Cardiac parasympathetic dysfunction concurrent with cardiac sympathetic denervation in Parkinson's disease

Short term cardiovascular symptoms improvement after deep brain stimulation in patients with Parkinson's disease: a systematic review

BACKGROUND

Autonomic dysfunction is common and disabling in Parkinson's disease (PD). The effects of deep brain stimulation (DBS) on the cardiovascular system in PD remain poorly understood. We aimed to assess the effect of DBS on cardiovascular symptoms and objective measures in PD patients.

METHODS

We conducted a systematic literature search in PubMed/MEDLINE.

RESULTS

36 out of 472 studies were included, mostly involving DBS of the subthalamic nucleus, and to a lesser extent the globus pallidus pars interna and pedunculopontine nucleus. Seventeen studies evaluated the effect of DBS on patient-reported or clinician-rated cardiovascular symptoms, showing an improvement in the first year after surgery but not with longer-term follow-up. DBS has no clear direct effects on blood pressure during an orthostatic challenge (n = 10 studies). DBS has inconsistent effects on heart rate variability (n = 10 studies).

CONCLUSION

Current evidence on the impact of DBS on cardiovascular functions in PD is inconclusive. DBS may offer short-term improvement of cardiovascular symptoms in PD, particularly orthostatic hypotension, which may be attributed to dopaminergic medication reduction after surgery. There is insufficient evidence to draw conclusions on the direct effect of DBS on blood pressure and heart rate variability.

Clinical and Non-Clinical Cardiovascular Disease Associated Pathologies in Parkinson's Disease

Despite considerable breakthroughs in Parkinson's disease (PD) research, understanding of non-motor symptoms (NMS) in PD remains limited. The lack of basic level models that can properly recapitulate PD NMS either in vivo or in vitro complicates matters. Even so, recent research advances have identified cardiovascular NMS as being underestimated in PD. Considering that a cardiovascular phenotype reflects sympathetic autonomic dysregulation, cardiovascular symptoms of PD can play a pivotal role in understanding the pathogenesis of PD. In this study, we have reviewed clinical and non-clinical published papers with four key parameters: cardiovascular disease risks, electrocardiograms (ECG), neurocardiac lesions in PD, and fundamental electrophysiological studies that can be linked to the heart. We have highlighted the points and limitations that the reviewed articles have in common. ECG and pathological reports suggested that PD patients may undergo alterations in neurocardiac regulation. The pathological evidence also suggested that the hearts of PD patients were involved in alpha-synucleinopathy. Finally, there is to date little research available that addresses the electrophysiology of in vitro Parkinson's disease models. For future reference, research that can integrate cardiac electrophysiology and pathological alterations is required.

Risk of myocardial infarction in Parkinson's disease: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Previous studies investigating cardiovascular disorders in patients with Parkinson's disease (PD) showed heterogeneous results regarding whether there is a higher or lower risk of myocardial infarction (MI) in these patients compared to the general population. Because of the inconsistency in findings, herein the aim was to perform a systematic review and meta-analysis to investigate the risk of MI in patients with PD.

METHODS

A comprehensive literature search was performed using four databases, PubMed, Web of Science, Scopus and Embase, in June 2022. Peer-reviewed observational studies comprising case-controls, cohort, cross-sectional and longitudinal studies that reported MI in the PD population were included.

RESULTS

After the screening, 20 studies with a total of 80,441 patients with PD and 802,857 controls were included in our qualitative and quantitative synthesis. The pooled estimated odds ratio for MI in PD patients compared to controls was 0.80 (95% confidence interval [CI] 0.56-1.05) which indicates that there is no association. The pooled prevalence of MI was 5% (95% CI 3%-7%) with a range of 1%-20% amongst patients with PD. The men (6%, 95% CI 1%-13%) and women (6%, 95% CI 1%-14%, Q = 29.27, I2 = 98.50%, p < 0.001) had similar MI prevalence.

CONCLUSION

This comprehensive systematic review and meta-analysis provide compelling evidence that PD is associated with a reduced risk of MI. Whilst the exact mechanism underlying this association remains to be fully elucidated, it is clear that certain risk factors for cardiac events appear to be less present in PD patients, which may serve as a protective factor. However, given the reports of increased risk for cerebrovascular events in PD patients, it is possible that the major risk factors for MI and cardiovascular accidents in this population differ. These findings have important implications for clinical management and further research in this area is warranted.

Parkinson's disease and cardiovascular involvement: Edifying insights (Review)

Parkinson's disease (PD) is one of the most common neurodegenerative illnesses, and is a major healthcare burden with prodigious consequences on life-quality, morbidity, and survival. Cardiovascular diseases are the leading cause of mortality worldwide and growing evidence frequently reports their co-existence with PD. Cardiac dysautonomia due to autonomic nervous system malfunction is the most prevalent type of cardiovascular manifestation in these patients, comprising orthostatic and postprandial hypotension, along with supine and postural hypertension. Moreover, many studies have endorsed the risk of patients with PD to develop ischemic heart disease, heart failure and even arrhythmias, but the underlying mechanisms are not entirely clear. As importantly, the medication used in treating PD, such as levodopa, dopamine agonists or anticholinergic agents, is also responsible for cardiovascular adverse reactions, but further studies are required to elucidate the underlying mechanisms. The purpose of this review was to provide a comprehensive overview of current available data regarding the overlapping cardiovascular disease in patients with PD.

Coefficient of R-R interval variations under deep breathing load in patients with wild-type transthyretin amyloid cardiomyopathy: A case-control study

BACKGROUND AND AIMS

An autonomic nervous disorder is an important characteristic of cardiac amyloidosis; however, the prevalence of autonomic dysfunction in wild-type transthyretin amyloidosis (ATTRwt) has not been established. Analysis of the R-R interval coefficient of variation (CVR-R) is a noninvasive method to measure parasympathetic activity. We aimed to assess autonomic dysfunction of ATTRwt and determine the utility of CVR-R for the detection of ATTRwt in other cardiac diseases.

METHODS

This is a single-center, retrospective, case-control study. Fifty patients with heart failure (HF) were studied. The etiologies of HF were as follows: ATTRwt, n = 10; previous myocardial infarction (MI), n = 20; and left ventricular hypertrophy (LVH) due to other disease processes (e.g., aortic stenosis), n = 20. We measured the CVR-R at rest (CVR-Rrest), CVR-R with deep breaths (CVR-Rbreath), and the change rate (CVR-Rdiff rate). The relative change formula is as follows: CVR-Rdiff rate = (CVR-Rbreath - CVR-Rrest)/CVR-Rrest×  100 (%).

