Multiple system atrophy: prognostic indicators of survival

Different neurotoxicity and seeding activity between α-synuclein oligomers formed in plasma of patients with Parkinson's disease and multiple system atrophy

Previous studies have shown that α-synuclein (α-Syn) aggregates derived from the brains of patients with Parkinson's disease (PD) and multiple system atrophy (MSA) exhibit different phosphorylation, cytotoxicity, and seeding activity. However, the mechanism underlying the differences remains poorly understood. Here, recombinant human α-Syn was incubated in the plasma of patients with PD and MSA, and the oligomers formed in the plasma (PD-O-α-Syn and MSA-O-α-Syn) were purified and analyzed for their phosphorylation, cytotoxicity and seeding activity. In vitro assays revealed that both PD-O-α-Syn and MSA-O-α-Syn were phosphorylated at serine 129. However, the phosphorylation degree of MSA-O-α-Syn was significantly higher than that of PD-O-α-Syn. In addition, MSA-O-α-Syn exhibited stronger cytotoxicity and seeding activity compared with PD-O-α-Syn. In vivo experiments showed that mice receiving intrastriatal inoculation of MSA-O-α-Syn developed more severe motor dysfunction and dopaminergic degeneration than mice receiving intrastriatal inoculation of PD-O-α-Syn. Compared with the mice inoculated with PD-O-α-Syn, the mice inoculated with MSA-O-α-Syn accumulated more phosphorylated and oligomerized α-Syn in the striatum and brain regions (substantia nigra, hippocampus and prefrontal cortex) away from the inoculated site. The results obtained suggest that α-Syn oligomers formed in PD and MSA plasma are different in phosphorylation, cytotoxicity, and seeding activity.

Epidemiologic and clinical features of multisystem atrophy: a population-based study in Navarre, Spain

BACKGROUND

Epidemiological studies on multisystem atrophy (MSA) are scarce. Our aim has been to analyse 10-year incidence, point prevalence, survival, and the time to diagnosis of MSA in Navarre, a northern Spanish region.

METHODS

This is a population-based observational retrospective study, from 2012 to 2021, which covered the population of Navarre (followed until 31 December 2021). Data from various sources of health information were reviewed in order to identify all potential diagnoses of MSA, that were validated from medical records. Patients were included if they fulfilled the new Movement Disorder Society criteria.

RESULTS

We observed a crude average annual incidence rate (IR) of 0.49/100,000 person-years, with the highest occurring in the age group of 60-69 years. No significant IR differences by sex or subtype were observed. Point prevalence in December 2021 was 2.43/100,000 inhabitants. Joinpoint analysis for global incidence and prevalence experienced stable annual rates during the whole period, showing an upward trend for prevalence without a statistically significant slop. The median age at symptom onset was 65 years (range 47-76). The median time to diagnosis was 36 months, without statistically significant differences between sex, age at diagnosis or subtypes. Median time of survival from clinical onset was 7 years. Age of onset above 70 years and autonomic onset were associated with reduced survival.

CONCLUSIONS

This is the first population-based epidemiological study on MSA in Spain. It provides detailed incidence and prevalence data for MSA that may be useful for appropriate management of health resources.

Severity of sleep apnea as a prognostic factor for mortality in patients with multiple system atrophy

BACKGROUND

We determined whether the severity of sleep apnea increases the risk of mortality in patients with multiple system atrophy (MSA) with and without stridor. MethodsThis retrospective study included patients who underwent polysomnography within one year after diagnosis of probable MSA. Stridor, sleep apnea, and arousal from sleep were determined using full-night polysomnography. Disease severity was measured using the Unified MSA Rating Scale (UMSARS). Survival data were collected and analyzed using Cox regression analysis.

RESULTS

Sixty-four patients with MSA were included. During a median follow-up of 34.5 months, 49 (76.6 %) patients died. Stridor was present in 56.3 % of patients. Patients with stridor had more severe sleep apnea and shorter sleep time than those without, but the hazard ratio (HR) for death did not differ between patients with and without stridor. Among patients without stridor, apnea-hypopnea index ≥30/h (HR, 6.850; 95 % confidence interval [CI], 1.983-23.664; p = 0.002) and a score of UMSARS I + II (HR, 1.080; 95 % CI, 1.040-1.121; p < 0.001) were independently associated with death. In contrast, among patients with stridor, frequent arousals from sleep (HR, 0.254; 95 % CI, 0.089-0.729; p = 0.011) were a significant factor associated with longer survival, while MSA-cerebellar type tended to be associated with poor survival (HR, 2.195; 95 % CI, 0.941-5.120; p = 0.069).

CONCLUSION

The severity of sleep apnea might be a significant predictor of shorter survival in MSA patients without stridor, whereas frequent arousals from sleep might be a significant predictor for longer survival in MSA patients with stridor.

Impaired vestibular function associated with orthostatic hypotension in patients with multiple system atrophy

BACKGROUND

Orthostatic hypotension (OH) is one of the most common symptoms in patients with multiple system atrophy (MSA). Vestibular system plays an important role in blood pressure regulation during orthostatic challenges through vestibular-sympathetic reflex. The current study aimed to investigate the relationship between vestibular function and OH in patients with MSA.

METHODS

Participants with MSA, including 20 with OH (mean age, 57.55 ± 8.44 years; 7 females) and 15 without OH (mean age, 59.00 ± 8.12 years; 2 females) and 18 healthy controls (mean age, 59.03 ± 6.44 years; 8 females) were enrolled. Cervical and ocular vestibular evoked myogenic potentials (cVEMPs and oVEMPs) tests were conducted to evaluate vestibular function.

RESULTS

Patients with MSA presented with significantly higher rate of absent cVEMPs (57.1% vs 11.1%, p = 0.001) and oVEMPs (25.7% vs 0, p = 0.021) than controls. MSA patients with OH showed more absent cVEMPs (75.0% vs 11.1%, Bonferroni corrected p < 0.001) and oVEMPs (40.0% vs 0, Bonferroni corrected p = 0.003) than controls. Patients with OH also showed higher rate of absent cVEMPs than those without OH (33.3%, Bonferroni corrected p = 0.014).

CONCLUSIONS

Our results demonstrated that impairment of vestibular function was associated with MSA, particularly in those with OH. Absent VEMPs may be a potential marker for MSA severity. Our findings suggest that impaired vestibular function is involved in OH development and may serve as an intervention target.

Sex-related differences in the clinical presentation of multiple system atrophy

PURPOSE

To investigate sex-related differences in the clinical presentation of multiple system atrophy (MSA) through a literature review and an analysis of a retrospective cohort.

METHODS

The PubMed database was searched for articles including sex-related information in MSA. In a retrospective Innsbruck cohort, we investigated the baseline to last available follow-up clinical-demographic differences between men and women with MSA in a univariate fashion, followed by multivariable binary regression analysis.

RESULTS

The literature search yielded 46 publications with sex-related information in MSA. Most studies found comparable survival rates between the sexes, while some recent reports suggested a potential survival benefit for women, possibly due to initial motor onset and overall less severe autonomic failure compared to men. The retrospective Innsbruck MSA cohort comprised 56 female and 60 male individuals with a comparable median follow-up of 27 months. At baseline, female sex was independently associated with depression (odds ratio [OR] 4.7; p = 0.007) and male sex with severe orthostatic hypotension (OR 5.5; p = 0.016). In addition, at last follow-up, female sex was associated with the intake of central nervous system-active drugs (OR 4.1; p = 0.029), whereas male sex was associated with the presence of supine hypertension (OR 3.0; p = 0.020) and the intake of antihypertensive medications (OR 8.7; p = 0.001). Male sex was also associated with initiation of antihypertensive medications over the observation period (OR 12.4; p = 0.004).

CONCLUSION

The available literature and findings of the present study indicate sex-related differences in the clinical presentation of MSA and its evolution over time, highlighting the importance of considering sex in symptom exploration, therapeutic decision-making, and future clinical trial design.

Clinical Characteristics and Outcomes in Young-Onset Multiple System Atrophy

BACKGROUND

Young-onset multiple system atrophy (YOMSA) is defined as the onset of multiple system atrophy (MSA) before the age of 40 years old. YOMSA is rare and there is much uncertainty of the phenotype and natural history in patients with YOMSA.

OBJECTIVE

The objective is to evaluate the characteristics and disease course of patients with YOMSA.

METHODS

We retrospectively reviewed medical records of patients with MSA who were evaluated at all Mayo Clinic sites from 1998 to 2021. We identified patients with YOMSA and evaluated clinical characteristics, autonomic function testing results, and disease course.

