallidus, thalamus, and raphe nuclie. CONCLUSION: These results indicate that patients with different motor subtypes may have different underlying mechanisms of PD pathogenesis. Therefore, accurate diagnosis of PD subtypes can aid prognosis evaluation and treatment decision-making.

Reorganization of intrinsic functional connectivity in early-stage Parkinson's disease patients with probable REM sleep behavior disorder.

REM sleep behavior disorder (RBD) symptoms in Parkinson's disease (PD) suggest both a clinically and pathologically malignant subtype. However, whether RBD symptoms are associated with alterations in the organization of whole-brain intrinsic functional networks in PD, especially at early disease stages, remains unclear. Here we use resting-state functional MRI, coupled with graph-theoretical approaches and network-based statistics analyses, and validated with large-scale network analyses, to characterize functional brain networks and their relationship with clinical measures in early PD patients with probable RBD (PD+pRBD), early PD patients without probable RBD (PD-pRBD) and healthy controls. Thirty-six PD+pRBD, 57 PD-pRBD and 71 healthy controls were included in the final analyses. The PD+pRBD group demonstrated decreased global efficiency (t = -2.036, P = 0.0432) compared to PD-pRBD, and decreased network efficiency, as well as comprehensively disrupted nodal efficiency and whole-brain networks (all eight networks, but especially in the sensorimotor, default mode and visual networks) compared to healthy controls. The PD-pRBD group showed decreased nodal degree in right ventral frontal cortex and more affected edges in the frontoparietal and ventral attention networks compared to healthy controls. Furthermore, the assortativity coefficient was negatively correlated with Montreal cognitive assessment scores in the PD+pRBD group (r = -0.365, P = 0.026, d = 0.154). The observation of altered whole-brain functional networks and its correlation with cognitive function in PD+pRBD suggest reorganization of the intrinsic functional connectivity to maintain the brain function in the early stage of the disease. Future longitudinal studies following these alterations along disease progression are warranted.

Effect of acute levodopa challenge test on cerebral blood flow in Parkinson's disease with the supine-to-standing transcranial Doppler test.

BACKGROUND: Levodopa, a common drug that improves symptoms of Parkinson's disease (PD), can induce a reduction in blood pressure (BP); however, the effect of levodopa on cerebral blood flow (CBF) remains unclear. OBJECTIVES: To observe the changes in BP and CBF during active standing before and after the acute levodopa challenge test (ALCT) and analyse the influencing factors of CBF in patients with PD. METHODS: BP and CBF velocity were simultaneously recorded by continuous beat-to-beat non-invasive BP monitoring and transcranial Doppler at supine and orthostatic positions twice, before and after ALCT. The patients were divided into two groups according to those with increased and decreased CBF at baseline after ALCT to analyse the influencing factors. RESULTS: We examined 64 patients with PD (59.2 ± 11.6 years, 33 males). BP decreased at all timepoints after ALCT, while there was no significant change in the magnitude of the drop in BP induced by standing. CBF was reduced after ALCT, especially within 15 s to 1 min of standing (15 s: 48.95 ± 13.50 vs. 44.93 ± 13.26, p < 0.001; 30 s: 52.46 ± 12.06 vs. 50.11 ± 12.56, p = 0.033; 1 min: 52.19 ± 11.83 vs. 50.17 ± 13.21, p = 0.044). Lower body mass index (ß = -0.280, p = 0.027) was an independent factor associated with CBF reduction after ALCT. CONCLUSIONS: Additional attention should be paid to changes in CBF and BP within 1 min after standing in patients with PD taking levodopa, especially in those with low bodyweight.

Dysconnectivity of the parafascicular nucleus in Parkinson's disease: A dynamic causal modeling analysis.

