Identifying prodromal Parkinson's disease: pre-motor disorders in Parkinson's disease

Digital health revolution: perfect storm or perfect opportunity for pharmaceutical R&D?

The convergence of technology and medicine has pushed healthcare to the brink of a major disruption that pharma has, until recently, been slow to recognize. Tech players have pioneered the emerging field of digital wellness and health, and pharma is ideally placed to use its expertise in drug development and embrace these technologies to create digital applications that address major medical needs. This review describes digital innovation from a pharma R&D perspective, outlining principal drivers, digital components, opportunities and challenges as well as a sustainable new business model predicated on empowered patients and achieving therapeutic outcomes.

Evaluation of Nonmotor Symptoms in Diagnosis of Parkinsonism and Tremor

Background. Nonmotor symptoms particularly olfactory dysfunction, RBD, depression, hallucinations, and constipation are currently not included in the typical clinical criteria for diagnosing Lewy body Parkinsonian disorders (LBPD). The aim of this study is to determine the diagnostic value of nonmotor symptoms in patients presenting with Parkinsonism and tremor. Methods. All new patients seen between January 2007 and May 2013 in the Movement Disorders Specialist Clinics of the Royal Melbourne Hospital (RMH), who were referred with a possible neurodegenerative syndrome or concerns of Parkinsonism and/or tremor, were included. Patients underwent routine evaluation with the four-minute “Sniffin Sticks” test, RBD, depression, and constipation. Results. 291 patients were included in the analysis. Conclusion. We found that lower olfaction scores based on “Sniffin Sticks” testing combined with reports of depression and constipation are independent predictors for the diagnosis of the spectrum of Lewy body Parkinsonian disorders (LBPD). Parkinson's disease (PD) cannot be reliably clinically differentiated from other causes of Parkinsonism that share symptomatology and structural abnormalities.

The KMDS-NATION Study: Korean Movement Disorders Society Multicenter Assessment of Non-Motor Symptoms and Quality of Life in Parkinson's Disease NATION Study Group

Background and Purpose

Nonmotor symptoms (NMS) in Parkinson's disease (PD) have multisystem origins with heterogeneous manifestations that develop throughout the course of PD. NMS are increasingly recognized as having a significant impact on the health-related quality of life (HrQoL). We aimed to determine the NMS presentation according to PD status, and the associations of NMS with other clinical variables and the HrQoL of Korean PD patients.

Methods

We surveyed patients in 37 movement-disorders clinics throughout Korea. In total, 323 PD patients were recruited for assessment of disease severity and duration, NMS, HrQoL, and other clinical variables including demographics, cognition, sleep scale, fatigability, and symptoms.

Results

In total, 98.1% of enrolled PD subjects suffered from various kinds of NMS. The prevalence of NMS and scores in each NMS domain were significantly higher in the PD group, and the NMS worsened as the disease progressed. Among clinical variables, disease duration and depressive mood showed significant correlations with all NMS domains (p<0.001). NMS status impacted HrQoL in PD (rS=0.329, p<0.01), and the association patterns differed with the disease stage.

Conclusions

The results of our survey suggest that NMS in PD are not simply isolated symptoms of degenerative disease, but rather exert significant influences throughout the disease course. A novel clinical approach focused on NMS to develop tailored management strategies is warranted to improve the HrQoL in PD patients.

α-Synuclein and nonhuman primate models of Parkinson's disease

Accumulation of α-synuclein (α-syn) leading to the formation of insoluble intracellular aggregates named Lewy bodies is proposed to have a significant role in Parkinson's disease (PD) pathology. Nonhuman primate (NHP) models of PD have proven essential for understanding the neurobiological basis of the disease and for the preclinical evaluation of first-in-class and invasive therapies. In addition to neurotoxin, aging and intracerebral gene transfer models, a new generation of models using inoculations of α-syn formulations, as well as transgenic methods is emerging. Understanding of their advantages and limitations will be essential when choosing a platform to evaluate α-syn-related pathology and interpreting the test results of new treatments targeting α-syn aggregation. In this review we aim to provide insight on this issue by critically analyzing the differences in endogenous α-syn, as well as α-syn pathology in PD and PD NHP models.