RESULTS

Of 1496 patients with a diagnosis of clinically probable or clinically established MSA, 20 patients had YOMSA. The median age of onset was 39.1 (interquartile range [IQR] = 37.1, 40.1) years; 13 patients (65%) were male. MSA-parkinsonism was the most common subtype (65%). The median duration of symptom onset to YOMSA diagnosis was 4.9 (IQR = 3.7, 9) years. At the time of medical record review, 17 patients were deceased with a median survival of 8.3 (IQR = 7, 10.9) years. Univariate analysis showed that initial onset of autonomic failure predicted unfavorable survival (hazard ratio = 2.89, P = 0.04) compared to those who presented with motor impairment only at onset. At the time of YOMSA diagnosis, composite autonomic severity score was available in 19 patients with a median of 5 (IQR = 4, 6.5).

CONCLUSIONS

YOMSA resembles MSA in most aspects including phenotype and prognosis, although the diagnosis is usually delayed. The presence of autonomic failure at symptom onset may be a poor predictor for survival.

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.

Development and Validation of a Prognostic Model to Predict Overall Survival in Multiple System Atrophy

Background

Multiple system atrophy (MSA) is a devastating disease characterized by a variable combination of motor and autonomic symptoms. Previous studies identified numerous clinical factors to be associated with shorter survival.

Objective

To enable personalized patient counseling, we aimed at developing a risk model of survival based on baseline clinical symptoms.

Methods

MSA patients referred to the Movement Disorders Unit in Innsbruck, Austria, between 1999 and 2016 were retrospectively analyzed. Kaplan-Meier curves and multivariate Cox regression analysis with least absolute shrinkage and selection operator penalty for variable selection were performed to identify prognostic factors. A nomogram was developed to estimate the 7 years overall survival probability. The performance of the predictive model was validated and calibrated internally using bootstrap resampling and externally using data from the prospective European MSA Study Group Natural History Study.

Results

A total of 210 MSA patients were included in this analysis, of which 124 patients died. The median survival was 7 years. The following clinical variables were found to significantly affect overall survival and were included in the nomogram: age at symptom onset, falls within 3 years of onset, early autonomic failure including orthostatic hypotension and urogenital failure, and lacking levodopa response. The time-dependent area under curve for internal and external validation was >0.7 within the first 7 years of the disease course. The model was well calibrated showing good overlap between predicted and actual survival probability at 7 years.

Conclusion

The nomogram is a simple tool to predict survival on an individual basis and may help to improve counseling and treatment of MSA patients.

Sex differences in alpha-synucleinopathies: a systematic review

Background

Past research indicates a higher prevalence, incidence, and severe clinical manifestations of alpha-synucleinopathies in men, leading to a suggestion of neuroprotective properties of female sex hormones (especially estrogen). The potential pathomechanisms of any such effect on alpha-synucleinopathies, however, are far from understood. With that aim, we undertook to systematically review, and to critically assess, contemporary evidence on sex and gender differences in alpha-synucleinopathies using a bench-to-bedside approach.

Methods

In this systematic review, studies investigating sex and gender differences in alpha-synucleinopathies (Rapid Eye Movement (REM) Behavior Disorder (RBD), Parkinson's Disease (PD), Dementia with Lewy Bodies (DLB), Multiple System Atrophy (MSA)) from 2012 to 2022 were identified using electronic database searches of PubMed, Embase and Ovid.

Results

One hundred sixty-two studies were included; 5 RBD, 6 MSA, 20 DLB and 131 PD studies. Overall, there is conclusive evidence to suggest sex-and gender-specific manifestation in demographics, biomarkers, genetics, clinical features, interventions, and quality of life in alpha-synucleinopathies. Only limited data exists on the effects of distinct sex hormones, with majority of studies concentrating on estrogen and its speculated neuroprotective effects.

Conclusion

Future studies disentangling the underlying sex-specific mechanisms of alpha-synucleinopathies are urgently needed in order to enable novel sex-specific therapeutics.

Factors impacting quality of life in multiple system atrophy

Background

Multiple system atrophy (MSA) is an atypical parkinsonian disorder marked by autonomic dysfunction, parkinsonism, cerebellar dysfunction, and poor response to dopaminergic medications such as levodopa. Patient-reported quality of life is an important benchmark for clinicians and clinical trials. The Unified Multiple System Atrophy Rating Scale (UMSARS) allows healthcare providers to rate and assess MSA progression. The MSA-QoL questionnaire is a health-related quality of life scale intended to provide patient-reported outcome measures. In this article, we investigated inter-scale correlations between the MSA-QoL and UMSARS to determine factors impacting the quality of life of patients with MSA.

Methods

Twenty patients at the Johns Hopkins Atypical Parkinsonism Center's Multidisciplinary Clinic with a diagnosis of clinically probable MSA and who filled out the MSA-QoL and UMSARS questionnaires within 2 weeks of each other were included. Inter-scale correlations between MSA-QoL and UMSARS responses were examined. Linear regressions were also performed to examine relationships between both scales.

Results

Significant inter-scale correlations were found between the MSA-QoL and UMSARS, both between MSA-QoL total score and UMSARS Part I subtotal scores and for individual scale items. There were no significant correlations between MSA-QoL life satisfaction rating and UMSARS subtotal scores or any specific UMSARS items. Linear regression analysis found significant associations between MSA-QoL total score and UMSARS Part I and total scores, and between MSA-QoL life satisfaction rating and UMSARS Part I, Part II, and total scores (after adjustment for age).

Conclusions

Our study demonstrates significant inter-scale correlations between MSA-QoL and UMSARS, particularly relating to activities of daily living and hygiene. MSA-QoL total score and UMSARS Part I subtotal scores, which assess patients' functional status, were significantly correlated. The lack of significant associations between MSA-QoL life satisfaction rating and any UMSARS item suggests there may be aspects to quality of life that are not fully captured by this assessment. Larger cross-sectional and longitudinal analyses utilizing UMSARS and MSA-QoL are warranted and modification of the UMSARS should be considered.

The characteristic of nonmotor symptoms with different phenotypes and onsets in multiple system atrophy patients

OBJECTIVES

The characteristic of nonmotor symptoms in patients with multiple system atrophy (MSA) has varied among previous studies. The objective was to investigatethe nonmotor characteristics in MSA patients with different phenotypes, sex and different onset patterns.

METHODS

We performed a retrospective review of 1492 MSA patients. All cases were evaluatedby neurologists and assessed with motormanifestations, nonmotor symptoms, auxiliary examinationand brain MRI scans.

RESULTS

Multiple system atrophy-cerebellar ataxia (MSA-C) was the predominant phenotype in 998 patients. Average age of onset (56.8 ± 9.2 years) was earlier, the disease duration (2.4 ± 2.2 year) was shorter and brain MRI abnormalities (49.2 %) were more frequently in MSA-C (P < 0.001). Multiple system atrophy-parkinsonism (MSA-P) patients were more likely to have nonmotor symptoms. After adjusted significant parameters, urinary dysfunction (OR 1.441, 95 %CI = 1.067-1.946, P = 0.017), constipation (OR 1.482, 95 %CI = 1.113-1.973, P = 0.007), cognitive impairment (OR 1.509, 95 %CI = 1.074-2.121, P = 0.018) and drooling (OR 2.095, 95 %CI = 1.248-3.518, P = 0.005) were associated with the MSA-P phenotype. Males were more likely to have orthostatic hypotension, urinary dysfunction, sexual dysfunction, drooling and females in constipation and probable RBD. In different onset patterns, constipation (59.2 %) and probable RBD (28.4 %) were more frequently in autonomiconset pattern.

CONCLUSIONS

MSA-C is the predominant phenotype in Chinese patients, while many nonmotor symptoms are more common in MSA-P phenotype. Patients with different sex and onset patterns have different nonmotor characteristics. The different clinical features identified could help the physician counseling of MSA patients more easily and more accurately.

Serotonin in synucleinopathies

Dysfunction of the serotonergic system represents an important feature in synucleinopathies like Parkinson disease (PD), dementia with Lewy bodies (DLB) and Multiple system atrophy (MSA). Serotonergic fibers from the raphe nuclei (RN) extend broadly throughout the central nervous system, innervating several brain areas affected in synucleinopathies. Alterations of the serotonergic system are associated with non-motor symptoms or motor complications in PD as well as with autonomic features of MSA. Postmortem studies, data from transgenic animal models and imaging techniques greatly contributed to the understanding of this serotonergic pathophysiology in the past, even leading to preclinical and clinical candidate drug tests targeting different parts of the serotonergic system. In this article, we review most recent work extending the knowledge of the serotonergic system and highlighting its relevance for the pathophysiology of synucleinopathies.

