Cardiovascular autonomic testing performed with a new integrated instrumental approach is useful in differentiating MSA-P from PD at an early stage

Early onset sleep disorders predict severity, progression and death in multiple system atrophy

BACKGROUND

Early stridor onset (≤ 3 years from disease onset) is a predictor of shorter survival in Multiple System Atrophy (MSA), but its role on disease progression is not yet established. In MSA, previous studies on trajectories of disease did not include stridor and REM sleep behavior disorder (RBD) as clinical variable. The aims of the study were: (1) to investigate disease progression in MSA patients with early stridor onset and with early stridor and/or RBD onset; (2) to assess cerebrospinal fluid (CSF) levels of neurofilament light chain protein (NfL) in MSA patients with early onset sleep disorders.

METHODS

This is a retrospective and prospective cohort study including 208 (120 males) MSA patients. Occurrence of symptoms/signs, milestones of disease progression, and their latency from disease onset were collected. RBD and stridor were video-polysomnography (VPSG)-confirmed. CSF NfL levels were analyzed. Survival data and predictors of mortality were calculated.

RESULTS

Out of 208 MSA patients (157 deceased), 91 were diagnosed with stridor and 160 with VPSG-confirmed RBD. Patients with early stridor onset (n = 41) and with early stridor and/or RBD onset (n = 132) showed an early autonomic involvement, developed a more progressive and severe disease and presented higher CSF NfL than those with late stridor and RBD onset. Early stridor and early RBD were independent risk factors on MSA survival.

CONCLUSIONS

The evidence of a more rapid and severe disease progression and of high CSF NfL levels in patients who early developed sleep disorders could define a different MSA phenotype with a widespread impairment of central-brainstem circuits.

Levodopa-induced orthostatic hypotension in parkinsonism: A red flag of autonomic failure

BACKGROUND AND PURPOSE

Levodopa (LD) is the main treatment for parkinsonism, but its use may be limited by a potential hypotensive effect.

METHODS

We evaluated the cardiovascular effect of LD performing head-up tilt test (HUTT) before and 60 min after 100/25 mg LD/dopa-decarboxylase inhibitor (pre-LD vs. post-LD HUTT) in 164 patients with parkinsonism on chronic LD treatment. Features predictive of LD-induced orthostatic hypotension (OH) were assessed by logistic regression analysis.

RESULTS

Basal supine blood pressure (BP) and heart rate (HR) decreased after LD. During post-LD HUTT, BP drop and HR increase were significantly greater than at pre-LD HUTT. Thirty-eight percent of patients had OH at post-LD HUTT compared to 22% of patients presenting OH at pre-LD HUTT (p < 0.001). Risk factors for LD-induced/worsened OH were pre-LD OH (odds ratio [OR] = 36, 95% confidence interval [CI] = 10-131), absence of overshoot at Valsalva maneuver (OR = 9, 95% CI = 4-20), and pathological Valsalva ratio (OR = 6, 95% CI = 2-15).

CONCLUSIONS

LD administration caused/worsened hypotension in both supine and orthostatic conditions. Patients with cardiovascular autonomic failure had a higher risk of developing LD-induced OH. In clinical practice, LD-induced OH could represent a red flag for cardiovascular autonomic failure.

Cardiovascular reflex tests detect autonomic dysfunction in symptomatic and pre-symptomatic subjects with hereditary transthyretin amyloidosis

PURPOSE

Autonomic dysfunction is a distinctive but undervalued feature of hereditary transthyretin amyloidosis (ATTRv). It may predate the onset of polyneuropathy and cardiomyopathy, thereby providing crucial prognostic and therapeutic information. The objective of this study was to assess autonomic function by means of the standardized cardiovascular autonomic reflex tests (CRTs) in a cohort of subjects with genetically proven ATTRv from non-endemic areas who were in the symptomatic and pre-symptomatic stages.

METHODS

All subjects enrolled in this cross-sectional study had genetically proven ATTRv. They underwent the head-up tilt test, Valsalva manoeuvre, deep breathing test, cold face test and handgrip test while under continuous blood pressure and heart rate monitoring. Based on the results of the nerve conduction study, the subjects were divided into two groups: those with polyneuropathy (ATTRv-wPN) and those without polyneuropathy (ATTRv-woPN). Age- and sex-matched healthy controls (HC) were used for comparison.

RESULTS

Thirty-seven ATTRv subjects (19 with ATTRv-wPN, 18 with ATTRv-woPN) and 41 HC performed the CRTs. Of these 37 subjects with ATTRv, four (11%) presented neurogenic orthostatic hypotension the during head-up tilt test. Based on the results of the CRTs, autonomic dysfunction characterized by either sympathetic or parasympathetic impairment was detected in 37% and 63% of ATTRv-wPN subjects, respectively. Subjects with ATTRv-woPN presented a significant impairment of autonomic responses to the Valsalva manoeuvre compared to the HC (overshoot p = 0.004; Valsalva ratio p = 0.001).

CONCLUSION

Autonomic dysfunctions are frequent in subjects with ATTRv when investigated by means of standardized CRTs, and are also relevant in the pre-symptomatic stage. Cardiovagal functions are the primary functions affected, among others. This may be crucial in defining the proper diagnostic workout for early diagnosis and improving the likelihood of providing the patient with prompt administration of disease-modifying treatments.

Predictive Value of Exercise Blood Pressure Changes for Orthostatic Hypotension in Patients With Parkinson's Disease

BACKGROUND AND PURPOSE

Orthostatic hypotension (OH) is common in patients with Parkinson's disease (PD). Early recognition OH is required with sensitive assessments. The purpose of this study was to determine whether blood pressure (BP) changes during exercise can predict the occurrence of OH in PD.