Autonomic dysfunction in subjects at high risk for Parkinson's disease

Aim of this project was to evaluate autonomic dysfunction in subjects proposed to be at high risk to develop Parkinson's disease (PD) compared to control subjects and PD patients at different disease stages. Combinations of substantia nigra hyperechogenicity (SN+) assessed by transcranial ultrasound (TCS), hyposmia, lifetime prevalence of depression and mild PD-specific motor signs were used to identify subjects at high risk for motor Parkinson's disease (HR-PD). Supine and standing blood pressure (BP), hearth rate (HR), orthostatic, urinary, sexual and bowel symptoms were evaluated in HR-PD, healthy control subjects and PD patients, divided into mild and advanced stages. The study group consisted of 113 PD patients (mild PD n = 71, advanced PD, n = 42), 40 HR-PD individuals and 50 controls. Compared to controls, HR-PD subjects complained more often about urinary (p = 0.002) and bowel dysfunction (p = 0.001) and had a higher diastolic BP drop after standing (p = 0.01). The cumulative number of autonomic symptoms differentiated PD as well as HR-PD significantly from controls (p < 0.001). Advanced PD patients presented often and severe orthostatic symptoms, not significantly different from mild PD after concomitant medication correction. Our results support the presence of urinary and bowel dysfunction in subjects at high risk for motor PD. Presence and severity of orthostatic symptoms was higher during stages and increase in advanced stages, at least partly due to increase in dopaminergic and conflicting medication. Understanding the progression of non-motor aspects in PD might offer the possibility to use them as targets for disease-modifying therapies.

REM sleep behavior disorder, as assessed by questionnaire, in G2019S LRRK2 mutation PD and carriers

BACKGROUND

Rapid eye movement sleep behavior disorder occurs with idiopathic Parkinson's disease (PD) and often precedes PD. Its frequency in LRRK2-PD and utility as a preclinical marker has not been established.

METHODS

One hundred forty-four idiopathic PD, 142 LRRK2 G2019S mutation PD, 117 non-manifesting carriers, 93 related noncarriers, and 40 healthy controls completed the Rapid eye movement sleep Behavior Disorder Screening Questionnaire.

RESULTS

Cut scores were met by 30.6% idiopathic PD, 19.7% LRRK2-PD, 6% nonmanifesting carriers, 20.4% related noncarriers, and 15% controls. The likelihood of abnormal scores was decreased in LRRK2-PD versus idiopathic PD (odds ratio = 0.55, P = 0.03), nonmanifesting carriers versus related noncarriers (OR = 0.25, P < 0.01), and PD of less than 3 years' duration, 1 of 19 LRRK2-PD versus 14 of 41 idiopathic PD (P < 0.05).

CONCLUSIONS

A lower frequency of abnormal questionnaire scores is seen in LRRK2-PD, especially in early LRRK2-PD, and in nonmanifesting carriers. Therefore, the Rapid eye movement sleep Behavior Disorder Questionnaire is unlikely to serve as a preclinical marker for phenoconversion to PD.

Diagnosis of Parkinson's disease on the basis of clinical and genetic classification: a population-based modelling study

BACKGROUND

Accurate diagnosis and early detection of complex diseases, such as Parkinson's disease, has the potential to be of great benefit for researchers and clinical practice. We aimed to create a non-invasive, accurate classification model for the diagnosis of Parkinson's disease, which could serve as a basis for future disease prediction studies in longitudinal cohorts.

METHODS

We developed a model for disease classification using data from the Parkinson's Progression Marker Initiative (PPMI) study for 367 patients with Parkinson's disease and phenotypically typical imaging data and 165 controls without neurological disease. Olfactory function, genetic risk, family history of Parkinson's disease, age, and gender were algorithmically selected by stepwise logistic regression as significant contributors to our classifying model. We then tested the model with data from 825 patients with Parkinson's disease and 261 controls from five independent cohorts with varying recruitment strategies and designs: the Parkinson's Disease Biomarkers Program (PDBP), the Parkinson's Associated Risk Study (PARS), 23andMe, the Longitudinal and Biomarker Study in PD (LABS-PD), and the Morris K Udall Parkinson's Disease Research Center of Excellence cohort (Penn-Udall). Additionally, we used our model to investigate patients who had imaging scans without evidence of dopaminergic deficit (SWEDD).

