Prediagnostic presentations of Parkinson's disease in primary care: a case-control study

Emergence of non-motor fluctuations with reference to motor fluctuations in Parkinson's disease

INTRODUCTION

Non-motor fluctuations (NMF) and motor fluctuations (MF) are frequent in patients with Parkinson's disease (PD) with long-term medical treatment. We aimed to examine the timing of the emergence of NMF with reference to MF in a prospective cohort of patients with PD without symptom fluctuations.

METHODS

A total of 334 patients with PD who had neither MF nor NMF were recruited. The exclusion criteria included a Mini-Mental State Examination score of less than 26 points at baseline and an alternative diagnosis or significant comorbidity during follow-up. The "SNUH-Fluctuation Questionnaire" consisting of 29 items (9 on MF and 20 on NMF) was administered on a semi-annually basis for 3 years.

RESULTS

Three hundred seven out of 334 patients were analyzed for symptom fluctuations with the Kaplan-Meier survival analysis. MF were observed in more patients and developed earlier than NMF (cumulative survival of 0.572 for MF and 0.619 for NMF at 36 months of follow-up). In 212 patients who finished the follow-up for 36 months, MF and NMF developed simultaneously in 58 (27.4%), MF developed first in 45 (21.2%), and NMF developed first in only 3 (1.4%). The remaining 106 patients (50.0%) did not develop either MF or NMF.

CONCLUSION

NMF developed simultaneously with or later than MF. From these data, we hypothesize that NMF develop in the disease state where the pathology in the brain has been severe enough to develop MF. Hence, pharmacologic management should consider targeting both dopaminergic and non-dopaminergic systems to treat NMF.

A survey of subjective constipation in Parkinson's disease patients in shanghai and literature review

Background

Constipation is one of the most frequent non-motor symptoms (NMS) in Parkinson’s disease (PD) and the prevalence of constipation in PD patients varies among different studies. We designed this study to survey the prevalence and clinical characteristics of subjective constipation and the appearance chronology between the emergence of constipation and onset of motor symptoms in PD patients from Shanghai, China.

Methods

268 PD patients were continuously recruited into this study. Parkinson’s related clinical information of the participants was collected. A spectrum of motor and nonmotor features was assessed with scales and questionnaires. Subjective constipation was defined by ROME III criteria.

Results

54.10% PD patients suffer from constipation. Among them, there was 47.59% having constipation before onset of motor symptoms. Compared with patients without constipation, patients with constipation reported lower daily water intake and less exercise, and were dominated by bradykinetic-rigid motor phenotype at onset and were prone to have anxiety, depression and insomnia. The time span between constipation and the onset of motor symptoms was (6.62 ± 9.32) years. Constipation occurred more frequently between 2 and 10 years before onset of motor symptoms. Patients suffering with constipation were then divided into two groups according to the time sequence of constipation and motor onset: ‘constipation pre-motor sign’ group and ‘constipation post-motor sign’ group. Total timespan from earliest initial symptoms to present was similar. Compared with ‘constipation post-motor sign’ group, the patients in ‘constipation pre-motor sign’ group experienced an older motor symptoms onset age, less serious motor symptoms, more serious constipation and less daily levodopa dosage.

Conclusions

Our results supported that constipation could be a pre-motor symptom of PD. Different clinical characteristics were found in different constipation-loading time relative to motor symptoms. Research of constipation may be useful to better understand the early stages of PD and assessment of constipation with validated criteria may have utility as a risk factor for predicting PD in the prodromal phase.

Role of Plant Derived Alkaloids and Their Mechanism in Neurodegenerative Disorders

Neurodegenerative diseases are conventionally demarcated as disorders with selective loss of neurons. Conventional as well as newer molecules have been tested but they offer just symptomatic advantages along with abundant side effects. The discovery of more compelling molecules that can halt the pathology of these diseases will be considered as a miracle of present time. Several synthetic compounds are available but they may cause several other health issues. Therefore, natural molecules from the plants and other sources are being discovered to replace available medicines. In conventional medicational therapies, several plants have been reported to bestow remedial effects. Phytochemicals from medicinal plants can provide a better and safer alternative to synthetic molecules. Many phytochemicals have been identified that cure the human body from a number of diseases. The present article reviews the potential efficacy of plant-derived alkaloids, which possess potential therapeutic effects against several NDDs including Alzheimer's disease (AD), Huntington disease (HD), Parkinson's disease (PD), Epilepsy, Schizophrenia, and stroke. Alkaloids include isoquinoline, indole, pyrroloindole, oxindole, piperidine, pyridine, aporphine, vinca, β-carboline, methylxanthene, lycopodium, and erythrine byproducts. Alkaloids constitute positive roles in ameliorating pathophysiology of these illnesses by functioning as muscarinic and adenosine receptors agonists, anti-oxidant, anti-amyloid and MAO inhibitors, acetylcholinestrase and butyrylcholinesterase inhibitor, inhibitor of α-synuclein aggregation, dopaminergic and nicotine agonist, and NMDA antagonist.

Performance of the Movement Disorders Society criteria for prodromal Parkinson's disease: A population-based 10-year study

OBJECTIVE

We aimed to identify prodromal Parkinson's disease (PD) and its predictive accuracy for incident PD in an unselected elderly population and to estimate the relevance of this approach for future neuroprotection trials.

METHODS

We applied the recently published Movement Disorders Society (MDS) research criteria for prodromal PD to participants of the prospective population-based Bruneck Study of the 2005 assessment (n = 574, ages 55-94 years). Cases of incident PD were identified at 3-year, 5-year, and 10-year follow-up visits. We calculated predictive accuracies of baseline prodromal PD status for incident cases, and, based on them, estimated sample sizes for neuroprotection trials with conversion to PD as the primary outcome.

RESULTS

Baseline status of probable prodromal PD (n = 12) had a specificity in predicting incident PD of 98.8% (95% confidence interval, 97.3%-99.5%), a sensitivity of 66.7% (29.6%-90.8%), and a positive predictive value of 40.0% (16.7%-68.8%) over 3 years. Specificity remained stable with increasing follow-up time, sensitivity decreased to 54.6% (28.0%-78.8%) over 5 years and to 35.0% (18.0%-56.8%) over 10 years, whereas positive predictive value rose to 60.0% (31.2%-83.3%) and 77.8% (44.3%-94.7%), respectively. Sample size estimates at 80% power in an intention-to-treat approach ranged from 108 to 540 patients with probable prodromal PD depending on trial duration (3-5 years) and effect size of the agent (30%-50%).

CONCLUSIONS

Our findings show that the MDS criteria for prodromal PD yield moderate to high predictive power for incident PD in a community-based setting and may thus be helpful to define target populations of future neuroprotection trials. © 2018 International Parkinson and Movement Disorder Society.