METHODS

This prospective cohort study included 80 consecutive patients with PD. All patients agreed to participate in a baseline evaluation and cardiopulmonary exercise test (CPET). According to the initial active standing test (AST), those without OH (PD-nonOH) at baseline had their AST results followed up for 6 months. The main outcome was defined as whether patients without OH at baseline would develop OH after 6 months. Logistic regression analysis was applied to identify the relevant variables. A nomogram was constructed based on clinical features and identified variables. The concordance index (C-index) and area under the receiver operating characteristic curve (AUC) were used to evaluate the accuracy and predictive ability of the nomogram, respectively.

RESULTS

CPET results indicated that peak load, peak heart rate, heart rate recovery at 1 min, and systolic BP change (ΔSBP) were lower in those with OH than in the PD-nonOH group (p<0.05) at baseline. Logistic regression analysis indicated that peak load and ΔSBP during CPET had significant effects on OH (p<0.05). Age, sex, peak load, and ΔSBP were used to construct the nomogram model (C-index=0.761). The prediction model had an AUC of 0.782 (95% confidence interval=0.649-0.889) and a specificity and sensitivity of 70.0% and 81.8%, respectively.

CONCLUSIONS

This study has identified predictive factors for OH development in patients with PD. CPET could be used as a complementary examination to identify patients at a high risk of OH.

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.

Effect of Acute Levodopa Up-Titration on Blood Pressure in Patients With Early Stage Parkinson's Disease: Results of a Levodopa Challenge Test

Objective: Levodopa up-titration is the primary therapeutic strategy as the Parkinson’s disease (PD) progresses. However, the effects of levodopa up-titration on blood pressure (BP) are inconclusive. This study aimed to investigate the effect of acute levodopa up-titration simulated by levodopa challenge test (LCT) on BP in patients with early stage PD.

Methods: We monitored BP in 52 patients with early stage PD using a standardized standing test. BP was assessed in supine position after 10 min of rest and at 1 and 3 min after standing up. BP was measured in the “off-state” and the best “on-state” during LCT in the morning at hospital. In another day, “off-state” and the best “on-state” BP was measured before and after anti-PD drug uptake in the morning at home. Demographic and clinical features of the patients were evaluated and analyzed.

Results: In the LCT, the prevalence of OH in the “off-state” and the best “on-state” was 11.5 and 13.5%, respectively. Additionally, the OH in the best “on-state” was associated with OH in the “off-state” and monoamine oxidase B inhibitor use. Although 38 (73.1%) patients experienced levodopa-induced hypotension during the LCT, no risk factors were identified. While BP reductions were observed after taking anti-PD drugs at home, no further reduction was seen during acute levodopa up-titration simulated by the LCT.

Conclusion: Our results demonstrate that acute levodopa up-titration does not exacerbate BP reduction induced by anti-PD drugs at home. BP monitoring is critical for the management of patients with PD.

Neurogenic orthostatic hypotension in early stage Parkinson's disease: New insights from the first 105 patients of the BoProPark study

OBJECTIVES

The prevalence of neurogenic orthostatic hypotension (NOH, due to cardiovascular autonomic failure) at early stage of Parkinson's disease (PD) is unknown. The aims of this study are to prospectively evaluate in a cohort of PD patients recruited within 3 years from motor onset (1) cardiovascular autonomic functions by means of cardiovascular reflex tests (CRTs) and the occurrence of NOH; (2) the frequency of orthostatic symptoms with a validated questionnaire.

METHODS

We included the first 105 PD patients of the prospective "BoProPark" study. Each patient underwent CRTs (head up tilt test; Valsalva manoeuvre; deep breathing; cold face test and handgrip test) under continuous blood pressure monitoring according to standardized procedures and SCOPA-Aut questionnaire at baseline (T0) and after 16 months (T1). A group of 50 age- and sex-matched controls was used for comparison.

RESULTS

At T0 (mean age 61 ± 9 years, disease duration 19 ± 9 months) NOH was detected in 4/105 (3.8%) patients, whereas at T1 in 8/105 (7.6%). CRTs responses assessing sympathetic function were impaired at T0 in PD patients compared to controls and progressively worsened at T1. Only 1 patient at T0 and 3 at T1 with NOH reported orthostatic symptoms with low frequency, while the majority of patients reporting these symptoms did not have OH at testing.

CONCLUSIONS

Our prospective study shows that NOH is not common at early PD stage. Asymptomatic mild sympathetic impairment was observed at first evaluation and progressed with disease evolution. Secondary OH may account for the higher prevalence of OH in PD reported so far.

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.

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.

Can Autonomic Testing and Imaging Contribute to the Early Diagnosis of Multiple System Atrophy? A Systematic Review and Recommendations by the Movement Disorder Society Multiple System Atrophy Study Group

Background

In the current consensus diagnostic criteria, the diagnosis of probable multiple system atrophy (MSA) is based solely on clinical findings, whereas neuroimaging findings are listed as aid for the diagnosis of possible MSA. There are overlapping phenotypes between MSA-parkinsonian type and Parkinson's disease, progressive supranuclear palsy, and dementia with Lewy bodies, and between MSA-cerebellar type and sporadic adult-onset ataxia resulting in a significant diagnostic delay and misdiagnosis of MSA during life.

Objectives

In light of an ongoing effort to revise the current consensus criteria for MSA, the Movement Disorders Society Multiple System Atrophy Study Group performed a systematic review of original articles published before August 2019.

Methods

We included articles that studied at least 10 patients with MSA as well as participants with another disorder or control group for comparison purposes. MSA was defined by neuropathological confirmation, or as clinically probable, or clinically probable plus possible according to consensus diagnostic criteria.