RESULTS

There was no difference in the CVR-Rrest levels among the three groups. The CVR-Rdiff rate levels in the ATTRwt group were significantly lower (ATTRwt: -8.77 [-43.8 to 10.9]; LVH: 67.4 [38.7 to 89.4]; MI: 83.7 [60.4 to 142.9]). Based on the receiver operative characteristic curve analysis to identify ATTRwt in HF, the best cut-off value for the CVR-Rdiff rate was 19.7 (area under the curve: 0.848).

CONCLUSION

Our data suggested autonomic dysfunction in patients with ATTRwt. Measurement of the CVR-R in HF patients may be a convenient support tool for the detection of ATTRwt.

Power spectral analysis of heart rate variability is useful as a screening tool for detecting sympathetic and parasympathetic nervous dysfunctions in Parkinson’s disease

Background

Parkinson’s disease (PD) is a progressive neurodegenerative disorder that causes motor symptoms and autonomic dysfunction. However, autonomic function tests commonly performed in PD can only evaluate either the sympathetic or parasympathetic nervous system. Therefore, the purpose of this pilot study is to investigate whether power spectral analysis of heart rate variability could detect both sympathetic and parasympathetic nervous dysfunctions in patients with PD.

Methods

Seventeen patients with PD and 11 healthy control subjects underwent electrocardiogram recording for the spectral analysis of heart rate variability to obtain values of low-frequency (LF) (0.04–0.15 Hz) and high-frequency (HF) (0.15–0.4 Hz) powers. Moreover, we examined the coefficient of variation of R–R intervals (CVRR) as a parameter of parasympathetic function in all participants and performed ¹²³I-metaiodobenzylguanidine scintigraphy to measure the heart-to-mediastinum ratio as a parameter of cardiac sympathetic innervation in patients with PD.

Results

The median age of control subjects and PD patients was 63 and 66 years old, respectively. The median Hoehn and Yahr scale of PD patients was stage 2. The values of resting LF and HF powers widely varied. The median values of resting LF powers of control subjects and PD patients and those of HF powers were 169 and 70 ms², 279 and 65 ms², respectively, the difference was statistically insignificant. Approximately 41% of patients with PD had values below the first quartile of resting LF powers (< 58 ms²) or HF powers (< 50 ms²); however, no control subject had such low values. Positive correlations were found between resting LF powers and heart-to-mediastinum ratios of ¹²³I-metaiodobenzylguanidine uptake (r = 0.6) and between resting HF powers and CVRRs (r = 0.7). The resting LF power was also associated with CVRRs and constipation. Furthermore, a positive correlation was observed between resting LF powers and resting HF powers in patients with PD (r = 0.8).

Conclusions

The power spectral analysis of heart rate variability may be useful as a screening tool for detecting autonomic dysfunctions by detecting low resting LF and HF powers in patients with PD. Sympathetic and parasympathetic nerves may be concurrently damaged in patients with PD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02872-2.

Effect of Parkinson’s Disease on Cardio-postural Coupling During Orthostatic Challenge

Cardiac baroreflex and leg muscles activation are two important mechanisms for blood pressure regulation, failure of which could result in syncope and falls. Parkinson’s disease is known to be associated with cardiac baroreflex impairment and skeletal muscle dysfunction contributing to falls. However, the mechanical effect of leg muscles contractions on blood pressure (muscle-pump) and the baroreflex-like responses of leg muscles to blood pressure changes is yet to be comprehensively investigated. In this study, we examined the involvement of the cardiac baroreflex and this hypothesized reflex muscle-pump function (cardio-postural coupling) to maintain blood pressure in Parkinson’s patients and healthy controls during an orthostatic challenge induced via a head-up tilt test. We also studied the mechanical effect of the heart and leg muscles contractions on blood pressure. We recorded electrocardiogram blood pressure and electromyogram from 21 patients with Parkinson’s disease and 18 age-matched healthy controls during supine, head-up tilt at 70°, and standing positions with eyes open. The interaction and bidirectional causalities between the cardiovascular and musculoskeletal signals were studied using wavelet transform coherence and convergent cross mapping techniques, respectively. Parkinson’s patients displayed an impaired cardiac baroreflex and a reduced mechanical effect of the heart on blood pressure during supine, tilt and standing positions. However, the effectiveness of the cardiac baroreflex decreased in both Parkinson’s patients and healthy controls during standing as compared to supine. In addition, Parkinson’s patients demonstrated cardio-postural coupling impairment along with a mechanical muscle pump dysfunction which both could lead to dizziness and falls. Moreover, the cardiac baroreflex had a limited effect on blood pressure during standing while lower limb muscles continued to contract and maintain blood pressure via the muscle-pump mechanism. The study findings highlighted altered bidirectional coupling between heart rate and blood pressure, as well as between muscle activity and blood pressure in Parkinson’s disease. The outcomes of this study could assist in the development of appropriate physical exercise programs to reduce falls in Parkinson’s disease by monitoring the cardiac baroreflex and cardio-postural coupling effect on maintaining blood pressure.

Cardiac Changes in Parkinson's Disease: Lessons from Clinical and Experimental Evidence

Dysautonomia is a common non-motor symptom in Parkinson's disease (PD). Most dysautonomic symptoms appear due to alterations in the peripheral nerves of the autonomic nervous system, including both the sympathetic and parasympathetic nervous systems. The degeneration of sympathetic nerve fibers and neurons leads to cardiovascular dysfunction, which is highly prevalent in PD patients. Cardiac alterations such as orthostatic hypotension, heart rate variability, modifications in cardiogram parameters and baroreflex dysfunction can appear in both the early and late stages of PD, worsening as the disease progresses. In PD patients it is generally found that parasympathetic activity is decreased, while sympathetic activity is increased. This situation gives rise to an imbalance of both tonicities which might, in turn, promote a higher risk of cardiac damage through tachycardia and vasoconstriction. Cardiovascular abnormalities can also appear as a side effect of PD treatment: L-DOPA can decrease blood pressure and aggravate orthostatic hypotension as a result of a negative inotropic effect on the heart. This unwanted side effect limits the therapeutic use of L-DOPA in geriatric patients with PD and can contribute to the number of hospital admissions. Therefore, it is essential to define the cardiac features related to PD for the monitorization of the heart condition in parkinsonian individuals. This information can allow the application of intervention strategies to improve the course of the disease and the proposition of new alternatives for its treatment to eliminate or reverse the motor and non-motor symptoms, especially in geriatric patients.