Sleep-wake disturbances in the premotor and early stage of Parkinson's disease

PURPOSE OF REVIEW

Review of recent literature pertaining to frequency, associations, mechanisms, and overall significance of sleep--wake disturbances (SWD) in the premotor and early phase of Parkinson's disease.

RECENT FINDINGS

SWD are frequent in Parkinson's disease and their prevalence increases with disease progression. Recent studies confirm previous findings that SWD can appear as initial manifestation of Parkinson's disease even decades before motor signs appear and highlight their clinical associations in these early stages. More intriguingly, new evidence underpins their role as risk factors, predictors, or even as driving force for the neurodegenerative process. As our understanding of sleep--wake neurobiology increases, new hypotheses emerge concerning the pathophysiology of SWD in early Parkinson's disease stages involving dopaminergic and nondopaminergic mechanisms.

SUMMARY

SWD are predictors for the development of parkinsonian syndromes including Parkinson's disease. This may offer the opportunity of developing new preventive strategies and interventions at an early stage of this neurodegenerative disease.

Predictors of Mortality in Nondemented Patients With Parkinson Disease: Motor Symptoms Versus Nonmotor Symptoms

BACKGROUND AND OBJECTIVE

The aim of this study is to identify risk factors for mortality in a community-based cohort of nondemented patients with Parkinson disease (PD) during prospective long-term follow-up, while also comparing the effect of motor complications to nonmotor symptoms (NMS) on risk of mortality.

METHODS

One hundred forty seven nondemented patients with PD (57.1% males; 70.9 ± 8.6 years old) were included in this 48 month follow-up, longitudinal, single, evaluation study. Motor and therapy-related complications were assessed using the Unified Parkinson's Disease Rating Scale/part-IV (UPDRS-IV). Non-Motor Symptoms Scale (NMSS) total score was used to assess NMS burden. Cox proportional hazard models were applied to identify independent predictors of mortality during follow-up.

RESULTS

Twenty-two patients of 146 (15.1%) died (1 case without information). Both UPDRS-IV and NMSS total scores were higher at baseline in patients with PD who died (3.5 ± 3.1 vs 2.4 ± 2.4, P = .049 and 96.9 ± 58.6 vs 61.9 ± 51.0, P = .004, respectively). Unadjusted hazard ratios (HRs) associated with UPDRS-IV and NMSS total scores among those who died during follow-up were 1.171 (95% confidence interval [CI]: 1.012-1.357; P = .035) and 1.008 (95% CI: 1.002-1.013; P = .006), respectively. Independent predictors of mortality during follow-up after adjusting for other covariates were UPDRS-IV (HR: 1.224; 95% CI: 1.002-1.494; P = .047), age (HR: 1.231; 95% CI: 1104-1.374; P < .0001), and comorbidity (Charlson Index; HR: 1.429; 95% CI: 1.023-1.994; P = .036), but not NMSS total score (HR: 1.005; 95% CI: 0.996-1.014; P = .263).

CONCLUSIONS

Both motor complications (UPDRS-IV) and NMS (NMSS) were associated with mortality at 4 years, being motor complications an independent predictor of it.

High-accuracy detection of early Parkinson's Disease using multiple characteristics of finger movement while typing

Parkinson's Disease (PD) is a progressive neurodegenerative movement disease affecting over 6 million people worldwide. Loss of dopamine-producing neurons results in a range of both motor and non-motor symptoms, however there is currently no definitive test for PD by non-specialist clinicians, especially in the early disease stages where the symptoms may be subtle and poorly characterised. This results in a high misdiagnosis rate (up to 25% by non-specialists) and people can have the disease for many years before diagnosis. There is a need for a more accurate, objective means of early detection, ideally one which can be used by individuals in their home setting. In this investigation, keystroke timing information from 103 subjects (comprising 32 with mild PD severity and the remainder non-PD controls) was captured as they typed on a computer keyboard over an extended period and showed that PD affects various characteristics of hand and finger movement and that these can be detected. A novel methodology was used to classify the subjects' disease status, by utilising a combination of many keystroke features which were analysed by an ensemble of machine learning classification models. When applied to two separate participant groups, this approach was able to successfully discriminate between early-PD subjects and controls with 96% sensitivity, 97% specificity and an AUC of 0.98. The technique does not require any specialised equipment or medical supervision, and does not rely on the experience and skill of the practitioner. Regarding more general application, it currently does not incorporate a second cardinal disease symptom, so may not differentiate PD from similar movement-related disorders.

[Epidemiology and causes of Parkinson's disease]

Parkinson's disease (PD) is the second most common neurodegenerative disease and has a growing socioeconomic impact due to demographic changes in the industrial nations. There are several forms of PD, a fraction of which (<5%) are monogenic, i. e. caused by mutations in single genes. At present, six genes have been established for the clinically classical form of parkinsonism including three autosomal dominantly (SNCA, LRRK2, VPS35) and three autosomal recessively inherited ones (Parkin, PINK1, DJ-1). In addition, there are a plethora of genes causing atypical forms of parkinsonism. In contrast, idiopathic PD is of a multifactorial nature. Genome-wide association studies have established a total of 26 genetic loci for this form of the disease; however, for most of these loci the underlying functional genetic variants have not yet been identified and the respective disease mechanisms remain unresolved. Furthermore, there are a number of environmental and life style factors that are associated with idiopathic PD. Exposure to pesticides and possibly a history of head trauma represent genuine risk factors. Other PD-associated factors, such as smoking and intake of coffee and alcohol may not represent risk factors per se and the cause-effect relationship has not yet been elucidated for most of these factors. A patient with a positive family history and/or an early age of disease onset should undergo counseling with respect to a possible monogenic form of the disease. Disease prediction based on genetic, environmental and life style factors is not yet possible for idiopathic PD and potential gene-specific therapies are currently in the development or early testing phase.

Longitudinal CSF biomarkers in patients with early Parkinson disease and healthy controls

OBJECTIVE

To analyze longitudinal levels of CSF biomarkers in drug-naive patients with Parkinson disease (PD) and healthy controls (HC), examine the extent to which these biomarker changes relate to clinical measures of PD, and identify what may influence them.

METHODS

CSF α-synuclein (α-syn), total and phosphorylated tau (t- and p-tau), and β-amyloid 1-42 (Aβ42) were measured at baseline and 6 and 12 months in 173 patients with PD and 112 matched HC in the international multicenter Parkinson's Progression Marker Initiative. Baseline clinical and demographic variables, PD medications, neuroimaging, and genetic variables were evaluated as potential predictors of CSF biomarker changes.

