Orthostatic Hypotension in Parkinson Disease

Orthostatic hypotension in Parkinson's disease: Sit-to-stand vs. supine-to-stand protocol and clinical correlates

BACKGROUND

Screening for orthostatic hypotension (OH) is integral in Parkinson's disease (PD) management, yet evidence-based guidelines on best practice methods for diagnosing OH in PD are lacking.

METHODS

We investigated the frequency and correlates of OH, symptomatic OH, and neurogenic OH, in a large consecutively recruited PD cohort (n = 318), and compared the diagnostic performance of the sit-to-stand vs. the supine-to-stand blood pressure (BP) test. We evaluated the utility of continuous BP monitoring and tilt table testing in patients with postural symptoms or falls who were undetected to have OH with clinic-based BP measurements. Disease severity, fluid intake, orthostatic and overactive bladder symptoms, falls, comorbidities and medication history were evaluated.

RESULTS

Patients' mean age was 66.1 ± 9.5years, with mean disease duration 7.8 ± 5.5years. OH frequency was 35.8 % based on the supine-to-stand test. OH in PD was significantly associated with older age, lower body mass index, longer disease duration, worse motor, cognitive and overactive bladder symptoms and functional disabilities, falls, and lower fluid intake. A similar profile was seen with asymptomatic OH. Three quarters of OH were neurogenic, with the majority also having supine hypertension. The sit-to-stand test had a sensitivity of only 0.39. One quarter of patients were additionally diagnosed with OH during continuous BP monitoring.

CONCLUSIONS

The sit-to-stand test substantially underdiagnoses OH in PD, with the important practice implication that supine-to-stand measurements may be preferred. Screening for OH is warranted even in asymptomatic patients. Adequate fluid intake, treatment of urinary dysfunction and falls prevention are important strategies in managing PD patients with OH.

Sleep and Overactive Bladder in Parkinson's Disease

Patients with Parkinson's disease (PD) have disturbances in their bladder and sleep physiology that lead to nocturia and overactive bladder (OAB). These symptoms can be extremely bothersome and impact not only their quality of life (QoL) but also the QoL of their caretakers. We aim to highlight the changes in bladder and sleep physiology in PD and explore OAB/nocturia treatment strategies in this population.

Parkinson's disease - The dentist's role as part of the healthcare team

Parkinson's disease is a neurodegenerative disease that results in patients exhibiting uncontrolled movements, changes in saliva production, and difficulty in swallowing and speech. Understanding the staging of the disease and the available therapies allows dentists to treat these patients safely and with compassion to meet their oral health care needs for an optimal quality of life. This appraisal discusses Parkinson's disease as it relates to clinically relevant facts to manage and treat the oral health care needs of these patients in the short and long term including general dental care recommendations. Important observations related to Parkinson's disease include disease causation,; stages, pharmacologic treatment, the effects on saliva, mastication, dysphagia, and aspiration pneumonia. Dental recommendations are made for the dentate, the partially edentulous, and the completely edentulous Parkinson's patients with a focus on late-stage concerns. Optimizing dental health will help maintain the quality of life as the disease progresses. In late stages of Parkinson's disease, dental treatment should focus on keeping the patient comfortable and out of pain.  While benign neglect is an often-used term, compassionate therapy in the late stages of Parkinson's disease is a more compelling term for defining the patient's needs.  Since dysphagia in Parkinson's patients has been underdiagnosed, neurologists must be aware of the important part that dentists play in the early diagnosis for these patients.  Early referral to a dentist is vital to mitigate the unfortunate consequence of the need for extensive dental care in late-stage patients.

[Afferent baroreflex failure with hyponatremia: A case report]

Afferent baroreflex failure (ABF) is a rare disease. It refers to the clinical syndrome caused by the impairment of the afferent limb of the baroreflex or its central connections at the level of the medulla. The recognized causes include trauma, surgery in related areas (radical neck tumor surgery, carotid endarterectomy), neck radiotherapy, brain stem stroke, tumor growth paraganglioma and hereditary diseases, among which the most common cause is extensive neck surgery or radiotherapy for neck cancer. The main manifestations are fluctuating hypertension, orthostatic hypotension, paroxysmal tachycardia and bradycardia. This case is a young man, whose main feature is blood pressure fluctuation, accom-panied by neurogenic orthostatic hypotension (nOH). After examination, the common causes of hypertension and nOH were ruled out. Combined with the previous neck radiotherapy and neck lymph node dissection, it was considered that the blood pressure regulation was abnormal due to the damage of carotid sinus baroreceptor after radiotherapy for nasopharyngeal carcinoma and neck lymph node dissection, which was called ABF. At the same time, the patient was complicated with chronic hyponatremia. Combined with clinical and laboratory examination, the final consideration was caused by syndrome of in- appropriate antidiuretic hormone (SIADH). Baroreceptors controlled the secretion of heart rate, blood pressure and antidiuretic hormone through the mandatory "inhibition" signal. We speculate that the carotid sinus baroreceptor was damaged after neck radiotherapy and surgery, which leads to abnormal blood pressure regulation and nOH, while the function of inhibiting ADH secretion was weakened, resulting in higher ADH than normal level and mild hyponatremia. The goal of treating ABF patients was to reduce the frequency and amplitude of sudden changes in blood pressure and heart rate, and to alleviate the onset of symptomatic hypotension. At present, drug treatment is still controversial, and non-drug treatment may alleviate some patients' symptoms, but long-term effective treatment still needs further study. The incidence of ABF is not high, but it may lead to serious cardiovascular and cerebrovascular events, and the mechanism involved is extremely complicated, and there are few related studies. The reports of relevant medical records warn that patients undergoing neck radiotherapy or surgery should minimize the da-mage to the baroreceptor in the carotid sinus in order to reduce the adverse prognosis caused by complications.