Cardiac and Autonomic Dysfunctions Assessed Through Recurrence Quantitative Analysis of Electrocardiogram Signals and an Application to the 6-Hydroxydopamine Parkinson's Disease Animal Model

A classic method to evaluate autonomic dysfunction is through the evaluation of heart rate variability (HRV). HRV provides a series of coefficients, such as Standard Deviation of n-n intervals (SDNN) and Root Mean Square of Successive Differences (RMSSD), which have well-established physiological associations. However, using only electrocardiogram (ECG) signals, it is difficult to identify proper autonomic activity, and the standard techniques are not sensitive and robust enough to distinguish pure autonomic modulation in heart dynamics from cardiac dysfunctions. In this proof-of-concept study we propose the use of Poincaré mapping and Recurrence Quantification Analysis (RQA) to identify and characterize stochasticity and chaoticity dynamics in ECG recordings. By applying these non-linear techniques in the ECG signals recorded from a set of Parkinson’s disease (PD) animal model 6-hydroxydopamine (6-OHDA), we showed that they present less variability in long time epochs and more stochasticity in short-time epochs, in their autonomic dynamics, when compared with those of the sham group. These results suggest that PD animal models present more “rigid heart rate” associated with “trembling ECG” and bradycardia, which are direct expressions of Parkinsonian symptoms. We also compared the RQA factors calculated from the ECG of animal models using four computational ECG signals under different noise and autonomic modulatory conditions, emulating the main ECG features of atrial fibrillation and QT-long syndrome.

6-hydroxydopamine and ovariectomy has no effect on heart rate variability parameters of females

OBJECTIVES

In addition to the classic motor symptoms of Parkinson's disease (PD), patients also present with non-motor symptoms, such as autonomic dysfunction, which is present in almost 90% of patients with PD, affecting the quality of life and mortality. Regarding sex differences in prevalence and presentation, there is increasing concern about how sex affects autonomic dysfunction. However, there are no previous data on autonomic cardiac function in females after 6-hydroxydopamine (6-OHDA) striatal injection.

METHODS

Wistar female rats were ovariectomized. After 20 days, the animals received bilateral injections of 6-OHDA (total dose per animal: 48 µg) or a vehicle solution in the striatum. Thirty days after 6-OHDA injection, subcutaneous electrodes were implanted for electrocardiogram (ECG) recording. Ten days after electrode implantation, ECG signals were recorded. Analyses of heart rate variability (HRV) parameters were performed, and the 6-OHDA lesion was confirmed by analyzing the number of tyrosine hydroxylase-positive neurons in the substantia nigra pars compacta (SNpc).

RESULTS

A high dose of 6-OHDA did not affect HRV of females, independent of ovariectomy. As expected, ovariectomy did not affect HRV or lesions in the SNpc after 6-OHDA injection.

CONCLUSIONS

We suggest that females with 6-OHDA present with cardioprotection, independent of ovarian hormones, which could be related to female vagal predominance.

Association Between Heart Rate Variability and Parkinson's Disease: A Meta-analysis

AIM

A systematic review which aims to assess the evidence regarding the function of the autonomic heart rate regulation system among Parkinson's disease (PD) patients. The main objective of the study is to compare heart rate variability (HRV) between those with and without PD from published studies. The subgroup analyses aimed to investigate the impact of treatment and disease duration on heart rate variability (HRV), assessed by measuring sympathetic and parasympathetic activity via low-frequency (LF) and high-frequency (HF) power spectrum scores, in patients with Parkinson's disease (PD).

METHODS

PubMed, Cochrane Library, Embase and Web of Science were searched using the keywords "Parkinson's disease" and "heart rate variability". Studies that reported at least one HRV variable were included. The quality of the included studies was evaluated, and the relevant information was extracted. A meta-analysis was carried out with Stata software. We followed the PRISMA guidelines for all stages of the meta-analysis. PROSPERO registration number: CRD42021242766.

RESULTS

Thirteen references (16 studies) were included in our analysis. The LF values (g -0.27; 95% confidence interval (CI) -0.53 to -0.01) of the patients with PD were lower than the controls. No significant differences in HF values (g -0.11; 95% CI -0.28 to 0.06) were observed between groups. Subgroup analyses of HRV outcomes in patients stratified by treatment status and disease duration were performed. For LF, patients with a disease duration of less than 5 years presented lower HF (g -0.25; 95% CI -0.44 to -0.06) values than controls. Regarding HF, patients receiving treatment presented lower HF (g -0.22; 95% CI -0.40 to 0.05) values than controls, and patients with a disease duration greater than 5 years also presented lower HF (g -0.29; 95% CI -0.56 to -0.03) values than controls.

DISCUSSION

We have confirmed and elaborated on the hypothesis of sympathovagal imbalance in PD. Knowledge of the effect of sympathovagal balance on HRV may inform the design of therapeutic regimens for PD. However, between-study heterogeneity and methodological issues limit the generalizability of the evidence; thus, future studies employing strict methodologies are warranted.

CONCLUSION

Our meta-analysis found that PD is associated with reduced HRV values, which indicates that both sympathetic and vagal activities are decreased. Patients in the early stage of PD have sympathetic autonomic nerve dysfunction, with only minor damage to sympathetic activity.

Could Small Heat Shock Protein HSP27 Be a First-Line Target for Preventing Protein Aggregation in Parkinson's Disease?

Small heat shock proteins (HSPs), such as HSP27, are ubiquitously expressed molecular chaperones and are essential for cellular homeostasis. The major functions of HSP27 include chaperoning misfolded or unfolded polypeptides and protecting cells from toxic stress. Dysregulation of stress proteins is associated with many human diseases including neurodegenerative diseases, such as Parkinson's disease (PD). PD is characterized by the presence of aggregates of α-synuclein in the central and peripheral nervous system, which induces the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and in the autonomic nervous system. Autonomic dysfunction is an important non-motor phenotype of PD, which includes cardiovascular dysregulation, among others. Nowadays, the therapies for PD focus on dopamine (DA) replacement. However, certain non-motor symptoms with a great impact on quality of life do not respond to dopaminergic drugs; therefore, the development and testing of new treatments for non-motor symptoms of PD remain a priority. Since small HSP27 was shown to prevent α-synuclein aggregation and cytotoxicity, this protein might constitute a suitable target to prevent or delay the motor and non-motor symptoms of PD. In the first part of our review, we focus on the cardiovascular dysregulation observed in PD patients. In the second part, we present data on the possible role of HSP27 in preventing the accumulation of amyloid fibrils and aggregated forms of α-synuclein. We also include our own studies, highlighting the possible protective cardiac effects induced by L-DOPA treatment through the enhancement of HSP27 levels and activity.