BACKGROUND: Recent animal model studies have suggested that the parafascicular nucleus has the potential to be an effective deep brain stimulation target for Parkinson's disease. However, our knowledge on the role of the parafascicular nucleus in Parkinson's disease patients remains limited. OBJECTIVE: We aimed to investigate the functional alterations of the parafascicular nucleus projections in Parkinson's disease patients. METHODS: We enrolled 72 Parkinson's disease patients and 60 healthy controls, then utilized resting-state functional MRI and spectral dynamic causal modeling to explore the effective connectivity of the bilateral parafascicular nucleus to the dorsal putamen, nucleus accumbens, and subthalamic nucleus. The associations between the effective connectivity of the parafascicular nucleus projections and clinical features were measured with Pearson partial correlations. RESULTS: Compared with controls, the effective connectivity from the parafascicular nucleus to dorsal putamen was significantly increased, while the connectivity to the nucleus accumbens and subthalamic nucleus was significantly reduced in Parkinson's disease patients. There was a significantly positive correlation between the connectivity of parafascicular nucleus-dorsal putamen projection and motor deficits. The connectivity from the parafascicular nucleus to the subthalamic nucleus was negatively correlated with motor deficits and apathy, while the connectivity from the parafascicular nucleus to the nucleus accumbens was negatively associated with depression. CONCLUSION: The present study demonstrates that the parafascicular nucleus-related projections are damaged and associated with clinical symptoms of Parkinson's disease. Our findings provide new insights into the impaired basal ganglia-thalamocortical circuits and give support for the parafascicular nucleus as a potential effective neuromodulating target of the disease.

The mechanism of impaired delayed recall verbal memory function in Parkinson's disease with orthostatic hypotension: a multiple imaging study.

Introduction: Orthostatic hypotension (OH) frequently accompanies autonomic dysfunction and is an important risk factor for cognitive impairment in Parkinson's disease (PD). However, the association between different cognitive functions and OH in PD patients is not yet fully understood. Methods: This study aimed to evaluate the scores of different cognitive domains and multiple parameters using different imaging techniques on PD patients with or without OH. A total number of 31 PD patients with OH (n = 20) and without OH (n = 11) were recruited from the Department of Neurology, Beijing Xuanwu Hospital for this study. All patients underwent beat-to-beat non-invasive blood pressure recordings and an active standing test to evaluate neurogenic OH and a global neuropsychological test to assess cognitive function. All patients underwent dynamic cerebral autoregulation (dCA) measurement, brain magnetic resonance imaging (MRI), and brain 18fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT). Results: The results showed that OH patients had poor delayed recall verbal memory when compared with the PD patients without OH (1.75 ± 1.59 vs. 3.10 ± 1.73, p = 0.042). The dCA test indicated a significant difference in the right very low-frequency (VLF) gain between two groups (1.27 ± 0.17 vs. 1.10 ± 0.26, p = 0.045) and the brain 18F-FDG PET/CT indicated a significant difference in the SUV (right medial temporal lobe) to SUV (occipital lobe) ratio (0.60 ± 0.08 vs. 0.67 ± 0.11, p = 0.049). Meanwhile, these two imaging parameters were negatively correlated (p < 0.001). Furthermore, the score of a delayed recall verbal memory in the OH group was positively correlated with the right medial temporal lobe to occipital lobe ratio (p < 0.001) and was negatively correlated with the right VLF gain (p = 0.023). Discussion: PD with OH patients had poor delayed recall memory, which might have been caused by the decreased metabolic dysfunction of specific medial temporal lobe due to the impaired dCA ability.

Effects of different levodopa doses on blood pressure in older patients with early and middle stages of Parkinson's disease.

Objective: Levodopa is the first-line treatment for patients with Parkinson's disease (PD). However, only a few studies have focused on the tolerance of this drug in older patients with PD in the early and middle stages. Therefore, this study aimed to explore the effects of different levodopa doses on blood pressure (BP) in this subpopulation. Methods: This cohort analysis enrolled 83 patients. The levodopa challenge test was used to evaluate drug responsiveness. After at least 12 h following anti-PD drug discontinuation, patients' BPs were measured in a lying position, after 1 min standing, and after 3 min standing, in "off state" and best "on state." Results: BP in the 250 mg and 375 mg levodopa/benserazide groups decreased significantly in the lying and standing positions. The 3-min standing-position systolic BP was significantly influenced by the dose of levodopa/benserazide. However, no statistical change was observed in the 125 mg group. The postural-mediated systolic BP disparity was significant at 3 min in the upright position. Nineteen (incidence, 22.9%) and Twenty-five patients (incidence, 30.1%) developed complications of orthostatic hypotension (OH) in the "off state" and best "on state," respectively. Mild cognitive impairment was a risk factor for OH occurrence in the "off state." The OH occurrence in the best "on state" was associated with OH in the "off state" and urinary incontinence. Conclusion: Our findings suggest that 250 mg or more of levodopa/benserazide could significantly reduce BP and orthostatic effect in older patients with PD in the early and middle stages. Therefore, they should routinely monitor their BP. Trial registration number: ChiCTR2200055707.