Machine-learning model for the prediction of acute orthostatic hypotension after levodopa administration

BACKGROUND

Levodopa could induce orthostatic hypotension (OH) in Parkinson's disease (PD) patients. Accurate prediction of acute OH post levodopa (AOHPL) is important for rational drug use in PD patients. Here, we develop and validate a prediction model of AOHPL to facilitate physicians in identifying patients at higher probability of developing AOHPL.

METHODS

The study involved 497 PD inpatients who underwent a levodopa challenge test (LCT) and the supine-to-standing test (STS) four times during LCT. Patients were divided into two groups based on whether OH occurred during levodopa effectiveness (AOHPL) or not (non-AOHPL). The dataset was randomly split into training (80%) and independent test data (20%). Several models were trained and compared for discrimination between AOHPL and non-AOHPL. Final model was evaluated on independent test data. Shapley additive explanations (SHAP) values were employed to reveal how variables explain specific predictions for given observations in the independent test data.

RESULTS

We included 180 PD patients without AOHPL and 194 PD patients with AOHPL to develop and validate predictive models. Random Forest was selected as our final model as its leave-one-out cross validation performance [AUC_ROC 0.776, accuracy 73.6%, sensitivity 71.6%, specificity 75.7%] outperformed other models. The most crucial features in this predictive model were the maximal SBP drop and DBP drop of STS before medication (ΔSBP/ΔDBP). We achieved a prediction accuracy of 72% on independent test data. ΔSBP, ΔDBP, and standing mean artery pressure were the top three variables that contributed most to the predictions across all individual observations in the independent test data.

CONCLUSIONS

The validated classifier could serve as a valuable tool for clinicians, offering the probability of a patient developing AOHPL at an early stage. This supports clinical decision-making, potentially enhancing the quality of life for PD patients.

Assessment of acetylcholinesterase activity in CD9-positive exosomes from patients with Parkinson's disease

Introduction

Parkinson's disease (PD) is a neurodegenerative disorder characterized by dopaminergic dysfunction and associated with abnormalities in the cholinergic system. However, the relationship between PD and cholinergic dysfunction, particularly in exosomes, is not fully understood.

Methods

We enrolled 37 patients with PD and 44 healthy controls (HC) to investigate acetylcholinesterase (AChE) activity in CD9-positive and L1CAM-positive exosomes. Exosomes were isolated from plasma using antibody-coupled magnetic beads, and their sizes and concentrations were assessed using transmission electron microscopy, nanoparticle tracking analysis, and western blotting. Subsequently, the AChE activity in these exosomes was analyzed in relation to various clinical parameters.

Results

A significant decrease in AChE activity was observed in CD9-positive exosomes derived from patients with PD, whereas no significant differences were found in L1CAM-positive exosomes. Further analysis with a larger sample size confirmed a substantial reduction in AChE activity in CD9-positive exosomes from the PD plasma, with moderate diagnostic accuracy. The decrease in AChE activity of CD9-positive exosomes did not show an association with cognitive impairment but displayed a trend toward correlation with PD progression.

Discussion

The reduction in AChE activity in CD9-positive exosomes suggests potential peripheral cholinergic dysfunction in PD, independent of the central cholinergic system. The observed alterations in AChE activity provide valuable insights into the association between cholinergic dysfunction and the pathogenesis of PD.

Quantitative cellular changes in multiple system atrophy brains

Multiple system atrophy (MSA) is a neurodegenerative disorder characterised by a combined symptomatology of parkinsonism, cerebellar ataxia, autonomic failure and corticospinal dysfunction. In brains of MSA patients, the hallmark lesion is the aggregation of misfolded alpha-synuclein in oligodendrocytes. Even though the underlying pathological mechanisms remain poorly understood, the evidence suggests that alpha-synuclein aggregation in oligodendrocytes may contribute to the neurodegeneration seen in MSA. The primary aim of this review is to summarise the published stereological data on the total number of neurons and glial cell subtypes (oligodendrocytes, astrocytes and microglia) and volumes in brains from MSA patients. Thus, we include in this review exclusively the reports of unbiased quantitative data from brain regions including the neocortex, nuclei of the cerebrum, the brainstem and the cerebellum. Furthermore, we compare and discuss the stereological results in the context of imaging findings and MSA symptomatology. In general, the stereological results agree with the common neuropathological findings of neurodegeneration and gliosis in brains from MSA patients and support a major loss of nigrostriatal neurons in MSA patients with predominant parkinsonism (MSA-P), as well as olivopontocerebellar atrophy in MSA patients with predominant cerebellar ataxia (MSA-C). Surprisingly, the reports indicate only a minor loss of oligodendrocytes in sub-cortical regions of the cerebrum (glial cells not studied in the cerebellum) and negligible changes in brain volumes. In the past decades, the use of stereological methods has provided a vast amount of accurate information on cell numbers and volumes in the brains of MSA patients. Combining different techniques such as stereology and diagnostic imaging (e.g. MRI, PET and SPECT) with clinical data allows for a more detailed interdisciplinary understanding of the disease and illuminates the relationship between neuropathological changes and MSA symptomatology.

Acute effect of levodopa on orthostatic hypotension and its association with motor responsiveness in Parkinson's disease: Results of acute levodopa challenge test

OBJECTIVE

Levodopa administration can induce or worsen orthostatic hypotension (OH) in patients with Parkinson's disease (PD). Understanding of acute OH post levodopa (AOHPL) is important for rational drug use in PD patients. Primary objective of this study was to investigate the incidence of AOHPL in PD patients. The secondary objectives were a) hemodynamic character of AOHPL; b) risk factors of AOHPL; c) relationship between motor responsiveness and blood pressure (BP) change.

