Consensus statement on the diagnosis of multiple system atrophy. American Autonomic Society and American Academy of Neurology

Pathophysiological Significance of α-Synuclein in Sympathetic Nerves: In Vivo Observations

BACKGROUND AND OBJECTIVES

Lewy body diseases (LBDs) such as Parkinson disease (PD) feature increased deposition of α-synuclein (α-syn) in cutaneous sympathetic noradrenergic nerves. The pathophysiologic significance of sympathetic intraneuronal α-syn is unclear. We reviewed data about immunoreactive α-syn, tyrosine hydroxylase (TH, a marker of catecholaminergic fibers), and the sympathetic neurotransmitter norepinephrine (NE) in skin biopsies from control participants and patients with PD, the related LBD pure autonomic failure (PAF), the non-LBD synucleinopathy multiple system atrophy (MSA), or neurologic postacute sequelae of severe acute respiratory syndrome coronavirus 2 (neuro-PASC).

METHODS

In a retrospective observational study, we reviewed data about α-syn-TH colocalization indexes and immunoreactive α-syn and TH signal intensities in arrector pili muscles, blood vessels, and sweat glands from neck skin biopsies and NE concentrations in simultaneously obtained thigh skin biopsies from participants studied at the NIH Clinical Center. LBD, MSA, and control group data were assessed by analyses of variance with the Tukey post hoc test for multiple comparisons. Similar analyses were performed for patients with PD or neuro-PASC vs control.

RESULTS

Dermal α-syn-TH colocalization indexes and α-syn signal intensities from neck skin biopsies were examined in 18 controls (mean age 58 years, 50% female) and 53 LBD (66, 34%), 15 MSA (61, 33%), and 11 neuro-PASC (52, 82%) patients. The LBD group had higher α-syn-TH colocalization indexes than the controls (mean difference = 1.495, 95% CI 1.081-1.909, p < 0.0001) and increased α-syn signal intensities in all 3 skin constituents (arrector pili: mean difference = 2.743, 95% CI 1.608-3.879, p < 0.0001; blood vessels: mean difference = 2.157, 95% CI 1.095-3.219, p < 0.0001; sweat glands: mean difference = 4.136, 95% CI 1.704-6.567, p < 0.0001). The groups did not differ in either immunoreactive TH or NE. The neuro-PASC and PD groups had elevated α-syn-TH colocalization indexes compared with the controls, also with no group differences in immunoreactive TH or NE contents.

DISCUSSION

LBDs and neuro-PASC entail increased α-syn-TH colocalization indexes in skin biopsies, without evidence of local denervation or noradrenergic deficiency. The results fail to support toxicity of intraneuronal α-syn in cutaneous sympathetic noradrenergic nerves in either LBDs or neuro-PASC. The neuro-PASC data raise the possibility of sympathetic intraneuronal α-syn deposition as part of postinfectious immune or inflammatory processes.

Brain-derived and in vitro-seeded alpha-synuclein fibrils exhibit distinct biophysical profiles

The alpha-synuclein (αSyn) seeding amplification assay (SAA) that allows the generation of disease-specific in vitro seeded fibrils (SAA fibrils) is used as a research tool to study the connection between the structure of αSyn fibrils, cellular seeding/spreading, and the clinicopathological manifestations of different synucleinopathies. However, structural differences between human brain-derived and SAA αSyn fibrils have been recently highlighted. Here, we characterize the biophysical properties of the human brain-derived αSyn fibrils from the brains of patients with Parkinson's disease with and without dementia (PD, PDD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and compare them to the 'model' SAA fibrils. We report that the brain-derived αSyn fibrils show distinct biochemical profiles, which were not replicated in the corresponding SAA fibrils. Furthermore, the brain-derived αSyn fibrils from all synucleinopathies displayed a mixture of 'straight' and 'twisted' microscopic structures. However, the PD, PDD, and DLB SAA fibrils had a 'straight' structure, whereas MSA SAA fibrils showed a 'twisted' structure. Finally, the brain-derived αSyn fibrils from all four synucleinopathies were phosphorylated (S129). Interestingly, phosphorylated αSyn were carried over to the PDD and DLB SAA fibrils. Our findings demonstrate the limitation of the SAA fibrils modeling the brain-derived αSyn fibrils and pay attention to the necessity of deepening the understanding of the SAA fibrillation methodology.

Multiple system atrophy: Diagnostic challenges and a proposed diagnostic algorithm

Multiple system atrophy (MSA) is a heterogenous condition, presenting with core clinical features of autonomic dysfunction, parkinsonism, and/or cerebellar ataxia. The presence of alpha-synuclein glial cytoplasmic inclusion is the hallmark of MSA. It shares a common pathological origin with Parkinson's disease (PD) and Lewy body dementia (DLB) and they are collectively grouped as "synucleinopathies." The pathological synuclein protein is now well- recognized in skin biopsies of these patients. Besides the pathological findings, radiological investigation is a useful diagnostic tool. Brain MRI helps rule out other etiologies, and findings like the "Hot-cross bun" sign, "putaminal atrophy," and "infratentorial findings" can assist with the diagnosis of MSA. Cardiac MIBG scan, autonomic testing, urodynamic studies can help differentiate MSA from other conditions. Although diagnostic tools are available for MSA diagnosis, clarity is needed on when to use these tests. We suggest a diagnostic algorithm to navigate the use of these tests. However, this algorithm is not intended to replace the use of current MDS diagnostic criteria of MSA.

A pathophysiological biomarker combination separates Lewy body from non-Lewy body neurogenic orthostatic hypotension ​

PURPOSE

Neurogenic orthostatic hypotension (nOH) results from deficient reflexive delivery of norepinephrine to cardiovascular receptors in response to decreased cardiac venous return. Lewy body (LB) forms of nOH are characterized by low 18F-dopamine-derived radioactivity (a measure of cardiac noradrenergic deficiency), olfactory dysfunction by the University of Pennsylvania Smell Identification Test (UPSIT), and increased deposition of alpha-synuclein (α-syn) in dermal sympathetic noradrenergic nerves by the α-syn-tyrosine hydroxylase (TH) colocalization index. This observational, cross-sectional study explored whether combinations of these biomarkers specifically identify LB forms of nOH.

METHODS

Clinical laboratory data were reviewed from patients referred for evaluation at the National Institutes of Health for chronic autonomic failure between 2011 and 2023. The cutoff value for low myocardial 18F-dopamine-derived radioactivity was 6000 nCi-kg/cc-mCi, for olfactory dysfunction an UPSIT score ≤ 28, and for an increased α-syn-TH colocalization index ≥ 1.57.

RESULTS

A total of 44 patients (31 LB, 13 non-LB nOH) had data for all three biomarkers. Compared to the non-LB group, the LB nOH group had low myocardial 18F-dopamine-derived radioactivity, low UPSIT scores, and high α-syn-TH colocalization indexes (p < 0.0001 each). Combining the three biomarkers completely separated the groups. Cluster analysis identified two distinct groups (p < 0.0001) independently of the clinical diagnosis, with one cluster corresponding exactly to LB nOH.

CONCLUSION

LB forms of nOH feature cardiac noradrenergic deficiency, olfactory dysfunction, and increased α-syn-TH colocalization in skin biopsies. Combining the data for these variables efficiently separates LB from non-LB nOH. Independently of the clinical diagnosis, this biomarker triad identifies a pathophysiologically distinct cluster of nOH patients.

Prevalence of multiple system atrophy: A literature review

INTRODUCTION

This paper aims to provide a literature overview on multiple system atrophy (MSA) prevalence in European and other pan-European populations.

METHODS

A literature search (PubMed, EMBASE) was performed through 2022 to identify published studies on MSA prevalence in European countries. Of these search results, titles and abstracts were screened for relevance. A standardized assessment tool was used for systematically data extraction and comparison. For studies where only the incidence rate was reported, MSA prevalence was derived based on the incidence and duration of disease.

RESULTS

A total of 24 studies conducted in 14 countries and published between 1995 and 2022 were identified. The prevalence of MSA was reported in 18 (75%) studies and was derived from six (25%) incidence studies. These studies were mainly prospective population-based studies or multi-center studies from specific regions or specialty clinical settings. Two earlier studies in Germany and the Netherlands were conducted using door-to-door design. The time period of evaluation of prevalence ranged from 1990 to 2018. The crude prevalence of MSA ranged from 0.5/100,000 in Spain to 17/100,000 in Japan. Age-specific prevalence rates were provided in five studies, and the reported age ranges varied. The gender-specific crude prevalence was estimated as 2.75/100,000 for men and 1.19/100.000 for women. The derived prevalence was higher (ranging from 0.7-18.9/100,000) than studies where the prevalence was reported.