RESULTS

CSF biomarkers were stable over 6 and 12 months, and there was a small but significant increase in CSF Aβ42 in both patients with patients with PD and HC from baseline to 12 months. The t-tau remained stable. The p-tau increased marginally more in patients with PD than in HC. α-syn remained relatively stable in patients with PD and HC. Ratios of p-tau/t-tau increased, while t-tau/Aβ42 decreased over 12 months in patients with PD. CSF biomarker changes did not correlate with changes in Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale motor scores or dopamine imaging. CSF α-syn levels at 12 months were lower in patients with PD treated with dopamine replacement therapy, especially dopamine agonists.

CONCLUSIONS

These core CSF biomarkers remained stable over 6 and 12 months in patients with early PD and HC. PD medication use may influence CSF α-syn. Novel biomarkers are needed to better profile progressive neurodegeneration in PD.

Non-motor symptoms and quality of life in subjects with mild parkinsonian signs

BACKGROUND

Mild parkinsonian signs (MPS) are frequent in the elderly population and associated with the presence of risk markers for Parkinson's disease (PD). Both MPS and non-motor signs may be present in prodromal PD and may significantly impair quality of life (QoL).

OBJECTIVE

To disentangle the contribution of motor impairment and extra-motor manifestations to QoL in subjects with MPS (n=63), manifest PD (n=69), disorders with motor symptoms due to non-neurodegenerative diseases (n=213) and healthy controls (n=258).

METHODS

Subjects with MPS, healthy controls, disease controls (patients with motor impairment due to, eg, arthrosis and spondylosis), and PD patients (total n=603) were selected from a large epidemiological longitudinal study, the EPIPARK cohort. Motor function was determined using the UPDRSIII protocol, and information on depressive symptoms, anxiety, sleep, and QoL was assessed via rating scales and data were analyzed.

RESULTS

Depressive symptoms, anxiety, and sleep problems were equally frequent in the MPS group and controls. Health-related QoL was slightly reduced in the MPS group. Motor impairment and its extent was comparable between the MPS group and disease controls (UPDRSIII 5-6 points). Higher motor dysfunction was associated with lower QoL. Depressive symptoms, but not anxiety and daytime sleepiness, was significant predictors of general QoL, independent of motor function.

CONCLUSIONS

Quality of life is slightly decreased in an elderly population with MPS. QoL is associated with severity of motor impairment but also with non-motor aspects, ie, depressive symptoms. Follow-up studies in large cohorts are warranted to determine the natural course of MPS and its impact on QoL.

Traumatic brain injury in the prodromal period of Parkinson's disease: A large epidemiological study using medicare data

OBJECTIVE

Studies suggest a greater risk of Parkinson's disease (PD) after traumatic brain injury (TBI), but it is possible that the risk of TBI is greater in the prodromal period of PD. We aimed to examine the time-to-TBI in PD patients in their prodromal period compared to population-based controls.

METHODS

We identified 89,790 incident PD cases and 118,095 comparable controls aged > 65 years in 2009 using Medicare claims data. Using data from the preceding 5 years, we compared time-to-TBI in PD patients in their prodromal period to controls. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for TBI in a Cox regression, while adjusting for age, sex, race/ethnicity, modified Charlson comorbidity index, smoking, and alcohol use.

RESULTS

Risk of TBI was greater in PD patients in their prodromal period across all age and sex groups, with HRs consistently increasing with proximity to PD diagnosis. HRs ranged from 1.64 (95% CI, 1.52, 1.77) 5 years preceding diagnosis to 3.93 (95% CI, 3.74, 4.13) in the year before. The interaction between PD, TBI, and time was primarily observed for TBI attributed to falls. Motor dysfunction and cognitive impairment, suggested by corresponding International Classification of Diseases, Ninth Revision codes, partially mediated the PD-TBI association.

INTERPRETATION

There is a strong association between PD and a recent TBI in the prodromal period of PD. This association strengthens as PD diagnosis approaches and may be a result of undetected nonmotor and motor symptoms, but confirmation will be required. Ann Neurol 2017;82:744-754.

Association of Restless Legs Syndrome With Incident Parkinson's Disease

Study Objectives

The association between restless legs syndrome (RLS) and Parkinson's disease (PD) has been extensively studied with inconclusive results; therefore, we prospectively examined the associations of the presence of RLS with development of incident PD.

Methods

From a nationally representative prospective cohort of almost 3.5 million US veterans (age: 60 ± 14 years, 93% male, median follow-up time of 7.8 years [interquartile range: 6.4-8.4 years]), we created a propensity-matched cohort of 100882 PD-free patients and examined the association between prevalent RLS and incident PD. This association was also assessed in the entire cohort. Associations were examined using Cox models.

Results

There were 68 incident PD events (0.13%, incidence rate 1.87 [1.48-2.37]/10000 patient-years) in the RLS-negative group, and 185 incident PD events (0.37%, incidence rate 4.72 [4.09-5.45]/10000 patient-years) in the RLS-positive group in the propensity-matched cohort. Prevalent RLS was associated with more than twofold higher risk of incident PD (hazard ratio [HR]: 2.57, 95% confidence interval [CI]: 1.95-3.39) compared to RLS-negative patients. Qualitatively similar results were found when we examined the entire 3.5 million cohort: Prevalent RLS was associated with more than twofold higher risk of incident PD (multivariable adjusted HR: 2.81, 95%CI: 2.41-3.27).

Conclusion

RLS and PD share common risk factors. In this large cohort of US veterans, we found that prevalent RLS is associated with higher risk of incident PD during 8 years of follow-up, suggesting that RLS could be an early clinical feature of incident PD.

Cognitive changes in prodromal Parkinson's disease: A review

Although other nonmotor phenomena representing possible prodromal symptoms of Parkinson's disease have been described in some detail, the occurrence and characteristics of cognitive decline in this early phase of the disease are less well understood. The aim of this review is to summarize the current state of research on cognitive changes in prodromal PD. Only a small number of longitudinal studies have been conducted that examined cognitive function in individuals with a subsequent PD diagnosis. However, when we consider data from at-risk groups, the evidence suggests that cognitive decline may occur in a substantial number of individuals who have the potential for developing PD. In terms of specific cognitive domains, executive function in particular and, less frequently, memory scores are reduced. Prospective longitudinal studies are thus needed to clarify whether cognitive, and specifically executive, decline might be added to the prodromal nonmotor symptom complex that may precede motor manifestations of PD by years and may help to update the risk scores used for early identification of PD. © 2017 International Parkinson and Movement Disorder Society.

