Longitudinal prevalence of neurogenic orthostatic hypotension in the idiopathic Parkinson Progression Marker Initiative (PPMI) cohort

BACKGROUND

Reported orthostatic hypotension (OH) prevalence in Parkinson's disease (PD) varies widely, with few studies evaluating specifically neurogenic-OH (nOH). The ratio of orthostatic heart rate (HR) to systolic blood pressure (SBP) change (Δ) is a valid screening method to stratify nOH/non-nOH but has had minimal epidemiologic application.

OBJECTIVE

To estimate the prevalence of nOH and non-nOH in the PPMI using the ΔHR/ΔSBP ratio and examine associations between nOH and various motor and non-motor measures.

METHODS

Longitudinal orthostatic vitals and motor and non-motor measures were extracted (baseline-month 48). Patients were consensus criteria classified as OH+/-, with ΔHR/ΔSBP sub-classification to nOH (ΔHR/ΔSBP < 0.5) or non-nOH (ratio ≥ 0.5). Prevalence was determined across visits. Independent linear mixed models tested associations between nOH/non-nOH and clinical variables.

RESULTS

Of N = 907 PD with baseline orthostatic vitals, 3.9 % and 1.8 % exhibited nOH and non-nOH, respectively. Prevalence of nOH/non-nOH increased yearly (P = 0.012, chi-square), though with modest magnitude (baseline: 5.6 % [95 % CI: 4.3-7.3 %]; month 48: 8.6 % [6.4-11.5 %]). nOH patients were older than PD with no OH and nOH was associated with greater impairment of motor and independent functioning than non-nOH/OH- groups. Cognitive function and typical OH symptoms were worse in PD + OH, generally.

CONCLUSIONS

nOH prevalence was greater than non-nOH in the PPMI early PD cohort, with modest prevalence increase over time. Our findings are consistent with prior studies of large cohorts that evaluated nOH, specifically. Those with early PD and nOH were likelier to be older and suffer from greater motor and functional impairment, but OH presence was generally associated with more cognitive impairment.

Effect of levodopa on postural blood pressure changes in Parkinson disease: a randomized crossover study

PURPOSE

We investigated the effect of levodopa on postural blood pressure changes in individuals with Parkinson disease (PD) with (PD+OH) and without neurogenic OH (PD-OH).

METHODS

We performed a prospective randomized crossover study with autonomic testing performed ON and OFF levodopa. The primary outcome was the change in systolic blood pressure (SBP) from supine to 70° tilt at 3 min (ΔSBP-3'). Secondary outcomes included indices of baroreflex function and blood pressure and heart rate during tilt.

RESULTS

We enrolled 40 individuals with PD (21 PD+OH, 19 PD-OH), mean age (SD) 73.2 years (7.9), 13 women (32.5%)). There was no difference in age, sex, disease duration, and severity between PD+OH and PD-OH. Mean difference in ΔSBP-3' ON versus OFF levodopa in the whole study population was - 3.20 mmHg [- 7.36 to 0.96] (p = 0.14). Mean difference in ΔSBP-3' was - 2.14 mmHg [- 7.55 to 3.28] (p = 0.45) in PD+OH and - 5.14 mmHg [- 11.63 to 1.35] (p = 0.14) in PD-OH. Mean difference in ΔSBP ON versus OFF levodopa was greater at 7 and 10 min (- 7.52 mmHg [- 11.89 to - 3.15], p = 0.002, and - 7.82 mmHg [- 14.02 to - 1.67], p = 0.02 respectively). Levodopa was associated with lower absolute values of blood pressure in both PD+OH and PD-OH and cardiovascular noradrenergic baroreflex impairment.

CONCLUSION

Levodopa decreases blood pressure in both PD with and without autonomic failure, but it does not cause a greater fall in blood pressure from supine to standing at 3 min. Levodopa-induced baroreflex sympathetic noradrenergic impairment may contribute to lower blood pressure. Lower standing blood pressure with levodopa may increase the risks of fall and syncope.

Study protocol for the Heads-Up trial: a phase II randomized controlled trial investigating head-up tilt sleeping to alleviate orthostatic intolerance in Parkinson's Disease and parkinsonism

BACKGROUND

In persons with Parkinson's Disease (PD) or certain forms of atypical parkinsonism, orthostatic hypotension is common and disabling, yet often underrecognized and undertreated. About half of affected individuals also exhibit supine hypertension. This common co-occurrence of both orthostatic hypotension and supine hypertension complicates pharmacological treatments as the treatment of the one can aggravate the other. Whole-body head-up tilt sleeping (HUTS) is the only known intervention that may improve both. Evidence on its effectiveness and tolerability is, however, lacking, and little is known about the implementability.

METHODS

In this double-blind multicenter randomized controlled trial (phase II) we will test the efficacy and tolerability of HUTS at different angles in 50 people with PD or parkinsonism who have both symptomatic orthostatic hypotension and supine hypertension. All participants start with one week of horizontal sleeping and subsequently sleep at three different angles, each maintained for two weeks. The exact intervention will vary between the randomly allocated groups. Specifically, the intervention group will consecutively sleep at 6°, 12° and 18°, while the delayed treatment group starts with a placebo angle (1°), followed by 6° and 12°. We will evaluate tolerability using questionnaires and compliance to the study protocol. The primary endpoint is the change in average overnight blood pressure measured by a 24-hour ambulatory blood pressure recording. Secondary outcomes include orthostatic blood pressure, orthostatic tolerance, supine blood pressure, nocturia and various other motor and non-motor tests and questionnaires.

DISCUSSION

We hypothesize that HUTS can simultaneously alleviate orthostatic hypotension and supine hypertension, and that higher angles of HUTS are more effective but less tolerable. The Heads-Up trial will help to clarify the effectiveness, tolerability, and feasibility of this intervention at home and can guide at-home implementation.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05551377; Date of registration: September 22, 2022.

Orthostatic hypotension: Review and expert position statement

Orthostatic hypotension is defined as a drop in systolic blood pressure of at least 20mmHg or a drop in diastolic blood pressure of at least 10mmHg within 3minutes of standing. It is a common disorder, especially in high-risk populations such as elderly subjects and patients with neurological diseases, and is associated with markedly increased morbidity and mortality. Its management can be challenging, particularly in cases where supine hypertension is associated with severe orthostatic hypotension. Education of the patient, non-pharmacological measures, and drug adaptation are the cornerstones of treatment. Pharmacological treatment should be individualized according to the severity, underlying cause, 24-hour blood pressure profile, and associated coexisting conditions. First-line therapies are midodrine and fludrocortisone, which may need to be combined for optimal care of severe cases.