CONCLUSION

The variations observed in MSA prevalence may result from differences in age distributions of the study populations, study methodology, diagnostic criteria and case assessment strategies of MSA. Thus, the comparability of these studies is limited.

Tilt-evoked, breathing-driven blood pressure oscillations: Independence from baroreflex-sympathoneural function

PURPOSE

Orthostasis increases the variability of continuously recorded blood pressure (BP). Low-frequency (LF) BP oscillations (Mayer waves) in this setting are related to the vascular-sympathetic baroreflex. Mechanisms of increased high-frequency (HF) BP oscillations at the periodicity of respiration during orthostasis have received less research attention. A previously reported patient with post-neurosurgical orthostatic hypotension (OH) and vascular-sympathetic baroreflex failure had large tilt-evoked, breathing-driven BP oscillations, suggesting that such oscillations can occur independently of vascular-sympathetic baroreflex modulation. In the present study we assessed effects of orthostasis on BP variability in the frequency domain in patient cohorts with or without OH.

METHODS

Power spectral analysis of systolic BP variability was conducted on recordings from 73 research participants, 42 with neurogenic OH [13 pure autonomic failure, 14 Parkinson's disease (PD) with OH, 12 parkinsonian multiple system atrophy, and 3 status post-brainstem neurosurgery] and 31 without OH (control group of 16 healthy volunteers and 15 patients with PD lacking OH), before, during, and after 5' of head-up tilt at 90 degrees from horizontal. The data were log transformed for statistical testing.

RESULTS

Across all subjects, head-up tilting increased HF power of systolic BP variability (p = 0.001), without a difference between the neurogenic OH and control groups. LF power during orthostasis was higher in the control than in the OH groups (p = 0.009).

CONCLUSIONS

The results of this observational cohort study confirm those based on our case report and lead us to propose that even in the setting of vascular-sympathetic baroreflex failure orthostasis increases HF power of BP variability.

Comparative Study between the Diagnostic Effectiveness of Brain SPECT with [123I]Ioflupane and [123I]MIBG Scintigraphy in Multiple System Atrophy

BACKGROUND

Multiple system atrophy (MSA) is a neurodegenerative disease. It has a fast progression, so early diagnosis is decisive. Two functional imaging tests can be involved in its diagnosis: [123I]Ioflupane SPECT and [123I]MIBG scintigraphy. Our aim is to comparatively analyze the diagnostic performance of both techniques.

METHODS

46 patients (24 males and 22 females) with MSA underwent [123I]Ioflupane SPECT and [123I]MIBG scintigraphy. In each of these techniques, qualitative assessment was compared with quantitative assessment.

RESULTS

SPECT visual assessment was positive in 93.5% of subjects (S = 95.24%; PPV = 93.02%). A cut-off of 1.363 was established for overall S/O index (S = 85.7%, E = 100%). Visual assessment of scintigraphy was positive in 73.1% (S = 78.57%, PPV = 94.29%). For the delayed heart/medistinum ratio (HMR) a cut-off of 1.43 (S = 85.3, E = 100%) was obtained. For each unit increase in delayed HMR, the suspicion of MSA increased by 1.58 (OR = 1.58, p < 0.05). The quantitative assessment showed an association with the visual assessment for each technique (p < 0.05).

CONCLUSIONS

Both tests are useful in MSA diagnosis. Comparatively, we did not observe a clear superiority of either. Striatal and myocardial deterioration do not evolve in parallel. Qualitative assessment is crucial in both techniques, together with the support of quantitative analysis. Delayed HMR shows a direct relationship with the risk of MSA.

Identifying New Subtypes of Multiple System Atrophy Using Cluster Analysis

Background

Multiple system atrophy (MSA) is a disease with diverse symptoms and the commonly used classifications, MSA-P and MSA-C, do not cover all the different symptoms seen in MSA patients. Additionally, these classifications do not provide information about how the disease progresses over time or the expected outcome for patients.

Objective

To explore clinical subtypes of MSA with a natural disease course through a data-driven approach to assist in the diagnosis and treatment of MSA.

Methods

We followed 122 cases of MSA collected from 3 hospitals for 3 years. Demographic characteristics, age of onset, clinical signs, scale assessment scores, and auxiliary examination were collected. Age at onset; time from onset to assisted ambulation; and UMSARS I, II, and IV, COMPASS-31, ICARS, and UPDRS III scores were selected as clustering elements. K-means, partitioning around medoids, and self-organizing maps were used to analyze the clusters.

Results

The results of all three clustering methods supported the classification of three MSA subtypes: The aggressive progression subtype (MSA-AP), characterized by mid-to-late onset, rapid progression and severe clinical symptoms; the typical subtype (MSA-T), characterized by mid-to-late onset, moderate progression and moderate severity of clinical symptoms; and the early-onset slow progression subtype (MSA-ESP), characterized by early-to-mid onset, slow progression and mild clinical symptoms.

Conclusions

We divided MSA into three subtypes and summarized the characteristics of each subtype. According to the clustering results, MSA patients were divided into three completely different types according to the severity of symptoms, the speed of disease progression, and the age of onset.

A Review on the Clinical Diagnosis of Multiple System Atrophy

Multiple system atrophy (MSA) is a rare, adult-onset, progressive neurodegenerative disorder with major diagnostic challenges. Aiming for a better diagnostic accuracy particularly at early disease stages, novel Movement Disorder Society criteria for the diagnosis of MSA (MDS MSA criteria) have been recently developed. They introduce a neuropathologically established MSA category and three levels of clinical diagnostic certainty including clinically established MSA, clinically probable MSA, and the research category of possible prodromal MSA. The diagnosis of clinically established and clinically probable MSA is based on the presence of cardiovascular or urological autonomic failure, parkinsonism (poorly L-Dopa-responsive for the diagnosis of clinically established MSA), and cerebellar syndrome. These core clinical features need to be associated with supportive motor and non-motor features (MSA red flags) and absence of any exclusion criteria. Characteristic brain MRI markers are required for a diagnosis of clinically established MSA. A research category of possible prodromal MSA is devised to capture patients manifesting with autonomic failure or REM sleep behavior disorder and only mild motor signs at the earliest disease stage. There is a number of promising laboratory markers for MSA that may help increase the overall clinical diagnostic accuracy. In this review, we will discuss the core and supportive clinical features for a diagnosis of MSA in light of the new MDS MSA criteria, which laboratory tools may assist in the clinical diagnosis and which major differential diagnostic challenges should be borne in mind.

Risk of hospitalization in synucleinopathies and impact of psychosis

Background

Few studies have investigated the risk of hospitalization among patients with synucleinopathies (Parkinson disease, Dementia with Lewy Bodies, Parkinson disease dementia, Multiple System Atrophy) with associated psychosis and the impact of antipsychotic treatments on hospital admissions and duration of the stay.

Objective

To determine the risk of hospitalization among patients with synucleinopathies and in patients with associated psychosis. To evaluate the impact of antipsychotic treatments on hospital admission of patients with synucleinopathies and psychosis in an incident cohort study in Olmsted County, Minnesota (MN).

Methods

We used the Rochester Epidemiology Project (REP) to define an incident cohort of patients with clinically diagnosed synucleinopathies (1991-2010) in Olmsted County, MN. A movement disorder specialist reviewed all medical records to confirm the clinical diagnosis of synucleinopathies using the NINDS/NIMH unified diagnostic criteria.

Results

We included 416 incident cases of clinically diagnosed synucleinopathies from 2,669 hospitalizations. 409 patients (98.3%) were admitted to the hospital at least once for any cause after the onset of parkinsonism. The median number of hospitalizations for a single patient was 5. In total, 195 (46.9%) patients met the criteria for psychosis: patients with psychosis had a 49% (HR = 1.49, p < 0.01) increased risk of hospitalization compared to patients without psychosis. Among patients with psychosis, 76 (39%) received antipsychotic medication. Treatment with antipsychotic medications did not affect the risk of hospitalization (HR = 0.93, p = 0.65). The median length of hospitalization among the entire cohort was 1 (IQR 0-4) day. There was no difference between hospitalization length for patients with no psychosis and patients with active psychosis (RR = 1.08, p = 0.43) or patients with resolved psychosis (RR = 0.79, p = 0.24).