METHODS

490 PD inpatients underwent acute levodopa challenge test (LCT). Supine-to-standing test (STS) was done 4 times during LCT, including before levodopa and every hour post levodopa intake within 3 h. Patients were classified into two groups, AOHPL and non-AOHPL. A comprehensive set of clinical features scales was assessed, including both motor (e.g., motor response, wearing-off) and nonmotor symptoms (e.g., autonomic dysfunction, neuropsychology).

RESULTS

33.1% PD patients had OH before drug, 50.8% the same subjects had AOHPL during levodopa effectiveness. PD patients who had better response to levodopa likely to have lower standing mean artery pressure (MAP) and severer systolic BP drop after levodopa intake. BP increased when the motor performance worsened and vice versa. Beneficial response was a risk factors of AOHPL (OR = 1.624, P = 0.017).

CONCLUSIONS

AOHPL was very common in PD patients. We suggested that PD patients with risk factors should monitor hemodynamic change during LCT to avoid AOHPL following the introduction or increase of oral levodopa. The fluctuations of BP were complicated and multifactorial, likely caused by the process of PD and levodopa both.

Non-Pharmacological Treatment of Autonomic Dysfunction in Parkinson's Disease and Other Synucleinopathies

Symptoms of autonomic dysfunction are prevalent and can be very debilitating, reducing the quality of life in patients with Parkinson's disease (PD) and other synucleinopathies such as dementia with Lewy bodies and multiple system atrophy. Non-pharmacological therapies are key to effective management and are frequently used alone in patients with mild autonomic symptoms, or in combination with pharmacological therapies in patients with moderate and severe symptoms. This article focuses on non-pharmacological approaches. Our objective was to review the non-drug and non-surgical approaches to treating autonomic symptoms in patients with PD and other synucleinopathies, focusing on cardiovascular, gastrointestinal, and genitourinary autonomic dysfunction. Evidence supporting the effectiveness of non-pharmacological treatment for the management of neurogenic orthostatic hypotension, supine hypertension, constipation, and bladder and sexual dysfunction is available. High-quality prospective trials are scarce, yet some non-pharmacological interventions (e.g., physical counter maneuvers) can be evaluated relatively quickly on an individual basis and often seem effective. The emerging variety of clinical presentations advocates for a stepwise, individualized, and non-pharmacological approach for the management of autonomic symptoms. Often, the first step is to reduce or discontinue drugs that cause or aggravate autonomic symptoms followed by lifestyle measures. While non-pharmacological and non-surgical treatments are available and, in many cases, effective to improve symptoms of autonomic dysfunction in PD and other synucleinopathies, they are often overlooked. Large randomized trials testing and comparing non-pharmacological approaches are warranted.

Hospitalization and the Risk of Initiation of Antipsychotics in Persons With Parkinson's Disease

OBJECTIVES

The use of antipsychotics in persons with Parkinson's disease (PD) is common, although their use may aggravate the symptoms of PD. Clozapine and quetiapine are the only antipsychotics recommended in PD treatment guidelines. Information on factors associated with initiation of antipsychotics is needed. We investigated whether recent hospitalization is associated with initiation of antipsychotics in persons with PD, and whether discharge diagnoses differ between those who had antipsychotics initiated and those who did not.

DESIGN

Nested case-control study in the nationwide register-based Finnish Study on Parkinson's disease (FINPARK).

SETTING AND PARTICIPANTS

The FINPARK study includes 22,189 persons who received an incident, clinically verified PD diagnosed during 1996-2015 and were community-dwelling at the time of diagnosis. The cases were 5088 persons who had antipsychotics initiated after PD diagnosis, identified with 1-year washout. The controls were 5088 age-, sex-, and time from PD diagnosis-matched persons who did not use antipsychotics on the matching date (antipsychotic purchase date). Recent hospitalization was defined as discharge in the 2-week period preceding the matching date.

METHODS

Associations were investigated with conditional logistic regression.

RESULTS

Quetiapine was the most commonly initiated antipsychotic (72.0% of cases), followed by risperidone (15.0%). Clozapine was initiated rarely (1.1%). Recent hospitalization associated strongly with antipsychotic initiation [61.2% of cases and 14.9% of controls, odds ratio (OR) 9.42, 95% CI 8.33-10.65], and longer hospitalizations were more common among cases. PD was the most common discharge diagnosis category (51.2% of hospitalized cases and 33.0% controls), followed by mental and behavioral disorders (9.3%) and dementia (9.0%) among cases. Antidementia and other psychotropic medication use were more common among cases.

CONCLUSIONS AND IMPLICATIONS

These results suggest that antipsychotics were initiated because of neuropsychiatric symptoms or aggravation of those symptoms. Antipsychotics should be prescribed after careful consideration to avoid adverse effects in persons with Parkinson's disease.

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

Introduction

Orthostatic hypotension (OH) frequently accompanies autonomic dysfunction and is an important risk factor for cognitive impairment in Parkinson's disease (PD). However, the association between different cognitive functions and OH in PD patients is not yet fully understood.

Methods

This study aimed to evaluate the scores of different cognitive domains and multiple parameters using different imaging techniques on PD patients with or without OH. A total number of 31 PD patients with OH (n = 20) and without OH (n = 11) were recruited from the Department of Neurology, Beijing Xuanwu Hospital for this study. All patients underwent beat-to-beat non-invasive blood pressure recordings and an active standing test to evaluate neurogenic OH and a global neuropsychological test to assess cognitive function. All patients underwent dynamic cerebral autoregulation (dCA) measurement, brain magnetic resonance imaging (MRI), and brain 18fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT).