FINDINGS

In the population from PPMI, our initial model correctly distinguished patients with Parkinson's disease from controls at an area under the curve (AUC) of 0·923 (95% CI 0·900-0·946) with high sensitivity (0·834, 95% CI 0·711-0·883) and specificity (0·903, 95% CI 0·824-0·946) at its optimum AUC threshold (0·655). All Hosmer-Lemeshow simulations suggested that when parsed into random subgroups, the subgroup data matched that of the overall cohort. External validation showed good classification of Parkinson's disease, with AUCs of 0·894 (95% CI 0·867-0·921) in the PDBP cohort, 0·998 (0·992-1·000) in PARS, 0·955 (no 95% CI available) in 23andMe, 0·929 (0·896-0·962) in LABS-PD, and 0·939 (0·891-0·986) in the Penn-Udall cohort. Four of 17 SWEDD participants who our model classified as having Parkinson's disease converted to Parkinson's disease within 1 year, whereas only one of 38 SWEDD participants who were not classified as having Parkinson's disease underwent conversion (test of proportions, p=0·003).

INTERPRETATION

Our model provides a potential new approach to distinguish participants with Parkinson's disease from controls. If the model can also identify individuals with prodromal or preclinical Parkinson's disease in prospective cohorts, it could facilitate identification of biomarkers and interventions.

FUNDING

National Institute on Aging, National Institute of Neurological Disorders and Stroke, and the Michael J Fox Foundation.

Parkinson's disease: From human genetics to clinical trials

Combining genetic insights into the pathogenesis of Parkinson's disease (PD) with findings from animal and cellular models of this disorder has advanced our understanding of the pathways that lead to the characteristic degeneration of dopaminergic neurons in the brain's nigrostriatal pathway. This has fueled an increase in candidate compounds designed to modulate these pathways and to alter the processes underlying neuronal death in this disorder. Using mitochondrial quality control and the macroautophagy/lysosomal pathways as examples, we discuss the pipeline from a comprehensive genetic architecture for PD through to clinical trials for drugs targeting pathways linked to neurodegeneration in PD. We also identify opportunities and pitfalls on the road to a clinically effective disease-modifying treatment for this disease.

[Identification of people at the latent stage of Parkinson's disease (the PARKINLAR study): first results and an optimization of the algorithm]

AIM

To work out an optimal algorithm to identify people at the latent stage of neurodegenerative process of «parkinsonian» type in the Russian population.

MATERIAL AND METHODS

Authors launched a two-step study aimed at identifying people at the latent stage of Parkinson's disease (PD) in the Russian population - the PARKINLAR (PARKINsonism, LAtent stage, Russia). As the first step, we formed a group of «primary risk» by the identification in neurologically healthy people of at least one of the following confirmed PD risk factors: a) the substantia nigra hyperechogenicity (ultrasound screening was performed in 193 people); b) mutations in «parkinsonian» genes (genetic screening was performed in 29 relatives of PD patients from families with LRRK2, PARK2 and GBA mutations). Thereby, 37 people comprised the «primary risk» group, of whom 23 agreed to continue further examination (44±10.2 years). A matched group of people without the aforementioned primary biomarkers of PD served as control. As the second step, we undertook in the prescreened groups a complex of investigations assessing the presence of secondary («minor») biomarkers of PD: Sniffin' Sticks olfactory testing; color visual evoked potentials; analysis of goal-directed eye-head-hand movements with the use of a special neuro-cybernetic system; assessment of motor and non-motor symptoms with the use of UPDRS and NMSS scales.

RESULTS

When comparing the «primary risk» group with controls, maximal differences in the occurrence of symptoms were seen for goal-directed eye movements (43.5% vs. 20.0%) and color vision (39.1% vs. 26.7%). Among these individuals, we found two people with 4 secondary biomarkers and one with 3, and no such observations in controls. People with the combination of a primary biomarker with several secondary biomarkers of PD comprised a group of «high risk» in our study.

CONCLUSION

Optimization of this algorithm of population screening of people predisposed to the development of PD may be done by expanding the spectrum of biomarkers and assessing their validity in a long-term prospective observational study.

Parkinson's disease

Parkinson's disease is a neurological disorder with evolving layers of complexity. It has long been characterised by the classical motor features of parkinsonism associated with Lewy bodies and loss of dopaminergic neurons in the substantia nigra. However, the symptomatology of Parkinson's disease is now recognised as heterogeneous, with clinically significant non-motor features. Similarly, its pathology involves extensive regions of the nervous system, various neurotransmitters, and protein aggregates other than just Lewy bodies. The cause of Parkinson's disease remains unknown, but risk of developing Parkinson's disease is no longer viewed as primarily due to environmental factors. Instead, Parkinson's disease seems to result from a complicated interplay of genetic and environmental factors affecting numerous fundamental cellular processes. The complexity of Parkinson's disease is accompanied by clinical challenges, including an inability to make a definitive diagnosis at the earliest stages of the disease and difficulties in the management of symptoms at later stages. Furthermore, there are no treatments that slow the neurodegenerative process. In this Seminar, we review these complexities and challenges of Parkinson's disease.