Conclusion

Psychosis increases the risk of hospitalization in patients with clinically defined synucleinopathies; however, it does not affect the length of hospital stays in our cohort. Antipsychotic treatment does not affect the risk of hospitalization in our study.

Diagnostic Effectiveness of [123I]Ioflupane Single Photon Emission Computed Tomography (SPECT) in Multiple System Atrophy

BACKGROUND

Multiple system atrophy (MSA) is a rapidly progressive neurodegenerative disorder that has no curative treatment. Diagnosis is based on a set of criteria established by Gilman (1998 and 2008) and recently updated by Wenning (2022). We aim to determine the effectiveness of [¹²³I]Ioflupane SPECT in MSA, especially at the initial clinical suspicion.

METHODS

A cross-sectional study of patients at the initial clinical suspicion of MSA, referred for [¹²³I]Ioflupane SPECT.

RESULTS

Overall, 139 patients (68 men, 71 women) were included, 104 being MSA-probable and 35 MSA-possible. MRI was normal in 89.2%, while SPECT was positive in 78.45%. SPECT showed high sensitivity (82.46%) and positive predictive value (86.24), reaching maximum sensitivity in MSA-P (97.26%). Significant differences were found when relating both SPECT assessments in the healthy-sick and inconclusive-sick groups. We also found an association when relating SPECT to the subtype (MSA-C or MSA-P), as well as to the presence of parkinsonian symptoms. Lateralization of striatal involvement was detected (left side).

CONCLUSIONS

[¹²³I]Ioflupane SPECT is a useful and reliable tool for diagnosing MSA, with good effectiveness and accuracy. Qualitative assessment shows a clear superiority when distinguishing between the healthy-sick categories, as well as between the parkinsonian (MSA-P) and cerebellar (MSA-C) subtypes at initial clinical suspicion.

Structural and Molecular Imaging for Clinically Uncertain Parkinsonism

Neuroimaging is an important adjunct to the clinical assessment of Parkinson disease (PD). Parkinsonism can be challenging to differentiate, especially in early disease stages, when it mimics other movement disorders or when there is a poor response to dopaminergic therapies. There is also a discrepancy between the phenotypic presentation of degenerative parkinsonism and the pathological outcome. The emergence of more sophisticated and accessible neuroimaging can identify molecular mechanisms of PD, the variation between clinical phenotypes, and the compensatory mechanisms that occur with disease progression. Ultra-high-field imaging techniques have improved spatial resolution and contrast that can detect microstructural changes, disruptions in neural pathways, and metabolic and blood flow alterations. We highlight the imaging modalities that can be accessed in clinical practice and recommend an approach to the diagnosis of clinically uncertain parkinsonism.

Lifelong constipation in Parkinson's disease and other clinically defined alpha-synucleinopathies: A population-based study in Southeast Minnesota

INTRODUCTION

Epidemiological studies show correlations between constipation and development of Parkinson's disease (PD); however, few studies have explored the association between constipation and dementia with Lewy bodies (DLB), Parkinson's disease dementia (PDD), and multiple system atrophy (MSA). We sought to explore the lifelong association of constipation and PD, DLB, PDD, and MSA (α-Synucleinopathies), compared to age- and sex-matched controls.

METHODS

Using the Rochester Epidemiology Project (REP), we established an incident cohort of clinically defined α-synucleinopathies. A movement-disorder specialist reviewed all medical charts to establish clinical diagnoses.

RESULTS

We identified 453 incident cases of clinically diagnosed α-synucleinopathies and an identical number of age- and sex-matched controls in Olmsted County (MN), 1991-2010. There were 303 cases of PD; 80, DLB; 54, PDD; and 16, MSA. Approximately 50% of α-synucleinopathies of all types reported constipation, compared to 27% in controls. The earliest pre-motor onset constipation was in DLB (median, 3.76 years prior to α-synucleinopathies motor-symptom onset); latest onset post-motor constipation was in PD (median, 5.15 years after motor-symptom onset). PD also had the highest longstanding constipation rate (18.2%). All α-synucleinopathies had higher odds of constipation compared to controls, except for MSA (p = 0.09), likely due to a limited sample size.

CONCLUSION

PD, DLB, and PDD had higher odds of constipation compared to controls; PD had the most widespread onset of lifelong constipation, both longstanding and pre- or post-motor onset symptoms. Our results indicate that constipation rates do not differ among α-synucleinopathies but do differ in terms of temporal onset compared to disease onset.

Urodynamic Study in Multiple System Atrophy: A Retrospective Observational Study

This retrospective study aimed to evaluate the characteristics of neurogenic bladder in patients with multiple systemic atrophy and distinguish between cerebellar and parkinsonian-type urodynamic patterns. We reviewed 19 patients diagnosed with multiple systemic atrophy with low urinary tract symptoms who underwent an urodynamic study at Pusan National University Yangsan Hospital between March 2010 and February 2022. This study did not account for the differences observed between the multiple system atrophy subtypes in the voiding phase. Urodynamic study is an effective tool to understand the complicated bladder pattern in patients with multiple system atrophy.

Autonomic failure: Clinicopathologic, physiologic, and genetic aspects

Over the past century, generations of neuroscientists, pathologists, and clinicians have elucidated the underlying causes of autonomic failure found in neurodegenerative, inherited, and antibody-mediated autoimmune disorders, each with pathognomonic clinicopathologic features. Autonomic failure affects central autonomic nervous system components in the α-synucleinopathy, multiple system atrophy, characterized clinically by levodopa-unresponsive parkinsonism or cerebellar ataxia, and pathologically by argyrophilic glial cytoplasmic inclusions (GCIs). Two other central neurodegenerative disorders, pure autonomic failure characterized clinically by deficits in norepinephrine synthesis and release from peripheral sympathetic nerve terminals; and Parkinson's disease, with early and widespread autonomic deficits independent of the loss of striatal dopamine terminals, both express Lewy pathology. The rare congenital disorder, hereditary sensory, and autonomic neuropathy type III (or Riley-Day, familial dysautonomia) causes life-threatening autonomic failure due to a genetic mutation that results in loss of functioning baroreceptors, effectively separating afferent mechanosensing neurons from the brain. Autoimmune autonomic ganglionopathy caused by autoantibodies targeting ganglionic α3-acetylcholine receptors instead presents with subacute isolated autonomic failure affecting sympathetic, parasympathetic, and enteric nervous system function in various combinations. This chapter is an overview of these major autonomic disorders with an emphasis on their historical background, neuropathological features, etiopathogenesis, diagnosis, and treatment.

Application of Periventricular White Matter Hyperintensities Combined with Homocysteine into Predicting Mild Cognitive Impairment in Parkinson's Disease

Purpose

To verify the associations between white matter hyperintensities (WMHs), plasma homocysteine (Hcy) levels, and mild cognitive impairment (MCI) in Parkinson's disease (PD) patients and evaluate the predictive value of combination of WMHs and plasma Hcy levels for MCI.

Patients and methods

In this study, 387 patients with PD were divided into MCI group and non-MCI group. Their cognition was evaluated with a comprehensive neuropsychological evaluation including 10 tests. Five cognitive domains, including the memory, attention/working memory, visuospatial, executive and language domains, were evaluated using two tests for each domain. MCI was determined when at least two tests demonstrated abnormal results, either one impaired test in two different cognitive domains or two impaired tests in a single cognitive domain. Multivariate analysis was performed to determine risk factors for MCI in PD patients. The receiver operating characteristic (ROC) curve was employed to assess the predictive values, and the Z test was employed to compare the area under curve (AUC).

Results

MCI was identified in 195 PD patients with an incidence of 50.4%. Multivariate analysis results showed that PWMHs (OR: 5.162, 95% CI: 2.318~9.527), Hcy levels (OR: 1.189, 95% CI: 1.071~1.405) and MDS-UPDRS part III score (OR: 1.173, 95% CI: 1.062~1.394) were independently correlated with MCI in PD patients after adjusting for confounders. ROC curves showed that the AUCs of PWMHs, Hcy levels and their combination were 0.701 (SE: 0.026, 95% CI: 0.647~0.752), 0.688 (SE: 0.027, 95% CI: 0.635~0.742) and 0.879 (SE: 0.018, 95% CI: 0.844~0.915), respectively. Z test showed that the AUC of combination prediction was significantly higher than those of individual predictions (0.879 vs 0.701, Z=5.629, P<0.001; 0.879 vs 0.688, Z=5.886, P<0.001).

Conclusion

The combination of WMHs and plasma Hcy levels could be applied in the prediction of MCI in PD patients.