Results

The results showed that OH patients had poor delayed recall verbal memory when compared with the PD patients without OH (1.75 ± 1.59 vs. 3.10 ± 1.73, p = 0.042). The dCA test indicated a significant difference in the right very low-frequency (VLF) gain between two groups (1.27 ± 0.17 vs. 1.10 ± 0.26, p = 0.045) and the brain 18F-FDG PET/CT indicated a significant difference in the SUV (right medial temporal lobe) to SUV (occipital lobe) ratio (0.60 ± 0.08 vs. 0.67 ± 0.11, p = 0.049). Meanwhile, these two imaging parameters were negatively correlated (p < 0.001). Furthermore, the score of a delayed recall verbal memory in the OH group was positively correlated with the right medial temporal lobe to occipital lobe ratio (p < 0.001) and was negatively correlated with the right VLF gain (p = 0.023).

Discussion

PD with OH patients had poor delayed recall memory, which might have been caused by the decreased metabolic dysfunction of specific medial temporal lobe due to the impaired dCA ability.

Ampreloxetine Versus Droxidopa in Neurogenic Orthostatic Hypotension: A Comparative Review

Neurogenic orthostatic hypotension (nOH) is a disabling problem of autonomic dysfunction in patients with Parkinson's disease, which is associated with poor quality of life and higher mortality rates. The purpose of this literature review was to explore and compare the efficacy and safety of droxidopa (an existing treatment) and ampreloxetine (a newer medication) in the treatment of nOH. We used a mixed-method literature review that addresses the epidemiology, pathophysiology, and pharmacological and non-pharmacological management of nOH in Parkinson's disease in a general way, with a more exploratory approach to droxidopa- and ampreloxetine-controlled trial studies. We included a total of 10 studies of randomized controlled trials with eight studies focused on droxidopa and two studies focused on ampreloxetine. These two drugs were analyzed and compared based on the collected individual study results. Treatment of nOH in Parkinson's disease patients with droxidopa or ampreloxetine showed clinically meaningful and statistically significant improvements relative to placebo on the components of the OHSA (Orthostatic Hypotension Symptom Assessment) composite score and OHDAS (Orthostatic Hypotension Daily Activity Scale composite scores) composite score. Droxidopa had an improved effect on daily activities, with an associated increase in standing systolic blood pressure (BP), but the long-term efficacy of droxidopa has not been documented. Standing systolic BP was maintained by ampreloxetine and worsened after the withdrawal phase. This highlights the importance of conducting further research which will help us to improve the therapeutic approach for patients with nOH and Parkinson's disease.

The role of LRRK2 in the periphery: link with Parkinson's disease and inflammatory diseases

Parkinson's disease (PD) is currently considered a multisystemic disorder rather than a pure brain disease, in line with the multiple hit hypothesis from Braak. However, despite increasing evidence that the pathology might originate in the periphery, multiple unknown aspects and contradictory data on the pathological processes taking place in the periphery jeopardize the interpretation and therapeutic targeting of PD. Mutations in the leucine-rich-repeat kinase 2 (LRRK2) gene have been widely linked with familial and sporadic PD cases. However, the actual role of LRRK2 in PD pathophysiology is far from understood. There is evidence that LRRK2 may be involved in alpha-synuclein (α-synuclein) pathology and immune cell regulation, but it has also been associated with inflammatory diseases such as inflammatory bowel disease, tuberculosis, leprosy, and several other bacterial infections. In this review, we focus on the different roles of LRRK2 in the periphery. More specifically, we discuss the involvement of LRRK2 in the propagation of α-synuclein pathology and its regulatory role in peripheral inflammation. A deeper understanding of the multidimensional functions of LRRK2 will pave the way for more accurate characterization of PD pathophysiology and its association with other inflammatory diseases.

Skin alpha-synuclein deposit patterns: A predictor of Parkinson's disease subtypes

Parkinson's disease (PD) is a neurodegenerative disease characterized pathologically by the formation of Lewy bodies comprised mainly of α-synuclein. Assessment of skin synuclein has the potential as an excellent diagnostic method with high sensitivity, specificity, and reproducibility that is also convenient and acceptable to patients. In this review, we summarize findings regarding the characteristics of cutaneous nerve p-α-syn or α-syn deposits and their correlations with clinical phenotypes in PD patients with and without orthostatic hypotension and LRRK2, GBA, and SNCA gene mutations. This review can serve as a reference for the diagnosis and classification of PD based on α-syn deposit patterns and to deeply explore its pathogenesis.

Funding statement

The work was partly supported by the National Natural Science Key Foundation of China (No. 81830040 and No 82130042) and the Program of Excellent Talents in Medical Science of Jiangsu Province (No. JCRCA2016006) .

Levodopa-Carbidopa Intestinal Gel Improves Symptoms of Orthostatic Hypotension in Patients with Parkinson’s Disease—Prospective Pilot Interventional Study

Parkinson’s disease (PD) is currently considered progressive neurodegeneration of both the central and peripheral nervous systems. Widespread neuropathological changes lead to a complex clinical presentation with typical motor (hypokinesia, tremor, and rigidity) and various nonmotor symptoms. Orthostatic hypotension is one of the most disabling nonmotor features contributing to increased morbidity and mortality and decreased quality of life (QoL). Our study aimed to disclose the effect of a continuous infusion of levodopa-carbidopa intestinal gel (LCIG) on symptoms of orthostatic hypotension. Nine patients indicated for LCIG and eight matched patients on optimized medical treatment (OMT) were examined with scales for orthostatic symptoms (SCOPA-AUT), nonmotor symptoms and motor fluctuations (MDS-UPDRS), and QoL (PDQ39) at both baseline and after six months. The scores of “light-headedness after standing” and “fainting” decreased in the LCIG group compared to the OMT group. Treatment with LCIG was associated with a significantly higher decrease in the score of “light-headedness after standing”. Change in the PDQ39 correlated positively with fluctuation improvement and with change in the scores of both “light-headedness” and “fainting”. LCIG treatment improved symptoms of orthostatic hypotension in patients with PD mainly by a reduction in motor complications. Decreased severity in both motor and nonmotor fluctuations was connected also with improved QoL. Continuous treatment with LCIG should be considered not only in the case of severe motor fluctuation but also in patients with nonmotor fluctuations responsive to dopaminergic treatment.