Autonomic dysfunction in Parkinson's disease: Implications for pathophysiology, diagnosis, and treatment

Parkinson's disease (PD) is a neurodegenerative disease with a 200 year-long research history. Our understanding about its clinical phenotype and pathogenesis remains limited, although dopaminergic replacement therapy has significantly improved patient outcomes. Autonomic dysfunction is an essential category of non-motor phenotypes that has recently become a cutting edge field that directs frontier research in PD. In this review, we initially describe the epidemiology of dysautonomic symptoms in PD. Then, we perform a meticulous analysis of the pathophysiology of autonomic dysfunction in PD and propose that the peripheral autonomic nervous system may be a key route for α-synuclein pathology propagation from the periphery to the central nervous system. In addition, we recommend that constipation, orthostatic hypotension, urinary dysfunction, erectile dysfunction, and pure autonomic failure should be viewed as prodromal dysautonomic markers in PD prediction and diagnosis. Finally, we summarize the strategies currently available for the treatment of autonomic dysfunction in PD and suggest that high-quality, better-designed, randomized clinical trials should be conducted in the future.

Cardiovascular autonomic function and MCI in Parkinson's disease

INTRODUCTION

dysautonomic dysfunction and cognitive impairment represent the most disabling non-motor features of Parkinson's Disease (PD). Recent evidences suggest the association between Orthostatic Hypotension (OH) and PD-Dementia. However, little is known on the interactions between cardiovascular dysautonomia and Mild Cognitive Impairment (MCI). We aimed to evaluate the association between cardiovascular dysautonomia and MCI in patients with PD.

METHODS

non-demented PD patients belonging to the PACOS cohort underwent a comprehensive instrumental neurovegetative assessment including the study of both parasympathetic and sympathetic function (30:15 ratio, Expiratory-Inspiratory ratio [E-I] and presence of Orthostatic Hypotension [OH]). Diagnosis of MCI was made according to the MDS criteria level II.

RESULTS

we enrolled 185 PD patients of whom 102 (55.1%) were men, mean age was 64.6 ± 9.7 years, mean disease duration of 5.6 ± 5.5 years with a mean UPDRS-ME score of 31.7 ± 10.9. MCI was diagnosed in 79 (42.7%) patients. OH was recorded in 52 (28.1%) patients, altered 30:15 ratio was recorded in 39 (24.1%) patients and an altered E-I ratio was found in 24 (19.1%) patients. Presence of MCI was associated with an altered 30:15 ratio (adjOR 2.83; 95%CI 1.25-6.40) but not with an altered E-I ratio, while OH was associated only with the amnestic MCI subgroup (OR 2.43; 95% CI 1.05-5.06).

CONCLUSION

in our study sample, MCI was mainly associated with parasympathetic dysfunction in PD.

Relationship of left ventricular global longitudinal strain with cardiac autonomic denervation as assessed by 123I-mIBG scintigraphy in patients with heart failure with reduced ejection fraction submitted to cardiac resynchronization therapy : Assessment of cardiac autonomic denervation by GLS in patients with heart failure with reduced ejection fraction submitted to CRT

BACKGROUND

Heart failure (HF) is associated with cardiac autonomic denervation (AD), which can be non-invasively assessed by 123I-metaiodobenzylguanidine (123I-mIBG) scintigraphy and has prognostic implications. We aimed to study the relationship between myocardial contractility assessed by global longitudinal strain (GLS) and AD assessed by 123I-mIBG scintigraphy in advanced HF.

METHODS/RESULTS

BETTER-HF is a prospective randomized clinical trial including HF patients (pts) submitted to cardiac resynchronization therapy (CRT) who are submitted to a clinical, echocardiographic, and scintigraphic assessment before and 6 months after CRT. 81 pts were included. An echocardiographic response (absolute increase in left ventricular ejection fraction ≥ 10%) was observed in 73.7% of pts. A higher baseline late heart-to-mediastinum ratio (HMR) was associated with a better echocardiographic response. There was a significant association between late HMR and GLS at baseline and 6 months. At baseline, GLS had an AUC of 0.715 for discrimination for a late HMR < 1.6. A GLS cut-off of - 9% maximized the likelihood of correctly classifying a pt as having severe AD (HMR < 1.6).

CONCLUSION

Myocardial contractility as assessed by GLS is moderately correlated with AD as assessed by 123I-mIBG scintigraphy and has a good discrimination for the identification of severe cardiac denervation. GLS may allow for a more readily accessible estimation of the degree of AD in advanced HF pts.

Hemodynamic responses to an exercise stress test in Parkinson's disease patients without orthostatic hypotension

The presence of postganglionic sympathetic denervation is well established in Parkinson's disease (PD). Denervation at cardiac and blood vessel sites may lead to abnormal cardiovascular and hemodynamic responses to exercise. The aim of the present investigation was to examine how heart rate (HR) and hemodynamics are affected by an exercise test in PD patients without orthostatic hypotension. Thirty individuals without orthostatic hypotension, 14 individuals with PD, and 16 age-matched healthy controls performed an exercise test on a cycle ergometer. Heart rate, blood pressure, and other hemodynamic variables were measured in a fasted state during supine rest, active standing, exercise, and supine recovery. Peak HR and percent of age-predicted maximum HR (HR_max) achieved were significantly blunted in PD (p < 0.05, p < 0.01). HR remained significantly elevated in PD during recovery compared with controls (p = 0.03, p < 0.05). Systolic, diastolic, and mean arterial pressures were significantly lower at multiple time-points during active standing in PD compared with controls. Systemic vascular resistance index (SVRI) decreased significantly at the onset of exercise in PD, and remained significantly lower during exercise and the first minute of supine recovery. End diastolic volume index (EDVI) was significantly lower in PD during supine rest and recovery. Our results indicate for the first time that normal hemodynamics are disrupted during orthostatic stress and exercise in PD. Despite significant differences in EDVI at rest and during recovery, and SVRI during exercise, cardiac index was unaffected. Our finding of significantly blunted HR_max and HR recovery in PD patients has substantial implications for exercise prescription and recovery guidelines.

Ageing, the autonomic nervous system and arrhythmia: From brain to heart

An ageing myocardium possesses significant electrophysiological alterations that predisposes the elderly patient to arrhythmic risk. Whilst these alterations are intrinsic to the cardiac myocytes, they are modulated by the cardiac autonomic nervous system (ANS) and consequently, ageing of the cardiac ANS is fundamental to the development of arrhythmias. A systems-based approach that incorporates the influence of the cardiac ANS could lead to better mechanistic understanding of how arrhythmogenic triggers and substrates interact spatially and temporally to produce sustained arrhythmia and why its incidence increases with age. Despite the existence of physiological oscillations of ANS activity on the heart, pathological oscillations can lead to defective activation and recovery properties of the myocardium. Such changes can be attributable to the decrease in functionality and structural alterations to ANS specific receptors in the myocardium with age. These altered ANS adaptive responses can occur either as a normal ageing process or accelerated in the presence of specific cardiac pathologies, such as genetic mutations or neurodegenerative conditions. Targeted intervention that seek to manipulate the ageing ANS influence on the myocardium may prove to be an efficacious approach for the management of arrhythmia in the ageing population.