Results

We discuss the pitfalls and benefits of each diagnostic test and provide specific recommendations on how to evaluate patients in whom MSA is suspected.

Conclusions

This systematic review of relevant studies indicates that imaging and autonomic function tests significantly contribute to increasing the accuracy of a diagnosis of MSA.

Cardiovascular autonomic function testing in multiple system atrophy and Parkinson's disease: an expert-based blinded evaluation

PURPOSE

Multiple system atrophy (MSA) and Parkinson's disease (PD) are sporadic neurodegenerative diseases characterized by an accumulation of misfolded α-synuclein. Cardiovascular autonomic failure develops in both MSA and PD, although studies indicate different sites of autonomic nervous system lesion. However, it is unclear whether this could potentially aid the differential diagnosis of these diseases. Here we determined whether cardiovascular autonomic function testing (CAFT) can discriminate between the parkinsonian variant of MSA (MSA-P) and PD based on either an expert-based blinded evaluation or a systematic comparison of cardiovascular autonomic function indices.

METHODS

We included 22 patients aged 55-80 with neurogenic orthostatic hypotension (nOH) who had been diagnosed with either clinically probable MSA-P (n = 11) according to current consensus criteria or clinically definite PD (n = 11) according to the Queen Square criteria. Three physicians with expertise in CAFT were blinded to the neurological diagnosis and were asked to identify the correct neurological diagnosis by applying a self-created evaluation scheme to the CAFT recordings. Afterwards, a systematic comparison of clinical-demographic characteristics and CAFT parameters was carried out.

RESULTS

Neither the raters (overall diagnostic accuracy: 58.46%) nor the evaluation scheme created post hoc (72.73%) showed reliable discriminatory capacity. The inter-rater reliability was slight (κ = 0.01). We observed no statistically significant differences in cardiovascular autonomic indices between PD and MSA-P patients.

CONCLUSION

CAFT is the gold standard for assessing the presence and severity of cardiovascular autonomic failure, but the results of our pilot study suggest that CAFT might be of limited value in the differential diagnosis between MSA-P and PD once nOH is present.

Progression and prognosis in multiple system atrophy presenting with REM behavior disorder

OBJECTIVES

To investigate (1) the prevalence of REM sleep behavior disorder (RBD) as mode of disease onset in a cohort of patients with multiple system atrophy (MSA) and (2) disease progression and prognosis in patients with MSA with RBD predating (pre-RBD) and following (post-RBD) disease onset.

METHODS

We retrospectively identified all patients with a clinical diagnosis of MSA evaluated at least once a year during the disease course. Type of onset was defined by the first reported motor or autonomic symptom/sign related to MSA. The occurrence of symptoms/signs and milestone of disease progression, and their latency from disease onset, were collected. Survival data were calculated. RBD was confirmed by video-polysomnography.

RESULTS

Of a total of 158 patients, pre-RBD represented the mode of disease onset in 27% of patients, preceding disease onset according to the international criteria with a median of 3 (2-5) years. Comparing pre-RBD and post-RBD patients, the first group showed an increased prevalence of autonomic onset of disease, a reduced prevalence of parkinsonism, an earlier onset of stridor, pyramidal signs, symptomatic orthostatic hypotension, urinary dysfunction, severe dysphagia, and wheelchair dependency. The risk of death was higher in patients with pre-RBD.

CONCLUSIONS

In our MSA cohort, RBD represented the most frequent mode of disease presentation. A more rapid progression of disease was observed in the pre-RBD group. These findings suggested a careful assessment of sleep disorders to early recognize RBD and a closer follow-up of autonomic dysfunction and stridor in patients with pre-RBD.

Relationship between the washout rate of I-123 MIBG scans and autonomic function in Parkinson's disease

Purpose

We have evaluated the clinical significance of the washout rate (WR) on I-123 MIBG scans through the analysis of the relationship between the I-123 MIBG scans and autonomic status in patients with Parkinson’s disease (PD).

Materials and methods

Sixty patients with clinical PD who had decreased HMR were enrolled. An autonomic symptom was evaluated using a head-up tilt test and the Composite Autonomic Severity Score (CASS). An I-123 MIBG scan and F-18 FP-CIT positron emission tomography (PET) were performed. All of the patients were classified into three groups according to the WR. The differences in patient characteristics and the imaging parameters among the three groups were evaluated, and a correlation analysis was also performed.

Results

The frequency of orthostatic hypotension was significantly different among the three groups. The difference in systolic pressure (dSysPr) and the difference in diastolic pressure (dDiaPr) of group 3 was significantly larger than those of groups 1 and 2. From the correlation analysis, it can be seen that age, Hoehn and Yahr (H&Y) stage, dSysPr, and dDiaPr had a weak positive correlation with the WR. The total CASS score was significantly higher in group 3 compared with groups 1 and 2. The WR had a moderate positive correlation with the cardiosympathetic score and the total CASS score.

Conclusion

The WR is related to autonomic dysfunction. An I-123 MIBG cardiac scan is considered to be a good method to evaluate not only the differential diagnosis of Parkinson's disease but also the degree of autonomic dysfunction.

Quantitative autonomic function test in differentiation of multiple system atrophy from idiopathic Parkinson disease

Supplemental Digital Content is available in the text

Background:

Differential diagnosis of idiopathic Parkinson disease (IPD) and multiple system atrophy-Parkinson type (MSA-P) is challenging since they share clinical features with parkinsonism and autonomic dysfunction. To distinguish MSA-P from IPD when the symptoms are relatively mild, we investigated the usefulness of the quantitative fractionalized autonomic indexes and evaluated the correlations of autonomic test indexes and functional status.