Longitudinal interrogation of sympathetic neural circuits and hemodynamics in preclinical models

Neurological disorders, including spinal cord injury, result in hemodynamic instability due to the disruption of supraspinal projections to the sympathetic circuits located in the spinal cord. We recently developed a preclinical model that allows the identification of the topology and dynamics through which sympathetic circuits modulate hemodynamics, supporting the development of a neuroprosthetic baroreflex that precisely controls blood pressure in rats, monkeys and humans with spinal cord injuries. Here, we describe the continuous monitoring of arterial blood pressure and sympathetic nerve activity over several months in preclinical models of chronic neurological disorders using commercially available telemetry technologies, as well as optogenetic and neuronal tract-tracing procedures specifically adapted to the sympathetic circuitry. Using a blueprint to construct a negative-pressure chamber, the approach enables the reproduction, in rats, of well-controlled and reproducible episodes of hypotension-mimicking orthostatic challenges already used in humans. Blood pressure variations can thus be directly induced and linked to the molecular, functional and anatomical properties of specific neurons in the brainstem, spinal cord and ganglia. Each procedure can be completed in under 2 h, while the construction of the negative-pressure chamber requires up to 1 week. With training, individuals with a basic understanding of cardiovascular physiology, engineering or neuroscience can collect longitudinal recordings of hemodynamics and sympathetic nerve activity over several months.

Non-motor symptoms in multiple system atrophy: A comparative study with Parkinson's disease and progressive supranuclear palsy

Background

Non-motor symptoms (NMS) are compulsory clinical features for the clinical diagnosis of multiple system atrophy (MSA), some of which precede motor symptoms onset. To date, few studies have systematically investigated NMS in MSA and the timing of presenting NMS as the disease progresses. Clinically, MSA is difficult to be differentiated from Parkinson's disease (PD) and progressive supranuclear palsy (PSP), and the differences in NMS between MSA and PD/PSP remain unclear. The aim of this study was to compare the burden of NMS between MSA and PD/PSP and to delineate the timing of NMS presentation relative to the onset of motor symptoms in MSA.

Methods

A total of 61, 87, and 30 patients with MSA, PD, and PSP, respectively, were enrolled in this study. NMS was systematically assessed in all patients using the NMS scale (NMSS), and the onset of NMS relative to the onset of motor symptoms in MSA was investigated.

Results

MSA group had higher total NMSS scores (82.15 ± 46.10) than the PD (36.14 ± 30.78) and PSP (50.30 ± 55.05) groups (p < 0.001 overall). The number distribution pattern of the NMS was significantly different among the three parkinsonian disorders (p < 0.001 overall). In total, 85.2% of patients with MSA had more than 10 NMS, which was significantly higher than PD (28.7%) and PSP (33.3%). The frequency and scores of many NMSS subdomains and symptoms were higher in MSA than in PD and PSP (all p < 0.05). Multivariate logistic regression analysis revealed that patients with fainting, lack of motivation, swallowing, and loss of sexual interest could be attributed to MSA rather than PD or PSP, while patients with loss of concentration and forgetfulness were characteristic features of PD or PSP rather than MSA. REM-sleep behavior disorder (RBD), constipation, problems having sex, and loss of sexual interest preceded the motor symptoms onset of MSA by 2.81 ± 4.51, 1.54 ± 6.32, 1.35 ± 4.70, and 0.45 ± 3.61 years, respectively.

Conclusion

The NMS spectrum in MSA differs from that of PD and PSP. Patients with MSA have a higher NMS burden than patients with PD or PSP. RBD, constipation, problems having sex, and loss of sexual interest may become early diagnostic clinical markers of MSA.

Predicting the Prognosis of Multiple System Atrophy Using Cluster and Principal Component Analysis

BACKGROUND

Multiple system atrophy (MSA) is an intractable neurodegenerative disorder with poorly understanding of prognostic factors.

OBJECTIVE

The purpose of this retrospective longitudinal study was to explore the main predictors of survival of MSA patients with new clinical subtypes based on cluster analysis.

METHODS

A total of 153 Chinese MSA patients were recruited in our study. The basic demographic data and motor and nonmotor symptoms were assessed. Cluster and principal component analysis (PCA) were used to eliminate collinearity and search for new clinical subtypes. The multivariable Cox regression was used to find factors associated with survival in MSA patients.

RESULTS

The median survival time from symptom onset to death (estimated using data from all patients by Kaplan-Meier analysis) was 6.3 (95% CI = 6.1-6.7) years. The survival model showed that a shorter survival time was associated with motor principal component (PC)1 (HR = 1.71, 95% CI: 1.26-2.30, p < 0.001) and nonmotor PC3 (HR = 1.68, 95% CI: 1.31-2.10, p < 0.001) through PCA. Four clusters were identified: Cluster 1 (mild), Cluster 2 (mood disorder-dominant), Cluster 3 (axial symptoms and cognitive impairment-dominant), and Cluster 4 (autonomic failure-dominant). Multivariate Cox regression indicated that Cluster 3 (HR = 4.15, 95% CI: 1.73-9.90, p = 0.001) and Cluster 4 (HR = 4.18, 95% CI: 1.73-10.1, p = 0.002) were independently associated with shorter survival time.

CONCLUSION

More serious motor symptoms, axial symptoms such as falls and dysphagia, orthostatic hypotension, and cognitive impairment were associated with poor survival in MSA via PCA and cluster analysis.

Pathological Appearance of a Case of Preclinical Multiple System Atrophy: A Comparison With Advanced Cases

We aimed to investigate the frequency of multiple system atrophy (MSA) in a large number of forensic autopsies and characterize the pathological appearance of preclinical MSA. We investigated a series of 1930 brains from forensic autopsies. In addition to performing immunohistochemistry for phosphorylated α-synuclein, the levels of 3 autonomic nervous system markers (catecholaminergic, serotonergic, and cholinergic) were used to assess the peripheral nerve (heart and superior cervical ganglion) and medulla oblongata. The results were compared to those of healthy control and Parkinson disease (PD) cases. Four cases (0.21%) were identified as having MSA. Cases 1-3 were symptomatic, and Case 4 was incipient; that is, although no neuronal loss was evident, the cerebellar dentate nucleus exhibited marked grumose degeneration. Immunohistochemistry revealed a marked reduction in autonomic nervous system marker levels expressed in the medulla; this reduction was more prominent in the 3 symptomatic MSA cases than in the PD case. The opposite occurred for the peripheral nerve. Case 4 exhibited mild cholinergic nerve reduction. Two cases showed possible significant pathological changes in the heart. Grumose degeneration, few oligodendroglial cytoplasmic inclusions without neuronal loss, and less reduction of autonomic nervous tissue were more prominent in the preclinical case than in symptomatic cases.

Laboratory prognostic factors for the long-term survival of multiple system atrophy

To elucidate the biomarkers related to survival in multiple system atrophy(MSA), we analyzed the predictability of retrospectively collected blood markers for survival in 650 probable MSA. High absolute neutrophil count, red-cell distribution width, C-reactive protein, erythrocyte sedimentation rate, and low hemoglobin, protein, albumin, and creatinine were correlated with higher mortality in MSA. Systemic alteration in inflammation and nutritional status in the early stage are associated with higher mortality in MSA.

Diagnosing Premotor Multiple System Atrophy: Natural History and Autonomic Testing in an Autopsy-Confirmed Cohort

BACKGROUND AND OBJECTIVES

Nonmotor features precede motor symptoms in many patients with multiple system atrophy (MSA). However, little is known about differences between the natural history, progression, and prognostic factors for survival in patients with MSA with nonmotor vs motor presentations. We aimed to compare initial symptoms, disease progression, and clinical features at final evaluation and investigate differences in survival and natural history between patients with MSA with motor and nonmotor presentations.

METHODS

Medical records of autopsy-confirmed MSA cases at Queen Square Brain Bank who underwent both clinical examination and cardiovascular autonomic testing were identified. Clinical features, age at onset, sex, time from onset to diagnosis, disease duration, autonomic function tests, and plasma noradrenaline levels were evaluated.

RESULTS

Forty-seven patients with autopsy-confirmed MSA (age 60 ± 8 years; 28 men) were identified. Time from symptom onset to first autonomic evaluation was 4 ± 2 years, and the disease duration was 7.7 ± 2.2 years. Fifteen (32%) patients presented with nonmotor features including genitourinary dysfunction, orthostatic hypotension, or REM sleep behavior disorder before developing motor involvement (median delay 1-6 years). A third (5/15) were initially diagnosed with pure autonomic failure (PAF) before evolving into MSA. All these patients had normal supine plasma noradrenaline levels (332.0 ± 120.3 pg/mL) with no rise on head-up tilt (0.1 ± 0.3 pg/mL). Patients with MSA with early cardiovascular autonomic dysfunction (within 3 years of symptom onset) had shorter survival compared with those with later onset of cardiovascular autonomic impairment (6.8 years [5.6-7.9] vs 8.5 years [7.9-9.2]; p = 0.026). Patients with early urinary catheterization had shorter survival than those requiring catheterization later (6.2 years [4.6-7.8] vs 8.5 years [7.6-9.4]; p = 0.02). The survival of patients with MSA presenting with motor and nonmotor symptoms did not differ (p > 0.05).