Subthalamic nucleus stimulation and levodopa modulate cardiovascular autonomic function in Parkinson's disease

We aimed to explore the effects of bilateral subthalamic nucleus stimulation and levodopa on cardiovascular autonomic function in Parkinson’s disease. Twenty-six Parkinson’s disease patients with bilateral subthalamic nucleus stimulation in a stable state were tested under stimulation off and dopaminergic medication off (OFF-OFF), stimulation on and dopaminergic medication off (ON-OFF), and stimulation on and medication (levodopa) on (ON-ON) conditions by recording continuously blood pressure, ECG, and respiration at rest, during metronomic deep breathing, and head-up tilt test. Thirteen patients were diagnosed as orthostatic hypotension by head-up tilt test. Baroreflex sensitivity and spectral analyses were performed by trigonometric regressive spectral analysis. Subthalamic nucleus stimulation and levodopa had multiple influences. (1) Systolic blood pressure during tilt-up was reduced by subthalamic nucleus stimulation, and then further by levodopa. (2) Subthalamic nucleus stimulation and levodopa had different effects on sympathetic and parasympathetic regulations in Parkinson’s disease. (3) Levodopa decreased baroreflex sensitivity and RR interval only in the orthostatic hypotension group, and had opposite effects on the non-orthostatic hypotension group. These findings indicate that subthalamic nucleus stimulation and levodopa have different effects on cardiovascular autonomic function in Parkinson’s disease, which are modulated by the presence of orthostatic hypotension as well.

Role of peripheral vascular resistance as an indicator of cardiovascular abnormalities in patients with Parkinson's disease

The aim of this study was to evaluate cardiovascular autonomic modulation in response to an orthostatic stress in healthy subjects and Parkinson's disease (PD). The study included 47 controls and 56 PD patients divided into groups (vasoconstrictor PD, vasodilator PD, control) according to vasodilation/vasoconstriction response during 70° head up tilt test. Using impedance cardiography (ICG) and electrocardiography (ECG) we measured stroke volume, cardiac output, left ventricular work index, left ventricular ejection time, acceleration index, index of contractility, Heather index, thoracic fluid content, total peripheral resistance, total arterial compliance. We also analyzed heart rate variability (HRV), using spectral analysis and continuous blood pressure (contBP). At rest, the vasodilator PD group showed significantly higher values of total peripheral resistance and lower values of stroke volume and cardiac output, compared to the vasoconstrictor PD and the control groups. A post-tilt drop in ∆ (change rest - tilt) systolic blood pressure, ∆mean blood pressure, ∆total peripheral resistance and ∆Heather index, and a significantly lower increase in ∆diastolic blood pressure was observed in subjects from the vasodilator PD group compared to the vasoconstrictor PD and the control groups. No statistically significant differences were observed for HRV parameters between the vasoconstrictor and vasodilator PD groups, P > .05. Longer duration and higher disease stage of PD correlated with a reduction in post-tilt systolic blood pressure changes in vasodilator group. Positive inotropy of the cardiac muscle represents a significant factor preventing orthostatic hypotension in PD subjects with a concurrent drop in peripheral vascular resistance during orthostatic stress.

Possible Involvement of Hypotension in Postprandial Headache: A Case Series

BACKGROUND

It is commonly known that headaches are induced by intake of specific food, drink, and/or additive. In addition, some patients experience postprandial headache independent of ingestion of specific items. Currently, information on the pathophysiology underlying this particular type of headache is scarce.

CASE REPORTS

We report two cases in which headaches were observed after each meal. Postprandial hypotension was demonstrated in both cases. Tonometry-based continuous blood pressure measurement during head-up tilt revealed sympathetic dysfunction. In one patient, meta-iodobenzylguanidine (MIBG) myocardial scintigraphy detected cardiac sympathetic denervation, and diagnosis of pure autonomic failure was made. In both cases, treatment of postprandial hypotension was effective in relieving postprandial headache.

DISCUSSION

The possibility of postprandial hypotension should be explored in patients with headache that occurs after meal. To this end, tonometry-based blood pressure measurement and MIBG myocardial scintigraphy may be useful diagnostic investigations. Treating postprandial hypotension may be effective in alleviating the symptoms.

Body weight and dysautonomia in early Parkinson's disease

OBJECTIVES

Patients with Parkinson's disease (PD) begin to lose weight several years before diagnosis, which suggests weight variation is associated with some factor(s) that precede the onset of motor symptoms. This study aimed to investigate the association of autonomic nervous system with body weight in patients with PD.

MATERIALS AND METHODS

The subjects were 90 patients with early de novo PD. We examined the associations of body mass index (BMI) with sympathetic nervous activity reflected in orthostatic intolerance or cardiac uptake of ¹²³ I-metaiodobenzylguanidine and parasympathetic nervous activity reflected in constipation or heart rate variability (HRV).

RESULTS

Twelve patients (13.3%) were overweight (BMI>25 kg/m² ), 62 patients (68.9%) were normal-weight (18.5≦BMI<25 kg/m² ), and 16 patients (17.8%) were underweight (BMI<18.5 kg/m² ). Underweight patients had greater disease severity and decrease in blood pressure on head-up tilt-table testing, higher cardiac washout ratio of ¹²³ I-metaiodobenzylguanidine, and lower HRV and complained of constipation more often than those with normal-weight or overweight patients. On multiple regression analyses, the correlation of these variables with BMI maintained statistical significance after adjustment for age, sex, symptom duration, and motor subtype.

CONCLUSIONS

Dysautonomia and disease severity are closely related to body weight independently of age, sex, symptom duration, and motor subtype. Dysautonomia may play a partial role on weight variation in the early stage of PD.

Presynaptic dopaminergic terminal imaging and non-motor symptoms assessment of Parkinson's disease: evidence for dopaminergic basis?

Parkinson's disease (PD) is now considered to be a multisystemic disorder consequent on multineuropeptide dysfunction including dopaminergic, serotonergic, cholinergic, and noradrenergic systems. This multipeptide dysfunction leads to expression of a range of non-motor symptoms now known to be integral to the concept of PD and preceding the diagnosis of motor PD. Some non-motor symptoms in PD may have a dopaminergic basis and in this review, we investigate the evidence for this based on imaging techniques using dopamine-based radioligands. To discuss non-motor symptoms we follow the classification as outlined by the validated PD non-motor symptoms scale.