Methods:

Thirty-six patients with parkinsonism (22 with IPD and 14 with MSA-P) in Soonchunhyang University Bucheon Hospital from February 2014 to June 2015 were prospectively enrolled in the study. We compared fractionalized autonomic indexes and composite autonomic scoring scale between patients with IPD and MSA-P with Hoehn and Yahr (H&Y) score ≤3. Parasympathetic indexes included expiratory/inspiratory ratio during deep breathing, Valsalva ratio (VR), and regression slope of systolic blood pressure (BP) in early phase II (vagal baroreflex sensitivity) during Valsalva maneuver. Sympathetic adrenergic indexes were pressure recovery time (PRT) and adrenergic baroreflex sensitivity (BRSa) (BP decrement associated with phase 3 divided by the PRT), sympathetic index 1, sympathetic index 3, early phase II mean BP drop, and pulse pressure reduction rate. Additionally, we compared the unified multiple system atrophy rating scale (UMSARS) and H&Y scores and the autonomic indexes in all patients.

Results:

PRT was significantly different between the IPD and MSA-P groups (P = 0.004) despite the similar BP drop during tilt. Cut-off value of PRT was 5.5 s (sensitivity, 71.4%; specificity, 72.7%). VR (r = −0.455, P = 0.009) and BRSa (r = −0.356, P = 0.036) demonstrated a significant correlation with UMSARS and H&Y scores.

Conclusions:

Among the cardiovascular autonomic indexes, PRT can be a useful parameter in differentiating the early stage of MSA-P from that of IPD. Moreover, VR, and BRSa may be the optimal indexes in determining functional symptom severity.

Technology-based assessment of motor and nonmotor phenomena in Parkinson disease

INTRODUCTION

The increasing development and availability of portable and wearable technologies is rapidly expanding the field of technology-based objective measures (TOMs) in neurological disorders, including Parkinson disease (PD). Substantial challenges remain in the recognition of disease phenomena relevant to patients and clinicians, as well as in the identification of the most appropriate devices to carry out these measurements. Areas covered: The authors systematically reviewed PubMed for studies employing technology as outcome measures in the assessment of PD-associated motor and nonmotor abnormalities. Expert commentary: TOMs minimize intra- and inter-rater variability in clinical assessments of motor and nonmotor phenomena in PD, improving the accuracy of clinical endpoints. Critical unmet needs for the integration of TOMs into clinical and research practice are the identification and validation of relevant endpoints for individual patients, the capture of motor and nonmotor activities from an ecologically valid environment, the integration of various sensor data into an open-access, common-language platforms, and the definition of a regulatory pathway for approval of TOMs. The current lack of multidomain, multisensor, smart technologies to measure in real time a wide scope of relevant changes remain a significant limitation for the integration of technology into the assessment of PD motor and nonmotor functional disability.

Daytime autonomic activity in idiopathic rapid eye movement sleep behavior disorder: a preliminary study

OJECTIVE

To investigate cardiovascular and sudomotor autonomic functions in patients with idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) during wakefulness compared to patients with Parkinson's disease (PD) and healthy subjects.

METHODS

Drug-naïve iRBD patients, PD patients and healthy controls underwent cardiovascular function tests including head-up tilt test (HUTT), Valsalva maneuver, deep breathing, hand grip, and cold face. Heart rate variability (HRV) analysis was performed in the frequency domain using an autoregressive algorithm in the rest supine condition and during HUTT. Sudomotor function was assessed through Sudoscan.

RESULTS

Fourteen iRBD patients, 17 PD patients and 12 healthy controls were included in the study. In the supine resting condition, the baseline values of systolic and diastolic blood pressure and heart rate were comparable in all groups. At Valsalva maneuver, iRBD patients and PD patients showed an overshoot which was significantly lower than controls. In addition, iRBD patients showed a significant reduction of sinus arrhythmia at deep breathing compared to controls. Cardiovascular responses to cold face were similar in the three groups while isometric handgrip was significantly reduced in PD patients with respect to healthy subjects. Spectral analysis of HRV showed no significant differences among iRBD, PD patients and controls in the supine resting condition; whereas during HUTT the low-frequency (LF) component of HRV was significantly higher in controls with respect to iRBD and the high-frequency (HF) component was significantly higher in iRBD patients compared to controls. In addition, a significant increase in the LF/HF ratio in healthy subjects was detected compared to iRBD. Finally, four out of 14 iRBD patients (29%) and nine of 17 PD patients (53%) had a sudomotor dysfunction.

CONCLUSIONS

Our findings obtained in de novo iRBD and PD patients indicate that some alterations of the autonomic nervous system are shared by both groups of patients, reinforcing the close link between the two pathologies, and show an autonomic fragility during wakefulness in iRBD that mainly arises under stress conditions.

The natural history of idiopathic autonomic failure: The IAF-BO cohort study

OBJECTIVE

To retrospectively describe clinical and instrumental features of a cohort of patients with at least a 5-year history of idiopathic autonomic failure (IAF) longitudinally evaluated at the Autonomic Unit of the University of Bologna (IAF-Bo cohort).

METHODS

We identified patients with at least a 5-year history of IAF who were referred to our department from 1989 to 2016 and evaluated at least once a year during the disease course. Clinical and instrumental data were collected from medical records. Clinical variables were categorized as early if presenting within 3 years from disease onset. Predictors associated with conversion to other synucleinopathies were identified in a Cox regression analysis.

RESULTS

The IAF-Bo cohort included 50 patients (39 male, 19 deceased at the last follow-up). At the last follow-up visit, 34 patients retained IAF phenotype (ncIAF group), while 16 developed a CNS synucleinopathy (converters group). Specific clinical and instrumental features were represented differently in the converters and ncIAF groups. The converters group showed a higher risk of death than the ncIAF group. Early onset of urinary dysfunction, early onset of REM sleep behavior disorder, and a Valsalva ratio ≥1.25 were identified as variables associated with phenoconversion.