Eye tracking identifies biomarkers in α-synucleinopathies versus progressive supranuclear palsy

OBJECTIVES

This study (1) describes and compares saccade and pupil abnormalities in patients with manifest alpha-synucleinopathies (αSYN: Parkinson's disease (PD), Multiple System Atrophy (MSA)) and a tauopathy (progressive supranuclear palsy (PSP)); (2) determines whether patients with rapid-eye-movement sleep behaviour disorder (RBD), a prodromal stage of αSYN, already have abnormal responses that may indicate a risk for developing PD or MSA.

METHODS

Ninety (46 RBD, 27 PD, 17 MSA) patients with an αSYN, 10 PSP patients, and 132 healthy age-matched controls (CTRL) were examined with a 10-min video-based eye-tracking task (Free Viewing). Participants were free to look anywhere on the screen while saccade and pupil behaviours were measured.

RESULTS

PD, MSA, and PSP spent more time fixating the centre of the screen than CTRL. All patient groups made fewer macro-saccades (> 2◦ amplitude) with smaller amplitude than CTRL. Saccade frequency was greater in RBD than in other patients. Following clip change, saccades were temporarily suppressed, then rebounded at a slower pace than CTRL in all patient groups. RBD had distinct, although discrete saccade abnormalities that were more marked in PD, MSA, and even more in PSP. The vertical saccade rate was reduced in all patients and decreased most in PSP. Clip changes produced large increases or decreases in screen luminance requiring pupil constriction or dilation, respectively. PSP elicited smaller pupil constriction/dilation responses than CTRL, while MSA elicited the opposite.

CONCLUSION

RBD patients already have discrete but less pronounced saccade abnormalities than PD and MSA patients. Vertical gaze palsy and altered pupil control differentiate PSP from αSYN.

Fluid markers of synapse degeneration in synucleinopathies

The abnormal accumulation of α-synuclein in the brain is a common feature of Parkinson's disease (PD), PD dementia (PDD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA), and synucleinopathies that present with overlapping but distinct clinical symptoms that include motor and cognitive deficits. Synapse degeneration is the crucial neuropathological event in these synucleinopathies and the neuropathological correlate of connectome dysfunction. The cognitive and motor deficits resulting from the connectome dysfunction are currently measured by scalar systems that are limited in their sensitivity and largely subjective. Ideally, a marker of synapse degeneration would correlate with measures of cognitive or motor impairment, and could therefore be used as a more objective, surrogate biomarker of the core clinical features of these diseases. Furthermore, an objective surrogate biomarker that can detect and monitor the progression of synapse degeneration would improve patient management and clinical trial design, and could provide a measure of therapeutic response. Here, we review the published findings relating to candidate biomarkers of synapse degeneration in PD, PDD, DLB, and MSA patient-derived biofluids and discuss the findings in the context of the mechanisms associated with α-synuclein-mediated synapse degeneration. Understanding these mechanisms is essential not only for discovery of biomarkers, but also to improve our understanding of the earliest changes in disease pathogenesis of synucleinopathies.

Structural and Functional Insights into α-Synuclein Fibril Polymorphism

Abnormal accumulation of aggregated α-synuclein (α-Syn) is seen in a variety of neurodegenerative diseases, including Parkinson's disease (PD), multiple system atrophy (MSA), dementia with Lewy body (DLB), Parkinson's disease dementia (PDD), and even subsets of Alzheimer's disease (AD) showing Lewy-body-like pathology. These synucleinopathies exhibit differences in their clinical and pathological representations, reminiscent of prion disorders. Emerging evidence suggests that α-Syn self-assembles and polymerizes into conformationally diverse polymorphs in vitro and in vivo, similar to prions. These α-Syn polymorphs arising from the same precursor protein may exhibit strain-specific biochemical properties and the ability to induce distinct pathological phenotypes upon their inoculation in animal models. In this review, we discuss clinical and pathological variability in synucleinopathies and several aspects of α-Syn fibril polymorphism, including the existence of high-resolution molecular structures and brain-derived strains. The current review sheds light on the recent advances in delineating the structure-pathogenic relationship of α-Syn and how diverse α-Syn molecular polymorphs contribute to the existing clinical heterogeneity in synucleinopathies.

Elevated plasma miR-133b and miR-221-3p as biomarkers for early Parkinson's disease

Blood circulating microRNAs (miRNAs) are proposed to be promising biomarkers for many neurodegenerative disorders, including Parkinson’s disease (PD). However, there is a lack of identified differentially expressed miRNAs in PD from different studies. The aim of this study was to evaluate miRNAs expression in PD. We measured plasma circulating miRNA expression in three independent sets with a total of 151 PD patients, 21 multiple system atrophy (MSA) patients and 138 healthy controls using high-throughput RT-PCR. We identified that elevated miR-133b and miR-221-3p discriminated early-stage PD from controls with 94.4% sensitivity and 91.1% specificity. Elevated miR-133b and miR-221-3p distinguished PD from controls with 84.8% sensitivity and 88.9% specificity. In addition, miR-4454 distinguished PD from MSA with 57.1% sensitivity and 82.6% specificity. Hence, elevated miR-133b and miR-221-3p potentially represent good biomarkers for early PD, and a combination of miR-133b, miR-221-3p and miR-4454 has the potential to serve as a non-invasive biomarker for PD diagnosis.

Early-Onset Parkinsonism and Early-Onset Parkinson's Disease: A Population-Based Study (2010-2015)

BACKGROUND

Early-onset Parkinson's disease (EOPD), occurring between ages 40 and 55, carries social, societal, and personal consequences and may progress, with fewer comorbidities than typical, later-onset disease.

OBJECTIVE

To examine the incidence and survival of EOPD and other Parkinsonism occurring before age 55 in the population-based cohort of residents in seven Minnesota counties.

METHODS

A movement-disorder specialist reviewed all the medical records in a 2010-2015 Parkinsonism-incident cohort to confirm diagnosis and subtypes.

RESULTS

We identified 27 patients diagnosed at ≤ 50 years with incident Parkinsonism 2010-15:11 (41%) cases of EOPD, 13 (48%) drug-induced Parkinsonism, and 3 (11%) other Parkinsonism; we also identified 69 incident cases of Parkinsonism ≤ 55 years, of which 28 (41%) were EOPD, 28 (41%) DIP, and 13 (19%) other Parkinsonism. Overall incidence for Parkinsonism ≤ 50 years was 1.98/100,000 person-years, and for EOPD was 0.81/100,000 person-years. In patients ≤ 55 years, Parkinsonism incidence was 5.05/100,000 person-years: in EOPD, 2.05/100,000 person-years. Levodopa-induced dyskinesia was present in 45%of EOPD (both ≤ 50 years and ≤ 55 years). Onset of cardinal motor symptoms was proximate to the diagnosis of EOPD, except for impaired postural reflexes, which occurred later in the course of EOPD. Among the 69 Parkinsonism cases ≤ 55 years, 9 (13%; all male) were deceased (only 1 case of EOPD). Men had a higher mortality risk compared to women (p = 0.049).

CONCLUSION

The incidence of EOPD ≤ 50 years was 0.81/100,000 person-years (1.98 in Parkinsonism all type); prior to ≤ 55 years was 2.05/100,000 person-years (5.05 in Parkinsonism all type) with higher incidence in men than women. Men with Parkinsonism, all type, had higher mortality compared to women.

Laryngeal Movement Disorders in Multiple System Atrophy: A Diagnostic Biomarker?

Background

Multiple system atrophy (MSA) is a rare neurodegenerative disorder, and its parkinsonian variant can be difficult to delineate from Parkinson's disease (PD). Despite laryngeal dysfunction being associated with decreased life expectancy and quality of life, systematic assessments of laryngeal dysfunction in large cohorts are missing.

Objectives

The objective of this study was to systematically assess laryngeal dysfunction in MSA and PD and identify laryngeal symptoms that allow for differentiating MSA from PD.

Methods

Patients with probable or possible MSA underwent flexible endoscopic evaluation of swallowing performing a systematic task protocol. Findings were compared with an age‐matched PD cohort.