Assessment of Abdominal Constrictor's Forces for Informing Computational Models of Orthostatic Hypotension

Orthostatic hypotension is defined as a sudden drop in blood pressure upon standing from a sitting or supine position. The prevalence of this condition increases exponentially with age. Nonpharmacological treatments are always the first step in the management of this condition, such as the use of an abdominal constriction belt to optimize the blood volume in the abdomen. A multitude of clinical trials have shown the efficacy of elastic abdominal compression as well as compression using an inflatable bladder; however, there are currently few accessible consumer products that can provide abdominal compression by using an inflatable bladder that ensures the correct amount of pressure is being exerted on the subject. This study serves to quantitatively analyze forces exerted in inflatable abdominal binders, a novel treatment that fits the criterion for a first-line intervention for orthostatic hypotension. Quantitative values aim to indicate both the anatomic regions of the body subjected to the highest pressure by abdominal binding. Quantitative values will also create a model that can correlate the amount of compression on the subject with varying levels of pressure in the inflatable bladder. Inflatable binders of varying levels of inflation are used and localized pressure values are recorded at 5 different vertical points along the abdomen in the midsternal line and midclavicular line, at the locations of the splanchnic veins. These findings indicate both the differences in the compressive force applied through elastic and inflatable binding, as well the regions on the abdomen subject to the highest force load during compression by an abdominal binder. A medical manikin called the iStan Manikin was used to collect data. The pressure values on a manikin were sensed by the JUZO pressure monitor, a special device created for the purpose of measuring the force under compressive garments. The pressure inside the inflatable bladder was extrapolated from a pressure gauge and the pressure was recorded at different degrees of inflation of the belt (mmHG) along two different areas of the abdomen, the midsternal line and the midclavicular line, to discern differences in force exerted on the patient (mmHG). Computational studies on the data from the JUZO pressure monitor as well as the data from the pressure gauge on the inflatable bladder allow us to create a model that can correlate the amount of pressure in the inflatable bladder to the amount of pressure exerted on the belt, thus making sure that the patient is not being harmed by the compressive force. The results of our study indicate that there is no significant difference between the pressures exerted on the midsternal and midclavicular lines of the body by the abdominal binder and that no significant difference exists between the external pressure measured by the inflatable belt and the pressure sensed on the human body by the JUZO sensor; however, we were able to extrapolate an equation that can tell the user the amount of pressure that is actually being exerted on them based on the pressure in the inflatable bladder as recorded by the gauge.

Passive Immunization in Alpha-Synuclein Preclinical Animal Models

Alpha-synucleinopathies include Parkinson’s disease, dementia with Lewy bodies, pure autonomic failure and multiple system atrophy. These are all progressive neurodegenerative diseases that are characterized by pathological misfolding and accumulation of the protein alpha-synuclein (αsyn) in neurons, axons or glial cells in the brain, but also in other organs. The abnormal accumulation and propagation of pathogenic αsyn across the autonomic connectome is associated with progressive loss of neurons in the brain and peripheral organs, resulting in motor and non-motor symptoms. To date, no cure is available for synucleinopathies, and therapy is limited to symptomatic treatment of motor and non-motor symptoms upon diagnosis. Recent advances using passive immunization that target different αsyn structures show great potential to block disease progression in rodent studies of synucleinopathies. However, passive immunotherapy in clinical trials has been proven safe but less effective than in preclinical conditions. Here we review current achievements of passive immunotherapy in animal models of synucleinopathies. Furthermore, we propose new research strategies to increase translational outcome in patient studies, (1) by using antibodies against immature conformations of pathogenic αsyn (monomers, post-translationally modified monomers, oligomers and protofibrils) and (2) by focusing treatment on body-first synucleinopathies where damage in the brain is still limited and effective immunization could potentially stop disease progression by blocking the spread of pathogenic αsyn from peripheral organs to the brain.

New approaches to treatments for sleep, pain and autonomic failure in Parkinson's disease - Pharmacological therapies

Non-motor symptoms (NMSs) are highly prevalent throughout the course of Parkinson's disease (PD). Pain, autonomic dysfunction and sleep disturbances remain at the forefront of the most common NMSs; their treatment is challenging and their effect on the quality of life of both patients and caregivers detrimental. Yet, the landscape of clinical trials in PD is still dominated by therapeutic strategies seeking to ameliorate motor symptoms; subsequently, effective strategies to successfully treat NMSs remain a huge unmet need. Wider awareness among industry and researchers is thus essential to give rise to development and delivery of high-quality, large-scale clinical trials in enriched populations of patients with PD-related pain, autonomic dysfunction and sleep. In this review, we discuss recent developments in the field of pharmacological treatment strategies designed or re-purposed to target three key NMSs: pain, autonomic dysfunction and sleep disturbances. We focus on emerging evidence from recent clinical trials and outline some exciting and intriguing findings that call for further investigations.

Sudden unexpected death in Parkinson's disease: Insights from clinical practice

Classified as the second most common neurodegenerative disorder associated with aging after Alzheimer's disease, Parkinson's disease (PD) is the most common movement disorder. In the last decade, despite advances in treatment, mortality rates linked with PD continued to reach significant figures. Available studies have shown that compared with healthy controls, patients with PD are accompanied by high rates of premature death. This is usually caused by factors such as pneumonia and cerebrovascular and cardiovascular diseases. Recently, it has been demonstrated that a significant proportion of patients with PD die suddenly. This is referred to as a sudden and unexpected death in PD (SUDPAR). Here, we focus on the magnitude of SUDPAR. Finally, it is important to learn more about SUDPAR for the implementation of effective prevention strategies.