CONCLUSIONS

This is one of the largest studies on the natural history of a cohort of patients with at least a 5-year history of IAF, showing a percentage of phenoconversion of 32%. We demonstrated that specific clinical and instrumental features entail an increased probability of phenoconversion. These findings could contribute to a better definition of the nature of IAF and to the identification of early markers of phenoconversion.

Diagnosis of multiple system atrophy

Multiple system atrophy (MSA) may be difficult to distinguish clinically from other disorders, particularly in the early stages of the disease. An autonomic-only presentation can be indistinguishable from pure autonomic failure. Patients presenting with parkinsonism may be misdiagnosed as having Parkinson disease. Patients presenting with the cerebellar phenotype of MSA can mimic other adult-onset ataxias due to alcohol, chemotherapeutic agents, lead, lithium, and toluene, or vitamin E deficiency, as well as paraneoplastic, autoimmune, or genetic ataxias. A careful medical history and meticulous neurological examination remain the cornerstone for the accurate diagnosis of MSA. Ancillary investigations are helpful to support the diagnosis, rule out potential mimics, and define therapeutic strategies. This review summarizes diagnostic investigations useful in the differential diagnosis of patients with suspected MSA. Currently used techniques include structural and functional brain imaging, cardiac sympathetic imaging, cardiovascular autonomic testing, olfactory testing, sleep study, urological evaluation, and dysphagia and cognitive assessments. Despite advances in the diagnostic tools for MSA in recent years and the availability of consensus criteria for clinical diagnosis, the diagnostic accuracy of MSA remains sub-optimal. As other diagnostic tools emerge, including skin biopsy, retinal biomarkers, blood and cerebrospinal fluid biomarkers, and advanced genetic testing, a more accurate and earlier recognition of MSA should be possible, even in the prodromal stages. This has important implications as misdiagnosis can result in inappropriate treatment, patient and family distress, and erroneous eligibility for clinical trials of disease-modifying drugs.

The Bulbocavernosus Reflex in the Differential Diagnosis of Multiple System Atrophy with Predominant Parkinsonism and Parkinson's Disease

Multiple system atrophy with predominant parkinsonism (MSA-P) is a degenerative disorder that presents with autonomic dysfunction, atypical parkinsonism, and ataxia. Parkinson's disease (PD) is an age-related neurological disorder of the central nervous system. Differentiation between MSA-P and PD is important because treatments, complications, and prognoses differ. The bulbocavernosus reflex (BCR) tests the afferent and efferent signals of the pudendal nerve as well as the sacral cord. In this study, we investigated differences in BCR parameters between MSA-P and PD patients. Thirty-eight MSA-P patients and 32 PD patients were selected to participate in our electrophysiological investigations. The Keypoint EMG/EP system was used to induce the BCR, and latencies and amplitudes were recorded for systematic statistical analyses. Area under the curve of the receiver operating characteristic was used to assess the specificity and sensitivity of the BCR parameters. A BCR was elicited in 76.32% of MSA-P patients and 93.75% of PD patients. The BCR latencies of the MSA-P group were longer than those of the PD group (p < 0.001). In addition, the MSA-P group had a lower BCR amplitude compared to the PD and control groups (p < 0.001). We discovered the difference between MSA-P and PD through BCR latencies and amplitudes. Compared to PD patients, MSA-P patients have longer latencies and lower amplitudes. Therefore, the BCR may be used to discriminate between MSA-P and PD in some cases.

Combined cardiovascular and sweating autonomic testing to differentiate multiple system atrophy from Parkinson's disease

OBJECTIVES

It can be difficult to differentiate multiple system atrophy (MSA) with predominant parkinsonism (MSA-P), a very disabling but rare disease, from Parkinson's disease (PD). Autonomic dysfunction, particularly cardiovascular autonomic neuropathy (CAN), is classically more pronounced in MSA. We investigated whether testing for CAN combined with sweat function assessment was helpful to differentiate patients with MSA from those with PD.

METHODS

In this retrospective study, 62 patients with MSA-P and 96 with PD, comparable in age, BMI and sex ratio with disease duration of 4.3±2.5 years for MSA vs. 11.5±6 years for PD (P<0.0001) were tested for CAN using heart rate changes with deep breathing (HR-DB), stand test (HR-ST) and Valsalva maneuver (HR-VM) and blood pressure changes during stand test (BPs-ST and BPd-ST), Valsalva maneuver (BPs-VM-II and IV), hand grip (BPd-HG) and the total "Ewing" score tests (EwS), and for sweating function using electrochemical skin conductance for hands and feet (HESC and FESC).

RESULTS

In MSA-P abnormal EwS, HR-DB, BP-ST and ESC were more frequent compared to PD, despite longer disease duration for PD. Using a model adjusted for sex, BMI, age, disease duration and treatment, the Odds Ratio for having MSA-P vs. PD based on EwS was 2.71, on HR-DB 2.36, on BP-ST 2.87 and on ESC 4.94 while it was 11.68 (2.17-62.79) for the combination of the three last tests.

CONCLUSION

Assessment of HR-DB, BP-ST and ESC, that is, rapid and non-invasive could be helpful in combination as a first simple screening to differentiate MSA-P from PD.