Cardiac parasympathetic dysfunction in the early phase of Parkinson's disease

Cardiac parasympathetic function is strongly affected by aging. Although sympathetic dysfunction has been well documented in Parkinson's disease (PD), cardiac parasympathetic dysfunction has not been well studied. The objective of this study was to clarify the development of cardiac parasympathetic dysfunction in the early phase of PD and to explore the age-corrected correlation between cardiac parasympathetic dysfunction and cardiac sympathetic dysfunction. We reviewed 25 healthy controls and 56 patients with idiopathic PD of Hoehn and Yahr stages I-III. We evaluated cardiac parasympathetic function using the Valsalva ratio, the baroreflex sensitivity (BRS) and the coefficient of variation of RR intervals in the resting state (resting-CVRR) and during deep breathing (DB-CVRR). In addition, we measured cardiac ¹²³I-metaiodobenzylguanidine (MIBG) uptake to investigate the relationship between cardiac sympathetic and parasympathetic dysfunction in PD. Compared with healthy controls, patients with PD showed significantly decreased cardiac parasympathetic parameters (resting-CVRR 2.8 ± 1.3 vs. 1.7 ± 0.6%, p < 0.001; DB-CVRR 5.8 ± 2.3 vs. 3.8 ± 1.7%, p < 0.001; Valsalva ratio 1.52 ± 0.26 vs. 1.34 ± 0.17, p < 0.01; BRS 10.6 ± 9.5 vs. 5.0 ± 5.4 ms/mmHg, p < 0.01). In particular, resting-CVRR and DB-CVRR were significantly decreased in the early phase of PD. In age-corrected analyses, none of the parasympathetic indices correlated with the delayed cardiac ¹²³I-MIBG uptake. These observations indicate that cardiac parasympathetic dysfunction occurs in the early phase of PD, but not necessarily in parallel with cardiac sympathetic dysfunction.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Mortality in Iranian Patients with Parkinson's Disease: Cumulative Impact of Cardiovascular Comorbidities as One Major Risk Factor

Mortality rate, life expectancy, survival, and the impact of comorbidities on them in people with Parkinson's disease (PD) need to be assessed in settings with different sociodemographic backgrounds. We investigated mortality features in Iranian PD patients focusing on the role of cardiovascular multimorbidity on their survival. Data on mortality and comorbidity profile was gathered in a cohort of 190 individuals with idiopathic PD referred to a Movement Disorders Clinic. Standardized mortality ratio (SMR) compared to the Tehran general population was 3.44 and the life expectancy at birth was 67.4 (95% CI: 59.1-75.8) yr. Patients with at least one cardiovascular comorbidity had a shorter survival time after PD onset (14.0 versus 29.2 yr, p = 0.012). The hazard ratio for death increased 2.8 times (95% CI: 1.5-5.2, p = 0.002) with one additional cardiovascular comorbidity. Among all comorbid conditions, stroke showed the strongest independent effect on mortality in PD patients [HR = 13.1 (95% CI: 2.4-71.7), p = 0.003]. Conclusively, life expectancy was slightly lower in Iranian PD patients compared to the general population, while the SMR was high. Cardiometabolic multimorbidity substantially decreased survival in people with PD. Our study highlights the need for assessment, prevention, and treatment of cardiovascular morbidities in parkinsonian patients, given their effect on survival.

Assessment of brainstem function with auricular branch of vagus nerve stimulation in Parkinson's disease

Background

The efferent dorsal motor nucleus of the vagal nuclei complex may degenerate early in the course of Parkinson’s disease (PD), while efferent nucleus ambiguous, the principal source of parasympathetic vagal neurons innervating the heart, and afferent somatosensory nuclei remain intact.

Objective

To obtain neurophysiological evidence related to this pattern, we tested processing of afferent sensory information transmitted via the auricular branch of the vagus nerve (ABVN) which is known to be connected to autonomic regulation of cardiac rhythm.

Methods

In this cross-sectional observational study, we recorded (i) somatosensory evoked potentials (ABVN-SEP) and (ii) cutaneo-cardioautonomic response elicited by stimulation of the ABVN (modulation of heart-rate variability (HRV index; low frequency power, ln(LF), high frequency power, ln(HF); ln(LF/HF) ratio)) in 50 PD patients and 50 age and sex matched healthy controls. Additionally, auditory evoked potentials and trigeminal nerve SEP were assessed.

Results

Neither ABVN-SEP nor any of the other functional brainstem parameters differed between patients and controls. Although HRV index was decreased in PD patients, modulation of ln(LF/HF) by ABVN-stimulation, likely indicating cardiac parasympathetic activation, did not differ between both groups.

Conclusions

Findings do not point to prominent dysfunction of processing afferent information from ABVN and its connected parasympathetic cardiac pathway in PD. They are consistent with the known pattern of degeneration of the vagal nuclei complex of the brainstem.

Cardiocirculatory manifestations in Parkinson's disease patients without orthostatic hypotension

The objective of this study was to characterize cardiac sympathetic denervation in Parkinson's disease (PD) patients without neurogenic orthostatic hypotension (NOH), both in terms of hemodynamics and in its relation with vascular denervation. We studied 20 PD patients without NOH. We analyzed the heart rate and blood pressure variability during various physical maneuvers. The following parameters were calculated: expiratory-inspiratory ratio, stroke volume, cardiac output, cardiac index, left ventricular ejection time, left ventricular work index, thoracic fluid content, total peripheral resistance and baroreflex sensitivity (BRS). We also measured direct and spectral derivatives of cardiac (cardiovagal) parasympathetic function. Myocardial I-123 metaiodobenzylguanidine (MIBG) scintigraphy was performed and early and late heart/mediastinum uptake ratios were analyzed. We observed that the late heart/mediastinum uptake ratio was 1.33±0.21. This parameter was correlated with years since diagnosis (correlation coefficient:-0.485; P=0.05), Unified Parkinson's Disease Rating Scale (UPDRS) III score (cc:-0.564; P=0.02) and pressure recovery time in the Valsalva maneuver (cc: 0.61; P<0.001). At rest, it was correlated with BRS (cc:0.75; P=0.003) and low-frequency diastolic blood pressure (LFDBP; cc: 0.58;P=0.017). We found no correlations with any of the cardiography impedance variables. In linear regression models, the variable that best correlated with MIBG results was LFDBP. Our results support that in absence of NOH the degree of denervation of the heart does not produce any effect on its inotropic function. Moreover, BRS and LFDBP can be used as an indirect measure of cardiac sympathetic denervation at rest.