Synucleinopathies

The α-synucleinopathies include pure autonomic failure, multiple system atrophy, dementia with Lewy bodies, and Parkinson disease. The past two decades have witnessed significant advances in the diagnostic strategies and symptomatic treatment of motor and nonmotor symptoms of the synucleinopathies. This chapter provides an in-depth review of the pathophysiology, pathology, genetic, epidemiology, and clinical and laboratory autonomic features that distinguish the different synucleinopathies with an emphasis on autonomic failure as a common feature. The treatment of the different synucleinopathies is discussed along with the proposal for multidisciplinary, individualized care models that optimally address the various symptoms. There is an urgent need for clinical scientific studies addressing patients at risk of developing synucleinopathies and the investigation of disease mechanisms, biomarkers, potential disease-modifying therapies, and further advancement of symptomatic treatments for motor and nonmotor symptoms.

Cerebrovascular regulation in patients with vasovagal syncope and autonomic failure due to familial amyloidotic polyneuropathy

INTRODUCTION

While there is strong evidence for autonomic involvement in cerebrovascular function acutely, long-term role of autonomic nervous system in cerebrovascular function has been controversial. We assessed autoregulation in 10 healthy individuals, nine patients with vasovagal syncope (VVS), and nine with Familial Amyloidotic Polyneuropathy (FAP), in response to head-up tilt test (HUTT).

METHODS

Arterial blood pressure heart rate, cardiac output, and bilateral cerebral blood flow velocity (CBFV) at the M1 segment of middle cerebral artery (transcranial Doppler ultrasound) were recorded during supine rest and 70° HUTT. Autoregulation was quantified using a validated nonlinear and nonparametric approach based on projection pursuit regression. Plasma adrenaline and noradrenaline were also measured at rest and during HUTT.

RESULTS

During supine rest and HUTT, plasma noradrenaline content was lower in FAP patients. During HUTT, VVS patients had a hyperadrenergic status; CBFV decreased in all groups, which was greater in FAP patients (p < 0.01). Healthy controls responded to HUTT with a reduction in CBFV responses to increases (p = 0.01) and decreases (p < 0.01) in arterial pressure without any change in the range or effectiveness of autoregulation. VVS patients responded to HUTT with a reduction in falling (p = 0.02), but not rising slope (p = 0.40). Autoregulatory range (p < 0.01) and effectiveness increased (p = 0.09), consistent with the rapid increase in levels of catecholamines. In FAP patients, the level of increase in range of autoregulation was significantly related to the magnitude of increase in plasma noradrenaline in response to HUTT (R² = 0.26, p = 0.05).

CONCLUSION

Autonomic dysfunction affects the cerebral autoregulatory response orthostatic to challenge.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Blood pressure regulation in autonomic failure by dietary sodium, blood volume and posture

In normal subjects natriuresis is tightly coupled to dietary salt ingestion to maintain sodium balance. Likewise, blood pressure remains unchanged over a wide range of salt intake because of pressure natriuresis, whereby an increase in blood pressure stimulates renal sodium excretion to restore homeostasis. These sodium handling mechanisms are impaired in autonomic failure. When exposed to salt restriction, autonomic failure patients are unable to reduce renal sodium excretion, and their orthostatic hypotension worsens. It follows that increased dietary salt would improve orthostatic tolerance. Indeed, most clinical practice guidelines emphasize a high salt intake (6-10 g/day) in the treatment of neurogenic orthostatic hypotension. This approach has been shown to improve other conditions such as syncope and postural tachycardia syndrome, but surprisingly there is no empirical evidence to support this recommendation in orthostatic hypotension. Even though there is expert opinion consensus in its favor, it would be reassuring if at least mechanistic proof of concept studies were available. Fludrocortisone is often added to a high salt diet to improve sodium retention and increase plasma volume, but these effects are transient. Fludrocortisone is contraindicated in patients with heart failure and should be used with caution, if at all, if supine hypertension is present. In patients with supine hypertension posture is an important determinant of sodium balance; blood pressure substantially increases while supine, triggering pressure natriuresis and extensive sodium loss. Thus, avoiding the supine posture may be as important as increasing dietary salt in the management of orthostatic hypotension.

Syndrome of the Trephined and ParoxySmal Sympathetic Hyperactivity in a 17-year-old minimally conscious state patient: A Case Report

Purpose: Syndrome of the Trephined (SoT) is one of the most unknown complications of the Decompressive Craniectomy (DC) after Traumatic Brain Injury (TBI). A combination of neurological clinical criteria and radiological signs after DC is necessary to make its diagnosis. In our case, as the patient was in a minimally conscious state (MCS), it was impossible to clinically assess any neurological deterioration according to the criteria found in the literature. There is no description of clinical diagnostic criteria suitable for patients with MCS apart from the visible 'Skin Flap.'Method: A 17-year-old patient sustained a severe TBI. Two months after the TBI and a DC he exhibited an MCS with a Glasgow Coma Scale (GCS) of 7 and a Wessex Head Injury Matrix (WHIM) of 5. He presented several paroxysmal sympathetic hyperactivity (PSH) episodes a day and developed a sinking skin flap. A cranioplasty was performed. Then, we noticed the gradual disappearance of PSH episodes plus an improvement of the CRS and the WHIM. Results: The evolution of the WHIM data revealed a statistically significant difference (p 0.0047). Conclusion: Further studies should be conducted to assess whether the WHIM and the frequency of PSH episodes may be part of the diagnostic criteria for SoT in MCS patients.

Management of Neurogenic Orthostatic Hypotension in Neurodegenerative Disorders: A Collaboration Between Cardiology and Neurology

Treatment of patients with α-synucleinopathies (e.g., Parkinson disease, multiple system atrophy, diffuse Lewy body disease) may require clinicians to manage both neurologic and cardiovascular issues due to autonomic dysfunction. In addition to the underlying neurodegenerative condition, patients often experience blood pressure dysregulation, such as neurogenic orthostatic hypotension (nOH) and/or supine hypertension. This commentary details the collaborative care between a cardiologist and neurologist to effectively manage medically complex patients with nOH by illustrating the case of a 76-year-old man with a history of multiple system atrophy who experienced recurrent syncope when standing or sitting and falls with loss of consciousness. The patient could walk only a few steps before experiencing a substantial drop in systolic blood pressure (100 mmHg). He also had features of profound parkinsonism (e.g., tremor, facial masking) that required treatment with levodopa, but orthostatic symptoms related to the blood pressure drop needed improvement first. The neurologist and cardiologist collaborated to diagnose nOH and initiate droxidopa treatment, which led to resolution of syncope, control of orthostatic symptoms, and improvement of orthostatic blood pressure. Considerations in the collaborative care of patients with nOH are outlined, including screening protocols, treatment goals and options, mitigation of supine hypertension risk (a condition that frequently coexists with nOH), and management of other comorbidities. In conclusion, collaboration between neurologists and cardiologists is an efficient method to improve outcomes for patients with nOH because this care model allows specialist providers to leverage their areas of expertise to manage the wide spectrum of clinical features associated with nOH. Further, communication and cooperation of the patient care team can lead to reduced patient morbidity, optimal relief of nOH symptoms, improvements in activities of daily living and quality of life, and decreased caregiver burden.