Evaluation of autonomic functions of patients with multiple system atrophy and Parkinson's disease by head-up tilt test

The aim of this study was to evaluate the autonomic neural function in Parkinson's disease (PD) and multiple system atrophy (MSA) with head-up tilt test and spectral analysis of cardiovascular parameters. This study included 15 patients with MSA, 15 patients with PD, and 29 healthy control (HC) subjects. High frequency power of the RR interval (RR-HF), the ratio of low frequency power of RR interval to RR-HF (RR-LF/HF) and LF power of systolic BP were used to evaluate parasympathetic, cardiac sympathetic and vasomotor sympathetic functions, respectively. Both patients with PD and MSA showed orthostatic hypotension and lower parasympathetic function (RR-HF) at tilt position as compared to HC subjects. Cardiac sympathetic function (RR-LF/HF) was significantly high in patients with PD than MSA at supine position. RR-LF/HF tended to increase in MSA and HC, but decreased in PD by tilting. Consequently, the change of the ratio due to tilting (ΔRR-LF/HF) was significantly lower in patients with PD than in HC subjects. Further analysis showed that compared to mild stage of PD, RR-LF/HF at the supine position was significantly higher in advanced stage. By tilting, it was increased in mild stage and decreased in the advanced stage of PD, causing ΔRR-LF/HF to decrease significantly in the advanced stage. Thus, we demonstrated that spectral analysis of cardiovascular parameters is useful to identify sympathetic and parasympathetic disorders in MSA and PD. High cardiac sympathetic function at the supine position, and its reduction by tilting might be a characteristic feature of PD, especially in the advanced stage.

The composite autonomic symptom scale 31 is a useful screening tool for patients with Parkinsonism

Differentiation of multiple system atrophy with predominant parkinsonism (MSA-P) and Parkinson's disease (PD) is important, but an effective tool for differentiation has not been identified. We investigated the efficacy of the composite autonomic symptom scale 31 (COMPASS 31) questionnaire as a tool for evaluating autonomic function in parkinsonism patients. In this study, we enrolled drug-naïve patients with MSA-P and PD, and administered the COMPASS-31 and an objective autonomic dysfunction test (AFT). Demographic and clinical data, including parkinsonism and autonomic dysfunction, were compared between the two groups. Additionally, we determined the optimal COMPASS 31 cut-off score to differentiate MSA-P from PD for use as a screening tool. In this study, 27 MSA-P patients and 41 PD patients were recruited. The total COMPASS 31 score was well correlated with the objective AFT results. When we compared the COMPASS 31 score between the two groups, MSA-P patients showed higher total scores and sub-scores in the orthostatic intolerance, gastrointestinal, and bladder domains compared with PD patients. Similarly, MSA-P patients had more abnormalities in expiration to inspiration ratio, Valsalva ratio and pressure recovery time than PD patients in objective AFT. With 13.25 as the cut-off score for diagnosis of MSA-P, the total COMPASS-31 score demonstrated high sensitivity (92.6%) and moderate specificity (51.2%) with an area under the curve of 0.765. Based on our results, the COMPASS 31 is an effective tool for evaluation of autonomic function in patients with parkinsonism. The COMPASS-31 could be used as a sensitive and convenient screening tool, especially for the differentiation between MSA-P and PD.

Advances in the Clinical Differential Diagnosis of Parkinson's Disease

The differential diagnosis of Parkinson's disease has widened considerably in recent years. This chapter aims to summarize the current knowledge on the clinical differential diagnoses of sporadic Parkinson's disease. As the number of monogenic familial Parkinson's disease variants and risk factors is growing, so is the number of appreciated etiologies of atypical parkinsonian and other pallidopyramidal syndromes. This work aims at summarizing the current knowledge on both motor and nonmotor neurological signs and symptoms that aid the clinical diagnosis of Parkinson's disease and its differential diagnoses.

Iodine-123-meta-iodobenzylguanidine Myocardial Scintigraphy in Isolated Autonomic Failure: Potential Red Flag for Future Multiple System Atrophy

Pure autonomic failure is challenging as it can be the presenting feature of a central nervous system syncleinopathy such as Parkinson’s disease (PD) or multiple system atrophy (MSA). Because the prognosis of MSA and PD is so different, predictive features for a possible conversion can be extremely valuable. In this paper, we report three cases (two with autopsy-proven diagnosis) that had isolated AF for many years before converting to MSA or PD. Of all the tests that were performed during the premotor stage, Iodine-123-meta-iodobenzylguanidine (MIBG) myocardial scintigraphy was predictive of the conversion to MSA. We suggest that MIBG myocardial scintigraphy, when performed in patients with isolated AF, may be a valuable predictor of conversion to MSA. On the contrary, the role of such test in parkinsonian patients irrespective of the presence of AF is still to be clarified.

The recommendations of a consensus panel for the screening, diagnosis, and treatment of neurogenic orthostatic hypotension and associated supine hypertension

Neurogenic orthostatic hypotension (nOH) is common in patients with neurodegenerative disorders such as Parkinson’s disease, multiple system atrophy, pure autonomic failure, dementia with Lewy bodies, and peripheral neuropathies including amyloid or diabetic neuropathy. Due to the frequency of nOH in the aging population, clinicians need to be well informed about its diagnosis and management. To date, studies of nOH have used different outcome measures and various methods of diagnosis, thereby preventing the generation of evidence-based guidelines to direct clinicians towards ‘best practices’ when treating patients with nOH and associated supine hypertension. To address these issues, the American Autonomic Society and the National Parkinson Foundation initiated a project to develop a statement of recommendations beginning with a consensus panel meeting in Boston on November 7, 2015, with continued communications and contributions to the recommendations through October of 2016. This paper summarizes the panel members’ discussions held during the initial meeting along with continued deliberations among the panel members and provides essential recommendations based upon best available evidence as well as expert opinion for the (1) screening, (2) diagnosis, (3) treatment of nOH, and (4) diagnosis and treatment of associated supine hypertension.