Novel mutations and molecular pathways identified in patients with brain iron accumulation disorders.

Brain iron accumulation disorders (BIADs) are a group of diseases characterized by iron overload in deep gray matter nuclei, which is a common feature of neurodegenerative diseases. Although genetic factors have been reported to be one of the etiologies, much more details about the genetic background and molecular mechanism of BIADs remain unclear. This study aimed to illustrate the genetic characteristics of BIADs and clarify their molecular mechanisms. A total of 84 patients with BIADs were recruited from April 2018 to October 2022 at Xuanwu Hospital. Clinical characteristics including family history, consanguineous marriage history, and age at onset (AAO) were collected and assessed by two senior neurologists. Neuroimaging data were conducted for all the patients, including cranial magnetic resonance imaging (MRI) and susceptibility-weighted imaging (SWI). Whole-exome sequencing (WES) and capillary electrophoresis for detecting sequence mutation and trinucleotide repeat expansion, respectively, were conducted on all patients and part of their parents (whose samples were available). Variant pathogenicity was assessed according to the American College of Medical Genetics and Association for Molecular Pathology (ACMG/AMP). The NBIA and NBIA-like genes with mutations were included for bioinformatic analysis, using Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genome (KEGG). GO annotation and KEGG pathway analysis were performed on Metascape platform. In the 84 patients, 30 (35.7%) were found to carry mutations, among which 20 carried non-dynamic mutations (missense, stop-gained, frameshift, inframe, and exonic deletion) and 10 carried repeat expansion mutations. Compared with sporadic cases, familial cases had more genetic variants (non-dynamic mutation: P=0.025, dynamic mutation: P=0.003). AAO was 27.85±10.42 years in cases with non-dynamic mutations, which was significantly younger than those without mutations (43.13±17.17, t=3.724, P<0.001) and those with repeated expansions (45.40±8.90, t=4.550, P<0.001). Bioinformatic analysis suggested that genes in lipid metabolism, autophagy, mitochondria regulation, and ferroptosis pathways are more likely to be involved in the pathogenesis of BIADs. This study broadens the genetic spectrum of BIADs and has important implications in genetic counselling and clinical diagnosis. Patients diagnosed as BIADs with early AAO and family history are more likely to carry mutations. Bioinformatic analysis provides new insights into the molecular pathogenesis of BIADs, which may shed lights on the therapeutic strategy for neurodegenerative diseases.

The differences of orthostatic hypotension in patients with Parkinson's disease and multiple system atrophy.

Background: Multiple system atrophy (MSA) and Parkinson's disease (PD) have similar clinical presentations in their early stages. Orthostatic hypotension (OH) is a common autonomic dysfunction associated with MSA and PD. Heart rate (HR) and systolic blood pressure (SBP) changes are measured in response to the active standing test, which is widely used to screen for cardiovascular autonomic function. Objectives and methods: Overall, 255 patients (67 MSA, 188 PD) underwent continuous beat-to-beat non-invasive BP monitoring and active standing test. The total standing time was 10 min, and the BP differences between both groups were compared to determine whether the ΔHR/ΔSBP can differentiate both conditions. Results: Classical orthostatic hypotension (COH) (52%) and initial OH (19%) were most common in MSA and PD, respectively. MSA had a higher HR (75.0 ± 9.7 vs. 71.0 ± 10.7, P = 0.008) than PD in the supine position. SBP (135.70 ± 15.68 mmHg vs. 127.31 ± 15.14 mmHg, P = 0.106), diastolic BP (78.45 ± 12.36 mmHg vs. 67.15 ± 13.39 mmHg, P = 0.009) and HR (73.94 ± 8.39 bpm vs. 71.08 ± 13.52 bpm, P = 0.389) at baseline were higher in MSA-COH than in PD-COH. After adjusting for age and disease duration, the ΔHR/ΔSBP-10 min significantly discriminated MSA-COH from PD-COH (P = 0.031). An ΔHR/ΔSBP-10 min of 0.517 showed a sensitivity of 67% and specificity of 84% (AUC = 0.77, 95% CI: 0.63-0.91). Conclusion: The SBP, diastolic BP, and HR were higher in the supine position; however, ΔHR and ΔSBP were lower after standing in MSA patients than in PD patients. The ΔHR/ΔSBP-10 min discriminated between MSA-COH and PD-COH with quiet acceptable accuracy.