Therapeutic approaches to target alpha-synuclein pathology

Starting two decades ago with the discoveries of genetic links between alpha-synuclein and Parkinson's disease risk and the identification of aggregated alpha-synuclein as the main protein constituent of Lewy pathology, alpha-synuclein has emerged as the major therapeutic target in Parkinson's disease and related synucleinopathies. Following the suggestion that alpha-synuclein pathology gradually spreads through the nervous system following a stereotypic pattern and the discovery that aggregated forms of alpha-synuclein can propagate pathology from one cell to another, and thereby probably aggravate existing deficits as well as generate additional symptoms, the idea that alpha-synuclein is a viable therapeutic target gained further support. In this review we describe current challenges and possibilities with alpha-synuclein as a therapeutic target. We briefly highlight gaps in the knowledge of the role of alpha-synuclein in disease, and propose that a deeper understanding of the pathobiology of alpha-synuclein can lead to improved therapeutic strategies. We describe several treatment approaches that are currently being tested in advanced animal experiments or already are in clinical trials. We have divided them into approaches that reduce alpha-synuclein production; inhibit alpha-synuclein aggregation inside cells; promote its degradation either inside or outside cells; and reduce its uptake by neighbouring cells following release from already affected neurons. Finally, we briefly discuss challenges related to the clinical testing of alpha-synuclein therapies, for example difficulties in monitoring target engagement and the need for relatively large trials of long duration. We conclude that alpha-synuclein remains one of the most compelling therapeutic targets for Parkinson's disease, and related synucleinopathies, and that the multitude of approaches being tested provides hope for the future.

Can Biomarkers Help the Early Diagnosis of Parkinson's Disease?

Parkinson's disease (PD) is a complex neurodegenerative disease with progressive loss of dopamine neurons. PD patients usually manifest a series of motor and non-motor symptoms. In order to provide better early diagnosis and subsequent disease-modifying therapies for PD patients, there is an urgent need to identify sensitive and specific biomarkers. Biomarkers can be divided into four categories: clinical, imaging, biochemical, and genetic. Ideal biomarkers not only improve our understanding of PD pathogenesis and progression, but also provide benefits for early risk evaluation and clinical diagnosis of PD. Although many efforts have been made and several biomarkers have been extensively investigated, few if any have been found useful for early diagnosis. Here, we summarize recent developments in the discovered biomarkers of PD and discuss their merits and limitations for the early diagnosis of PD.

A predictive model to identify Parkinson disease from administrative claims data

OBJECTIVE

To use administrative medical claims data to identify patients with incident Parkinson disease (PD) prior to diagnosis.

METHODS

Using a population-based case-control study of incident PD in 2009 among Medicare beneficiaries aged 66-90 years (89,790 cases, 118,095 controls) and the elastic net algorithm, we developed a cross-validated model for predicting PD using only demographic data and 2004-2009 Medicare claims data. We then compared this model to more basic models containing only demographic data and diagnosis codes for constipation, taste/smell disturbance, and REM sleep behavior disorder, using each model's receiver operator characteristic area under the curve (AUC).

RESULTS

We observed all established associations between PD and age, sex, race/ethnicity, tobacco smoking, and the above medical conditions. A model with those predictors had an AUC of only 0.670 (95% confidence interval [CI] 0.668-0.673). In contrast, the AUC for a predictive model with 536 diagnosis and procedure codes was 0.857 (95% CI 0.855-0.859). At the optimal cut point, sensitivity was 73.5% and specificity was 83.2%.

CONCLUSIONS

Using only demographic data and selected diagnosis and procedure codes readily available in administrative claims data, it is possible to identify individuals with a high probability of eventually being diagnosed with PD.

Urinary Incontinence, Incident Parkinsonism, and Parkinson's Disease Pathology in Older Adults

OBJECTIVE

To test the hypothesis that urinary incontinence (UI) is associated with incident parkinsonism in older adults.

METHODS

We used data from 2,617 older persons without dementia. Assessment included baseline self-report UI and annual structured exam which assessed parkinsonian signs, motor performances, cognitive function, and self-report disabilities. We used a series of Cox proportional hazards models to examine the association of UI with parkinsonism and adverse health outcomes and a mixed-effect model to examine the association of UI with the annual rate of cognitive decline. In decedents, regression models were used to examine if UI proximate to death was related to postmortem indices of neuropathologies.

RESULTS

At baseline, more than 45% of participants reported some degree of UI. Over an average of nearly 8 years of follow-up, UI was associated with incident parkinsonism (hazard ratio [HR] = 1.07, 95% CI = 1.02, 1.12), death (HR = 1.07, 95% CI = 1.03, 1.11), incident ADL disability (HR = 1.11, 95% CI = 1.07, 1.16), and incident mobility disability (HR = 1.07, 95% CI = 1.02, 1.13). UI was not related to incident MCI (HR = 1.02, 95% CI = 0.97, 1.07), incident AD dementia (HR = 1.00, 95% CI = 0.95, 1.05) or to the rate of cognitive decline (Estimate = -.002, standard error = .002, p = .167). In 1,024 decedents with brain autopsy, UI proximate to death was related to PD pathology (Lewy body pathology and nigral neuronal loss), but not Alzheimer's disease pathology or other age-related neuropathologies.

CONCLUSION

UI in older adults is associated with incident parkinsonism and may identify older adults at risk for accumulating PD brain pathology.

The nasal and gut microbiome in Parkinson's disease and idiopathic rapid eye movement sleep behavior disorder

Background

Increasing evidence connects the gut microbiota and the onset and/or phenotype of Parkinson's disease (PD). Differences in the abundances of specific bacterial taxa have been reported in PD patients. It is, however, unknown whether these differences can be observed in individuals at high risk, for example, with idiopathic rapid eye movement sleep behavior disorder, a prodromal condition of α‐synuclein aggregation disorders including PD.

Objectives

To compare microbiota in carefully preserved nasal wash and stool samples of subjects with idiopathic rapid eye movement sleep behavior disorder, manifest PD, and healthy individuals.

Methods

Microbiota of flash‐frozen stool and nasal wash samples from 76 PD patients, 21 idiopathic rapid eye movement sleep behavior disorder patients, and 78 healthy controls were assessed by 16S and 18S ribosomal RNA amplicon sequencing. Seventy variables, related to demographics, clinical parameters including nonmotor symptoms, and sample processing, were analyzed in relation to microbiome variability and controlled differential analyses were performed.

Results

Differentially abundant gut microbes, such as Akkermansia, were observed in PD, but no strong differences in nasal microbiota. Eighty percent of the differential gut microbes in PD versus healthy controls showed similar trends in idiopathic rapid eye movement sleep behavior disorder, for example, Anaerotruncus and several Bacteroides spp., and correlated with nonmotor symptoms. Metagenomic sequencing of select samples enabled the reconstruction of genomes of so far uncharacterized differentially abundant organisms.