Female sexual dysfunction in multiple system atrophy: a prospective cohort study

Purpose

The diagnosis of probable multiple system atrophy relies on the presence of severe cardiovascular or urogenital autonomic failure. Erectile dysfunction is required to fulfil the latter criterion in men, whereas no corresponding item is established for women. In this study, we aimed to investigate sexual dysfunction in women with multiple system atrophy.

Methods

We administered the Female Sexual Function Index questionnaire and interviewed women with multiple system atrophy and age-matched controls regarding the presence of “genital hyposensitivity.”

Results

We recruited 25 women with multiple system atrophy and 42 controls. Female Sexual Function Index scores in sexually active women with multiple system atrophy were significantly lower (multiple system atrophy = 10; 15.4, 95% CI [10.1, 22.1], controls = 37; 26.1 [24.1, 28.1], p = 0.0004). The lowest scores concerned the domains of desire, arousal and lubrication. Genital hyposensitivity was reported by 56% of the patients with multiple system atrophy and 9% controls (p < 0.0001).

Conclusions

Sexual dysfunction is highly prevalent in women with multiple system atrophy. Screening for disturbances in specific sexual domains should be implemented in the clinical evaluation of women with suggestive motor symptoms.

The relationship between lower urinary tract function and 123ioflupane scintigraphy in drug-naïve Parkinson's disease

OBJECTIVES

Parkinson's disease (PD) is the most common degenerative cause of movement disorder, and autonomic dysfunction has been recognized in this disorder. PD patients' lower urinary tract (LUT) function is not established. We investigated LUT function in PD by single-photon emission computerized tomography (SPECT) imaging of the dopamine transporter with ¹²³I-ioflupane and clinical-urodynamic observations.

PATIENTS AND METHODS

We retrospectively analyzed the cases of 30 patients diagnosed with PD based on published criteria who completed a systematized lower urinary tract symptoms (LUTS) questionnaire and a urodynamics examination irrespective of the presence of LUTS. None of the patients were taking anti-parkinsonian medication during the study.

RESULTS

The questionnaire revealed that all 30 patients had LUTS: night-time urinary frequency (in 70%), urinary incontinence (40%), and daytime urinary frequency (80%). A urodynamic study revealed a mean volume at the first sensation at 92.3 ml, bladder capacity at 200.9 ml, and detrusor overactivity in 50%. Sphincter electromyography revealed neurogenic change in 13.6% of those for whom the test was performed. The average SBR showed a significant correlation with bladder capacity (Spearman's correlation coefficient p = 0.0076) and Hoehn Yahr motor stage (Spearman's correlation coefficient p = 0.012).

CONCLUSION

Our findings demonstrate that the striatum is relevant to the higher control of storage in micturition function in PD.

Pharmacokinetics and pharmacodynamics of ampreloxetine, a novel, selective norepinephrine reuptake inhibitor, in symptomatic neurogenic orthostatic hypotension

Purpose

Ampreloxetine is a novel, selective, long-acting norepinephrine reuptake (NET) inhibitor being investigated as a once-daily oral treatment for symptomatic neurogenic orthostatic hypotension (nOH) in patients with autonomic synucleinopathies. The purpose of this study was to characterize the pharmacokinetic and pharmacodynamic profiles of ampreloxetine in this target population.

Methods

Patients with nOH were enrolled in a multicenter, phase II clinical trial of ampreloxetine (NCT02705755). They received escalating doses over 5 days in the clinical research unit, followed by 20 weeks of open-label treatment and then a 4-week withdrawal. As neurochemical biomarkers of NET inhibition, we assayed plasma concentrations of norepinephrine (NE) and its main intraneuronal metabolite 3,4-dihydroxyphenylglycol (DHPG) pre- and post-ampreloxetine.

Results

Thirty-four patients with nOH were enrolled. Plasma ampreloxetine concentrations increased with repeated escalating doses, with peak concentrations observed 6–9 h post-drug administration. The median ampreloxetine dose in the 20-week treatment phase was 10 mg once daily. Plasma ampreloxetine concentrations reached steady state by 2 weeks, with stable plasma levels over 24 h. No influence of age or renal function on ampreloxetine plasma concentrations was observed. On treatment, compared to baseline, plasma NE significantly increased by 71% (p < 0.005), plasma DHPG significantly declined by 22% (p < 0.05), and the NE:DHPG ratio significantly increased (p < 0.001).

Conclusions

Persistent elevation of plasma NE levels accompanied by reduced DHPG levels after ampreloxetine suggests reduced neuronal reuptake and metabolism of NE in postganglionic efferent sympathetic neurons. The findings are consistent with long-lasting NET inhibition, which may increase vasoconstrictor tone, supporting once-daily ampreloxetine dosing in patients with nOH.

Sympathetic and sensory nerve fiber function in multiple system atrophy and idiopathic Parkinson's disease

OBJECTIVE

To explore small fiber somatosensory and sympathetic function in PD and MSA.

METHODS

We recruited 20 PD patients (7 women, median age 65.5 years; IQR 54.75-70.0), 10 MSA patients (4 women; median age 68 years; IQR 66.25-74.0), and 10 healthy subjects (HC; 4 women, median age 68; IQR 59.0-71.0 years). Autonomic testing included forehead cooling, intradermal microdialysis of norepinephrine (NE; 10^-5; 10^-6; 10^-7; and 10^-8), and orthostatic hypotension (OH); somatosensory testing included quantitative sensory testing (QST) according to the protocol of the German Research Network on Neuropathic Pain (DFNS).

RESULTS

OH occurred more frequently in PD (p = 0.018) and MSA (p = 0.002) compared to HC. Vasoconstriction responses were stronger in PD compared to MSA during forehead cooling (p = 0.044) and microdialysis of physiologically concentrated NE solutions (10^-7; 10-8; p = 0.017). PD and MSA had impaired cold (PD: p < 0.01; MSA: p < 0.05) and warm detection thresholds (PD and MSA, both p < 0.05). The mechanical detection threshold was higher in PD (p < 0.01). Conversely, mechanical pain thresholds were decreased in PD and MSA (both p < 0.001), indicating mechanical hyperalgesia.

CONCLUSION

In contrast to MSA, we found evidence of peripheral adrenoreceptor hypersensitivity in PD, probably caused by peripheral sympathetic denervation. Sensory testing revealed peripheral neuropathy and central pain sensitization in PD and MSA. Jointly, our data demonstrate autonomic and somatosensory dysfunction in PD and MSA.

Inverted circadian variation of arterial pressure in a geriatric patient: an indicator of autonomic dysfunction

BACKGROUND

Orthostatic hypotension (OH) in geriatric patients frequently involves a component of autonomic failure (AF). The combination of OH with nocturnal hypertension (NHT) is indicative of AF, which is described as pure (PAF), when neurologic symptoms are absent, or as multisystem atrophy (MSA), when combined with motor disturbance (Parkinsonism or Parkinson disease).