Gastrointestinal Symptoms in Parkinson Disease: Clinical Aspects and Management

Although it is now generally recognized that the clinical spectrum of Parkinson disease (PD) is broader than its defining motor aspects, its various non-motor symptoms are often not routinely assessed in the clinical setting. As most of these symptoms are amenable to treatment, improved recognition would lead to more comprehensive management of the disease, and ultimately improve the quality of life for PD patients. In an attempt to increase the general awareness of physicians caring for these patients, this article focuses on the clinical manifestations and treatment of the gastrointestinal symptoms most commonly experienced by PD patients, as well as on the gastrointestinal side effects of antiparkinsonian treatments.

Cardiovascular variability in Mexican patients with Parkinson's disease

Cardiovascular variability (CVV) has been evaluated in patients with Parkinson's disease (PD) in other countries and exhibit ethnic differences. Objective We investigated heart rate variability (HRV) and blood pressure variability (BPV) in Mexican patients with PD. Method We further compared HRV and BPV between this group and young healthy controls (YHC) in order to estimate, for the first time in our country, the magnitude of the difference. Twenty patients were examined. Time- and frequency-domain CVV parameters were studied during supine rest (SR), active standing (AS) and controlled breathing. These measurements were compared to those of 20 YHC. Results In the three conditions tested, our study showed a decrease in almost all HRV parameters in PD patients; on the contrary, decreased BPV parameters were found less frequently and only during SR and AS. Conclusion Our results indicate that HRV is impaired in PD. Some BPV parameters are also diminished.

Hyposmia and cardiovascular dysautonomia correlatively appear in early-stage Parkinson's disease

OBJECTIVE

Olfactory dysfunction is considered to precede motor symptoms and early markers of Parkinson's disease (PD), while the relative time at which cardiovascular dysautonomia appears in PD is not well understood. To assess the appearance of cardiovascular dysautonomia in PD, we evaluated its relation to olfactory dysfunction in early-stage PD patients.

METHODS

Twenty-three non-demented PD patients within 2 years from the onset of motor symptoms were enrolled. We evaluated olfactory dysfunction by the Odor Stick Identification Test for Japanese (OSIT-J) and analyzed its relationship to the results of other cardiovascular autonomic tests and cardiac (123)I-metaiodobenzylguanidine (MIBG) scintigraphy.

RESULTS

There was a correlation between olfactory scores and increased blood pressure in both the norepinephrine (r = 0.75, p < 0.0001, n = 21) and dobutamine (r = 0.57, p = 0.0087, n = 20) infusion tests and cardiac MIBG uptake (r = 0.42, p = 0.049, n = 23). The fall in orthostatic blood pressure during the head-up tilt test was not correlated with the olfactory scores, but the Valsalva maneuver revealed that OSIT-J scores correlated with the pressure recovery time from phase III to the return of blood pressure to baseline (r = 0.54, p = 0.037, n = 15) and with the magnitude of blood pressure overshoot during phase IV (r = 0.67, p = 0.0016, n = 20).

CONCLUSION

Our results demonstrate that extensive components of the cardiovascular sympathetic system as well as the olfactory system are correlatively impaired in the early stage of PD, suggesting that degeneration of broad aspects of the cardiovascular sympathetic system occurs concurrently with olfactory system degeneration during the premotor phase of PD.

Parkinson's disease and risk of mortality: meta-analysis and systematic review

To evaluate the existing prospective observational studies on the morality risk among Parkinson's disease (PD) patients and determine the overall risk ratio (RR) of mortality by conducting a meta-analysis and systematic review. Original articles published in English were searched in PubMed and Embase databases prior to March 2013. Only prospective observational studies providing adjusted risk estimates related to PD and future mortality were considered eligible. Pooled adjusted RR and 95% confidence interval (CI) were computed either by fixed-effects models or by random-effects models. Eight studies with 72,833 participants were identified and analysed. In the pooled analyses, patients with PD had a greater risk of all-cause mortality (RR = 2.22; 95% CI: 1.78-2.77). Subgroup analyses based on the design, gender, follow-up duration and sample size showed that a consistent positive association between PD and the mortality risk in each subgroup. However, no statistical significance was found for the baseline age <65 years (RR = 1.42; 95% CI: 0.72-2.77). PD patients with dementia had particularly high mortality risks (RR = 3.78; 95% CI: 2.06-6.92). This meta-analysis indicated that among patients with PD, the all-cause mortality increased by 2.22-fold compared with the general population. PD patients with dementia particularly had higher risks of mortality.

Role of cardiac sympathetic nerves in preventing orthostatic hypotension in Parkinson's disease

PURPOSE

Cardiac sympathetic denervation is associated with orthostatic hypotension (OH) in Parkinson's disease (PD); however, the physiological role of cardiac sympathetic nerves has yet to be elucidated. To clarify the role of the heart in orthostatic stress, we evaluated whether cardiac sympathetic nerves can alter cardiac activity and systolic blood pressure (BP) in association with elevations or depressions of total peripheral resistance during the head-up tilt test.

METHODS

Ninety-five PD patients and 17 normal controls were enrolled. Using impedance cardiography, we measured total peripheral resistance, stroke volume, heart rate, and systolic BP during the head-up tilt test. Cardiac denervation was defined as a heart-to-mediastinum ratio <1.7 for cardiac (123)I-metaiodobenzylguanidine uptake on delayed images.

RESULTS

At 60° tilt, total peripheral resistance decreased from the initial value in 49 PD patients. Among these, 36 patients exhibited cardiac denervation with severe reductions in systolic BP but little change in stroke volume; among these patients 22 had OH. The remaining 13 patients without cardiac denervation exhibited significant increases in stroke volume and well-preserved systolic BP with no OH. On the other hand, 46 patients had elevations in total peripheral resistance and reduced stroke volume, but little change in systolic BP, regardless of the presence or absence of cardiac denervation. Only one of these patients experienced OH.

CONCLUSION

Under orthostatic stress, cardiac sympathetic denervation with failure to increase total peripheral resistance leads to large reductions in systolic BP. However, patients without cardiac denervation exhibited a positive inotropic response against vasodilatation, which may prevent OH.

Autonomic dysfunction according to disease progression in Parkinson's disease

BACKGROUND

Although autonomic dysfunction is common in patients with Parkinson's disease (PD), few data are available regarding its pattern and quantitative severity with increasing Hoehn and Yahr (H&Y) stage. We conducted autonomic function tests to quantify autonomic dysfunction in PD patients and to elucidate its possible relationship with disease progression.