DISCUSSION

Almost one-third of patients with MSA presented with nonmotor features, which could predate motor symptoms by up to 6 years. Cardiovascular autonomic failure and early urinary catheterization were predictors of poorer outcomes. A normal supine plasma noradrenaline level in patients presenting with PAF phenotype is a possible autonomic biomarker indicating later conversion to MSA.

Disease Progression in Multiple System Atrophy-Novel Modeling Framework and Predictive Factors

BACKGROUND

Multiple system atrophy (MSA) is a rare and aggressive neurodegenerative disease that typically leads to death 6 to 10 years after symptom onset. The rapid evolution renders it crucial to understand the general disease progression and factors affecting the disease course.

OBJECTIVES

The aims of this study were to develop a novel disease-progression model to estimate a population-level MSA progression trajectory and predict patient-specific continuous disease stages describing the degree of progress into the disease.

METHODS

The disease-progression model estimated a population-level progression trajectory of subscales of the Unified MSA Rating Scale and the Unified Parkinson's Disease Rating Scale using patients in the European MSA natural history study. The predicted disease continuum was validated via multiple analyses based on reported anchor points, and the effect of MSA subtype on the rate of disease progression was evaluated.

RESULTS

The predicted disease continuum spanned approximately 6 years, with an estimated average duration of 51 months for a patient with global disability score 0 to reach the highest level of 4. The predicted continuous disease stages were shown to be correlated with time of symptom onset and predictive of survival time. MSA motor subtype was found to significantly affect disease progression, with MSA-parkinsonian (MSA-P) type patients having an accelerated rate of progression.

CONCLUSIONS

The proposed modeling framework introduces a new method of analyzing and interpreting the progression of MSA. It can provide new insights and opportunities for investigating covariate effects on the rate of progression and provide well-founded predictions of patient-level future progressions. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Implanted System for Orthostatic Hypotension in Multiple-System Atrophy

Orthostatic hypotension is a cardinal feature of multiple-system atrophy. The upright posture provokes syncopal episodes that prevent patients from standing and walking for more than brief periods. We implanted a system to restore regulation of blood pressure and enable a patient with multiple-system atrophy to stand and walk after having lost these abilities because of orthostatic hypotension. This system involved epidural electrical stimulation delivered over the thoracic spinal cord with accelerometers that detected changes in body position. (Funded by the Defitech Foundation.).

Tracheostomy is associated with increased survival in multiple system atrophy patients with stridor

Background and purpose

Stridor treatment in multiple system atrophy (MSA) mainly comprises tracheostomy or continuous positive airway pressure (CPAP), but guidelines for the use of these treatments are lacking. The aim of the study was to evaluate the predictive value of stridor treatment in an MSA cohort.

Methods

This is a retrospective and prospective monocentric cohort study including MSA patients evaluated at least once a year during the disease course. Stridor was video‐polysomnography confirmed. The time of stridor treatment (CPAP or tracheostomy) and latency from stridor onset were collected. Survival and predictors of survival were calculated.

Results

A total of 182 (107 males, mean age at disease onset 57.3 ± 8.4 years) MSA patients were included in the study; 141 were deceased at the time of study. Of the total sample, 75 patients were diagnosed with stridor: 22 patients were treated with tracheostomy and 29 with CPAP, whilst 24 patients did not receive treatment. Treatment with tracheostomy showed longer survival compared with both treatment with CPAP or no treatment (incidence rate of death 12 vs. 21 vs. 23 per 100 person‐years, respectively). Tracheostomy remained an independent factor associated with longer survival (hazard ratio 0.38, p = 0.029), also after adjustment for other confounders and latency for stridor treatment.

Conclusions

This is the largest monocentric and long‐term follow‐up study comparing survival between tracheostomy and CPAP in MSA patients with stridor. Treatment with tracheostomy showed longer survival compared with both treatment with CPAP or no treatment. A careful multidisciplinary approach is required for the management of MSA patients with stridor.

Clinical and pathological characteristics of later onset multiple system atrophy

BACKGROUND

In the current consensus criteria, onset after age 75 is considered as non-supporting for diagnosis of multiples system atrophy (MSA); however, some MSA patients present after age 75. Clinical and pathological characteristics of such later onset MSA (LO-MSA) compared to usual onset MSA (UO-MSA) remain poorly understood.

METHODS

The clinical cohort included patients from Kobe University Hospital and Amagasaki General Medical Center Hospital, while the autopsy cohort was from the brain bank at Mayo Clinic Florida. We identified 83 patients in the clinical cohort and 193 patients in the autopsy cohort. We divided MSA into two groups according to age at onset: UO-MSA (≤ 75) and LO-MSA (> 75). We compared clinical features and outcomes between the two groups in the clinical cohort and compared the findings to the autopsy cohort.

RESULTS

LO-MSA accounted for 8% in the clinical cohort and 5% in the autopsy cohort. The median time from onset to death or to life-saving tracheostomy was significantly shorter in LO-MSA than in UO-MSA in both cohorts (4.8 vs 7.9 years in the clinical cohort and 3.9 vs 7.5 years in the autopsy cohort; P = 0.043 and P < 0.0001, respectively). The median time from diagnosis to death was less than 3 years in LO-MSA in the clinical cohort.

CONCLUSIONS

Some MSA patients have late age of onset and short survival, limiting time for clinical decision making. MSA should be considered in the differential diagnosis of elderly patients with autonomic symptoms and extrapyramidal and/or cerebellar syndromes.

Diagnostic and Prognostic Value of External Anal Sphincter EMG Patterns in Multiple System Atrophy

Background

It is debated whether external anal sphincter (EAS) electromyography can distinguish between multiple system atrophy (MSA) and Parkinson's disease (PD), whereas its usefulness for MSA prognosis is unknown.

Objectives

We explored the diagnostic and prognostic value and clinical correlations of EAS electromyography patterns in MSA.

Methods

We collected clinical data and EAS electromyography findings in 72 patients with MSA and 21 with PD.

Results

We identified four EAS patterns. The normal pattern was frequently observed in PD and associated with prolonged survival when identified in MSA. Abnormal patterns were predominant in MSA. The most severe pattern was associated with the highest likelihood of MSA diagnosis and with the worst prognosis in the MSA cohort. MSA patients with EAS abnormalities often showed urogenital symptoms and fecal incontinence.

Conclusions

The increasing severity of EAS electromyography patterns paralleled diagnostic accuracy and survival in MSA, and correlated with prevalence of bladder and bowel symptoms. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

Effects of Non-invasive Brain Stimulation on Multiple System Atrophy: A Systematic Review

Background/Objective: Multiple system atrophy (MSA) refers to a progressive neurodegenerative disease characterized by autonomic dysfunction, parkinsonism, cerebellar ataxia, as well as cognitive deficits. Non-invasive brain stimulation (NIBS) has recently served as a therapeutic technique for MSA by personalized stimulation. The primary aim of this systematic review is to assess the effects of NIBS on two subtypes of MSA: parkinsonian-type MSA (MSA-P) and cerebellar-type MSA (MSA-C).

Methods: A literature search for English articles was conducted from PubMed, Embase, Web of Science, Cochrane Library, CENTRAL, CINAHL, and PsycINFO up to August 2021. Original articles investigating the therapeutics application of NIBS in MSA were screened and analyzed by two independent reviewers. Moreover, a customized form was adopted to extract data, and the quality of articles was assessed based on the PEDro scale for clinical articles.

Results: On the whole, nine articles were included, i.e., five for repetitive transcranial magnetic stimulation (rTMS), two for transcranial direct current stimulation (tDCS), one for paired associative stimulation, with 123 patients recruited. The mentioned articles comprised three randomized controlled trials, two controlled trials, two non-controlled trials, and two case reports which assessed NIBS effects on motor function, cognitive function, and brain modulatory effects. The majority of articles demonstrated significant motor symptoms improvement and increased cerebellar activation in the short term after active rTMS. Furthermore, short-term and long-term effects on improvement of motor performance were significant for tDCS. As opposed to the mentioned, no significant change of motor cortical excitability was reported after paired associative stimulation.

Conclusion: NIBS can serve as a useful neurorehabilitation strategy to improve motor and cognitive function in MSA-P and MSA-C patients. However, further high-quality articles are required to examine the underlying mechanisms and standardized protocol of rTMS as well as its long-term effect. Furthermore, the effects of other NIBS subtypes on MSA still need further investigation.

Ambulatory blood pressure and drug treatment for orthostatic hypotension as predictors of mortality in patients with Multiple System Atrophy

OBJECTIVES

Multiple system atrophy (MSA) is a rare fatal neurodegenerative disease characterized by parkinsonism, cerebellar ataxia and autonomic failure. This study aimed at investigating possible associations between mortality, 24H blood pressure (BP) level and variability, and drug treatments for orthostatic hypotension (OH) in MSA patients.