CASE PRESENTATION

An 87-year-old man presented with long-lasting OH. He frequently fell, causing several fractures, and he developed heart failure. Blood pressure (BP) registration revealed a reversal of the day-night rhythm with NHT. An 18-FDG PET brain CT scan showed cerebellar hypometabolism, indicating MSA.

CONCLUSIONS

This case demonstrates the use of continuous BP registration in geriatric patients with OH for diagnosing NHT. It illustrates the usefulness of 18-FDG PET brain CT scan to specify the nature of the AF. The case also illustrates the difficulty of managing the combination of OH and NHT.

Clinical and neurohormonal characteristics in African Americans with neurogenic orthostatic hypotension

PURPOSE

Neurogenic orthostatic hypotension (nOH) is the hallmark of neurodegenerative forms of autonomic failure, including pure autonomic failure, multiple system atrophy, and Parkinson's disease. Studies have shown autonomic physiological differences in Africans Americans (AA) such as lower heart rate variability, enhanced blood pressure reactivity, and blunted sympathetic neural response compared to non-Hispanic whites. However, the clinical characteristics and neurohormonal profile of autonomic failure in AA is unknown.

METHODS

A total of 65 patients with nOH participated in this study (9 AA and 56 non-Hispanic whites). Both groups were of similar age and comorbidity status, and they underwent standardized autonomic testing and assessment of neurohormonal levels and renin activity and aldosterone in supine and upright positions.

RESULTS

There were no significant differences in baseline autonomic clinical characteristics between non-Hispanic whites and AA with nOH. Non-Hispanic whites demonstrated a significant increase in upright renin activity compared to AA (295 ± 88% vs. 13 ± 13%, respectively). AA showed a blunted increase in aldosterone compared to non-Hispanic whites (188 ± 27% vs. 59 ± 38%, respectively). These results indicated persistent suppression of the renin-angiotensin system in AA, particularly during upright posture.

CONCLUSION

Our findings demonstrate that AA with nOH have similar clinical characteristics and hemodynamic autonomic profiles, but lower upright renin activity and aldosterone levels, compared to non-Hispanic whites. Renin suppression persists in AA with severe autonomic failure and can potentially contribute to postural changes and supine hypertension.

Evidence of Impaired Cerebellar Connectivity at Rest and During Autonomic Maneuvers in Patients with Autonomic Failure

The objective of the current study was to investigate whether patients with neurogenic orthostatic hypotension (NOH) secondary to autonomic failure have impaired functional connectivity between the cerebellum and central autonomic structures during autonomic challenges. Fifteen healthy controls (61 ± 14 years) and 15 NOH patients (67 ± 6 years; p = 0.12) completed the following tasks during a functional brain MRI: (1) 5 min of rest, (2) 5 min of lower-body negative pressure (LBNP) performed at - 35 mmHg, and (3) Three, 15-s Valsalva maneuvers (VM) at 40 mmHg. Functional connectivity (Conn Toolbox V18) between central autonomic structures and discrete cerebellar regions involved in cardiovascular autonomic control, including the vermis and posterior cerebellum, was assessed using a regions-of-interest approach during rest, LBNP and VM. Functional connectivity was contrasted between controls and patients with autonomic failure. At rest, controls had significantly more intra-cerebellar connectivity and more connectivity between cerebellar lobule 9 and key central autonomic structures, including: bilateral anterior insula (T_R-value: 4.84; T_L-value: 4.51), anterior cingulate cortex (T-value: 3.41) and bilateral thalamus (T_R-value: 3.95; T_L-value: 4.51). During autonomic maneuvers, controls showed significantly more connectivity between cardiovascular cerebellar regions (lobule 9 and anterior vermis) and important autonomic regulatory sites, including the brainstem, hippocampus and cingulate: vermis-brainstem (T-value: 4.31), lobule 9-brainstem (T_R-value, 5.29; T_L-value, 4.53), vermis-hippocampus (T-value, 4.63), and vermis-cingulate (T-value, 4.18). Anatomical and functional studies in animals and humans substantiate a significant role for the cerebellum in cardiovascular autonomic control during postural adjustments. In the current study, patients with NOH related to autonomic failure showed evidence of reduced connectivity between cardiovascular cerebellar regions and several important central autonomic structures, including the brainstem. The cerebellum is an established structure in cardiovascular autonomic control; therefore, evidence of impaired cerebellar connectivity to other autonomic structures may further contribute to the inability to properly regulate blood pressure during postural changes in NOH patients.

Morbidity and mortality in orthostatic hypotension

This review summarizes the current literature on the epidemiology of orthostatic hypotension (OH) in the elderly and in patients with autonomic impairment also known as neurogenic OH (nOH); these two conditions have distinct pathophysiologies and affect different patient populations. The prevalence of OH in the elderly varies depending on the study population. In community dwellers, OH prevalence is estimated at 16%, whereas in institutionalized patients, it may be as high as 60%. The prevalence of OH increases exponentially with age, particularly in those 75 years and older. Multiple epidemiological studies have identified OH as a risk factor for all-cause mortality and cardiovascular disease including heart failure and stroke. Real-world data from administrative databases found polypharmacy, multiple co-morbid conditions, and high health-care utilization as common characteristics in OH patients. A comprehensive evaluation of medications associated with OH is discussed with particular emphasis on the use of anti-hypertensive therapy from two large clinical trials on high-intensive versus standard blood pressure management. Finally, we also review the epidemiology of nOH based on the underlying neurodegenerative disorder (either Parkinson's disease or multiple system atrophy), and the presence of co-morbid conditions such as hypertension and cognitive impairment.

Management of neurogenic orthostatic hypotension in the heart failure patient

Neurogenic orthostatic hypotension (nOH) is a common comorbidity in patients with neurodegenerative diseases. It is associated with an increased risk of falls, incident cardiovascular disease, and all-cause mortality. There are over 5 million individuals in the U.S. with heart failure (HF) with an associated 50% mortality rate at 5 years. The prevalence of nOH and HF increase with age and, as the population continues to age, will be increasingly common comorbid conditions. Thus, the effective management of these conditions has important implications for public health. The management of orthostatic hypotension in the context of congestive heart failure is challenging due to the fact that the fundamental principles of management of these disease states are in opposition to each other. In this review, we will discuss the principles of management of nOH and HF and outline strategies for the effective treatment of these comorbid conditions.

The impact of supine hypertension on target organ damage and survival in patients with synucleinopathies and neurogenic orthostatic hypotension

INTRODUCTION

In addition to neurogenic orthostatic hypotension (nOH), patients with synucleinopathies frequently have hypertension when supine. The long-term consequences of both abnormalities are difficult to disentangle. We aimed to determine if supine hypertension is associated with target organ damage and worse survival in patients with nOH.

METHODS

Patients with nOH due to multiple system atrophy (MSA), Parkinson disease (PD), or pure autonomic failure (PAF) were classified into those with or without supine hypertension (systolic BP of at least 140 mmHg or diastolic BP of at least 90 mmHg). Organ damage was assessed by measuring cerebral white matter hyperintensities (WMH), left ventricular hypertrophy (LVH), and renal function. We prospectively followed patients for 30 months (range: 12-66 months) and recorded incident cardiovascular events and all-cause mortality.