Cardiovascular dysfunction in untreated Parkinson's disease: A multi-modality assessment

BACKGROUND

The clinical presentation of Parkinson's disease (PD) includes a wide spectrum of non-motor features, including cardiovascular autonomic failure.

OBJECTIVE

To evaluate cardiovascular autonomic status and cardiac functional capacity in drug-naïve PD patients.

METHODS

18 newly-diagnosed PD patients underwent laboratory cardiovascular autonomic function tests using power spectral analysis of the R-R interval, blood pressure (BP) short-term variability and non-invasive baroreflex sensitivity (BRS). A two-dimensional (2D) transthoracic echocardiogram, spirometry and cardiopulmonary exercise test (CPET) were also performed. Thirteen patients underwent myocardial scintigraphy with [¹²³I] metaiodobenzylguanidine (MIBG).

RESULTS

At rest, total power spectral analysis of heart rate variability was lower in PD patients than in controls. BRS decreased during sympathetic activation in both patients and controls. While echocardiography and spirometry were normal, a mild degree of exercise intolerance was observed at the CPET in PD patients (mean V'O_2max: 83% of predicted; mean W_max: 80% of predicted). The heart-to-mediastinum (H/M) ratio of MIBG uptake was pathologically impaired in 9 patients, one of whom displayed a definite cardiovascular dysautonomic pattern.

CONCLUSIONS

Our results confirm that subclinical to overt cardiovascular autonomic failure may occur from the early stages of PD. The less efficient adaptive response to physical stimuli during the CPET and postural changes observed in untreated PD patients possibly reflect cardiac sympathetic denervation, although the involvement of PD-related motor impairment in physical deconditioning cannot be excluded.

Superficial siderosis associated with peripheral autonomic failure and tetraventricular hydrocephalus: a case report

We describe the case of a man whose initial clinical presentation included sensorineural hearing loss and orthostatic hypotension. The patient was diagnosed with superficial siderosis associated with peripheral autonomic failure and tetraventricular hydrocephalus.

Tilt table test today - state of the art

A tilt table test (TTT) is an inexpensive, noninvasive tool for the differential diagnosis of syncope and orthostatic intolerance and has good diagnostic yield. The autonomic system malfunction which underlines the reflex syncope is manifested as either hypotension or bradycardia, while an orthostatic challenge is applied. The timing of the response to the orthostatic challenge, as well as the predominant component of the response help to differentiate between various forms of neurocardiogenic syncope, orthostatic hypotension and non-cardiovascular conditions (e.g., pseudosyncope). Medications, such as isoproterenol and nitrates, may increase TTT sensitivity. Sublingual nitrates are easiest to administer without the need of venous access. TTT can be combined with carotid sinus massage to evaluate carotid sinus hypersensitivity, which may not be present in supine position. TTT is not useful to access the response to treatment. Recently, implantable loop recorders (ILR) have been used to document cardioinhibitory reflex syncope, because pacemakers are beneficial in many of these patients, especially those over 45 years of age. The stepwise use of both TTT and ILR is a promising approach in these patients. Recently, TTT has been used for indications other than syncope, such as assessment of autonomic function in Parkinson's disease and its differentiation from multiple system atrophy.

Dysautonomia in prodromal α-synucleinopathy: peripheral versus central autonomic degeneration

BACKGROUND AND PURPOSE

There is an urgent need for early predictive markers for the course of disease in prodromal α-synucleinopathies such as idiopathic rapid eye movement (REM) sleep behaviour disorder. Autonomic cardiac/vascular dysfunction is a prominent feature in advanced α-synucleinopathies, but its diagnostic value as an early neurodegenerative marker remains unclear. The latter may be complicated since synuclein-mediated neurodegeneration may involve central and peripheral components of the autonomic nervous system.

METHODS

The diagnostic value of autonomic symptoms and central and peripheral autonomic markers of blood pressure and heart rate regulation were prospectively evaluated in 20 subjects with idiopathic REM sleep behaviour disorder and 20 age-matched healthy controls.

RESULTS

Although subjects with REM sleep behaviour disorder showed no clinical autonomic symptoms, blood pressure (P ≤ 0.035) and heart rate response (P ≤ 0.065) were slightly diminished during orthostatic challenge. Autonomic dysregulation was distinctively reflected in lower resting heart rate (all components, P ≤ 0.05) and blood pressure variability (low frequency component, P ≤ 0.024) indicating peripheral cardiac/vascular denervation. In contrast, baroreflex sensitivity and central cardiac autonomic outflow (sympathovagal balance) were well preserved indicating intact central autonomic regulation. Heart rate variability [very low frequency component, receiver operating characteristic (ROC) area under the curve (AUC) 0.80, P ≤ 0.001] and blood pressure variability (low frequency component ROC AUC 0.73, P ≤ 0.01) but not baroreflex sensitivity and sympathovagal balance showed an excellent diagnostic accuracy in identifying subjects with REM sleep behaviour disorder and healthy controls.

CONCLUSIONS

Cardiac/vascular dysfunction in prodromal α-synucleinopathy arises from peripheral rather than from central autonomic degeneration. Autonomic indices encoded in heart rate and blood pressure variability are precise functional markers of early synuclein-mediated neurodegeneration.