Conclusion

Our study reveals differential abundances of gut microbial taxa in PD and its prodrome idiopathic rapid eye movement sleep behavior disorder in comparison to the healthy controls, and highlights the potential of metagenomics to identify and characterize microbial taxa, which are enriched or depleted in PD and/or idiopathic rapid eye movement sleep behavior disorder. © 2017 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Merging Clinical and Imaging Biomarkers to Tackle Parkinson's Disease

Background

In Parkinson's disease, biomarkers represent tools that are potentially suitable for either clinical or research settings and are useful in predicting onset, confirming diagnosis, detecting progression, and evaluating response to potential disease-modifying treatments. The range of available biomarkers in Parkinson's disease is fast expanding and includes an increasing amount of laboratory, clinical, and imaging data. Indeed, the latter 2 represent the cornerstones of the diagnostic criteria for Parkinson's disease recently proposed by the International Parkinson and Movement Disorders Society Task Force on the definition of Parkinson's disease.

Methods and Results

In this review, we describe current knowledge and emerging findings on clinical (with emphasis on nonmotor symptoms) and imaging biomarkers for Parkinson's disease, with a focus on prodromal, diagnostic, and middle/advanced phases.

Conclusion

An increasing body of evidence suggests that merging clinical and imaging biomarkers through disease stages may be the best, fastest track to tackle Parkinson's disease.

Clinical Significance of REM Sleep Behavior Disorders and Other Non-motor Symptoms of Parkinsonism

Rapid eye movement sleep behavior disorder (RBD) is one of the most common non-motor symptoms of parkinsonism, and it may serve as a prodromal marker of neurodegenerative disease. The mechanism underlying RBD is unclear. Several prospective studies have reported that specific non-motor symptoms predict a conversion risk of developing a neurodegenerative disease, including olfactory dysfunction, abnormal color vision, autonomic dysfunction, excessive daytime sleepiness, depression, and cognitive impairment. Parkinson's disease (PD) with RBD exhibits clinical heterogeneity with respect to motor and non-motor symptoms compared with PD without RBD. In this review, we describe the main clinical and pathogenic features of RBD, focusing on its association with other non-motor symptoms of parkinsonism.

Premotor Diagnosis of Parkinson's Disease

Typical Parkinsonian symptoms consist of bradykinesia plus rigidity and/or resting tremor. Some time later postural instability occurs. Pre-motor symptoms such as hyposmia, constipation, REM sleep behavior disorder and depression may antecede these motor symptoms for years. It would be ideal, if we had a biomarker which would allow to predict who with one or two of these pre-motor symptoms will develop the movement disorder Parkinson's disease (PD). Thus, it is interesting to learn that biopsies of the submandibular gland or colon biopsies may be a means to predict PD, if there is a high amout of abnormally folded alpha-synuclein and phosphorylated alpha-synuclein. This would be of relevance if we would have available means to stop the propagation of abnormal alpha-synuclein which is otherwise one of the reasons of this spreading disease PD.

Nonmotor Subtyping in Parkinson's Disease

Nonmotor symptoms are integral to Parkinson's disease. Several subtypes dominated by specific nonmotor symptoms have emerged. In this chapter, the rationale behind nonmotor subtyping and currently proposed nonmotor subgroups within Parkinson's disease based on data-driven cluster analysis and clinical observations will be summarized. Furthermore, the concept of seven clinical nonmotor subtypes will be discussed in detail including the clinical presentation, potential biomarkers, and the clinical relevance. In future, nonmotor subtypes will possibly play a major role within the aim to achieve personalized medicine.

Nicotine from cigarette smoking and diet and Parkinson disease: a review

Evidence from epidemiological studies suggest a relationship between cigarette smoking and low risk of Parkinson disease (PD). As a major component of tobacco smoke, nicotine has been proposed to be a substance for preventing against PD risk, with a key role in regulating striatal activity and behaviors mediated through the dopaminergic system. Animal studies also showed that nicotine could modulate dopamine transmission and reduce levodopa-induced dyskinesias. However, previous clinical trials yield controversial results regarding nicotine treatment. In this review, we updated epidemiological, preclinical and clinical data, and studies on nicotine from diet. We also reviewed interactions between genetic factors and cigarette smoking. As a small amount of nicotine can saturate a substantial portion of nicotine receptors in the brain, nicotine from other sources, such as diet, could be a promising therapeutic substance for protection against PD.

Neuropathology of Nonmotor Symptoms of Parkinson's Disease

Parkinson's disease (PD), a multiorgan neurodegenerative disorder associated with α-synuclein deposits throughout the nervous system and many organs, is clinically characterized by motor and nonmotor features, many of the latter antedating motor dysfunctions by 20 or more years. The causes of the nonmotor manifestations such as olfactory, autonomic, sensory, neuropsychiatric, visuospatial, sleep, and other disorders are unlikely to be related to single lesions. They are mediated by the involvement of both dopaminergic and nondopaminergic systems, and diverse structures outside the nigrostriatal system that is mainly responsible for the motor features of PD. The nonmotor alterations appear in early/prodromal stages of the disease and its further progression, suggesting a topographical and chronological spread of the lesions. This lends further support for the notion that PD is a multiorgan proteinopathy, although the exact relationship between presymptomatic and later developing nonmotor features of PD and neuropathology awaits further elucidation.

The Epidemiology of Nonmotor Symptoms in Parkinson's Disease (Cohort and Other Studies)

Nonmotor symptoms (NMS) of Parkinson's disease (PD) were recognized by James Parkinson himself and are now considered to be an integral part of PD. While clinical assessment had focused on prevalence and severity of individual NMS such as dementia and depression, work in the last decade has concentrated on global or holistic assessment of NMS using validated tools such as the NMS questionnaire and NMS scale. These studies from cohorts of varying sizes have allowed comparison of NMS across different disease stages, duration, age, and ethnicity in PD. The data also allow exploration of the concept of the nonlinear relationship of NMS to disease duration of PD and motor stages as well as nonmotor subtypes of PD. In this chapter, these aspects of epidemiological studies of NMS in PD cohorts are described.

Premotor symptoms and the risk of Parkinson's disease: A case-control study in Mexican population

OBJECTIVES

To assess the prevalence of pre-motor symptoms and estimate the risk for developing Parkinson's disease in Mexican population.

PATIENTS AND METHODS

A case-control study was carried out with consecutive subjects with Parkinson's disease from two different referral centers in Mexico. Gender- and age-matched controls were randomly selected from the participating hospitals. All subjects were assessed using a structured questionnaire for the assessment of pre-motor symptoms (hyposmia, depression, anxiety, constipation, and sleep disorders). Odds ratios (OR) were calculated using logistic regression analysis.