Qualitative Characteristics of Depression in Parkinson's Patients and Controls

BACKGROUND

Depression is common in Parkinson's disease (PD); in light of typical PD pathology it may differ phenomenologically from depression in the general population.

OBJECTIVE

To assess depressive symptoms in PD patients and control groups and compare symptom profiles.

METHODS

After postal screening of 10,000 citizens of Lübeck, 642 participants were examined and the Beck Depression Inventory (BDI) was sufficiently answered by 477 subjects. Based on motor examinations, we distinguished PD patients, Healthy Controls (HC, no motor impairment), and Disease Controls (DC, motor impairment other than PD).

RESULTS

The sample comprised 331 men and 311 women, aged 65 ± 8 years. Out of the overall sample, 198 (41.5%) had a BDI score ≥9. BDI results above 9 points occurred in 34.5% of HC, 50.3% of DC, and 42.4% of PD patients. Compared to the control groups (HC, DC) the PD patients endorsed more "dissatisfaction" and "loss of appetite" but less "feelings of guilt," "self-hate," and "loss of libido."

CONCLUSION

Depressive symptoms are more frequent in PD patients compared to HC but not DC. Interestingly, the distribution of individual symptoms of the BDI differs between groups with an emphasis on loss of pleasure/enjoyment in the PD group, a symptom typically considered to be dopaminergically transmitted.

Clinical and imaging markers in premotor LRRK2 G2019S mutation carriers

BACKGROUND

Substantia nigra hyperechogenicity (SN+) has been proposed as a risk marker of Parkinson's disease (PD). Asymptomatic LRRK2 mutation carriers (aLRRK2+), at high risk for developing PD, provide an opportunity for the study of preclinical biomarkers.

OBJECTIVE

To assess SN echogenicity and other echographic features in LRRK2 G2019S carriers and their clinical and imaging correlates.

METHODS

Transcranial sonography was performed in 26 LRRK2 G2019S PD patients, 50 first-degree relatives, 31 idiopathic PD (IPD) patients and 26 controls. SN echogenicity and other echographic features were assessed in all study subjects. Dopamine transporter imaging (DAT-SPECT) was performed in 29 first-degree relatives.

RESULTS

75% of the LRRK2-PD and 87.5% of the IPD showed SN+ (p = 0.087). aLRRK2+ had a higher frequency of SN+ than non carriers (58.3% vs. 25%, p = 0.039) and controls (58.3% vs. 12.5%; p = 0.002) and had a larger area of SN echogenicity than non carriers (p = 0.030) and controls (p < 0.001). The width of the third ventricle was significantly lower in LRRK2-PD than in IPD (1.9 mm [1.38; 2.75] vs. 3.0 mm [2.3; 5.3]; p = 0.003). Four out of 5 (80%) of the aLRRK2+ with an abnormal DAT-SPECT and four of the 5 (80%) of those with REM sleep behaviour disorder (RBD) had SN+.

CONCLUSIONS

SN+ is very frequent in LRRK2-PD and aLRRK2+. Most aLRRK2 with possible surrogate markers of PD such as abnormal DAT-SPECT or RBD, also had SN+, which supports that this echofeature might be a marker of PD in these asymptomatic population.

Probable RBD and association with neurodegenerative disease markers: A population-based study

BACKGROUND

The prevalence of rapid eye movement sleep behavior disorder (RBD) and its association with markers of neurodegeneration in the general population are poorly defined.

METHODS

We assessed the prevalence of probable RBD defined by two validated questionnaires, the RBD Screening Questionnaire (RBDSQ) and the Innsbruck RBD-Inventory (RBD-I), and studied its associations with clinical and imaging markers for neurodegeneration in the Bruneck Study cohort aged 60 y or older.