Pharmacodynamics of a low subacute levodopa dose helps distinguish between multiple system atrophy with predominant Parkinsonism and Parkinson's disease

The differential diagnosis between multiple system atrophy with predominant parkinsonism (MSA-P) and Parkinson's disease (PD) may be challenging at disease onset. Levodopa responsiveness helps distinguish the two groups, but studies evaluating this issue using objective standardized tests are scanty. We retrospectively examined the extent of levodopa response by an objective kinetic-dynamic test in a series of patients prospectively followed up for a parkinsonian syndrome and eventually diagnosed as MSA-P or PD. Sixteen MSA-P and 31 PD patients under chronic levodopa therapy received a first morning fasting dose of levodopa/benserazide (100/25 mg) or levodopa/carbidopa (125/12.5 or 100/25 mg) and underwent simultaneous serial assessments of plasma levodopa concentration and alternate finger tapping frequency up to 3 h post dosing. The main levodopa pharmacodynamic variables were the maximum percentage increase in tapping frequency over baseline values (ΔTapmax %) and the area under the tapping effect-time curve (AUCTap). Levodopa pharmacokinetics did not show significant differences between MSA-P and PD, whereas both the magnitude and overall extent of levodopa tapping effect were markedly reduced in the MSA-P group (p < 0.001). The combined use of specific cut-off values for both the main pharmacodynamic variables, ΔTapmax % <20% and AUCTap <1900 [(tapping/min)·min], correctly discriminated 15 out of 16 MSA-P patients from PD patients. A combined estimation of these pharmacodynamic variables after a subacute low levodopa dose may be a simple and practical clinical tool to aid the differential diagnosis between MSA-P and PD.

Clinical features and autonomic testing predict survival in multiple system atrophy

Multiple system atrophy is characterized by autonomic failure along with motor symptoms of parkinsonism and/or cerebellar ataxia. There are differing reports on the influence of certain clinical features, including motor subtype (multiple system atrophy-parkinsonism versus multiple system atrophy-cerebellar ataxia), age of onset, gender, and early autonomic symptoms, on the survival in patients with multiple system atrophy. We sought to evaluate overall survival and predictors of survival in a large cohort of patients with multiple system atrophy seen at a single referral centre where objective autonomic testing is routinely performed for this indication. All cases of multiple system atrophy evaluated at Mayo Clinic, Rochester and assessed with an autonomic reflex screen between January 1998 and December 2012 were retrospectively reviewed. A total of 685 patients were identified; 594 met criteria for probable multiple system atrophy, and 91 for possible multiple system atrophy. Multiple system atrophy-parkinsonism was the predominant subtype in 430 patients (63%). Average age of onset was earlier in multiple system atrophy-cerebellar ataxia (58.4 years) compared to multiple system atrophy-parkinsonism (62.3 years; P < 0.001). Median disease duration from symptom onset to death was 7.51 years (95% confidence interval 7.18-7.78) while time from diagnosis to death was 3.33 years (95% confidence interval 2.92-3.59). There was no difference in survival between motor subtypes of multiple system atrophy (P = 0.232). An initial motor symptom was most common (61%) followed by autonomic onset (28%) and combined motor and autonomic symptoms (11%). The initial onset of either motor or autonomic symptoms did not influence length of survival. However, a number of clinical and autonomic laboratory features predicted unfavourable survival in a univariate analysis. A multivariate model retained the following unfavourable predictors of survival: (i) falls within 3 years of onset (hazard ratio 2.31, P < 0.0001); (ii) bladder symptoms (hazard ratio 1.96, P < 0.0001); (iii) urinary catheterization within 3 years of symptom onset (hazard ratio 1.67, P < 0.003); (iv) orthostatic intolerance within 1 year of symptom onset (hazard ratio 1.28, P < 0.014); (v) older age of onset (hazard ratio 1.02, P = 0.001); and (vi) degree of autonomic failure as measured by a validated composite autonomic severity score (hazard ratio 1.07, P < 0.0023). We conclude that carefully selected clinical features can be used to predict survival in patients with multiple system atrophy. Autonomic testing adds an additional, independent predictor of survival, demonstrating its value not only in the diagnosis of multiple system atrophy but also as prognostic marker.

Autonomic Function Tests and MIBG in Parkinson's Disease: Correlation to Disease Duration and Motor Symptoms

AIMS

Disorders of the autonomic nervous system (ANS) have a variable degree of clinical relevance in patients with Parkinson's disease (PD). Here, we assessed whether subclinical autonomic dysfunction, as evaluated by a complete battery of autonomic function tests (AFTs), correlates with PD progression.

METHODS

A series of 27 consecutive patients with PD underwent extensive ANS investigations including the head-up tilt test (HUTT), Valsalva maneuver, deep-breathing test, and handgrip test (HG); further, they performed 123I-meta-iodobenzylguanidine (MIBG) scintigraphy.

RESULTS

Seven of the 27 patients showed orthostatic hypotension (OH) at HUTT and pathological responses to the deep-breathing and HG test and Valsalva maneuver. The majority of the remaining 20 patients with PD showed pathological responses to deep-breathing (n = 13) and/or HG (n = 11). Only 3 of 27 suffered relevant OH. MIBG uptake of myocardium was decreased in 19 patients with PD (H/M ratio 1.3 ± 0.2). Prolonged clinical observation (>3 years), persistent response to levodopa, and MIBG repetition allowed us to exclude negative MIBG as attributable to atypical Parkinsonism. MIBG uptake did not correlate with OH and other AFTs. Both HG test response and MIBG did correlate with the Unified Parkinson's Disease Rating Scale (UPDRS) motor score and disease duration. A positive correlation emerged between diastolic blood pressure (DBP) response to HG test and MIBG and with systolic blood pressure (SBP) response at tilt test.

CONCLUSIONS

Our investigation suggests that ANS impairment affects the majority of patients with PD, even those PD patients showing negative MIBG, irrespective of clinical neurovegetative symptoms. The strict correlation that has been revealed with disease progression supports the routine utilization of AFTs as a reliable and inexpensive tool for monitoring peripheral sympathetic dysfunction in PD and optimizing therapy.