RESULTS

Fifty-seven patients (35 with probable MSA, 14 with PD and 8 with PAF) completed all evaluations. In addition to nOH (average fall 35 ± 21/17 ± 14 mmHg, systolic/diastolic, mean ± SD), 38 patients (67%) had supine hypertension (systolic BP > 140 mmHg). Compared to those without hypertension, patients with hypertension had higher blood urea nitrogen levels (P = 0.005), lower estimated glomerular filtration rate (P = 0.008), higher prevalence of LVH (P = 0.040), and higher WMH volume (P = 0.019). Longitudinal follow-up of patients for over 2 years (27.1 ± 14.5 months) showed that supine hypertension was independently associated with earlier incidence of cardiovascular events and death (HR = 0.25; P = 0.039).

CONCLUSIONS

Supine hypertension in patients with nOH was associated with an increased risk for target organ damage, cardiovascular events, and premature death. Defining management strategies and safe blood pressure ranges in patients with nOH remains an important research question.

Orthostatic Hypotension in Parkinson Disease

Orthostatic hypotension (OH) is a sustained fall in blood pressure on standing that can cause symptoms of organ hypoperfusion. OH is associated with increased morbidity and mortality and leads to a significant number of hospital admissions. OH can be caused by volume depletion, blood loss, cardiac pump failure, large varicose veins, medications, or defective activation of sympathetic nerves and reduced norepinephrine release upon standing. Neurogenic OH is a frequent and disabling problem in patients with synucleinopathies such as Parkinson disease, multiple system atrophy, and pure autonomic failure, and it is commonly associated with supine hypertension. Several therapeutic options are available.

Orthostatic hypotension in hereditary transthyretin amyloidosis: epidemiology, diagnosis and management

Purpose

Neurogenic orthostatic hypotension is a prominent and disabling manifestation of autonomic dysfunction in patients with hereditary transthyretin (TTR) amyloidosis affecting an estimated 40–60% of patients, and reducing their quality of life. We reviewed the epidemiology and pathophysiology of neurogenic orthostatic hypotension in patients with hereditary TTR amyloidosis, summarize non-pharmacologic and pharmacological treatment strategies and discuss the impact of novel disease-modifying treatments such as transthyretin stabilizers (diflunisal, tafamidis) and RNA interference agents (patisiran, inotersen).

Methods

Literature review.

Results

Orthostatic hypotension in patients with hereditary transthyretin amyloidosis can be a consequence of heart failure due to amyloid cardiomyopathy or volume depletion due to diarrhea or drug effects. When none of these circumstances are apparent, orthostatic hypotension is usually neurogenic, i.e., caused by impaired norepinephrine release from sympathetic postganglionic neurons, because of neuronal amyloid fibril deposition.

Conclusions

When recognized, neurogenic orthostatic hypotension can be treated. Discontinuation of potentially aggravating medications, patient education and non-pharmacologic approaches should be applied first. Droxidopa (Northera^®), a synthetic norepinephrine precursor, has shown efficacy in controlled trials of neurogenic orthostatic hypotension in patients with hereditary TTR amyloidosis and is now approved in the US and Asia. Although they may be useful to ameliorate autonomic dysfunction in hereditary TTR amyloidosis, the impact of disease-modifying treatments on neurogenic orthostatic hypotension is still uninvestigated.

Reduced brainstem functional connectivity in patients with peripheral autonomic failure

Autonomic homeostasis is dependent upon several brainstem nuclei, as well as several cortical and subcortical structures. Together, these sites make up, in part, the central autonomic network. Neurogenic orthostatic hypotension (NOH) is a cardinal feature of autonomic failure that occurs due to a failure to increase sympathetic efferent activity in response to postural changes. Therefore, the purpose of the current study was to investigate brainstem functional connectivity in NOH patients with peripheral autonomic lesions resulting in autonomic failure. Fifteen controls (63 ± 13 years) and fifteen Neurogenic Orthostatic Hypotension patients (67 ± 6 years; p = .2) with peripheral autonomic dysfunction completed 5-min of rest and three Valsalva maneuvers during a functional brain scan. Functional connectivity from the brainstem to cortical and subcortical structures were contrasted between patients and controls. At rest controls had significantly greater brainstem connectivity to the anterior cingulate cortex (T-value: 4.29), left anterior insula (T-value:3.31), left putamen (T-value:3.31) and bilateral thalamus (T_RIGHT-value: 3.83; T_LEFT-value:4.25) (p-FDR < 0.005). During Valsalva, controls showed significantly more connectivity between the brainstem and both the left anterior (cerebellum 4/5) and bilateral posterior cerebellum (cerebellar 9 and left cerebellar 6). Other cerebellar regions included brainstem-to-vermis. Other brainstem-to-cortical and subcortical regions included: bilateral putamen, posterior cingulate cortex (PCC), amygdala and medial prefrontal cortex. There was a significant negative correlation between the brainstem-cerebellar connectivity and severity of autonomic dysfunction (p < .01). During recovery phase of the Valsalva, controls had greater brainstem connectivity to the left thalamus (T-value:4.17); PCC (T-value:3.32); right putamen (T-value:3.28); right paracingulate gyrus (T-value:3.25) and left posterior cerebellum (C9) (T-value:3.21) (p-FDR < 0.05). The effect sizes for each brainstem connectivity during Valsalva and recovery ranged from moderate to strong. Patients with autonomic failure show reduced coupling between the brainstem and regions of the central autonomic network, including the cerebellum, insula, thalamus and cingulate cortices. Connectivity was associated with autonomic impairment. These findings may suggest impaired brainstem connectivity in patients with autonomic failure.

Autonomic Disorders

Autonomic complaints are frequently encountered in clinical practice. They can be due to primary autonomic disorders or secondary to other medical conditions. Primary autonomic disorders can be categorized as orthostatic intolerance syndromes and small fiber neuropathies; the latter are associated with autonomic failure, pain, or their combinations. The review outlines orthostatic intolerance syndromes (neurally mediated syncope, orthostatic hypotension, postural tachycardia syndrome, inappropriate sinus tachycardia, orthostatic cerebral hypoperfusion syndrome, and hypocapnic cerebral hypoperfusion) and small fiber neuropathies (sensory/autonomic/mixed, acute/subacute/chronic, idiopathic/secondary, inflammatory and noninflammatory). Several specific autonomic syndromes (diabetic neuropathy, primary hyperhidrosis, paroxysmal sympathetic hyperactivity, autonomic dysreflexia), neurogenic bladder, and gastrointestinal motility disorders are discussed as well.