RESULTS

A total of 430 subjects with PD and 430 healthy subjects were included. Premotor symptoms prevalence was 77.7% (n=334) for the PD group, compared to 41.3% (n=178) in the control group (p<0.001). After logistic multivariate analysis, previous history of hyposmia (OR 2.02 [95% CI 1.33-3.06]), depression (OR 2.52 [95% CI 1.67-3.84]), anxiety (OR 4.37 [95% CI 2.73-6.98]) and sleep disorders (OR 2.03 [95% CI 1.41-2.93]) were independently associated with Parkinson's disease. Overall prediction success of the model was 81.2% for controls and 61.2% for subjects with PD.

CONCLUSION

All five premotor symptoms assessed were more commonly reported in PD subjects than healthy controls. The presence of non-motor symptoms yield a prediction success of 71.2% to discriminate between PD subjects and healthy controls.

Non-motor features of Parkinson disease

Many of the motor symptoms of Parkinson disease (PD) can be preceded, sometimes for several years, by non-motor symptoms that include hyposmia, sleep disorders, depression and constipation. These non-motor features appear across the spectrum of patients with PD, including individuals with genetic causes of PD. The neuroanatomical and neuropharmacological bases of non-motor abnormalities in PD remain largely undefined. Here, we discuss recent advances that have helped to establish the presence, severity and effect on the quality of life of non-motor symptoms in PD, and the neuroanatomical and neuropharmacological mechanisms involved. We also discuss the potential for the non-motor features to define a prodrome that may enable the early diagnosis of PD.

Nonmotor Aspects of Parkinson's Disease-How Do They Help Diagnosis?

Not only are nonmotor aspects of Parkinson's disease important because of their impact, they also can help diagnose Parkinson's. This chapter summarizes the ways in which recognition of the nonmotor profile of Parkinson's can help in clinical diagnosis. It also emphasizes the essential role that nonmotor Parkinson's disease plays in the diagnosis of prodromal stages of disease.

Biomarkers of Parkinson's Disease: An Introduction

The development of biomarkers is of great importance in Parkinson's disease (PD) as it may contribute to confirmation and support of the diagnosis, tracking of progression, and prediction of the natural history of PD. Biomarkers also help in the identification of targets for treatment and measuring the efficacy of interventions. Biomarkers are, therefore, crucial to understanding the pathophysiology of PD, the second commonest neurodegenerative disorder in the world. Modern understanding of PD suggests that it is a multipeptide, multiorgan disorder presenting with a heterogeneous clinical condition, both motor and nonmotor. Biomarkers need to reflect this neuropathological and clinical heterogeneity of PD. In this review, we outline some key advances in the field of clinical, genetic, neuroimaging, and tissue-based biomarkers proposed or used for PD. The individual sections will be covered in relevant chapters and our review is largely a primer aimed to alert readers to the current state of the various biomarkers proposed for PD. In doing so, we have also underlined the important role multimodal rather than single biomarkers could play in our future understanding of PD.

Pain perception in Parkinson's disease: A systematic review and meta-analysis of experimental studies

While hyperalgesia (increased pain sensitivity) has been suggested to contribute to the increased prevalence of clinical pain in Parkinson's disease (PD), experimental research is equivocal and mechanisms are poorly understood. We conducted a meta-analysis of studies comparing PD patients to healthy controls (HCs) in their response to experimental pain stimuli. Articles were acquired through systematic searches of major databases from inception until 10/2016. Twenty-six studies met inclusion criteria, comprising 1292 participants (PD=739, HCs=553). Random effects meta-analysis of standardized mean differences (SMD) revealed lower pain threshold (indicating hyperalgesia) in PD patients during unmedicated OFF states (SMD=0.51) which was attenuated during dopamine-medicated ON states (SMD=0.23), but unaffected by age, PD duration or PD severity. Analysis of 6 studies employing suprathreshold stimulation paradigms indicated greater pain in PD patients, just failing to reach significance (SMD=0.30, p=0.06). These findings (a) support the existence of hyperalgesia in PD, which could contribute to the onset/intensity of clinical pain, and (b) implicate dopamine deficiency as a potential underlying mechanism, which may present opportunities for the development of novel analgesic strategies.

The PRIAMO study: urinary dysfunction as a marker of disease progression in early Parkinson's disease

BACKGROUND AND PURPOSE

New venues are currently being explored to predict disease progression in Parkinson's disease (PD), such as non-motor subtypes and models merging motor and non-motor symptoms (NMS). By involving a subgroup of 585 patients from the PRIAMO (Parkinson Disease Non-motor Symptoms) study, the present 24-month longitudinal prospective analysis aimed to demonstrate that urinary dysfunction is an early marker of higher motor and non-motor burden as well as lower health-related quality of life.

METHODS AND RESULTS

Multivariable mixed-effect logistic regression models controlling for demographic and clinical variables showed that the following NMS domains were associated with urinary dysfunction: gastrointestinal [odds ratio (OR) 2.57, 95% confidence interval (CI) 1.67-3.97, P < 0.001], cardiovascular (OR 2.22, 95% CI 1.18-4.17, P = 0.013), skin (OR 1.81, 95% CI 1.06-3.08, P = 0.029), sleep (OR 2.06, 95% CI 1.34-3.16, P = 0.001), pain (OR 1.85, 95% CI 1.21-2.83, P = 0.004), fatigue (OR 2.40, 95% CI 1.56-3.68, P < 0.001), apathy (OR 2.79, 95% CI 1.72-4.52, P < 0.001) and respiratory (OR 1.82, 95% CI 1.02-3.23, P = 0.039). Analysis also demonstrated that urinary dysfunction was associated with higher motor disability (coefficient 1.73, 95% CI 0.68-2.78, P = 0.001) and lower health-related quality of life (coefficient -0.05, 95% CI -0.08 to -0.02, P < 0.001, and coefficient -3.49, 95% CI -5.21 to -1.77, P < 0.001) but not with more severe cognitive disability (coefficient -0.34, 95% CI -0.92 to 0.24, P = 0.251).

CONCLUSIONS

This is the first prospective longitudinal study involving a large cohort of PD patients demonstrating the relevance of urinary dysfunction as an early marker of higher motor and non-motor disability as well as lower health-related quality of life. These findings support a role for urinary dysfunction as an early marker of more severe disease progression.