Results

A total of 57 patients with MSA (64 [59–71] years; 35 women) were included, and task assessments during endoscopic examination compared with 57 patients with PD (67 [60–73]; 28 women). Patients with MSA had a shorter disease duration (4 [3–5] years vs 7 [5–10]; P < 0.0001) and higher disease severity (Hoehn & Yahr stage 4 [3–4] vs 3 [2–4]; P < 0.0001). Of the patients with MSA, 43.9% showed clinically overt laryngeal dysfunction with inspiratory stridor. During endoscopic task assessment, however, 93% of patients with MSA demonstrated laryngeal dysfunction in contrast with only 1.8% of patients with PD (P < 0.0001). Irregular arytenoid cartilages movements were present in 91.2% of patients with MSA, but in no patients with PD (P < 0.0001). Further findings included vocal fold motion impairment (75.4%), paradoxical vocal fold motion (33.3%), and vocal fold fixation (19.3%). One patient with PD showed vocal fold motion impairment.

Conclusion

Laryngeal movement disorders are highly prevalent in patients with MSA when assessed by a specific task protocol despite the lack of overt clinical symptoms. Our data suggest that irregular arytenoid cartilage movements could be used as a clinical marker to delineate MSA from PD with a specificity of 1.0 and sensitivity 0.9. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

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.

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.

How to approach a patient with parkinsonism - red flags for atypical parkinsonism

Parkinsonism is a clinical syndrome defined by bradykinesia plus rigidity or tremor. Though most commonly encountered in the setting of idiopathic Parkinson's disease, a number of neurodegenerative, structural, metabolic and toxic neurological disorders can result in parkinsonism. Accurately diagnosing the underlying cause of parkinsonism is of both therapeutic and prognostic relevance, especially as we enter the era of disease-modifying treatment trials for neurodegenerative disorders. Being aware of the wide array of potential causes of parkinsonism is of paramount importance for clinicians. In this chapter, we present a pragmatic clinical approach to patients with parkinsonism, specifically focusing on 'red flags', which should alert one to consider diagnoses other than idiopathic Parkinson's disease.

Association of innervation-adjusted alpha-synuclein in arrector pili muscles with cardiac noradrenergic deficiency in autonomic synucleinopathies

BACKGROUND

Autonomic synucleinopathies feature deposition of the protein alpha-synuclein (AS) in neurons [e.g., Lewy body neurogenic orthostatic hypotension (nOH)] or glial cells (multiple system atrophy, MSA). AS in skin biopsies might provide biomarkers of these diseases; however, this approach would be complicated or invalidated if there were substantial loss of AS-containing nerves. We report AS content in arrector pili muscles in skin biopsies after adjustment for local innervation in patients with Lewy body nOH or MSA. Cardiac sympathetic neuroimaging by myocardial ¹⁸F-dopamine positron emission tomography (PET) was done to examine pathophysiological correlates of innervation-adjusted AS.

METHODS

Thirty-one patients (19 Lewy body nOH, 12 MSA) underwent thoracic ¹⁸F-dopamine PET and skin biopsies. AS signal intensity analyzed by immunofluorescence microscopy was adjusted for innervation by the ratio of AS to protein gene product (PGP) 9.5, a pan-axonal marker (Harvard lab site), or the ratio of AS to tyrosine hydroxylase (TH), an indicator of catecholaminergic neurons (NIH lab site).

RESULTS

The Lewy body nOH group had higher ratios of AS/PGP 9.5 or log AS/TH than did the MSA group (0.89 ± 0.05 vs. 0.66 ± 0.04, -0.13 ± 0.05 vs. -1.60 ± 0.33; p < 0.00001 each). All 19 Lewy body patients had AS/PGP 9.5 > 0.8 or log AS/TH > 1.2 and had myocardial ¹⁸F-dopamine-derived radioactivity < 6000 nCi-kg/cc-mCi, the lower limit of normal. Two MSA patients (17%) had increased AS/PGP or log AS/TH, and two (17%) had low ¹⁸F-dopamine-derived radioactivity.

CONCLUSIONS

Lewy body forms of nOH are associated with increased innervation-adjusted AS in arrector pili muscles and neuroimaging evidence of myocardial noradrenergic deficiency.

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.

Dystonia in atypical parkinsonian disorders

Dystonia is common in the classic atypical parkinsonian disorders such as multiple system atrophy, progressive supranuclear palsy and corticobasal degeneration, and to a lesser extent in dementia with Lewy bodies. Its clinical phenomenology, including body distribution, timing of appearance, severity, and relationship to dopaminergic and other medications may vary considerably within and between atypical parkinsonian disorders. From a pathophysiological standpoint, the coexistence of dystonia with parkinsonism challenges the functional model of the basal ganglia. Clinical recognition of specific dystonic features may assist in the differential diagnosis of atypical parkinsonian disorders and in distinguishing them from Parkinson's disease. The presence of dystonia in atypical parkinsonian disorders informs management decisions. Reduction or withdrawal of levodopa should be considered if there is a close relationship between the onset of dystonia with periods of high dopaminergic tone. Botulinum neurotoxin may be considered in focal presentations. We here provide an updated overview of dystonia arising in the setting of atypical parkinsonian disorders, summarizing relevant clinical and clinicopathological studies, underlying pathophysiological mechanisms, diagnostic clues and potential pitfalls in the diagnosis. Finally, we suggest a tailored therapeutic approach for the management of these patients.

Efficacy of Parenteral Amantadine Therapy in the Treatment of Multiple System Atrophy With Predominant Parkinsonism

OBJECTIVE

The aim of this study was to assess clinical response to a high-dose intravenous (IV) amantadine given for 5 consecutive days in patients with multiple system atrophy parkinsonism (MSA-P).

METHODS

Subjects with a diagnosis of MSA-P treated with IV amantadine were included. Patients' disease severity before and after therapy was evaluated using the Unified Multiple System Atrophy Rating Scale (UMSARS).

RESULTS

Fourteen subjects (8 females) were included. In 10 subjects (71.4%), clinical improvement was noted. The UMSARS score after treatment decreased by 2 points (median [interquartile range, 0-3]) when compared with UMSARS score at baseline (P = 0.0020). Upon examining the walking parameter, a trend of improvement was shown (P = 0.0625) (range, 0-1 points). Neither specific demographic parameters nor occurrence of adverse effects was found to be a predictive factor for improvement. Adverse events were mild and transient except for one patient who experienced acute psychosis prompting treatment cessation, upon which psychosis resolved.

CONCLUSIONS

Our preliminary data show that IV amantadine may be a safe and effective therapy in MSA-P. A double-blind placebo-controlled trial is needed to establish the true benefit of amantadine therapy.

Factors associated with deterioration of health-related quality of life in multiple system atrophy: 1-year follow-up study

The aim of this study was to identify the main contributors to the health-related quality of life (HRQoL) in multiple system atrophy with predominant parkinsonism (MSA-P) and to determine the usefulness of SF-36 in capturing the HRQoL changes over 1-year follow-up. A total of 45 MSA-P and 150 Parkinson's disease (PD) patients were studied. The hierarchical multiple regression analysis was conducted to identify predictors of the SF-36 total score. The magnitude of any change for the HRQoL over 1-year of follow-up, was calculated as an effect size. The average scores for each SF-36 domains, except for the bodily pain, were lower in MSA-P than in PD patients (p < 0.05). The most important predictors of HRQoL in MSA-P, were female gender, older age at onset, SCOPA-AUT score and UMSARS IV, which together with other selected clinical variables accounted for 84% of the variance in the total SF-36 score in the final model in hierarchical analyses. During the 1-year follow-up, the SF 36 was found capable of detecting changes in MSA-P. Our study provided some new insights into potential predictors of the HRQoL and its longitudinal changes in MSA-P, which should be considered when healthcare programs are developed.

The Relationship between Bladder, Periarterial and Somatic Neuropathy in Diabetes

Objective Diabetes commonly affects the bladder nerves. However, the relationship among bladder, periarterial and somatic neuropathy in diabetes is not well known. In the present study we investigated these relationships. Methods A total of 110 diabetic subjects were enrolled in the study. All were referred for screening for diabetic neuropathy, irrespective of their symptoms. The patients included 61 men and 49 women; the mean age was 59.3 years (31-85 years); the mean disease duration was 14.0 years (5-30 years); and the mean HbA1c value was 10.1% (5.1-16.3%). We performed a nerve conduction study (NCS, A-alpha/beta and B fiber), ultrasound-based measurement of the post-void residual (PVR) volume (abnormal, >50 mL, mainly A-delta/C fiber) and postural blood pressure measurement (abnormal, >-20 mmHg, A-delta/C fiber). Fisher's exact probability test and Student's t-test were used to analyze the significance of differences. Results NCS abnormality, an abnormal PVR volume, and postural hypotension were noted in 74, 19, and 36 of the subjects, respectively. There were clear relationships between NCS and an abnormal PVR volume (p<0.05), postural hypotension and an abnormal PVR volume (p<0.05), or NCS and postural hypotension (p<0.01). There were also subjects who had NCS abnormality alone, a high PVR volume alone or postural hypotension alone. An abnormal PVR volume was not associated with the HbA1c value, but was clearly related to the duration of diabetes (p<0.05). Conclusion Bladder dysfunction was correlated with somatic and periarterial neuropathy. On the other hand, 16% of the cases of bladder dysfunction occurred in patients without somatic or periarterial neuropathy; thus, the regular measurement of the PVR volume is necessary.