METHODS

One hundred and twenty-nine patients followed at the French Reference Center for MSA who underwent routine 24H ambulatory BP monitoring, were included. Unified MSA Rating Scale (UMSARS) scores, drug treatments and the occurrence and cause of death were recorded.

RESULTS

Seventy patients died during follow-up (2.9±1.8 years), mainly from terminal illness, pulmonary or sudden death. Multivariate Cox regression analysis, after adjustment for gender, disease duration and severity (UMSARS I+II score), showed that increased daytime systolic BP variability, OH severity and OH drug treatment were independently correlated with mortality. OH treatment was associated with the risk of cardiac causes and/or sudden death (p=0.01). In a fully adjusted model, male gender [(female vs male) Hazard ratio (HR): 0.56 95% CI [0.34-0.94] p=0.03], UMSARS I+II score [HR: 1.04 95% CI [1.02-1.06] p<0.01], systolic BP daytime variability [HR: 3.66 95% CI (1.46-9.17 p<0.01] and OH treatment [HR: 2.13 95 % CI [1.15- 3.94]; p=0.02] predicted mortality.

CONCLUSION

Increased daytime BP variability and OH treatment were predictive of mortality in patients with MSA, independently from disease severity. Further studies are required to assess if these associations are explained by more severe autonomic dysfunction or if OH treatment exposes "per se" to a specific risk in this population.

Neurofilament Light Chain Predicts Disease Severity and Progression in Multiple System Atrophy

BACKGROUND

Neurofilament light chain (NFL), a potential biomarker of multiple system atrophy (MSA), has been reported in several studies.

OBJECTIVES

The objective of this study was to investigate whether plasma NFL levels are correlated with the progression of motor and cognition function in MSA.

METHODS

Patients with MSA were part of a prospective cohort study with assessments at baseline and after 1 year. Plasma NFL was quantified using ultrasensitive Simoa technology.

RESULTS

A total of 91 patients with MSA and 60 healthy controls (HCs) were enrolled. NFL levels increased from baseline to 1-year follow-up (P = 0.010). Baseline plasma NFL levels were significantly associated with motor severity and progression in patients with MSA (P < 0.05) but not with cognitive progression (P > 0.05).

CONCLUSIONS

Plasma NFL is a reliable biomarker for the disease severity of MSA and monitoring the progression of MSA, but not the progression of cognition. © 2021 International Parkinson and Movement Disorder Society.

A historical review of multiple system atrophy with a critical appraisal of cellular and animal models

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder characterized by striatonigral degeneration (SND), olivopontocerebellar atrophy (OPCA), and dysautonomia with cerebellar ataxia or parkinsonian motor features. Isolated autonomic dysfunction with predominant genitourinary dysfunction and orthostatic hypotension and REM sleep behavior disorder are common characteristics of a prodromal phase, which may occur years prior to motor-symptom onset. MSA is a unique synucleinopathy, in which alpha-synuclein (aSyn) accumulates and forms insoluble inclusions in the cytoplasm of oligodendrocytes, termed glial cytoplasmic inclusions (GCIs). The origin of, and precise mechanism by which aSyn accumulates in MSA are unknown, and, therefore, disease-modifying therapies to halt or slow the progression of MSA are currently unavailable. For these reasons, much focus in the field is concerned with deciphering the complex neuropathological mechanisms by which MSA begins and progresses through the course of the disease. This review focuses on the history, etiopathogenesis, neuropathology, as well as cell and animal models of MSA.

Early recognition and diagnosis of multiple system atrophy: best practice and emerging concepts

Introduction: Multiple system atrophy (MSA) is a progressive degenerative disorder of the central and autonomic nervous systems characterized by parkinsonism, cerebellar ataxia, dysautonomia, and pyramidal signs. The confirmatory diagnosis is pathological, but clinical-diagnostic criteria have been developed to help clinicians. To date, the early diagnosis of MSA is challenging due to the lack of reliable diagnostic biomarkers.Areas covered: The authors reappraised the main clinical, neurophysiological, imaging, genetic, and laboratory evidence to help in the early diagnosis of MSA in the clinical and in the research settings. They also addressed the practical clinical issues in the differential diagnosis between MSA and other parkinsonian and cerebellar syndromes. Finally, the authors summarized the unmet needs in the early diagnosis of MSA and proposed the next steps for future research efforts in this field.Expert opinion: In the last decade, many advances have been achieved to help the correct MSA diagnosis since early stages. In the next future, the early diagnosis and correct classification of MSA, together with a better knowledge of the causative mechanisms of the disease, will hopefully allow the identification of suitable candidates to enroll in clinical trials and select the most appropriate disease-modifying strategies to slow down disease progression.

Quantitative gait and postural analyses in patients with diabetic polyneuropathy

BACKGROUND

Although gait disturbances are relatively common symptoms in diabetic polyneuropathy (DPN), few studies have quantitatively analyzed gait and posture in DPN patients. This study aimed to analyze gait and posture quantitatively in DPN patients and to determine the association between clinical and electrophysiological parameters and gait and posture parameters.

METHODS

Sixty-four DPN patients were enrolled in this study. DPN was clinically assessed using the Toronto clinical neuropathy score (TCNS). All participants underwent nerve conduction study (NCS), three-dimensional motion analysis, and static posturography. We evaluate the correlation of gait and posture parameters with electrophysiological and clinical parameters.

RESULTS

Foot height, step length, and stride length among gait parameters were inversely correlated with the TCNS. Anteroposterior range during eyes-closed and mediolateral distance and range during eyes-open and eyes-closed were inversely correlated with the sensory nerve action potential amplitude in the sural nerve. Mediolateral distance during eyes-open and eyes-closed was correlated with the compound muscle action potential amplitude in the peroneal nerve.

CONCLUSIONS

Gait parameters are associated with clinical parameters, and postural parameters are associated with electrophysiological parameters, particularly sensory NCS. Gait and postural analysis can be a useful tool for assessing the neurological status in DPN patients.

Interrelationships between Survival, Sex, and Blood Pressure in Patients with Multiple System Atrophy

OBJECTIVE

The aim of this study is to estimate survival among patients with multiple system atrophy-parkinsonian type (MSA-P) or cerebellar type MSA (MSA-C) in relation to blood pressure (BP) measurements, by sex.

METHODS

A cohort of 99 MSA patients was studied retrospectively. Their BP measurements were obtained during prolonged (40 min, vertical position) drug-free tilt testing. We used K-M survival curves and Cox regression to calculate adjusted (to age of onset) hazard ratios (HRs) of BP measurements on time to death by MSA subtype and sex.

RESULTS

Fifty-two MSA patients were males and 47 were females. Sixty-three of them had MSA-P and 36 had MSA-C. The mean age at motor symptom onset was 61.1 ± 10.4 years, and mean disease duration at the time of BP assessment was 8.0 ± 4.7 years. The 2 study groups (MSA-P and MSA-C) did not differ significantly in age at MSA onset, sex ratio, or disease duration. Survival time did not differ between the groups {medians: 12 years (95% confidence interval [CI]: 8-28) and 10 years (95% CI: 8-13), respectively}. The MSA-P group showed a trend towards better survival for males (log-rank p = 0.0925). The maximal diastolic orthostatic BP decline during tilt testing had a borderline positive association with death risk among MSA-C males (adjusted HR = 1.18, p = 0.0665), and systolic BP after 10 min in a supine position had a significant positive association with death risk among MSA-P males (adjusted HR = 1.06, p = 0.0354).

CONCLUSIONS

The findings of a sex-based difference in the effect of BP on death risk may be important for adjusting the therapeutic approach to MSA patients.

Electrodiagnostic assessment of the autonomic nervous system: A consensus statement endorsed by the American Autonomic Society, American Academy of Neurology, and the International Federation of Clinical Neurophysiology

Evaluation of disorders of the autonomic nervous system is both an art and a science, calling upon the physician's most astute clinical skills as well as knowledge of autonomic neurology and physiology. Over the last three decades, the development of noninvasive clinical tests that assess the function of autonomic nerves, the validation and standardization of these tests, and the growth of a large body of literature characterizing test results in patients with autonomic disorders have equipped clinical practice further with a valuable set of objective tools to assist diagnosis and prognosis. This review, based on current evidence, outlines an international expert consensus set of recommendations to guide clinical electrodiagnostic autonomic testing. Grading and localization of autonomic deficits incorporates scores from sympathetic cardiovascular adrenergic, parasympathetic cardiovagal, and sudomotor testing, as no single test alone is sufficient to diagnose the degree or distribution of autonomic failure. The composite autonomic severity score (CASS) is a useful score of autonomic failure that is normalized for age and gender. Valid indications for autonomic testing include generalized autonomic failure, regional or selective system syndromes of autonomic impairment, peripheral autonomic neuropathy and ganglionopathy, small fiber neuropathy, orthostatic hypotension, orthostatic intolerance, syncope, neurodegenerative disorders, autonomic hyperactivity, and anhidrosis.