Parkinson's disease and parkinsonism: Clinicopathological discrepancies on diagnosis in three patients

Parkinson's disease (PD) is one of the most common neurodegenerative disorders. The cardinal neuropathological features of PD include selective and progressive loss of pigmented neurons in the substantia nigra, deficiencies in dopaminergic signaling in the striatum, and occurrence of phosphorylated α-synuclein-identified Lewy bodies in the nervous system. Parkinsonism, the clinical presentation of movement disorders seen in PD, is a feature shared commonly by other pathologically distinct neurodegenerative diseases, such as progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and multiple system atrophy (MSA). Consequently, it is sometimes difficult to distinguish PD from such parkinsonism-related neurological disorders. In addition, parkinsonism is not always a feature of certain neurodegenerative diseases, and it can sometimes develop as a result of various forms of drug intoxication or cerebrovascular disease. Here, we describe the clinicopathological features of three patients (cases 1, 2, and 3) diagnosed as having PSP, MSA, and PD, respectively, in each of whom the postmortem histopathological diagnosis differed from the final clinical diagnosis. Neuropathologically, they had suffered from coexistent disorders: PD, MSA, and argyrophilic grain disease (case 1); PD (case 2); and vascular parkinsonism (case 3). The variety of patients showing features of parkinsonism underlines the importance of careful long-term follow up followed by postmortem neuropathological evaluation.

[Baroreceptor failure syndrome after head and neck tumor surgery]

With the continuous updating of head and neck surgery concepts and techniques, more and more head and neck surgeries are developing in the direction of refinement.however, the more complete the surgery, the greater the possibility of subsequent nerve exposure and injury. Even a slight perturbation of the nerve may cause serious complications, such as pressure receptor failure.It is necessary to review the mechanisms and the characteristics of baroreceptor failure syndrome after head and neck tumor surgery.

Ageing promotes pathological alpha-synuclein propagation and autonomic dysfunction in wild-type rats

Neuronal aggregates of misfolded alpha-synuclein protein are found in the brain and periphery of patients with Parkinson's disease. Braak and colleagues have hypothesized that the initial formation of misfolded alpha-synuclein may start in the gut, and then spread to the brain via peripheral autonomic nerves hereby affecting several organs, including the heart and intestine. Age is considered the greatest risk factor for Parkinson's disease, but the effect of age on the formation of pathology and its propagation has not been studied in detail. We aimed to investigate whether propagation of alpha-synuclein pathology from the gut to the brain is more efficient in old versus young wild-type rats, upon gastrointestinal injection of aggregated alpha-synuclein. Our results demonstrate a robust age-dependent gut-to-brain and brain-to-gut spread of alpha-synuclein pathology along the sympathetic and parasympathetic nerves, resulting in age-dependent dysfunction of the heart and stomach, as observed in patients with Parkinson's disease. Moreover, alpha-synuclein pathology is more densely packed and resistant to enzymatic digestion in old rats, indicating an age-dependent maturation of alpha-synuclein aggregates. Our study is the first to provide a detailed investigation of alpha-synuclein pathology in several organs within one animal model, including the brain, skin, heart, intestine, spinal cord and autonomic ganglia. Taken together, our findings suggest that age is a crucial factor for alpha-synuclein aggregation and complete propagation to heart, stomach and skin, similar to patients. Given that age is the greatest risk factor for human Parkinson's disease, it seems likely that older experimental animals will yield the most relevant and reliable findings. These results have important implications for future research to optimize diagnostics and therapeutics in Parkinson's disease and other age-associated synucleinopathies. Increased emphasis should be placed on using aged animals in preclinical studies and to elucidate the nature of age-dependent interactions.

Autonomic Function in Patients With Parkinson's Disease: From Rest to Exercise

Parkinson’s disease (PD) is a common neurodegenerative disorder classically characterized by symptoms of motor impairment (e.g., tremor and rigidity), but also presenting with important non-motor impairments. There is evidence for the reduced activity of both the parasympathetic and sympathetic limbs of the autonomic nervous system at rest in PD. Moreover, inappropriate autonomic adjustments accompany exercise, which can lead to inadequate hemodynamic responses, the failure to match the metabolic demands of working skeletal muscle and exercise intolerance. The underlying mechanisms remain unclear, but relevant alterations in several discrete central regions (e.g., dorsal motor nucleus of the vagus nerve, intermediolateral cell column) have been identified. Herein, we critically evaluate the clinically significant and complex associations between the autonomic dysfunction, fatigue and exercise capacity in PD.

Baroreflex dysfunction in Parkinson's disease: integration of central and peripheral mechanisms

The incidence of Parkinson's disease (PD) is increasing worldwide. Although the PD hallmark is the motor impairments, nonmotor dysfunctions are now becoming more recognized. Recently, studies have suggested that baroreflex dysfunction is one of the underlying mechanisms of cardiovascular dysregulation observed in patients with PD. However, the large body of literature on baroreflex function in PD is unclear. The baroreflex system plays a major role in the autonomic, and ultimately blood pressure and heart rate, adjustments that accompany acute cardiovascular stressors on a daily basis. Therefore, impaired baroreflex function (i.e., decreased sensitivity or gain) can lead to altered neural cardiovascular responses. Since PD affects parasympathetic and sympathetic branches of the autonomic nervous system and both are orchestrated by the baroreflex system, understanding of this crucial mechanism in PD is necessary. In the present review, we summarize the potential altered central and peripheral mechanisms affecting the feedback-controlled loops that comprise the reflex arc in patients with PD. Major factors including arterial stiffness, reduced number of C1 and activation of non-C1 neurons, presence of central α-synuclein aggregation, cardiac sympathetic denervation, attenuated muscle sympathetic nerve activity, and lower norepinephrine release could compromise baroreflex function in PD. Results from patients with PD and from animal models of PD provide the reader with a clearer picture of baroreflex function in this clinical condition. By doing so, our intent is to stimulate future studies to evaluate several unanswered questions in this research area.