Treatment of autonomic dysfunction in Parkinson disease and other synucleinopathies

Dysfunction of the autonomic nervous system afflicts most patients with Parkinson disease and other synucleinopathies such as dementia with Lewy bodies, multiple system atrophy, and pure autonomic failure, reducing quality of life and increasing mortality. For example, gastrointestinal dysfunction can lead to impaired drug pharmacodynamics causing a worsening in motor symptoms, and neurogenic orthostatic hypotension can cause syncope, falls, and fractures. When recognized, autonomic problems can be treated, sometimes successfully. Discontinuation of potentially causative/aggravating drugs, patient education, and nonpharmacological approaches are useful and should be tried first. Pathophysiology-based pharmacological treatments that have shown efficacy in controlled trials of patients with synucleinopathies have been approved in many countries and are key to an effective management. Here, we review the treatment of autonomic dysfunction in patients with Parkinson disease and other synucleinopathies, summarize the nonpharmacological and current pharmacological therapeutic strategies including recently approved drugs, and provide practical advice and management algorithms for clinicians, with focus on neurogenic orthostatic hypotension, supine hypertension, dysphagia, sialorrhea, gastroparesis, constipation, neurogenic overactive bladder, underactive bladder, and sexual dysfunction. © 2018 International Parkinson and Movement Disorder Society.

Extensive Delayed Brain Atrophy after Resuscitation in a Patient with Multiple System Atrophy

Brain magnetic resonance imaging (MRI) of multiple system atrophy (MSA) shows atrophy in the cerebrum, cerebellum, and brainstem. It is also characterized by specific patterns such as hyperintense lateral putaminal rim. MRI of hypoxic encephalopathy shows atrophy mainly in the gray matter, and laminar necrosis in the cerebral cortex is often observed. Here, we report an MSA patient damaged by hypoxic insult and resuscitated after 18-min cardiac arrest. The brain of the patient developed severe atrophy within a period of 10 months. Furthermore, brain atrophy was observed in the white and gray matter, which preserved the brain atrophy pattern in MSA. We assume that alpha-synuclein oligomerization is involved in the neural cell death and brain atrophy. It might have caused further neural cell death in the brain damaged by hypoxia. Alpha-synuclein, which is involved in the pathogenesis of MSA, is suggested to be a prion. Misfolded alpha-synuclein may propagate through cell-to-cell transmission and cause wide pathological change, visible as atrophied MR imaging.

Parkinson disease with and without Dementia: A prevalence study and future projections

BACKGROUND

Limited population-based information is available on the co-occurrence of dementia and PD. However, projecting the prevalence of PD with and without dementia during the next 50 years is crucial for planning public-health and patient-care initiatives.

OBJECTIVES

The objective of this study was to project the prevalence of PD with and without dementia in the United States by 2060.

METHODS

We used the Rochester Epidemiology Project medical records-linkage system to identify all persons with PD with or without dementia residing in Olmsted County, Minnesota, on January 1, 2006. A movement disorders specialist reviewed the complete medical records of each person to confirm the presence of PD. We calculated the age- and sex-specific prevalence of PD with and without dementia and projected U.S. prevalence through 2060.

RESULTS

We identified 296 persons with PD with and without dementia on the prevalence date (187 men, 109 women); the overall prevalence increased with age from 0.01% (30-39 years) to 2.83% (≥90 years). The prevalence of PD without dementia increased with age from 0.01% (30-39 years) to 1.25% (≥90 years). The prevalence of PD with dementia increased with age from 0.10% (60-69 years) to 1.59% (≥90 years). The prevalence was higher in men than in women for all subtypes and all age groups. We project by 2060 an approximate doubling of the number of persons with PD without dementia and a tripling of the number of persons with PD with dementia in the United States.

CONCLUSIONS

The prevalence of PD with and without dementia increases with age and is higher in men than women. We project that the number of persons with PD in the United States will increase substantially by 2060. © 2018 International Parkinson and Movement Disorder Society.

Multiple system atrophy: experimental models and reality

Multiple system atrophy (MSA) is a rapidly progressing fatal synucleinopathy of the aging population characterized by parkinsonism, dysautonomia, and in some cases ataxia. Unlike other synucleinopathies, in this disorder the synaptic protein, α-synuclein (α-syn), predominantly accumulates in oligodendroglial cells (and to some extent in neurons), leading to maturation defects of oligodendrocytes, demyelination, and neurodegeneration. The mechanisms through which α-syn deposits occur in oligodendrocytes and neurons in MSA are not completely clear. While some studies suggest that α-syn might transfer from neurons to glial cells, others propose that α-syn might be aberrantly overexpressed by oligodendroglial cells. A number of in vivo models have been developed, including transgenic mice overexpressing α-syn under oligodendroglial promoters (e.g.: MBP, PLP, and CNP). Other models have been recently developed either by injecting synthetic α-syn fibrils or brain homogenates from patients with MSA into wild-type mice or by using viral vectors expressing α-syn under the MBP promoter in rats and non-human primates. Each of these models reproduces some of the neuropathological and functional aspects of MSA; however, none of them fully replicate the spectrum of MSA. Understanding better the mechanisms of how α-syn accumulates in oligodendrocytes and neurons will help in developing better models that recapitulate various pathogenic aspects of MSA in combination with translatable biomarkers of early stages of the disease that are necessary to devise disease-modifying therapeutics for MSA.

Clinicopathologic discrepancies in a population-based incidence study of parkinsonism in olmsted county: 1991-2010

OBJECTIVE

The purpose of this study was to examine the discrepancies between the clinical diagnosis of parkinsonism and neuropathological findings in a population-based cohort with parkinsonian disorders.

BACKGROUND

The specific clinical diagnosis of parkinsonism is challenging, and definite confirmation requires neuropathological evaluation. Currently, autopsies are seldom performed, and most brain autopsies represent atypical or diagnostically unresolved cases.

METHODS

We used a defined population-based incidence cohort with clinical parkinsonism (n = 669) from the Rochester Epidemiology Project in Olmsted County, Minnesota, 1991-2010. We reviewed reports of all patients who underwent neuropathologic examination at autopsy (n = 60; 9%) and applied consensus pathologic guidelines for neurodegenerative disease diagnosis.

RESULTS

Among the 60 patients examined pathologically, the median time from the last recorded clinical diagnosis to death was 7 years (range from 2 to 17 years). Clinical-pathological concordance was found in 52 cases (86.7%), whereas 8 (13.3%) had a clinical-pathological discrepancy. Four patients with a clinical diagnosis of idiopathic Parkinson's disease had no pathological evidence of Lewy bodies or α-synucleinopathy; of these, pathological diagnoses were Alzheimer's disease (2 cases), progressive supranuclear palsy (1 case), and vascular parkinsonism (1 case). Two patients with clinical diagnoses of "dementia with Lewy bodies" and one patient with an "unspecified parkinsonism" had a pathological diagnosis of Alzheimer's disease without concomitant α-synuclein lesions. One patient with clinically diagnosed "progressive supranuclear palsy" had indeterminate pathological findings without α-synuclein or Aβ- or tau-immunoreactive lesions at autopsy.

CONCLUSIONS

Overall, the clinical diagnoses of parkinsonian subtypes had good concordance with pathological confirmation (86.7%). However, clinical-pathological discrepancies were documented in 13.3%. © 2017 International Parkinson and Movement Disorder Society.

Nonmotor Features in Atypical Parkinsonism

Atypical parkinsonism (AP) comprises mainly multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD), which are distinct pathological entities, presenting with a wide phenotypic spectrum. The classic syndromes are now called MSA-parkinsonism (MSA-P), MSA-cerebellar type (MSA-C), Richardson's syndrome, and corticobasal syndrome. Nonmotor features in AP have been recognized almost since the initial description of these disorders; however, research has been limited. Autonomic dysfunction is the most prominent nonmotor feature of MSA, but also gastrointestinal symptoms, sleep dysfunction, and pain, can be a feature. In PSP and CBD, the most prominent nonmotor symptoms comprise those deriving from the cognitive/neuropsychiatric domain. Apart from assisting the clinician in the differential diagnosis with Parkinson's disease, nonmotor features in AP have a big impact on quality of life and prognosis of AP and their treatment poses a major challenge for clinicians.