Respiratory and sleep-related complications of multiple system atrophy

PURPOSE OF REVIEW

The purpose of this article is to provide a contemporary review of sleep issues affecting patients with multiple system atrophy (MSA).

RECENT FINDINGS

Prodromal symptoms of MSA may occur years prior to diagnosis, including autonomic dysfunction such as orthostatic hypotension, urogenital dysfunction, rapid eye movement (REM) sleep behavior disorder (RBD), and stridor. Patients may also develop sleep-related respiratory disorders such as obstructive sleep apnea (OSA), central sleep apnea (CSA), and stridor. The development of stridor is associated with a shortened lifespan and sudden death, which may be further accelerated by autonomic instability. MSA appears to follow a 'prion-like' disease progression.

SUMMARY

MSA is a rapidly progressive neurodegenerative disease characterized by a combination of autonomic failure and motor symptoms. MSA is often misdiagnosed as the initial presentation mimics other neurodegenerative disorders. There are diagnostic criteria to identify possible, probable, and definite MSA. Prodromal symptoms may occur years prior to diagnosis, including autonomic dysfunction such as orthostatic hypotension, urogenital dysfunction, REM RBD, and stridor. In previous years, treatment consisted of tracheostomy but did not address the component of CSA, which commonly coexisted or developed later because of destruction of medullary chemoreceptors. Positive airway pressure may be as effective as tracheostomy alone in ameliorating obstruction at the vocal cord level.

Alpha-Synuclein Oligomers and Neurofilament Light Chain in Spinal Fluid Differentiate Multiple System Atrophy from Lewy Body Synucleinopathies

OBJECTIVE

To explore the role of alpha-synuclein (αSyn) oligomers and neurofilament light chain (NFL) in cerebrospinal fluid (CSF) as markers of early multiple system atrophy (MSA) and to contrast findings with Lewy body synucleinopathies.

METHODS

In a discovery cohort of well-characterized early MSA patients (n = 24) and matched healthy controls (CON, n = 14), we utilized enzyme-linked immunosorbent assay to measure NFL and protein misfolding cyclic amplification (PMCA) to detect αSyn oligomers in CSF. We confirmed findings in a separate prospectively enrolled cohort of patients with early MSA (n = 38), Parkinson disease (PD, n = 16), and dementia with Lewy bodies (DLB, n = 13), and CON subjects (n = 15).

RESULTS

In the discovery cohort, NFL was markedly elevated in MSA patients, with perfect separation from CON. αSyn-PMCA was nonreactive in all CON, whereas all MSA samples were positive. In the confirmatory cohort, NFL again perfectly separated MSA from CON, and was significantly lower in PD and DLB compared to MSA. PMCA was again nonreactive in all CON, and positive in all but 2 MSA cases. All PD and all but 2 DLB samples were also positive for αSyn aggregates but with markedly different reaction kinetics from MSA; aggregation occurred later, but maximum fluorescence was higher, allowing for perfect separation of reactive samples between MSA and Lewy body synucleinopathies.

INTERPRETATION

NFL and αSyn oligomers in CSF faithfully differentiate early MSA not only from CON but also from Lewy body synucleinopathies. The findings support the role of these markers as diagnostic biomarkers, and have important implications for understanding pathophysiologic mechanisms underlying the synucleinopathies. ANN NEUROL 2020;88:503-512.

An update on MSA: premotor and non-motor features open a window of opportunities for early diagnosis and intervention

In this review, we describe the wide clinical spectrum of features that can be seen in multiple system atrophy (MSA) with a focus on the premotor phase and the non-motor symptoms providing an up-to-date overview of the current understanding in this fast-growing field. First, we highlight the non-motor features at disease onset when MSA can be indistinguishable from pure autonomic failure or other chronic neurodegenerative conditions. We describe the progression of clinical features to aid the diagnosis of MSA early in the disease course. We go on to describe the levels of diagnostic certainty and we discuss MSA subtypes that do not fit into the current diagnostic criteria, highlighting the complexity of the disease as well as the need for revised diagnostic tools. Second, we describe the pathology, clinical description, and investigations of cardiovascular autonomic failure, urogenital and sexual dysfunction, orthostatic hypotension, and respiratory and REM-sleep behavior disorders, which may precede the motor presentation by months or years. Their presence at presentation, even in the absence of ataxia and parkinsonism, should be regarded as highly suggestive of the premotor phase of MSA. Finally, we discuss how the recognition of the broader spectrum of clinical features of MSA and especially the non-motor features at disease onset represent a window of opportunity for disease-modifying interventions.

Inflammatory cytokine levels in multiple system atrophy: A protocol for systematic review and meta-analysis

BACKGROUND

Multiple system atrophy (MSA) is a fatal neurodegenerative disease that progresses very rapidly and has a poor prognosis. Some studies indicate that the level of inflammatory cytokines may be related to MSA. However, no consistent conclusion has been drawn yet. The purpose of our research is to perform a meta-analysis to investigate whether the level of inflammatory cytokines is altered in MSA.

METHODS

Case-control studies on inflammatory cytokine levels in MSA will be searched in the following 3 databases: PubMed, Embase, and Web of Science from the database start time to March 17, 2020. Two independent authors will conduct research selection, data extraction, and quality evaluation. Data synthesis, subgroup analysis, sensitivity analysis, and the meta-analysis will be performed using Stata15.0 software.

RESULTS

This study will provide a comprehensive review of all studies on inflammatory cytokine levels in MSA.

CONCLUSION

To the best of our knowledge, this study will be the first meta-analysis that provides the quantitative evidence of inflammatory cytokine levels in MSA.

REGISTRATION NUMBER

INPLASY202060034.

Elevated serum growth differentiation factor 15 in multiple system atrophy patients: A case control study

BACKGROUND

Multiple system atrophy (MSA) is a serious progressive neurodegenerative disease. Early diagnosis of MSA is very difficult, and diagnostic biomarkers are limited. Growth differentiation factor 15 (GDF15) is involved in the differentiation and progression of the central nervous system, and is widely distributed in peripheral blood, which may be a novel biomarker for MSA.

AIM

To determine serum GDF15 levels, related factors and their potential diagnostic value in MSA patients, compared with Parkinson’s disease (PD) patients and healthy controls.

METHODS

A case-control study was conducted, including 49 MSA patients, 50 PD patients and 50 healthy controls. Serum GDF15 levels were measured by human enzyme-linked immunosorbent assay, and the differences between the MSA, PD and control groups were analyzed. Further investigations were performed in different MSA subgroups according to age of onset, sex, clinical subtypes, diagnostic criteria, and disease duration. Receiver-operating characteristic curve analysis was used to evaluate the diagnostic value of GDF15, especially for the differential diagnosis between MSA and PD.

RESULTS

Serum GDF15 levels were significantly higher in MSA patients than in PD patients and healthy controls (P = 0.000). Males and those with a disease duration of more than three years showed higher serum GDF15 levels (P = 0.043 and 0.000; respectively). Serum GDF15 levels may be a potential diagnostic biomarker for MSA patients compared with healthy controls and PD patients (cutoff: 470.42 pg/mL, sensitivity: 85.7%, specificity: 88.0%; cutoff: 1075.91 pg/mL, sensitivity: 51.0%, specificity: 96.0%; respectively).

CONCLUSION

Serum GDF15 levels are significantly higher in MSA patients and provide suggestions on the etiology of MSA.

Is There a Difference in Autonomic Dysfunction Between Multiple System Atrophy Subtypes?

Background

Autonomic dysfunction forms the diagnostic cornerstone in MSA. Data are limited on autonomic dysfunction differences between the two subtypes, MSA-C and MSA-P.

Objectives

To assess autonomic dysfunction in MSA subtypes and Parkinson's disease (PD) and compare it to healthy controls.

Methods

We conducted a cross-sectional study. A validated questionnaire (Scales for Outcomes in Parkinson's Disease-Autonomic Dysfunction; SCOPA-AUT) was used for symptom screening. Cardiovascular autonomic testing included deep breathing (change in heart rate, E: I ratio), Valsalva ratio, diastolic blood pressure (BP) rise (hand grip, cold pressor), and postural (tilt, 30:15 ratio) tests. Disease severity was assessed by the Unified MSA Rating Scale (UMSARS), H & Y stage, and International Parkinson and Movement Disorder Society Unified Parkinson's Disease Rating scale part III.