Parkinson's disease and comorbid myasthenia gravis: a case report and literature review.

Background: Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease. Myasthenia gravis (MG) is a rare autoimmune disease caused by antibodies against the neuromuscular junction. PD and comorbid MG are rarely seen. Case presentation: Here we report on a patient who was diagnosed with PD and MG. A 74-year-old man had a 4-year history of bradykinesia and was diagnosed with PD. He subsequently developed incomplete palpebral ptosis, apparent dropped head, and shuffling of gait. The results of neostigmine tests were positive. Repetitive nerve stimulation (RNS) showed significant decremental responses at 3 and 5 Hz in the orbicularis oculi. The patient's anti-acetylcholine receptor (anti-AchR) antibody serum level was also elevated. Meanwhile, 9-[18F]fluoropropyl-(+)-dihydrotetrabenazine positron emission tomography-computed tomography (18F-AV133 PET-CT) scan revealed a significant decrease in uptake in the bilateral putamen. After addition of cholinesterase inhibitors, his symptoms of palpebral ptosis and head drop improved greatly and he showed a good response to levodopa. Conclusion: Although PD with MG is rare, we still need to notice the possibility that a PD patient may have comorbid MG. The underlying mechanism of PD and comorbid MG remains unknown, but an imbalance between the neurotransmitters dopamine and acetylcholine and the immune system are likely to play significant roles in the pathogenesis. In this article, we present our case and a literature review on the co-occurrence of PD and MG, reviewing their clinical features, and discuss the underlying pathogenic mechanism of this comorbidity.

Elderly-Onset Paroxysmal Kinesigenic Dyskinesia: A Case Report.

Paroxysmal kinesigenic dyskinesia (PKD) is characterized by transient and recurrent involuntary movements that are triggered by a sudden movement. Here, we report an elderly female patient with a 1-month history of paroxysmal rigidity of the right limb. As the symptoms were characterized as paroxysmal, transient, and repetitive, her condition was initially thought to be epilepsy. Subsequent examinations showed no abnormality in the continuous video-electroencephalogram (EEG) monitoring, magnetic resonance imaging (MRI), fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT), and genetic testing. The final diagnosis was identified as clinically diagnosed PKD, and the symptoms were well controlled after oxcarbazepine treatment. To our knowledge, this is the first report to show elderly-onset PKD. This case expands our understanding of the age of onset of PKD. However, it is necessary to differentiate PKD from reflex epilepsy and hysteria attacks. For patients with typical clinical manifestations, we should adhere to the standard diagnostic workflow for the efficient diagnosis of PKD, aiming at avoiding misdiagnosis and mistreatment.

Impaired dynamic cerebral autoregulation: A potential mechanism of orthostatic hypotension and dementia in Parkinson's disease.

Background: Orthostatic hypotension (OH) and cognitive impairment are common non-motor symptoms of Parkinson's disease (PD). This study aimed to investigate whether impaired dynamic cerebral autoregulation (dCA) is associated with OH and Parkinson's disease dementia (PDD), and analyze the related risk factors in patients with PDD. Materials and methods: We enrolled 89 patients with PD and 20 age- and sex-matched healthy controls (HCs). Cognition and different cognitive domains were assessed by the Montreal Cognitive Assessment scale. Non-invasive continuous beat-to-beat blood pressure and cerebral blood flow velocity were assessed using a servo-controlled finger plethysmograph and transcranial Doppler, respectively. dCA was examined using supine and orthostatic changes with transfer function analysis to derive the autoregulatory parameters of phase, gain, and coherence. Logistic regression analysis was performed to determine the risk factors for PDD. Results: We found that 21 (23.6%) patients with PD had OH. These patients showed worse cognitive performance in specific cognitive tasks, such as language and orientation. The patients with OH also had poorer dCA; the very low frequency (VLF) phase in two different postures was lower than that in patients without OH as well as HCs (both P < 0.05). And the normalized gain in the VLF and low frequency (LF) in standing position was higher in PD patients with and without OH than in HCs. PDD patients also had significantly higher LF normalized gain when standing than patients without dementia (P = 0.015), indicating impaired dCA. LF normalized gain in standing (odds ratio: 3.756, 95% confidence interval: 1.241-11.367) and education were significantly associated with PDD. Conclusion: Diminished dCA may represent a potential mechanism for OH and cognitive impairment and low educational level might be a significant factor contributing to the increased risk of PDD.