Non-motor complications in late stage Parkinson's disease: recognition, management and unmet needs

Introduction: The burden of non-motor symptoms (NMS) is a major determinant of health-related quality of life in Parkinson's disease (PD), particularly at its late stage.Areas covered: The late stage is usually defined as the period from unstable advanced to the palliative stage, characterized by a combination of emerging treatment-resistant axial motor symptoms (freezing of gait, postural instability, falls and dysphagia), as well as both non-dopaminergic and dopaminergic NMS: cognitive decline, neuropsychiatric symptoms, aspects of dysautonomia, pain and sleep disturbances (insomnia and excessive day-time sleepiness). Here, the authors summarize the current knowledge on NMS dominating the late stage of PD and propose a pragmatic and clinically focused approach for their recognition and treatment.Expert opinion: The NMS progression pattern is complex and remains under-researched. While dopamine-dependent NMS may improve with dopamine replacement therapy, non-dopamine dependent NMS worsen progressively and culminate at the late stages of PD. Furthermore, some PD specific features could interact negatively with other comorbidities, multiple medication use and frailty - the evaluation of these aspects is important in the creation of personalized management plans in the late stage of PD.

Heart Matters: Cardiac Dysfunction and Other Autonomic Changes in Parkinson's Disease

It has been more than 200 years since James Parkinson made the first descriptions of the disease that bears his name. Since then, knowledge about Parkinson's disease has been improved, and its pathophysiology, diagnosis, and treatments are well described in the scientific and medical literature. However, there is no way to prevent the disease from its progressive nature yet and only its symptoms can be minimized. It is known that the process of neurodegeneration begins before the onset of motor signs and symptoms of the disease, when diagnosis is usually made. Therefore, recognizing manifested non-motor symptoms can make an early diagnosis possible and lead to a better understanding of the disease. Autonomic dysfunctions are important non-motor manifestations of Parkinson's disease and affect the majority of patients. Importantly, heart failure is the third leading cause of death in people suffering from Parkinson's disease. Several evidences have shown the correlation between Parkinson's disease and the preexistence of cardiovascular diseases. Therefore, cardiovascular monitoring and identification of its dysfunctions can have a prodromal role for Parkinson's disease. This review presents studies of the literature that can lead to a better understanding of Parkinson's disease with special attention to its relation to heart and cardiovascular parameters.

Autonomic Dysfunctions in Parkinson's Disease: Prevalence, Clinical Characteristics, Potential Diagnostic Markers, and Treatment

Parkinson's disease (PD) is a common neurodegenerative disease in the middle-aged and the elderly. Symptoms of autonomic dysfunctions are frequently seen in PD patients, severely affecting the quality of life. This review summarizes the epidemiology, clinical manifestations, and treatment options of autonomic dysfunctions. The clinical significance of autonomic dysfunctions in PD early diagnosis and differential diagnosis is also discussed.

Update on Parkinson's Disease Therapy

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Rivastigmine in Parkinson's Disease Dementia with Orthostatic Hypotension

OBJECTIVE

The purpose of this study was to evaluate if the cognitive benefit of rivastigmine is affected by the presence of orthostatic hypotension (OH) in patients with Parkinson's disease dementia (PDD).

METHODS

We conducted a post hoc analysis on 1,047 patients with PDD from 2 randomized controlled trials comparing rivastigmine versus placebo at week 24 (n = 501) and rivastigmine patch versus capsule at week 76 (n = 546). A drop ≥ 20 mm Hg in systolic blood pressure (SBP) or ≥ 10 in diastolic blood pressure (DBP) upon standing classified subjects as OH positive (OH+); otherwise, OH negative (OH-). The primary end point was the Alzheimer's Disease Assessment Scale - Cognitive subscale (ADAS-Cog) at week 24 and the Mattis Dementia Rating Scale (MDRS) at week 76, using intention-to-treat with retrieved dropout at week 24 and observed cases at week 76, consistent with the original analyses.

RESULTS

Overall safety was comparable between OH+ (n = 288, 27.5%) and OH- (n = 730, 69.7%), except for higher frequency of syncope (9.2%) in the OH+ placebo arm. The placebo-adjusted effect of rivastigmine on ADAS-Cog at week 24 was 5.6 ± 1.2 for OH+ and 1.9 ± 0.9 in OH- (p = 0.0165). Among subjects with OH, the MDRS change from baseline at week 76 was higher for rivastigmine capsules versus patch (10.6 ± 2.9 vs -1.5 ± 3.0, p = 0.031). The overall prevalence of OH was lower for rivastigmine than placebo at week 24 (28.3% vs 44.6%, p = 0.0476).

INTERPRETATION

The cognitive benefit from rivastigmine is larger in patients with PDD with OH, possibly mediated by a direct antihypotensive effect. ANN NEUROL 2021;89:91-98.

Autonomic Dysfunction in Parkinson's Disease

Recognition of the importance of nonmotor dysfunction as a component of Parkinson's disease has exploded over the past three decades. Autonomic dysfunction is a frequent and particularly important nonmotor feature because of the broad clinical spectrum it covers. Cardiovascular, gastrointestinal, urinary, sexual, and thermoregulatory abnormalities all can appear in the setting of Parkinson's disease. Cardiovascular dysfunction is characterized most prominently by orthostatic hypotension. Gastrointestinal dysfunction can involve virtually all levels of the gastrointestinal tract. Urinary dysfunction can entail either too frequent voiding or difficulty voiding. Sexual dysfunction is frequent and frustrating for both patient and partner. Alterations in sweating and body temperature are not widely recognized but often are present. Autonomic dysfunction can significantly and deleteriously impact quality of life for individuals with Parkinson's disease. Because effective treatment for many aspects of autonomic dysfunction is available, it is vitally important that assessment of autonomic dysfunction be a regular component of the neurologic history and exam and that appropriate treatment be initiated and maintained.