A case of autoimmune autonomic ganglionopathy with prolonged delirium

Autoimmune autonomic ganglionopathy (AAG) is a rare acquired immune-mediated disorder that leads to autonomic failure. It is sometimes complicated by mental and behavioral symptoms. We report a case of 72-year-old male with AAG who was admitted to the psychiatric department for prolonged severe delirium. Repeated loss of consciousness attributed to severe orthostatic hypotension disturbed recovery from delirium. In addition, intracerebral hemorrhage occurred during hospitalization, and this cerebrovascular event may have been substantially affected by unstable blood pressure due to AAG. This case suggests importance of differential diagnosis of AAG in patients with mental and behavioral symptoms accompanying severe autonomic failure.

Substantial renal conversion of L-threo-3,4-dihydroxyphenylserine (droxidopa) to norepinephrine in patients with neurogenic orthostatic hypotension

BACKGROUND

The pressor effect of L-threo-3,4-dihydroxyphenylserine (L-DOPS, droxidopa, Northera™) results from conversion of L-DOPS to norepinephrine (NE) in cells expressing L-aromatic-amino-acid decarboxylase (LAAAD). After L-DOPS administration the increase in systemic plasma NE is too small to explain the increase in blood pressure. Renal proximal tubular cells abundantly express LAAAD. Since NE generated locally in the kidneys could contribute to the pressor effect of L-DOPS, in this study we assessed renal conversion of L-DOPS to NE.

METHODS

Ten patients who were taking L-DOPS for symptomatic orthostatic hypotension had blood and urine sampled about 2 h after the last L-DOPS dose. L-DOPS and NE were assayed by alumina extraction followed by liquid chromatography with electrochemical detection. Data were compared in patients off vs. on levodopa/carbidopa.

RESULTS

In patients off levodopa/carbidopa the ratio of NE/L-DOPS in urine averaged 63 times that in plasma (p = 0.0009 by t test applied to log-transformed data). In marked contrast, in the three patients on levodopa/carbidopa the ratio of NE/L-DOPS in urine did not differ from that in plasma.

CONCLUSION

There is extensive renal production of NE from L-DOPS. Carbidopa seems to attenuate the conversion of L-DOPS to NE in the kidneys. Further research is needed to assess whether the proposed paracrine effect of L-DOPS in the kidneys contributes to the systemic pressor response.

Autonomic involvement in Guillain-Barré syndrome: an update

BACKGROUND

Guillain-Barré syndrome (GBS), an inflammatory, usually demyelinating polyradiculopathy, is characterized by ascending symmetrical limb weakness, sensory disturbances, and absent or reduced deep tendon reflexes. There is extensive literature suggesting that GBS is associated with autonomic dysfunction in up to two-thirds of patients. However, it is interesting that there is still no consensus amongst medical professionals regarding whether GBS patients should be routinely screened for autonomic nervous system (ANS) neuropathy. This is an important issue, as the mortality rate from presumed ANS abnormalities now exceeds that of respiratory failure. Given the long interval since this literature was last comprehensively reviewed, an update on this topic is warranted.

METHODS

A PubMed search yielded 193 results with the terms "GBS or Guillain-Barré syndrome and autonomic symptoms" and 127 results with the terms "GBS or Guillain-Barré syndrome and dysautonomia."

RESULTS

This review will summarize the current literature involving GBS and autonomic dysfunction in terms of presentation, management, and a brief discussion of prognosis. We also examine prospective approaches that may be helpful and update a proposed management plan.

High norepinephrinergic orthostatic hypotension in early Parkinson's disease

INTRODUCTION

Plasma norepinephrine concentration reflects lesions causing OH. We investigate whether patients with high norepinephrinergic orthostatic hypotension (OH) whose supine plasma norepinephrine concentration (NE_supine) is above the mean value in all patients with Parkinson's disease (PD) have central sympathetic denervation.

METHODS

We analyzed data from 110 non-demented patients with early de novo PD who underwent cardiovascular examinations. We divided the patients into three groups according to the presence or absence of orthostatic hypotension and NE_supine: patients without OH, patients with OH+high NE_supine, and patients with OH+low NE_supine.

RESULTS

The mean NE_supine in all patients was 251.6 pg/ml. Twelve patients (10.9%) had OH+high NE_supine (≥251.6 pg/ml), and 45 patients (40.9%) had OH+low NE_supine (<251.6 pg/ml). OH was more pronounced in patients with OH+high NE_supine than in those with OH+low NE_supine (p = 0.024). Vasopressin release and percent increase of NE after orthostatic stress were well preserved in patients with OH+low NE_supine, but not in patients with OH+high NE_supine. Cognition was lower in patients with OH+high NE_supine than in patients with OH+low NE_supine (p = 0.019) and was associated with vasopressin release during orthostatic stress on multiple regression analysis. The degree of cardiac sympathetic denervation did not differ between two groups with OH.

CONCLUSIONS

Patient with PD and high norepinephrinergic OH are a subset of patients who have early cognitive decline and impaired vasopressin release. Vasopressin release after orthostatic stress was closely related to global cognition in PD.

Consensus statement on the definition of neurogenic supine hypertension in cardiovascular autonomic failure by the American Autonomic Society (AAS) and the European Federation of Autonomic Societies (EFAS) : Endorsed by the European Academy of Neurology (EAN) and the European Society of Hypertension (ESH). Clin Auton Res. 2018;28:355-362. [PMID: 29766366 PMCID: PMC6097730 DOI: 10.1007/s10286-018-0529-8]

PURPOSE

Patients suffering from cardiovascular autonomic failure often develop neurogenic supine hypertension (nSH), i.e., high blood pressure (BP) in the supine position, which falls in the upright position owing to impaired autonomic regulation. A committee was formed to reach consensus among experts on the definition and diagnosis of nSH in the context of cardiovascular autonomic failure.

METHODS

As a first and preparatory step, a systematic search of PubMed-indexed literature on nSH up to January 2017 was performed. Available evidence derived from this search was discussed in a consensus expert round table meeting in Innsbruck on February 16, 2017. Statements originating from this meeting were further discussed by representatives of the American Autonomic Society and the European Federation of Autonomic Societies and are summarized in the document presented here. The final version received the endorsement of the European Academy of Neurology and the European Society of Hypertension.

RESULTS

In patients with neurogenic orthostatic hypotension, nSH is defined as systolic BP ≥ 140 mmHg and/or diastolic BP ≥ 90 mmHg, measured after at least 5 min of rest in the supine position. Three severity degrees are recommended: mild, moderate and severe. nSH may also be present during nocturnal sleep, with reduced-dipping, non-dipping or rising nocturnal BP profiles with respect to mean daytime BP values. Home BP monitoring and 24-h-ambulatory BP monitoring provide relevant information for a customized clinical management.

CONCLUSIONS

The establishment of expert-based criteria to define nSH should standardize diagnosis and allow a better understanding of its epidemiology, prognosis and, ultimately, treatment.