METHODS

We performed autonomic function tests including Valsalva ratio, heart rate response to deep breathing, quantitative sudomotor axon reflex test, and head-up tilt test in 66 patients with PD. We compared clinical characteristics and results of autonomic function tests between stages, and correlated the proportion of abnormal patients in each test with their H&Y stage. In addition, logistic regression analyses were conducted to examine the contribution of increasing H&Y stage to impairments of each domain of the autonomic nervous system.

RESULTS

We found that PD patients with higher disease stage tended to have impairments in cardiovagal and sudomotor domains of the autonomic nervous system. Cardiovagal function was the domain most influenced by disease progression. Our findings also demonstrated that the pattern of sudomotor impairment in PD was similar to that in patients with peripheral autonomic neuropathy.

CONCLUSIONS

Our study demonstrates that autonomic dysfunction is not only common in early stage PD but it increases in severity with increasing disease stage. Given that the patterns of sudomotor impairments in PD are similar to those in peripheral neuropathy, our data support a previous hypothesis that pathophysiology of PD involves both the central and peripheral nervous systems.

The natural history of Parkinson's disease in the province of Segovia: mortality in a longitudinal study (20-year follow-up)

OBJECTIVE

We determined mortality rates and predictors of survival in 273 patients with Parkinson's disease based on a 20-year follow-up longitudinal study.

MATERIAL AND METHODS

We examined 273 patients with Parkinson's disease during a 20-year follow-up, recruited between 1978 and 1998. All patients were regularly followed at the Department of Neurology until December 31, 1998, or death.

RESULTS

By then, 69 patients had died, crude mortality was rate 4.43, and standardized mortality ratio for the total patient group was 1.39 (95% CI, 1.10-1.50). As Parkinson's disease is a chronic progressive disorder in adult life, disease-related mortality would be expected to increase in later stages after 15 or 20 years. Mean age at death in our cohort was 78.27 (95% CI, 76.90-79.20). Median time of death was 11 years (95% CI, 9.50-12.49). Independent predictors of mortality during the follow-up were age at onset (hazard ratio, 1.05; 95% CI, 1.01-1.09; P = 0.01), clinical form - akinesia and rigidity (hazard ratio, 2.20; 95% CI, 1.06-4.88; P = 0.03) - and treatment with dopaminergic agonist (hazard ratio, 0.49; 95% CI, 0.23-1.03; P = 0.06). Cardiovascular disease was the most frequent cause of death in 42%.

CONCLUSIONS

This study suggests a link between mortality with age of onset and treatment without dopamine agonists as initial treatment. So, there is an association between decreased mortality and tremor as initial clinical forms at onset.

Unimpaired postprandial pancreatic polypeptide secretion in Parkinson's disease and REM sleep behavior disorder

BACKGROUND

Pancreatic polypeptide is released immediately after food ingestion. The release is operated by vagal-abdominal projections and has therefore been suggested as a test for vagal nerve integrity. Pathoanatomical and clinical studies indicate vagal dysfunction in early Parkinson's disease (PD).

METHODS

We assessed the postprandial secretion of pancreatic polypeptide and motilin in healthy controls (n = 18) and patients with idiopathic rapid-eye-movement sleep behavior disorder (iRBD, n = 10), a potential premotor stage of PD, as well as in drug-naive (n = 19) and treated (n = 19) PD patients.

RESULTS

The postprandial pancreatic polypeptide secretion showed a physiological pattern in all groups and even an enhanced response in drug-naive PD and iRBD. Motilin concentrations correlated with pancreatic polypeptide concentrations.

CONCLUSIONS

Postprandial pancreatic polypeptide secretion is not a suitable test for vagal nerve integrity in PD. The unimpaired pancreatic polypeptide response in iRBD and PD might be explained by partially intact vagal-abdominal projections or compensatory mechanisms substituting a defective neuronal brain-gut axis.

The management of gastrointestinal symptoms in Parkinson's disease

The involvement of the autonomic nervous system in Parkinson's disease causes many non-motor symptoms, among which gastrointestinal complaints are prominent. Drooling, dyspepsia, constipation, abdominal pain and fecal incontinence are frequently a source of patient distress. Dysphagia is recognized as causing both discomfort and increased risk of serious complications. Although a diagnosis can often be established based on the reports of patients and/or caregivers, and additional testing is seldom required, these diagnoses are clearly under recognized in clinical practice. These symptoms respond to the same treatment measures used in the general population, although certain drugs with a potential to increase parkinsonian symptoms should be avoided. Increased and early identification of these symptoms can result in a significant improvement in the quality of life of Parkinson's disease patients.

Biomarker candidates of neurodegeneration in Parkinson's disease for the evaluation of disease-modifying therapeutics

Reliable biomarkers that can be used for early diagnosis and tracking disease progression are the cornerstone of the development of disease-modifying treatments for Parkinson's disease (PD). The German Society of Experimental and Clinical Neurotherapeutics (GESENT) has convened a Working Group to review the current status of proposed biomarkers of neurodegeneration according to the following criteria and to develop a consensus statement on biomarker candidates for evaluation of disease-modifying therapeutics in PD. The criteria proposed are that the biomarker should be linked to fundamental features of PD neuropathology and mechanisms underlying neurodegeneration in PD, should be correlated to disease progression assessed by clinical rating scales, should monitor the actual disease status, should be pre-clinically validated, and confirmed by at least two independent studies conducted by qualified investigators with the results published in peer-reviewed journals. To date, available data have not yet revealed one reliable biomarker to detect early neurodegeneration in PD and to detect and monitor effects of drug candidates on the disease process, but some promising biomarker candidates, such as antibodies against neuromelanin, pathological forms of α-synuclein, DJ-1, and patterns of gene expression, metabolomic and protein profiling exist. Almost all of the biomarker candidates were not investigated in relation to effects of treatment, validated in experimental models of PD and confirmed in independent studies.

Autonomic involvement in Parkinson's disease: pathology, pathophysiology, clinical features and possible peripheral biomarkers

Autonomic nervous system involvement occurs at early stages in both Parkinson's disease (PD) and incidental Lewy body disease (ILBD), and affects the sympathetic, parasympathetic, and enteric nervous systems (ENS). It has been proposed that alpha-synuclein (α-SYN) pathology in PD has a distal to proximal progression along autonomic pathways. The ENS is affected before the dorsal motor nucleus of the vagus (DMV), and distal axons of cardiac sympathetic nerves degenerate before there is loss of paravertebral sympathetic ganglion neurons. Consistent with neuropathological findings, some autonomic manifestations such as constipation or impaired cardiac uptake of norepinephrine precursors, occur at early stages of the disease even before the onset of motor symptoms. Biopsy of peripheral tissues may constitute a promising approach to detect α-SYN neuropathology in autonomic nerves and a useful early biomarker of PD.