Acute Levodopa Challenge Test in Patients with de novo Parkinson's Disease: Data from the DeNoPa Cohort

Background

The precise clinical diagnosis of Parkinson's disease (PD) can be difficult in the early stages. Diagnostic criteria include the response of key motor features to levodopa as a supportive prospective criterion. Data are sparse on the diagnostic value of the acute levodopa challenge test (LDCT) in patients with de novo PD. The objective of this study was to validate the LDCT as a tool in the early clinical diagnosis of PD.

Methods

We performed the standardized LDCT with 250 mg levodopa in the prospective longitudinal cohort study "DeNoPa," comprising 159 patients with de novo PD, and carried out longitudinal clinical follow-up for 24 months. Motor assessments at baseline using the motor part (part III) of the Unified Parkinson's Disease Rating Scale before and 1 hr after drug administration were documented. The optimal cutoff score on the LDCT was calculated using the Youden index.

Results

Clinical reassessment of 144 patients who returned for follow-up confirmed the diagnosis of PD in 120 patients (83%). In 24 patients (17%), the initial diagnoses were revised and classified as other neurologic disorders. The optimal cutoff at 33% improvement of motor symptoms on the part 3 of the Unified Parkinson's Disease Rating Scale during the LDCT reached a sensitivity of 70% a specificity of 71%. The positive and negative predictive values were 92% and 32%, respectively. Sensitivity (91%), specificity (79%), and positive/negative (96%/63%) predictive values improved with the addition of further clinical information (urinary incontinence, fainting, asymmetric tremor, and amount of further drug-intake).

Conclusions

The LDCT is a reliable tool in the early diagnosis of PD. The accuracy of this test can be further improved by additional, easy-to-acquire clinical information provided by patients. © 2017 International Parkinson and Movement Disorder Society.

Time Trends in the Incidence of Parkinson Disease

IMPORTANCE

Changes over time in the incidence of parkinsonism and Parkinson disease (PD) remain uncertain.

OBJECTIVE

To investigate secular trends (period effects) and birth cohort trends in the incidence of parkinsonism and PD over 30 years in a geographically defined American population.

DESIGN, SETTING, AND PARTICIPANTS

We used the medical records-linkage system of the Rochester Epidemiology Project to identify incidence cases of PD and other types of parkinsonism in Olmsted County, Minnesota, from 1976 to 2005. All cases were classified by a movement disorder specialist using defined criteria through the review of the complete medical records within the system. The analyses for this study were conducted between May 2015 and January 2016.

MAIN OUTCOMES AND MEASURES

Incidence rates of parkinsonism and PD over 30 years. We tested for secular trends (period effects) using negative binomial regression models and for birth cohort effects using age-period-cohort models.

RESULTS

Of 906 patients with parkinsonism, 501 were men, and the median age at onset was 74 years (interquartile range, 66-81 years). Of the 464 patients with PD, 275 were men, and the median age at onset was 73 years (interquartile range, 64-80 years). The overall incidence rates increased significantly over 30 years in men for both parkinsonism (relative risk [RR], 1.17 per decade; 95% CI, 1.03-1.33) and PD (RR, 1.24 per decade; 95% CI, 1.08-1.43). These trends were driven primarily by the older age groups. In particular, for men 70 years or older, incidence rates increased for both parkinsonism (RR, 1.24 per decade; 95% CI, 1.07-1.44) and PD (RR, 1.35 per decade; 95% CI, 1.10-1.65). The secular trends were not significant for women overall or in age strata. We observed an increased risk for both men and women born in the 1920 cohort (1915-1924). However, this birth cohort effect was significant only for PD and only in men.

CONCLUSIONS AND REVELANCE

Our study suggests that the incidence of parkinsonism and PD may have increased between 1976 and 2005, particularly in men 70 years and older. These trends may be associated with the dramatic changes in smoking behavior that took place in the second half of the 20th century or with other lifestyle or environmental changes. However, the trends could be spurious and need to be confirmed in other populations.

Topography of Dopamine Transporter Availability in the Cerebellar Variant of Multiple System Atrophy

Background

Voxel-wise comparison of [¹²³I]-2β-carbomethoxy-3beta-(4-iodophenyl)tropane ([¹²³I]β-CIT) radioligand distribution measured by single-photon emission computed tomography (SPECT) revealed distinct patterns of reduced dopamine transporter (DAT) availability in the Parkinson's variant of MSA (MSA-P). The aim of this study was to identify the monoamine transporter distribution pattern in patients with the cerebellar variant of MSA (MSA-C). Additionally, monoamine transporter availability was investigated in a small cohort of patients with sporadic adult-onset ataxia (SAOA).

Methods

[¹²³I]β-CIT SPECT was performed in patients with MSA-C (n = 12), MSA-P (n = 14), SAOA (n = 5), and controls (n = 15) matched for age. Parametric images of [¹²³I]β-CIT binding potential (BP_ND) were generated and analyzed by statistical parametric mapping (SPM) and region of interest (ROI) analysis.

Results

SPM localized significant reductions of [¹²³I]β-CIT BP_ND in the striatum, midbrain, and pons in MSA-C compared to controls. When compared with MSA-P, the striatal DAT decline was significantly less affected in MSA-C. ROI analysis revealed reductions of striatal and midbrain [¹²³I]β-CIT binding in MSA-C compared to SAOA, whereas no significant difference was apparent between the SAOA and control groups.

Conclusions

Midbrain and pontine monoaminergic transporter binding was severely impaired in MSA-C, matching the underlying pathological features. Striatal DAT availability was relatively less affected in MSA-C compared to MSA-P, reflecting measureable, but less-profound, degeneration of the nigrostriatal dopaminergic projections. Preliminary results of reduced striatal and midbrain [¹²³I]β-CIT binding in MSA-C, compared to SAOA, suggest that the potential of DAT-SPECT as a surrogate marker in the diagnostic workup of patients with adult-onset cerebellar ataxia should be further investigated.

Incidence and time trends of drug-induced parkinsonism: A 30-year population-based study

Background

Epidemiological studies of drug‐induced parkinsonism remain limited.

Objectives

To investigate the incidence and time trends of drug‐induced parkinsonism over 30 years in a geographically defined American population.

Methods

We used the medical records‐linkage system of the Rochester Epidemiology Project to identify all persons in Olmsted County, Minnesota, who received a screening diagnostic code for parkinsonism from 1976 through 2005. A movement disorders specialist reviewed the complete medical records of each person to confirm the presence of drug‐induced parkinsonism associated with dopamine‐blocking or dopamine‐depleting medications.

Results

Among 906 incident cases of parkinsonism from 1976 to 2005, 108 persons had drug‐induced parkinsonism (11.9%). The average annual incidence rate of drug‐induced parkinsonism was 3.3 per 100,000 person‐years, was higher in women, and increased with older age. Drug‐induced parkinsonism was the fifth‐most common type of parkinsonism overall; however, it was the most common type among persons younger than age 40 years. Typical antipsychotic drugs were the most common class of drugs associated with parkinsonism, whereas atypical antipsychotic drugs were rarely involved. The incidence rate of drug‐induced parkinsonism decreased 32.0% per decade (relative risk = 0.68; 95% confidence interval: 0.49–0.94) and 68.6% over the 30 years of the study. The decrease was similar in men (65.2%) and women (69.4%); however, the trend was significant only in women.