Seronegative and seropositive autoimmune autonomic ganglionopathy (AAG): Same clinical picture, same response to immunotherapy

Two patients with a syndrome of pandisautonomia with clinical criteria of AAG are provided. Both patients present a similar clinical picture and response to immunosuppressive treatment. One of them has positive antibodies against the ganglionic nicotinic acetylcholine (gAChr) and the other does not. This brief article serves to reflect the spectrum of AAG, at a clinical level, in laboratory tests and in the response to immunotherapy, independently of the presence of positive gAChr antibodies.

Career perspective: Kenneth J. Collins

A career interest in thermoregulation research has included wide contrasts in the subjects of enquiry, extending from heat stroke to hypothermia, special investigations in many different purpose-built climatic chambers, laboratory-based biomedical studies together with hospital practice, and field work in tropical climates to physiological surveys on urban populations in temperate environments. The scientific process and need to focus on careful planning of experiments, using the most appropriate methods, selecting the right controls and eventually applying correct statistical analysis do not always follow a smooth transition, as illustrated in this account. The result of endeavour to resolve a human environmental problem, however, is greatly satisfying, and sometimes becomes a unique experience when the solution reveals new fundamental facts.

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.

Transcranial Doppler in autonomic testing: standards and clinical applications

When cerebral blood flow falls below a critical limit, syncope occurs and, if prolonged, ischemia leads to neuronal death. The cerebral circulation has its own complex finely tuned autoregulatory mechanisms to ensure blood supply to the brain can meet the high metabolic demands of the underlying neuronal tissue. This involves the interplay between myogenic and metabolic mechanisms, input from noradrenergic and cholinergic neurons, and the release of vasoactive substrates, including adenosine from astrocytes and nitric oxide from the endothelium. Transcranial Doppler (TCD) is a non-invasive technique that provides real-time measurements of cerebral blood flow velocity. TCD can be very useful in the work-up of a patient with recurrent syncope. Cerebral autoregulatory mechanisms help defend the brain against hypoperfusion when perfusion pressure falls on standing. Syncope occurs when hypotension is severe, and susceptibility increases with hyperventilation, hypocapnia, and cerebral vasoconstriction. Here we review clinical standards for the acquisition and analysis of TCD signals in the autonomic laboratory and the multiple methods available to assess cerebral autoregulation. We also describe the control of cerebral blood flow in autonomic disorders and functional syndromes.

Epidemiology, Diagnosis, and Management of Neurogenic Orthostatic Hypotension

BACKGROUND

Orthostatic hypotension (OH) is a sustained fall in blood pressure on standing which can cause symptoms of organ hypoperfusion. OH is associated with increased morbidity and mortality and leads to a significant number of hospital admissions particularly in the elderly (233 per 100,000 patients over 75 years of age in the US). OH can be due to volume depletion, blood loss, large varicose veins, medications, or due to defective activation of sympathetic nerves and reduced norepinephrine release upon standing (i.e., neurogenic OH).

METHODS AND FINDINGS

Literature review. Neurogenic OH is a frequent and disabling problem in patients with synucleinopathies such as Parkinson disease, multiple system atrophy, and pure autonomic failure, and is commonly associated with supine hypertension. Several pharmacological and non-pharmacological therapeutic options are available.

CONCLUSIONS

Here we review the epidemiology, diagnosis, and management of neurogenic OH, and provide an algorithm for its treatment emphasizing the importance of removing aggravating factors, implementing non-pharmacologic measures, and selecting appropriate pharmacological treatments.

Sepiapterin reductase gene-disrupted mice suffer from hypertension with fluctuation and bradycardia

(6R)‐l‐erythro‐5,6,7,8‐Tetrahydrobiopterin (BH4) is an essential cofactor for monoamine and nitric oxide (NO) production. Sepiapterin reductase (SPR) catalyzes the final step in BH4 biosynthesis. We analyzed the cardiovascular function of adult Spr gene‐disrupted (Spr^−/−) mice for the first time. After weaning, Spr^−/− mice suffered from hypertension with fluctuation and bradycardia, while the monoamine contents in these mice were less than 10% of those in the wild‐type mice as a result of BH4 depletion. Heart rate variability analysis indicated the sympathetic dominant state in Spr^−/− mice. The endothelium‐dependent vascular relaxation in response to acetylcholine was significantly impaired in Spr^−/− mice after sexual maturation (above 4 months old). Protein amounts of α₁ adrenergic receptor and eNOS in the aorta were not altered. Spr^−/− mice exhibited hypoglycemia and elevation of plasma renin activity. Our results suggest that the hypertension with fluctuation and bradycardia of Spr^−/− mice would be caused by an imbalance of sympathetic and parasympathetic input and impaired nitric oxide production in endothelial cells. We suggest an important role of BH4 and SPR in age‐related hypertension and a possible relationship with the cardiovascular instabilities in autonomic diseases, including Parkinson's disease and spinal cord injury.

Autoimmunity-associated autonomic failure with sympathetic denervation

We report a case of autoimmunity-associated autonomic failure in a young adult woman who developed arthritis followed 3 years later by pandysautonomia. There was early recovery of parasympathetic functions but persistent neurogenic orthostatic hypotension from post-ganglionic sympathetic denervation. Clinical laboratory testing indicated variable amounts of sympathetic neuronal re-sprouting in the heart, kidneys, eyes, and body as a whole upon follow-up evaluation after 1.5 years.

Ventilatory Response to Hypercapnia Predicts Dementia with Lewy Bodies in Late-Onset Major Depressive Disorder

BACKGROUND

Studies have shown that developing major depressive disorder (MDD) at 50 years of age or older can predict dementia. Depression is particularly common in dementia with Lewy bodies (DLB), and occasionally occurs before the onset of extrapyramidal symptoms. Moreover, systemic autonomic dysfunction, including an abnormal ventilatory response to hypercapnia (VRH), is common in patients with DLB.

OBJECTIVE

Here, we aimed to determine whether the VRH is useful for distinguishing depression that is predictive of DLB from other types of MDD.

METHODS

Participants were 35 consecutive patients with first onset MDD at 50 years or older with bradykinesia. After diagnosing the clinical subtype of MDD according to DSM-IV criteria, each subject underwent a battery of psychological tests, autonomic examinations including VRH, brain magnetic resonance imaging, and 123I-meta-iodobenzylguanidine scintigraphy.

RESULTS

Longitudinal follow-up showed that all 18 patients with abnormal VRH results developed DLB, whereas none of the 17 patients with normal VRH results converted to DLB within the study period (sensitivity: 100% , specificity: 100%). Additionally, over half of the DLB converters showed abnormalities on other autonomic examinations. For converters, the most common MDD subtype had psychotic and melancholic features simultaneously. The frequency of hypersensitivity to psychotropics was higher in converters than it was in non-converters.

CONCLUSION

In the present study, patients with abnormal VRH results were very likely to develop DLB. Thus, for patients with late-onset MDD accompanied by bradykinesia, the VRH in combination with the clinical subtype of MDD or hypersensitivity to psychotropics may be useful for diagnosing prodromal DLB.