Tobacco Use, Oral Health, and Risk of Parkinson's Disease

Few studies have investigated the associations between use of Swedish moist snuff (snus), associated poor oral health, and risk of Parkinson's disease (PD). We followed 20,175 participants who were free of PD in 1973-1974 in Uppsala, Sweden, until the end of 2012. We used Cox proportional hazards regression models to estimate hazard ratios and corresponding 95% confidence intervals for the associations between tobacco use, oral health indicators, and PD risk. We found that tobacco use was associated with a lower risk of PD in males. Compared with males who never used any tobacco daily, pure ever tobacco smokers, pure ever snus users, and combined users had adjusted hazard ratios of 0.68 (95% confidence interval (CI): 0.49, 0.93; n = 83), 0.51 (95% CI: 0.27, 0.95; n = 11), and 0.21 (95% CI: 0.07, 0.67; n = 3), respectively. No association was observed for number of teeth, dental plaque, or detectable oral mucosal lesions and PD risk, although there was a suggestive association with Candida-related oral mucosal lesions in males (hazard ratio = 1.56, 95% CI: 0.92, 2.65; P = 0.098). Use of snus is associated with a lower risk of PD in males, while poor oral health seems not to be associated with PD occurrence.

Insomnia and somnolence in idiopathic RBD: a prospective cohort study

Although some sleep disorders are markers of prodromal Parkinson's disease and dementia with Lewy bodies, it is unclear whether insomnia and somnolence can predict disease. We assessed a large cohort of patients with idiopathic rapid eye movement sleep behavior disorder and age/sex matched controls, comparing the Epworth sleepiness scale, the Insomnia Severity Index, the Pittsburgh Sleep Quality Index, and polysomnographic variables. In those with repeated scales, we assessed change over time. Finally, we assessed whether sleep abnormalities predicted defined neurodegenerative disease. The 151 patients (age = 65.9, 75% male) completed sleep scales and were included. Epworth scores were similar between patients and controls (7.0+/-4.6 vs. 7.2+/-4.7, p = 0.77), and did not progress with time (change = +0.46+/-2.1, p = 0.45). Epworth scores were similar between those who developed neurodegenerative disease and those remaining disease-free (6.7+/-4.4 vs. 7.1+/-4.7, p = 0.70). Pittsburgh Index scores were higher in patients than controls (7.2+/-3.8 vs. 4.9+/-3.4, p = 0.004), mainly driven by the sleep disturbance/medication components (reflecting rapid eye movement sleep behavior disorder symptoms/treatment). Baseline Pittsburgh scores did not predict conversion to neurodegeneration, although sleep duration increased over time in those converting to neurodegenerative disease (+0.88+/-1.32 h, p = 0.014). Insomnia index scores were higher in patients than controls (10.0+/-5.5 vs. 6.35+/-4.66, p < 0.001), but declined over time (-1.43+/-5.09, p = 0.029) particularly in those converting to neurodegenerative disease. Finally, on polysomnogram, those with increased tonic rapid eye movement had higher risk of developing defined neurodegenerative disease (HR = 1.88, p = 0.039). In summary, we found that somnolence and insomnia do not predict neurodegeneration in idiopathic rapid eye movement sleep behavior disorder. As neurodegeneration progresses through prodromal stages, patients may have increasing sleep drive and duration.

Serotonin and dopamine transporter PET changes in the premotor phase of LRRK2 parkinsonism: cross-sectional studies

Background

Patients with Parkinson’s Disease (PD) may exhibit premotor neurochemical changes in dopaminergic (DA) and nondopaminergic systems. Using positron emission tomography (PET), we studied participants with leucine-rich repeat kinase 2 (LRRK2) mutations and with sporadic PD to assess whether DA and serotonin transporter (SERT) changes were similar in LRRK2 PD and sporadic PD, and whether asymptomatic LRRK2 mutation carriers exhibited PET changes in the absence of motor symptoms.

Methods

Between July 1999 and May 2016, we did two cross sectional PET studies at the Pacific Parkinson’s Research Centre (Vancouver, Canada) with LRRK2 mutation carriers with or without manifest PD, patients with sporadic PD, and age-matched healthy controls, all aged 18 years or older. Patients with PD were diagnosed by a neurologist with movement disorder training in accordance with the UK Parkinson’s Disease Society Brain Bank criteria. LRRK2 carrier status was confirmed by bi-directional Sanger sequencing. First, affected and unaffected LRRK2 carriers seen from July 1999 to January 2012 were imaged with PET tracers for the membrane dopamine transporter (DAT) and dopamine synthesis and storage (¹⁸F-6-fluoro-L-dopa; FDOPA) and compared with sporadic PD and age-matched healthy controls. Second, distinct groups of LRRK2 mutation carriers, sporadic PD patients, and age-matched healthy controls seen from November 2012 to May 2016 were studied with tracers for the SERT and vesicular monoamine transporter 2 (VMAT2). Striatal DAT binding, DTBZ binding, FDOPA uptake and SERT binding in multiple brain regions were compared using analysis of covariance adjusted for age.

Findings

Using data from 40 LRRK2 mutation carriers, 63 patients with sporadic PD, and 35 controls, we identified significant group differences in striatal DAT binding (all age ranges p<0·0001 in caudate and putamen) and FDOPA uptake (age 50 or lower in caudate, p=0·0002; all other age ranges p<0·0001; in putamen, all age ranges p<0·0001). Affected LRRK2 mutation carriers (n=15) had reduced striatal DAT binding and FDOPA uptake, comparable to sporadic PD of similar duration. Unaffected carriers (n=25) had greater FDOPA uptake and DAT binding than sporadic PD (n=63), with FDOPA uptake comparable to and DAT binding lower than healthy controls. Unaffected LRRK2 carriers (n=9) had significantly elevated SERT binding in hypothalamus (greater than healthy controls, 7 LRRK2 PD and 13 sporadic PD subjects; p<0·0001), striatum (greater than sporadic PD; p=0·02) and brainstem (greater than affected LRRK2 carriers; p=0·01) after adjustment for age. SERT binding in cortex was not significantly different between groups after age adjustment. Striatal DTBZ binding was reduced in all affected patients and asymmetrically reduced in one unaffected carrier.

Interpretation

Dopaminergic and serotonergic changes progress in a similar fashion in LRRK2 PD and sporadic PD, but unaffected LRRK2 mutation carriers exhibit increased SERT binding in striatum, brainstem and hypothalamus, possibly reflecting compensatory changes in serotonergic innervation preceding the motor onset of PD.