Conclusions

The incidence of drug‐induced parkinsonism increased with older age and was higher in women at all ages. Typical antipsychotic drugs were the most common cause. The incidence of drug‐induced parkinsonism decreased over the 30 years of the study because of changes in drug use. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

[Expanding concept of clinical conditions and symptoms in multiple system atrophy]

Multiple system atrophy (MSA) is an adult-onset, progressive neurodegenerative disorder. MSA patients show various phenotypes during the course of their illness including parkinsonism, cerebellar ataxia, autonomic failure, and pyramidal signs. MSA is classified into the parkinsonian (MSA-P) or cerebellar (MSA-C) variant depending on the clinical motor phenotype at presentation. MSA-P and MSA-C are predominant in Western countries and Japan, respectively. The mean age at onset is 55 to 60 years. Prognosis ranges from 6 to 10 years, but some cases survive for more than 15 years. Early and severe autonomic failure is a poor prognostic factor. MSA patients sometimes present with isolated autonomic failure or motor symptoms/signs, and the median duration from onset to the concomitant appearance of motor and autonomic symptoms was approximately 2 years in our previous study. As the presence of the combination of motor and autonomic symptoms is essential for the current diagnostic criteria, early diagnosis is difficult when patients present with isolated autonomic failure or motor symptoms/signs. We experienced MSA patients who died before presentation of the motor symptoms/signs diagnostic for MSA (i.e., premotor MSA). Detection of the nature of autonomic failure consistent with MSA and identification of the dysfunctional anatomical sites may increase the probability of a diagnosis of premotor MSA. Dementia is another problem in MSA. Although dementia had been thought to be rare in MSA, frontal lobe dysfunction is observed frequently during the early course of the illness. Magnetic resonance imaging can show progressive cerebral atrophy in longstanding cases. More recently, MSA patients presenting with frontotemporal dementia preceding the presence of motor and autonomic manifestations diagnostic of MSA have been reported. Novel diagnostic criteria based on an expanding concept of the clinical conditions and symptoms of MSA will be needed for the development of disease-modifying therapies and better management.

Significance of combined use of MRI and perfusion SPECT for evaluation of multiple system atrophy, cerebellar type

BACKGROUND

Multiple system atrophy, cerebellar type (MSA-C) sometimes shows asymmetrical findings on magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT).

PURPOSE

To assess the frequency and clinical significance of asymmetrical MRI and (99m)Tc-ethyl cysteinate dimer perfusion (ECD) SPECT findings of the cerebellum, middle cerebellar peduncle (MCP), and pons in MSA-C patients.

MATERIAL AND METHODS

We retrospectively reviewed 28 patients with MSA-C who underwent MRI and (99m)Tc-ECD SPECT and evaluated laterality of atrophy and signal changes on MRI, and laterality of perfusion on (99m)Tc-ECD SPECT transversely and longitudinally.

RESULTS

Laterality was identified for 64%, 61%, and 21% of atrophy in the cerebellum, MCP, and pons, respectively, on MRI and for 71% of atrophy in the cerebellum on perfusion SPECT. Concerning comparisons between the latest MRI and SPECT findings, laterality of cerebellar/MCP atrophy on MRI and decreased cerebellar perfusion on SPECT was matched in 57%, mismatched in 11%, and absent in 25% of patients. On past images, MRI and SPECT showed matched laterality in 33%, mismatched laterality in 27%, no laterality in 13%, and SPECT precedent laterality in 27% of patients. Including the latest and past images, asymmetrical changes were observed in 75% of patients. We could not identify any correlation between laterality of image findings and cerebellar symptoms in most patients.

CONCLUSION

Asymmetrical changes on MRI and perfusion SPECT are common in MSA-C patients. Perfusion SPECT is useful for diagnosing MSA-C in the early stages from a functional perspective.

Neurogenic orthostatic hypotension: roles of norepinephrine deficiency in its causes, its treatment, and future research directions

BACKGROUND

Although a diversity of neurotransmitters and hormones participate in controlling blood pressure, norepinephrine released from postganglionic sympathetic nerve terminals is an important mediator of the rapid regulation of cardiovascular function required for homeostasis of cerebral perfusion. Hence, neurogenic orthostatic hypotension (NOH) often represents a deficiency of noradrenergic responsiveness to postural change.

RESEARCH DESIGN AND METHODS

PubMed searches with 'orthostatic hypotension' and 'norepinephrine' as conjoint search terms and no restriction on language or date, so as to survey the pathophysiologic and clinical relevance of norepinephrine deficiency for current NOH interventions and for future directions in treatment and research.

RESULTS

Norepinephrine deficiency in NOH can arise peripherally, due to cardiovascular sympathetic denervation (as in pure autonomic failure, Parkinson's disease, and a variety of neuropathies), or centrally, due to a failure of viscerosensory signals to generate adequate sympathetic traffic to intact sympathetic nerve endings (as in multiple system atrophy). Nonpharmacologic countermeasures such as pre-emptive water intake may yield blood-pressure increases exceeding those achieved pharmacologically. For patients with symptomatic NOH unresponsive to such strategies, a variety of pharmacologic interventions have been administered off-label on the basis of drug mechanisms expected to increase blood pressure via blood-volume expansion or vasoconstriction. Two pressor agents have received FDA approval: the sympathomimetic midodrine and more recently the norepinephrine prodrug droxidopa.

CONCLUSIONS

Pressor agents are important for treating symptomatic NOH in patients unresponsive to lifestyle changes alone. However, the dysautonomia underlying NOH often permits blood-pressure excursions toward both hypotension and hypertension. Future research should aim to shed light on the resulting management issues, and should also explore the possibility of pharmacotherapy selectively targeting orthostatic blood-pressure decreases.

Residual sympathetic tone is associated with reduced insulin sensitivity in patients with autonomic failure

PURPOSE

Parkinson disease, an α-synucleinopathy, is associated with reduced insulin sensitivity, impaired glucose tolerance, and diabetes mellitus. Importantly, these metabolic alterations have been shown to contribute to disease progression. The purpose of this study was to determine if reduced insulin sensitivity is also present in other α-synucleinopathies associated with autonomic failure.

METHODS

We studied 19 patients with multiple system atrophy and 26 patients with pure autonomic failure. For comparison, we studied 8 healthy controls matched for body mass index. Insulin sensitivity and beta cell function were calculated using fasting glucose and insulin levels according to the homeostatic model assessment 2. A multiple linear regression model was performed to determine factors that predict insulin sensitivity in autonomic failure.

RESULTS

There was a significant difference in insulin sensitivity among groups (P = 0.048). This difference was due to lower insulin sensitivity in multiple system atrophy patients: 64% [interquartile range (IQR), 43 to 117] compared to healthy controls 139% (IQR, 83 to 212), P = 0.032. The main factor that contributed to the reduced insulin sensitivity was the presence of supine hypertension and residual sympathetic tone.

CONCLUSIONS

Multiple system atrophy patients have reduced insulin sensitivity that is associated with residual sympathetic activation and supine hypertension. These patients may therefore be at high risk for development of impaired glucose tolerance and diabetes mellitus.

Atypical parkinsonism: diagnosis and treatment

Atypical parkinsonism comprises typically progressive supranuclear palsy, corticobasal degeneration, and mutilple system atrophy, which are distinct pathologic entities; despite ongoing research, their cause and pathophysiology are still unknown, and there are no biomarkers or effective treatments available. The expanding phenotypic spectrum of these disorders as well as the expanding pathologic spectrum of their classic phenotypes makes the early differential diagnosis challenging for the clinician. Here, clinical features and investigations that may help to diagnose these conditions and the existing limited treatment options are discussed.

Prevalence of REM sleep behavior disorder in multiple system atrophy: a multicenter study and meta-analysis

OBJECTIVE

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia frequently affecting patients with synucleinopathies, but its exact prevalence in multiple system atrophy (MSA) is unclear. Whether questionnaires alone are sufficient to diagnose RBD is also unknown.

METHODS

We performed a cross-sectional study of patients with probable MSA from six academic centers in the US and Europe. RBD was ascertained clinically and with polysomnography; we also performed a meta-analysis according to PRISMA guidelines for studies published before September 2014 that reported the prevalence of RBD in MSA. A random-effects model was constructed using weighted prevalence proportions. Only articles in English were included. Studies were classified into those that ascertained the presence of RBD in MSA clinically and with polysomnography. Case reports or case series (≤ 5 patients) were not included.

RESULTS

Forty-two patients completed questionnaires and underwent polysomnography. Of those, 32 (76.1%) had clinically suspected RBD and 34 (81%) had polysomnography-confirmed RBD. Two patients reported no symptoms of RBD but had polysomnography-confirmed RBD. The primary search strategy yielded 374 articles of which 12 met the inclusion criteria. The summary prevalence of clinically suspected RBD was 73% (95 % CI, 62-84%) in a combined sample of 324 MSA patients. The summary prevalence of polysomnography-confirmed RBD was 88 % (95% CI, 79-94%) in a combined sample of 217 MSA patients.

INTERPRETATION

Polysomnography-confirmed RBD is present in up to 88% of patients with MSA. RBD was present in some patients that reported no symptoms. More than half of MSA patients report symptoms of RBD before the onset of motor deficits.