Predictors of postprandial hypotension in elderly patients with de novo Parkinson's disease

Postprandial hypotension is one of the most important autonomic disorders in Parkinson's disease. However, its predictors remain unclear. We investigated which variable(s) predict the presence of postprandial hypotension in elderly patients with Parkinson's disease. The subjects were 64 patients with de novo Parkinson's disease who were 70 years or older. Postprandial hypotension was evaluated on a 75-g oral glucose tolerance test. Olfactory function, constipation, cardiac sympathetic or parasympathetic denervation, orthostatic intolerance on head-up tilt table testing, and other baseline characteristics were evaluated. The results showed the presence of postprandial hypotension was associated with severe dysosmia, constipation, orthostatic hypotension (a decrease in systolic blood pressure ≥30 mmHg) and preprandial hypertension at rest. On multiple logistic regression analyses adjusted for age, sex, symptom duration, disease severity, and motor subtype, the odds ratio was 4.02 for severe dysosmia (p = 0.027), 9.99 for constipation (p = 0.006), 6.42 for orthostatic hypotension with alternative definition (p = 0.004) and 7.90 for preprandial hypertension at rest (p = 0.001). Each multiple logistic regression analysis revealed that female sex was also a risk factor for postprandial hypotension. The variables with the highest sensitivity and specificity for postprandial hypotension were constipation (89.6 %) and preprandial hypertension at rest or orthostatic hypotension with alternative definition (both 77.1 %), respectively. Our results suggest that these variables predict the presence of postprandial hypotension in elderly patients with Parkinson's disease, suggesting that postprandial hypotension shares etiologic factors with these potential predictors.

Clinical Relevance of Orthostatic Hypotension in Neurodegenerative Disease

The autonomic nervous system appears to be uniquely susceptible to degeneration in disorders of α-synuclein pathology. Clinically, autonomic dysfunction in these disorders manifests as neurogenic orthostatic hypotension (nOH), a condition that results in substantial morbidity and mortality. nOH results from pathology affecting either the central autonomic pathways or peripheral autonomic nerve fibers. Determining the localization and pathophysiology of nOH is critical in effectively managing this disorder and selecting appropriate treatment options. In this review, we discuss the pathophysiology of nOH with respect to the various α-synuclein-related neurodegenerative conditions. We highlight the associated clinical features, including gait instability, rapid eye movement behavior disorder, and hyposmia. We also review the current pharmacologic treatment options for nOH. Overall, the goals of therapy are to improve symptoms and prevent syncope and falls. Non-pharmacologic interventions should be introduced first, followed by carefully selected pharmacologic therapies. Treatment decisions should be directed by an understanding of the underlying pathophysiology, as well as the comorbidities and potential contributing factors present in each individual patient.

Clinical characteristics of supine hypertension in de novo Parkinson disease

PURPOSE

Supine hypertension is frequently associated with autonomic failure. However, its clinical characteristics in patients with Parkinson disease (PD) remain unclear. The present study aimed to clarify the characteristics of supine hypertension in patients with de novo PD.

METHODS

The subjects were 72 patients with de novo PD. We studied blood pressure and plasma norepinephrine levels after the patients rested for 20 min in the supine position. Changes in blood pressure were also examined on head-up tilt-table testing.

RESULTS

The disease duration was 1.7 ± 1.6 years (average ± SD). Thirty-three (45.8 %) patients had supine hypertension (defined as a blood pressure of ≥140/90 mmHg). Supine blood pressure positively correlated with the degree of orthostatic hypotension. Age and the proportion of patients with akinetic-rigid motor subtype or preexisting hypertension were higher among patients with supine hypertension than among those without supine hypertension. The Mini-Mental State Examination score was lower in patients with supine hypertension than in those without supine hypertension. Sex, disease duration, disease severity, and peripheral sympathetic nervous activity as evaluated by the cardiac uptake of (123)I-metaiodobenzylguanidine and the plasma norepinephrine level did not differ between patients with and those without supine hypertension.

CONCLUSION

Older age, akinetic-rigid motor subtype, and preexisting hypertension are independent risk factors for supine hypertension. Supine hypertension alone may be associated with milder peripheral sympathetic nervous denervation than orthostatic hypotension alone. As for global cognitive decline, supine hypertension is a far riskier comorbidity of early-stage PD than is orthostatic hypotension.

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.

Preserved functional autonomic phenotype in adult mice overexpressing moderate levels of human alpha-synuclein in oligodendrocytes

Mice overexpressing human alpha‐synuclein in oligodendrocytes (MBP1‐α‐syn) recapitulate some key functional and neuropathological features of multiple system atrophy (MSA). Whether or not these mice develop severe autonomic failure, which is a key feature of human MSA, remains unknown. We explored cardiovascular autonomic regulation using long‐term blood pressure (BP) radiotelemetry and pharmacological testing. We instrumented 12 MBP1‐α‐syn mice and 11 wild‐type mice aged 9 months for radiotelemetry. Animals were tested with atropine, metoprolol, clonidine, and trimethaphan at 9 and 12 months age. We applied spectral and cross‐spectral analysis to assess heart rate (HR) and BP variability. At 9 months of age daytime BP (transgenic: 101 ± 2 vs. wild type: 99 ± 2 mmHg) and HR (497 ± 11 vs. 505 ± 16 beats/min) were similar. Circadian BP and HR rhythms were maintained. Nighttime BP (109 ± 2 vs. 108 ± 2 mmHg) and HR (575 ± 15 vs. 569 ± 14 beats/min), mean arterial BP responses to trimethaphan (−21 ± 8 vs. −10 ± 5 mmHg, P = 0.240) and to clonidine (−8 ± 3 vs. −5 ± 2 mmHg, P = 0.314) were similar. HR responses to atropine (+159 ± 24 vs. +146 ± 22 beats/min), and to clonidine (−188 ± 21 vs. −163 ± 33 beats/min) did not differ between strains. Baroreflex sensitivity (4 ± 1 vs. 4 ± 1 msec/mmHg) and HR variability (total power, 84 ± 17 vs. 65 ± 21 msec²) were similar under resting conditions and during pharmacological testing. Repeated measurements at 12 months of age provided similar results. In mice, moderate overexpression of human alpha‐synuclein in oligodendrocytes is not sufficient to induce overt autonomic failure. Additional mechanisms may be required to express the autonomic failure phenotype including higher levels of expression or more advanced age.

Mice overexpressing human alpha‐synuclein in oligodendrocytes recapitulate key functional and neuropathological features of multiple system atrophy (MSA). Whether or not these mice model MSA abnormalities in cardiovascular autonomic regulation is unknown. Therefore, we explored cardiovascular autonomic regulation using long‐term blood pressure radiotelemetry combined with detailed pharmacological testing in mice overexpressing moderate levels of human alpha‐synuclein under the control of the oligodendrocyte‐specific murine myelin basic protein promoter. The major finding was that the moderate overexpression of human alpha‐synuclein in oligodendrocytes was not sufficient to induce overt autonomic failure in this mouse model.