Case report: Combined therapy of bilateral subthalamic nucleus deep brain stimulation and spinal cord stimulation significantly improves motor function in a patient with multiple system atrophy with predominant parkinsonism.

Multiple system atrophy with predominant parkinsonism (MSA-P) is a highly incapacitating disease with a short life expectancy and symptomatic therapy is still limited. In this report, we presented the case of a 65-year-old woman with a 3-year history of severe rigidity, bradykinesia, and gait dysfunction alongside severe freezing of gait diagnosed with MSA-P. She underwent combined therapy of bilateral subthalamic nucleus deep brain stimulation (DBS) and low-thoracic spinal cord stimulation (SCS). The double-blind evaluation of the Movement Disorder Society Sponsored Revision of the Unified Parkinson's Disease Rating Scale part III and 7-m Timed Up and Go at follow-ups showed her cardinal parkinsonian symptoms benefit significantly from DBS stimulation, while the improvement of SCS was mainly embodied in lower-limb symptoms. The combined stimulation achieved a better improvement of motor function than either DBS or SCS stimulation alone. Most notably, the improvement of lower-limb symptoms was significantly enhanced by the combined stimulation.

Impaired Cerebral Autoregulation in Parkinson's Disease: An Orthostatic Hypotension Analysis.

Orthostatic hypotension (OH) is an early non-motor manifestation of Parkinson's disease (PD). However, the underlying mechanism of hemodynamic changes in patients with PD and OH remains unclear. This study aimed to investigate the dynamic cerebral autoregulation changes in patients with PD with OH. Ninety patients with PD and 20 age- and sex-matched healthy controls (HCs) were recruited. The patients' non-invasive blood pressure (BP) and cerebral blood flow velocity were simultaneously recorded at supine and orthostatic positions during the active standing test (AST). Transfer function analysis was used to determine autoregulatory parameters including gain [i.e., damping effect of dynamic cerebral autoregulation (dCA) on the magnitude of BP oscillation] and phase difference (i.e., the time delay of the cerebral blood flow response to BP). Sixteen patients (17.8%) in the PD population were diagnosed with OH (PD-OH). The AST results were normal for 74 patients (82.2%) (PD-NOR). In the supine position, the PD-OH group had a lower phase degree than the PD-NOR group (50.3 ± 23.4 vs. 72.6 ± 32.2 vs. 68.9 ± 12.1, p = 0.020); however, no significant difference was found upon comparing with the HC group. In the orthostatic position, the normalized gain was significantly higher for the symptomatic OH group than for the asymptomatic OH group and HC group (1.50 ± 0.58 vs. 0.97 ± 0.29 vs. 1.10 ± 0.31, p = 0.019). A symptomatic OH in the PD population indicates an impaired cerebral autoregulation ability in the orthostatic position. Cerebral autoregulation tends to be impaired in the supine position in the OH population.

Detection of Motor Dysfunction With Wearable Sensors in Patients With Idiopathic Rapid Eye Movement Disorder.

Patients with idiopathic rapid eye movement sleep behavior disorder (iRBD) are at high risk for conversion to synucleinopathy and Parkinson disease (PD). This can potentially be monitored by measuring gait characteristics of iRBD patients, although quantitative data are scarce and previous studies have reported inconsistent findings. This study investigated subclinical gait changes in polysomnography-proven iRBD patients compared to healthy controls (HCs) during 3 different walking conditions using wearable motor sensors in order to determine whether gait changes can be detected in iRBD patients that could reflect early symptoms of movement disorder. A total 31 iRBD patients and 20 HCs were asked to walk in a 10-m corridor at their usual pace, their fastest pace, and a normal pace while performing an arithmetic operation (dual-task condition) for 1 min each while using a wearable gait analysis system. General gait measurements including stride length, stride velocity, stride time, gait length asymmetry, and gait variability did not differ between iRBD patients and HCs; however, the patients showed decreases in range of motion (P = 0.004) and peak angular velocity of the trunk (P = 0.001) that were significant in all 3 walking conditions. iRBD patients also had a longer step time before turning compared to HCs (P = 0.035), and the difference between groups remained significant after adjusting for age, sex, and height. The decreased trunk motion while walking and increased step time before turning observed in iRBD may be early manifestations of body rigidity and freezing of gait and are possible prodromal symptoms of PD.