Results

MSA-P (48 subjects; age, 63.6 ± 9.7 years; UMSARS, 45.0 ± 16.5), MSA-C (52 subjects; age, 58.0 ± 8.1 years; UMSARS, 44.0 ± 12.8), PD (50 subjects; age, 57.6 ± 6.7 years), and healthy controls (50 subjects; age, 58.0 ± 8.0 years) were enrolled. MSA patients had higher SCOPA-AUT scores in gastrointestinal, urinary, cardiovascular, and sexual domains than controls and in gastrointestinal, urinary, and cardiovascular domains compared to PD. The two MSA subtypes did not differ in autonomic dysfunction. Heart-rate change on tilt and deep breathing, and diastolic BP rise on cold pressor test, differed significantly between MSA and PD patients.

Conclusions

Autonomic dysfunction symptomatology and cardiovascular autonomic tests were similar between MSA-P and MSA-C patients. Autonomic symptoms were more prominent in MSA than PD. Emphasis on these domains may improve likelihood of accurate clinical diagnosis of MSA at earlier stages.

Neurogenic lower urinary tract dysfunction predicts prognosis in patients with multiple system atrophy

PURPOSE

To evaluate whether neurogenic lower urinary tract dysfunction and urodynamic parameters predict the outcomes of patients with multiple system atrophy (MSA).

METHODS

A retrospective study was performed in patients who were diagnosed with MSA and underwent urodynamic studies simultaneously from September 2014 to July 2018. The urodynamic traces were reviewed by urologists. Detrusor contractility was evaluated by the bladder contractility index (BCI) and Schäfer nomogram. Telephone follow-up was conducted in July 2019 to acquire survival data. Clinical and urodynamic parameters were analyzed for survival using Cox regression analysis.

RESULTS

Overall, 70 MSA patients were eligible for analysis, and 61 of them underwent urodynamic study within 3 years of initial symptom onset. The parkinsonian subtype of MSA (MSA-P) had a smaller proportion of men as well as longer motor and lower urinary tract symptom durations than the cerebellar subtype (MSA-C). MSA-P also had a lower mean BCI than MSA-C (32.0 ± 27.0 versus 53.6 ± 33.4, p = 0.025). The mean MSA survival time was 5.4 [95% confidence interval (CI) 4.8-6.3] years. Cox regression analysis showed that survival from baseline was correlated only with BCI [hazard ratio (HR) 0.983, 95% CI 0.969-0.997, p = 0.020]. Overall survival was correlated with BCI (HR 0.982, 95% CI 0.966-0.999, p = 0.039) and the presence of urinary incontinence (HR 3.007, 95% CI 0.993-9.220, p = 0.052).

CONCLUSION

Detrusor contractility can be a prognostic marker in MSA patients. A high BCI value is a protective factor for survival from baseline and overall survival. The presence of urinary incontinence predicts shortened overall survival.

Disease progression and prognostic factors in multiple system atrophy: A prospective cohort study

Multiple system atrophy (MSA) is a rare neurodegenerative disease, with limited understanding of disease progression and prognostic factors. We leveraged the data of a large prospective cohort of MSA to study both clinical progression and survival and assess their determinants. All consecutive patients seen at the French Reference Centre for MSA since 2007 were included in a prospective cohort with an annual follow-up including the Unified MSA Rating Scale (UMSARS). We used joint models to evaluate the risk of death, the mean trajectory of each UMSARS subscale and to determine the potential factors. Investigated factors included gender, age at baseline, MSA subtype, diagnosis certainty, type of first symptoms and the duration between symptom onset and the first visit. Among the 261 MSA patients included in our cohort, the median duration of clinical follow-up was 2.1 years (up to 10.3 years) and the median survival was 4.0 years since the first visit. Main factors for poor survival were the progression over time of UMSARS score (I + II and IV) and the severity of orthostatic hypotension. MSA subtype had no effect on progression or survival. The UMSARS I + II score progressed faster over time in subjects with autonomic dysfunction as the initial feature and in women. Despite a faster progression, women and men had similar survival. From this large MSA cohort, we confirm the rapid progression and poor prognosis of MSA. We provide additional evidence for a negative impact of early autonomic dysfunction and the severity of orthostatic hypotension on both disease progression and survival.

Stridor in multiple system atrophy: Consensus statement on diagnosis, prognosis, and treatment

Multiple system atrophy (MSA) is a neurodegenerative disorder characterized by a combination of autonomic failure, cerebellar ataxia, and parkinsonism. Laryngeal stridor is an additional feature for MSA diagnosis, showing a high diagnostic positive predictive value, and its early occurrence might contribute to shorten survival. A consensus definition of stridor in MSA is lacking, and disagreement persists about its diagnosis, prognosis, and treatment. An International Consensus Conference among experts with methodological support was convened in Bologna in 2017 to define stridor in MSA and to reach consensus statements for the diagnosis, prognosis, and treatment. Stridor was defined as a strained, high-pitched, harsh respiratory sound, mainly inspiratory, occurring only during sleep or during both sleep and wakefulness, and caused by laryngeal dysfunction leading to narrowing of the rima glottidis. According to the consensus, stridor may be recognized clinically by the physician if present at the time of examination, with the help of a witness, or by listening to an audio recording. Laryngoscopy is suggested to exclude mechanical lesions or functional vocal cord abnormalities related to different neurologic conditions. If the suspicion of stridor needs confirmation, drug-induced sleep endoscopy or video polysomnography may be useful. The impact of stridor on survival and quality of life remains uncertain. Continuous positive airway pressure and tracheostomy are both suggested as symptomatic treatment of stridor, but whether they improve survival is uncertain. Several research gaps emerged involving diagnosis, prognosis, and treatment. Unmet needs for research were identified.

[123I]FP-CIT SPECT in Clinically Uncertain Parkinsonism Predicts Survival: A Data-Driven Analysis

BACKGROUND

Dopamine transporter SPECT is an established method to investigate nigrostriatal integrity in case of clinically uncertain parkinsonism.

OBJECTIVE

The present study explores whether a data-driven analysis of [123I]FP-CIT SPECT is able to stratify patients according to mortality after SPECT.

METHODS

Patients from our clinical registry were included if they had received [123I]FP-CIT SPECT between 10/2008 and 06/2016 for diagnosis of parkinsonism and if their vital status could be determined in 07/2017. Specific binding ratios (SBR) of the whole striatum, its asymmetry (asymmetry index, AI; absolute value), and the rostrocaudal gradient of striatal binding (C/pP: caudate SBR divided by posterior putamen SBR) were used as input for hierarchical clustering of patients. We tested differences in survival between these groups (adjusted for age) with a Cox proportional hazards model.

RESULTS

Data from 518 patients were analyzed. Median follow-up duration was 3.3 years [95% C.I. 3.1 to 3.7]. Three subgroups identified by hierarchical clustering were characterized by relatively low striatal SBR, high AI, and low C/pP (group 1), low striatal SBR, high AI, and high C/pP (group 2), and high striatal SBR, low AI, and low C/pP (group 3). Mortality was significantly higher in group 1 compared to each of the other two groups (p = 0.029 and p = 0.003, respectively).

CONCLUSION

Data-driven analysis of [123I]FP-CIT SPECT identified a subgroup of patients with significantly increased mortality during follow-up. This suggests that [123I]-FP-CIT SPECT might not only serve as a diagnostic tool to verify nigrostriatal degeneration but also provide valuable prognostic information.

Multiple system atrophy

Multiple system atrophy (MSA) is a sporadic, adult-onset, relentlessly progressive neurodegenerative disorder, clinically characterized by various combinations of autonomic failure, parkinsonism and ataxia. The neuropathological hallmark of MSA are glial cytoplasmic inclusions consisting of misfolded α-synuclein. Selective atrophy and neuronal loss in striatonigral and olivopontocerebellar systems underlie the division into two main motor phenotypes of MSA-parkinsonian type and MSA-cerebellar type. Isolated autonomic failure and REM sleep behavior disorder are common premotor features of MSA. Beyond the core clinical symptoms, MSA manifests with a number of non-motor and motor features. Red flags highly specific for MSA may provide clues for a correct diagnosis, but in general the diagnostic accuracy of the second consensus criteria is suboptimal, particularly in early disease stages. In this chapter, the authors discuss the historical milestones, etiopathogenesis, neuropathological findings, clinical features, red flags, differential diagnosis, diagnostic criteria, imaging and other biomarkers, current treatment, unmet needs and future treatments for MSA.