Baroreflex function in Parkinson's disease: insights from the modified-Oxford technique

Nonmotor symptoms are common in Parkinson's disease (PD) and they include dysregulation of cardiovascular system, which adversely affects quality of life. Recent studies provide indirect evidence that baroreflex dysfunction may be one of the mechanisms of cardiovascular dysregulation in PD. Herein, we tested the hypothesis that the baroreflex gain, assessed across an extensive range of the reflex arc by eliciting rapid changes in blood pressure (BP) induced by sequential boluses of vasoactive drugs (modified-Oxford technique) would be attenuated in middle-aged patients with PD. Beat-to-beat heart rate (electrocardiography) and BP (finger photoplethysmography) were obtained during 10 min of supine rest preceding the modified-Oxford (bolus of nitroprusside followed by phenylephrine 1 min afterward) in 11 patients with PD (51 ± 6 yr) and 7 age-matched controls (47 ± 6 yr). The resulting systolic BP and R-R interval responses were plotted and fitted with segmental linear regression and symmetric sigmoid model. Spontaneous indices obtained via sequence technique were also used to estimate baroreflex gain. Compared with controls, the estimated gains measured by segmental linear regression (patients: 3.83 ± 2.6 ms/mmHg versus controls: 7.78 ± 1.7 ms/mmHg; P = 0.003) and symmetric sigmoid model (patients: 12.36 ± 6.9 ms/mmHg versus controls: 32.02 ± 19.0 ms/mmHg; P = 0.009) were lower in patients with PD. The operating range of BP was larger in patients with PD compared with controls (13 ± 7 mmHg versus controls: 7 ± 3 mmHg; P = 0.032). Of note, the gain obtained from spontaneous indices was similar between groups. These data indicate that baroreflex gain was reduced by >50% in PD, thereby providing clear and direct evidence that cardiovagal baroreflex dysfunction occurs in PD.NEW & NOTEWORTHY Attenuated baroreflex gain may contribute to adverse cardiovascular outcomes, including orthostatic intolerance symptoms typically observed in patients with Parkinson's disease. We found that the baroreflex gain (assessed by the modified-Oxford technique) is attenuated and accompanied by an increased operating range in patients with Parkinson's disease. These findings highlight that cardiovascular perturbations are required to detect baroreflex impairments and that spontaneous indices do not reveal cardiovagal-baroreflex dysfunction in a middle-aged group of patients with Parkinson's disease.

Pharmacologic treatment of orthostatic hypotension

Neurogenic orthostatic hypotension (OH) is a disabling disorder caused by impairment of the normal autonomic compensatory mechanisms that maintain upright blood pressure. Nonpharmacologic treatment is always the first step in the management of this condition, but a considerable number of patients will require pharmacologic therapies. Denervation hypersensitivity and impairment of baroreflex buffering makes these patients sensitive to small doses of pressor agents. Understanding the underlying pathophysiology can help in selecting between treatment options. In general, patients with low "sympathetic reserve", i.e., those with peripheral noradrenergic degeneration (pure autonomic failure, Parkinson's disease) and low plasma norepinephrine, tend to respond better to "norepinephrine replacers" (midodrine and droxidopa). On the other hand, patients with relatively preserved "sympathetic reserve", i.e., those with impaired central autonomic pathways but spared peripheral noradrenergic fibers (multiple system atrophy) and normal or slightly reduced plasma norepinephrine, tend to respond better to "norepinephrine enhancers" (pyridostigmine, atomoxetine, and yohimbine). There is, however, a spectrum of responses within these extremes, and treatment should be individualized. Other nonspecific treatments include fludrocortisone and octreotide. The presence of associated clinical conditions, such as supine hypertension, heart failure, postprandial hypotension, PD, MSA, and diabetes need to be considered in the pharmacologic management of these patients.

Altered cardiorespiratory regulation during exercise in patients with Parkinson's disease: A challenging non-motor feature

The incidence of Parkinson’s disease is increasing worldwide. The motor dysfunctions are the hallmark of the disease, but patients also experience non-motor impairments, and over 40% of the patients experience coexistent abnormalities, such as orthostatic hypotension. Exercise training has been suggested as a coping resource to alleviate Parkinson’s disease symptoms and delay disease progression. However, the body of knowledge is showing that the cardiovascular response to exercise in patients with Parkinson’s disease is altered. Adequate cardiovascular and hemodynamic adjustments to exercise are necessary to meet the metabolic demands of working skeletal muscle properly. Therefore, since Parkinson’s disease affects parasympathetic and sympathetic branches of the autonomic nervous system and the latter are crucial in ensuring these adjustments are adequately made, the understanding of these responses during exercise in this population is necessary. Several neural control mechanisms are responsible for the autonomic changes in the cardiovascular and hemodynamic systems seen during exercise. In this sense, the purpose of the present work is to review the current knowledge regarding the cardiovascular responses to dynamic and isometric/resistance exercise as well as the mechanisms by which the body maintains appropriate perfusion pressure to all organs during exercise in patients with Parkinson’s disease. Results from patients with Parkinson’s disease and animal models of Parkinson’s disease provide the reader with a well-rounded knowledge base. Through this, we will highlight what is known and not known about how the neural control of circulation is responding during exercise and the adaptations that occur when individuals exercise regularly.