Recommendations for the diagnosis and treatment of paroxysmal kinesigenic dyskinesia: an expert consensus in China.

Paroxysmal dyskinesias are a group of neurological diseases characterized by intermittent episodes of involuntary movements with different causes. Paroxysmal kinesigenic dyskinesia (PKD) is the most common type of paroxysmal dyskinesia and can be divided into primary and secondary types based on the etiology. Clinically, PKD is characterized by recurrent and transient attacks of involuntary movements precipitated by a sudden voluntary action. The major cause of primary PKD is genetic abnormalities, and the inheritance pattern of PKD is mainly autosomal-dominant with incomplete penetrance. The proline-rich transmembrane protein 2 (PRRT2) was the first identified causative gene of PKD, accounting for the majority of PKD cases worldwide. An increasing number of studies has revealed the clinical and genetic characteristics, as well as the underlying mechanisms of PKD. By seeking the views of domestic experts, we propose an expert consensus regarding the diagnosis and treatment of PKD to help establish standardized clinical evaluation and therapies for PKD. In this consensus, we review the clinical manifestations, etiology, clinical diagnostic criteria and therapeutic recommendations for PKD, and results of genetic analyses in PKD patients performed in domestic hospitals.

Case Report: Progressive Asymmetric Parkinsonism Secondary to CADASIL Without Dementia.

Parkinsonism is a rare phenotype of cerebral autosomal dominant arteriopathy with subcortical infarction and leukoencephalopathy (CADASIL), all of which involve cognitive decline. Normal cognition has not been reported in previous disease studies. Here we report the case of a 60-year-old female patient with a 2-year history of progressive asymmetric parkinsonism. On examination, she showed severe parkinsonism featuring bradykinesia and axial and limb rigidity with preserved cognition. Magnetic resonance imaging (MRI) revealed white matter hyperintensity in the external capsule and periventricular region. Dopaminergic response was limited. A missense mutation c.1630C>T (p.R544C) on the NOTCH3 gene was identified on whole-exome sequencing, which confirmed the diagnosis of vascular parkinsonism secondary to CADASIL. A diagnosis of CADASIL should be considered in asymmetric parkinsonism without dementia. Characteristic MRI findings support the diagnosis.

Risk factors for possible REM sleep behavior disorders: A community-based study in Beijing.

OBJECTIVE: To explore the risk factors for idiopathic REM sleep behavior disorder (RBD) in a community population in Beijing. METHODS: Participants aged 55 years and above were recruited from the Beijing Longitudinal Study on Aging II cohort. We identified individuals with possible RBD (pRBD) using the validated RBD Questionnaire-Hong Kong in 2010. A series of environmental, lifestyle, and other potential risk factors were assessed via standardized questionnaires in 2009. Multivariable logistic regression analysis was performed to investigate the association between the studied factors and pRBD. RESULTS: Of 7,225 participants who were free of parkinsonism and dementia, 219 (3.0%) individuals were considered as having pRBD. Participants with pRBD reported more nonmotor and motor symptoms of Parkinson disease (PD) with adjusted odds ratios (ORs) ranging from 1.10 to 4.40. Participants with pRBD were more likely to report a family history of parkinsonism or dementia (OR 3.03, 95% confidence interval [CI] 1.23-7.46). There was a significant association between pRBD and self-reported hyperlipidemia (OR 1.51, 95% CI 1.09-2.10), ever smoking (OR 1.79, 95% CI 1.20-2.65), prior carbon monoxide (CO) poisoning (OR 2.30, 95% CI 1.39-3.83), and nonoccupational exposure to pesticides (OR 2.21, 95% CI 1.40-3.50). CONCLUSION: Our study replicated previously reported associations between pRBD and hyperlipidemia, smoking, pesticide exposure, and several prodromal PD symptoms. We also found previously unreported links with a positive family history of parkinsonism or dementia and CO poisoning. Risk factor profiles for pRBD partially resemble those defined for PD, but also differ in distinct ways.