Funding

Canada Research Chairs, Michael J. Fox Foundation, National Institutes of Health, Pacific Alzheimer Research Foundation, Pacific Parkinson’s Research Institute, National Research Council of Canada

Associations between Early Markers of Parkinson's Disease and Sarcopenia

Introduction: Sarcopenia and Parkinson's disease (PD) are both common age-related syndromes, and there is preliminary evidence that the probability of the co-occurrence of these syndromes within one individual is higher than expected. However, it is unclear to date whether one of the syndromes induces the other, or whether there may be common underlying causes. This pilot study thus aimed at investigating the association of the features of increased risk for PD with early stage sarcopenia (ESS). Method: Two hundred and fifty-five community-dwelling individuals were recruited from the Tübinger evaluation of Risk factors for Early detection of NeuroDegeneration (TREND) study. The following features that are associated with an increased risk for future PD were evaluated: the motor part of the Unified PD Rating Scale (UPDRS-III), hyperechogenicity of the substantia nigra, prevalence of lifetime depression, hyposmia, REM sleep behavior disorder and the recently introduced probability score for prodromal PD. Sarcopenia was defined according to the European Working Group on Sarcopenia in Older People, which was adapted to this cohort of healthy adults. Multiple linear regression analysis was used to identify associations of PD-related features with ESS. Results: The UPDRS-III score was significantly associated with ESS. The result remained significant after the adjustment for age, gender and physical activity. No association was found between the other PD-related features and ESS. Conclusion: The significant association of the UPDRS-III score with ESS in this cohort might indicate a common and early pathway in both diseases and supports the existence of an "extended neurodegenerative overlap syndrome." Moreover, the potential of EES to serve as a prodromal marker of PD should be evaluated in future studies.

Subtle motor disturbances in PREDICT-PD participants

OBJECTIVE

The PREDICT-PD study aims to identify increased risk of Parkinson''s disease (PD) using online assessments of previously identified risk and early features of PD and an evidence-based scoring algorithm. We sought to determine whether higher risk participants (defined as those above the 15th centile of risk estimates) were more likely to have mild parkinsonian signs compared with lower risk participants.

METHODS

Video recordings of neurological examinations, including the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III, of 208 individuals who had previously completed an online risk assessment were scored blindly and independently by two movement-disorders experts. Higher risk and lower risk subjects were compared for MDS-UPDRS part III score (and derivations of this) to identify subclinical parkinsonism, and association of risk estimates with MDS-UPDRS III scores assessed.

RESULTS

Higher risk subjects had significantly higher median UPDRS part III scores (3, IQR 1-5.5) than lower risk subjects (1, IQR 0-3.0; p<0.001), and there was a significantly greater proportion of individuals classified as having subclinical parkinsonism. 18% of the higher risk subjects and 6% of the lower risk subjects exceeded the most stringent published cut-off for subtle parkinsonism of three definitions examined (p=0.027). Linear regression analysis demonstrated a continuous relationship of log-transformed risk estimates with UPDRS part III scores (increase in MDS-UPDRS per doubling of odds 0.52, 95% CI 0.31 to 0.72; p<0.001), which remained after adjustment for multiple vascular risk factors and scores on the Montreal Cognitive Assessment (0.58, 95% CI 0.30 to 0.87; p<0.001).

CONCLUSIONS

The PREDICT-PD algorithm identifies a population with an increased rate of motor disturbances.

The underlying mechanism of prodromal PD: insights from the parasympathetic nervous system and the olfactory system

Neurodegeneration of Parkinson's disease (PD) starts in an insidious manner, 30-50% of dopaminergic neurons have been lost in the substantia nigra before clinical diagnosis. Prodromal stage of the disease, during which the disease pathology has started but is insufficient to result in clinical manifestations, offers a valuable window for disease-modifying therapies. The most focused underlying mechanisms linking the pathological pattern and clinical characteristics of prodromal PD are the prion hypothesis of alpha-synuclein and the selective vulnerability of neurons. In this review, we consider the two potential portals, the vagus nerve and the olfactory bulb, through which abnormal alpha-synuclein can access the brain. We review the clinical, pathological and neuroimaging evidence of the parasympathetic nervous system and the olfactory system in the neurodegenerative process and using the two systems as models to discuss the internal homogeneity and heterogeneity of the prodromal stage of PD, including both the clustering and subtyping of symptoms and signs. Finally, we offer some suggestions on future directions for imaging studies in prodromal Parkinson's disease.

Is increased spinal nociception another hallmark for Parkinson's disease?

Augmented spinal nociception during the "off" phase has been observed early in Parkinson's disease further increasing with disease duration. To find out whether increased spinal nociception represents a premotor feature, experimental pain sensitivity was assessed in idiopathic REM-sleep behavior disorder (IRBD) patients with or without signs of a neurodegenerative disorder compared to early Parkinson's disease (ePD) patients and healthy controls (HC). Spinal nociception as measured by the nociceptive flexion reflex (NFR) and experimental pain sensitivity as measured by heat and electrical pain thresholds were determined in 14 IRBD, 15 ePD patients in the medication-defined "off" state and 27 HC in an explorative cohort study. No significant differences between IRBD and HC were found with regard to spinal nociception (NFR) and experimental pain sensitivity. However, IRBD patient with anosmia and/or abnormal DaTSCAN tended to increased experimental pain sensitivity. In contrast, early PD patients exhibited increased NFR responses compared to HC, and a tendency for increased spinal nociception compared to IRBD patients. Increased spinal nociception may represent an early but not a premotor, non-motor feature of PD. Whether increased pain sensitivity already presents a premotor feature should be assessed in further studies.

PREDICT-PD: An online approach to prospectively identify risk indicators of Parkinson's disease

Background

A number of early features can precede the diagnosis of Parkinson's disease (PD).

Objective

To test an online, evidence‐based algorithm to identify risk indicators of PD in the UK population.

Methods

Participants aged 60 to 80 years without PD completed an online survey and keyboard‐tapping task annually over 3 years, and underwent smell tests and genotyping for glucocerebrosidase (GBA) and leucine‐rich repeat kinase 2 (LRRK2) mutations. Risk scores were calculated based on the results of a systematic review of risk factors and early features of PD, and individuals were grouped into higher (above 15th centile), medium, and lower risk groups (below 85th centile). Previously defined indicators of increased risk of PD (“intermediate markers”), including smell loss, rapid eye movement–sleep behavior disorder, and finger‐tapping speed, and incident PD were used as outcomes. The correlation of risk scores with intermediate markers and movement of individuals between risk groups was assessed each year and prospectively. Exploratory Cox regression analyses with incident PD as the dependent variable were performed.

Results

A total of 1323 participants were recruited at baseline and >79% completed assessments each year. Annual risk scores were correlated with intermediate markers of PD each year and baseline scores were correlated with intermediate markers during follow‐up (all P values < 0.001). Incident PD diagnoses during follow‐up were significantly associated with baseline risk score (hazard ratio = 4.39, P = .045). GBA variants or G2019S LRRK2 mutations were found in 47 participants, and the predictive power for incident PD was improved by the addition of genetic variants to risk scores.

Conclusions

The online PREDICT‐PD algorithm is a unique and simple method to identify indicators of PD risk. © 2017 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.