Converging Patterns of α-Synuclein Pathology in Multiple System Atrophy

We aimed to determine patterns of α-synuclein (α-syn) pathology in multiple system atrophy (MSA) using 70-µm-thick sections of 20 regions of the central nervous system of 37 cases with striato-nigral degeneration (SND) and 10 cases with olivo-ponto-cerebellar atrophy (OPCA). In SND cases with the shortest disease duration (phase 1), α-syn pathology was observed in striatum, lentiform nucleus, substantia nigra, brainstem white matter tracts, cerebellar subcortical white matter as well as motor cortex, midfrontal cortex, and sensory cortex. SND with increasing duration of disease (phase 2) was characterized by involvement of spinal cord and thalamus, while phase 3 was characterized by involvement of hippocampus and amygdala. Cases with the longest disease duration (phase 4) showed involvement of the visual cortex. We observed an increasing overlap of α-syn pathology with increasing duration of disease between SND and OPCA, and noted increasingly similar regional distribution patterns of α-syn pathology. The GBA variant, p.Thr408Met, was found to have an allele frequency of 6.94% in SND cases which was significantly higher compared with normal (0%) and other neurodegenerative disease pathologies (0.74%), suggesting that it is associated with MSA. Our findings indicate that SND and OPCA show distinct early foci of α-syn aggregations, but increasingly converge with longer disease duration to show overlapping patterns of α-syn pathology.

Multiple System Atrophy: Phenotypic spectrum approach coupled with brain 18-FDG PET

OBJECTIVE

The 2008 diagnostic criteria classify Multiple System Atrophy (MSA) patients in a predominantly parkinsonian (MSA-P) or cerebellar (MSA-C) type. Phenotypic descriptions have since highlighted a clinical heterogeneity among patients (e.g., mixed-type, cognitive impairment, atypical longer survival). This study attempts to identify different phenotypes of patients with MSA and to describe corresponding brain 18-FDG Positron Emission Tomography (PET) patterns.

METHODS

Patients with a "probable" MSA diagnosis for whom a brain 18-FDG PET was performed were included. A retrospective analysis (from 2006 to 2017) was conducted using standardized data collection. We used Latent Class Analysis (LCA), an innovative statistical approach, to identify profiles of patients based on common clinical characteristics. Brain metabolism of different groups was studied at rest.

RESULTS

Eighty-five patients were included. Three different profiles were revealed (entropy = 0.835): 1. extrapyramidal, axial, laryngeal-pharyngeal involvement (LPI) and cerebellar symptoms (n = 46, 54.1%); 2. cerebellar and LPI symptoms (n = 30, 35.3%); 3. cerebellar and cognitive symptoms (n = 9, 10.6%). Brain metabolism analyses (k > 89; p < 0.001) showed hypometabolism of the basal ganglia, frontal/prefrontal, temporal cortices and left posterior cerebellum in profile 1. In profile 2 there was hypometabolism of the medulla, prefrontal, temporal, cingular cortices, putamen and bilateral cerebellar hemispheres. In profile 3 there was hypometabolism of bilateral posterior cerebellar hemispheres and vermis.

CONCLUSION

Beyond the two most common phenotypes of MSA, a third and particularly atypical profile with cerebellar and cognitive symptoms but without LPI involvement is described. These profiles are supported by different brain metabolic abnormalities which could be useful for diagnostic purposes.

Survival and Progression in Synucleinopathy Phenotypes With Parkinsonism: A Population-Based Study

OBJECTIVE

To compare survival by the presenting parkinsonism symptoms at diagnosis among patients with incident clinically diagnosed synucleinopathies.

PATIENTS AND METHODS

Using the Rochester Epidemiology Project medical records-linkage system, we identified all persons residing in Olmsted County, Minnesota, who received a diagnostic code of parkinsonism from January 1, 1991, through December 31, 2010. A movement disorder specialist reviewed the complete medical records of each individual to confirm the presence of parkinsonism, determine the type of synucleinopathy, and identify the onset dates of each cardinal symptom (tremor at rest, bradykinesia, rigidity, and impaired postural reflexes). We determined the median time from age at diagnosis to death or censoring (June 30, 2015) for each presenting symptom and the age- and sex-adjusted risk of death.

RESULTS

From 1991 through 2010, a total of 433 individuals had a synucleinopathy diagnosed (301 [69.5%], Parkinson disease; 68 [15.7%], dementia with Lewy bodies; 52 [12.0%], Parkinson disease dementia; and 12 [2.8%], multiple systems atrophy with parkinsonism). Overall, the risk of death in the tremor-predominant group was less than that in the bradykinesia/rigidity-only group (hazard ratio [HR], 0.59; 95% CI, 0.40-0.87; P=.007). Similarly, risk of death in the bradykinesia/rigidity-only group was significantly greater than in the tremor-predominant group (HR, 1.75; 95% CI, 1.23-2.51; P=.002) and compared with tremor before bradykinesia (HR, 1.75; 95% CI, 1.24-2.47; P=.001).

CONCLUSION

Patients with tremor as a presenting symptom have longer survival. In contrast, the presence of bradykinesia/rigidity as a presenting symptom correlates with reduced survival across all types of synucleinopathies.

Urodynamic study for distinguishing multiple system atrophy from Parkinson disease

OBJECTIVE

To evaluate the differences in urodynamic findings between multiple system atrophy (MSA) and Parkinson disease (PD) and to identify the differential diagnostic ability of urodynamic study.

METHODS

We reviewed patients with MSA or PD who underwent urodynamic studies between January 2011 and August 2018. Patients with probable MSA and PD determined by movement disorder specialists at our center were included. Patients with alleged MSA or PD from outside hospitals, atypical or secondary parkinsonism, and any history of pelvic operation or radiation therapy were excluded.

RESULTS

A total of 219 patients, 107 with MSA (male:female 50:57) and 112 with PD (male:female 57:55), were included. Patients with MSA had shorter disease duration and were referred for urologic evaluation earlier (p < 0.001). Detrusor overactivity and associated urine leakage were prominent in PD (p < 0.001). Patients with MSA showed lower maximal flow rate (4.0 ± 5.8 vs 9.1 ± 8.3 mL/s, p < 0.001) and larger postvoid residual (290.8 ± 196.7 vs 134.0 ± 188.1 mL, p < 0.001) with decreased compliance (44.9% vs 10.7%, p < 0.001) and impaired contractility (24.9 ± 33.8 vs 65.7 ± 51.1, p < 0.001). Postvoid residual from a pressure-flow study had the highest sensitivity and specificity (74.8% and 75.9%), followed by detrusor pressure at maximal uroflow (72.6% and 70.5%), bladder contractility index, and postvoid residual from uroflowmetry (71.0% and 70.5%, respectively).

CONCLUSIONS

Patients with MSA showed lower maximal flow rate, larger postvoid residual with decreased compliance, and impaired contractility, whereas patients with PD had higher incidence of detrusor overactivity and associated leakage. For differential diagnosis, postvoid residual from a pressure-flow study provided the best sensitivity and specificity.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that urodynamic measures can distinguish patients with MSA from those with PD.

Dissecting α-synuclein inclusion pathology diversity in multiple system atrophy: implications for the prion-like transmission hypothesis

Synucleinopathies are a group of neurodegenerative diseases characterized by the accumulation of insoluble, aggregated α-synuclein (αS) pathological inclusions. Multiple system atrophy (MSA) presents with extensive oligodendroglial αS pathology and additional more limited neuronal inclusions while most of the other synucleinopathies, such as Parkinson's disease and dementia with Lewy bodies (DLB), develop αS pathology primarily in neuronal cell populations. αS biochemical alterations specific to MSA have been described but thorough examination of these unique and disease-specific protein deposits is further warranted especially given recent findings implicating the prion-like nature of synucleinopathies perhaps with distinct strain-like properties. Taking advantage of an extensive panel of antibodies that target a wide range of epitopes within αS, we investigated the distinct properties of the various types of αS inclusion present in MSA brains with comparison to DLB. Brain biochemical fractionation followed by immunoblotting revealed that the immunoreactive profiles were significantly more consistent for DLB than for MSA. Furthermore, epitope-specific immunohistochemistry varied greatly between different types of MSA αS inclusions and even within different brain regions of individual MSA brains. These studies highlight the importance of using a battery of antibodies for adequate appreciation of the various pathology in this distinct synucleinopathy. In addition, it can be posited that if the spread of pathology in MSA undergoes prion-like mechanisms, "strains" of αS aggregated conformers must be inherently unstable and readily mutable, perhaps resulting in a more stochastic progression process.

Sex and gender influence symptom manifestation and survival in multiple system atrophy

To evaluate the influence of sex and gender on clinical characteristics and survival in multiple system atrophy (MSA), we reviewed MSA patients with autonomic testing 1998-2012. Of 685 patients, 52% were male. Median survival overall was 7.3 years for males, 7.6 years for females. Survival from diagnosis was 2.9 years in males, 3.8 years in females. Females were more likely to initially manifest motor symptoms. Males were more likely to have orthostatic intolerance and early catheterization. In conclusion, our data show longer survival from diagnosis in females and slight overall survival benefit which may be related to initial motor manifestations.