RESULTS

Of the 456 participants without Parkinson's disease, 4.6% (RBDSQ; 95%CI, 3.0%-7.0%) and 7.7% (RBD-I; 95%CI, 5.6%-10.5%) had probable RBD. Probable RBD diagnosed with either of the questionnaires was associated with hyposmia (trend; P < 0.1), anxiety (P < 0.05), depression (P < 0.05), antidepressant use (P < 0.05), and self-reported non-motor symptoms (P < 0.01), specifically, dribbling saliva, memory problems, apathy, concentration problems, and anxiety.

CONCLUSIONS

Our findings may provide a basis for future studies intending to identify cohorts at risk for Lewy body diseases through screening of the general elderly population for RBD.

Clinical phenotype of drug-naïve Parkinson's disease based on nonmotor symptoms

BACKGROUND

Nonmotor symptoms in Parkinson's disease (PD) are heterogeneous and can result in a variety of symptoms at various disease stages. The objective of the present study was to identify clinically meaningful nonmotor symptoms and to assess the relationship between changes in nonmotor symptoms and cognition and motor symptoms.

METHODS

A total of 159 patients who had drug-naïve PD participated in this study. Nonmotor symptoms (Nonmotor Symptoms Scale), PD status (Unified Parkinson's Disease Rating Scale), depression (Geriatric Depression Scale or Montgomery-Asberg Depression Scale) and health-related quality of life (39-item Parkinson's Disease Questionnaire) were assessed. An exploratory factor analysis was performed to establish a nonmotor symptom factor, which was analyzed to evaluate whether the results were associated with the clinical severity measures.

RESULTS

Exploratory factor analysis revealed one factor comprised of sleep/fatigue, attention/memory and mood/cognition. The modified Hoehn and Yahr Stage, Unified Parkinson's Disease Rating Scale Part III, Montgomery-Asberg Depression Scale and the 39-item Parkinson's Disease Questionnaire Summary Index were independently associated with the sleep/fatigue, attention/memory and mood/cognition domains. The presence of these domains was associated with advanced Parkinson's disease or depressed mood.

CONCLUSIONS

This study shows that motor impairment and depressed mood in PD are related to sleep/fatigue, attention/memory and mood/cognition. Sleep/fatigue, attention/memory and mood/cognition also had a major impact on health-related quality of life. It is appropriate to identify patients with severe motor symptoms and depressed mood in order to signify the need to consider more detailed care and further assessment.

Correlates of excessive daytime sleepiness in de novo Parkinson's disease: A case control study

OBJECTIVE

This study was undertaken to determine the frequency and correlates of excessive daytime sleepiness in de novo, untreated Parkinson's disease (PD) patients compared with the matched healthy controls.

METHODS

Data were obtained from the Parkinson's Progression Markers Initiative, an international study of de novo, untreated PD patients and healthy controls. At baseline, participants were assessed with a wide range of motor and nonmotor scales, including the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS). Excessive daytime sleepiness was assessed based on the Epworth Sleepiness scale (ESS), with a cutoff of 10.

RESULTS

Four hundred twenty-three PD subjects and 196 healthy controls were recruited into the study. Mean ESS (min, max) score was 5.8 (0, 20) for the PD subjects and 5.6 (0, 19) for healthy controls (P = 0.54). Sixty-six (15.6%) PD subjects and 24 (12%) healthy controls had ESS of at least 10 (P = 0.28). No difference was seen in demographic characteristics, age of onset, disease duration, PD subtype, cognitive status, or utilization of sedatives between the PD sleepiness-positive versus the negative group. The sleepiness-positive group had higher MDS-UPDRS Part I and II but not III scores, and higher depression and autonomic dysfunction scores. Sleepiness was associated with a marginal reduction of A-beta (P = 0.05) but not alpha-synuclein spinal fluid levels in PD.

CONCLUSIONS

This largest case control study demonstrates no difference in prevalence of excessive sleepiness in subjects with de novo untreated PD compared with healthy controls. The only clinical correlates of sleepiness were mood and autonomic dysfunction. Ongoing longitudinal analyses will be essential to further examine clinical and biological correlates of sleepiness in PD and specifically the role of dopaminergic therapy.

Cognitive performance and neuropsychiatric symptoms in early, untreated Parkinson's disease

This study was undertaken to determine the prevalence and correlates of cognitive impairment (CI) and neuropsychiatric symptoms (NPS) in early, untreated patients with Parkinson's disease (PD).

BACKGROUND

Both CI and NPS are common in PD and impact disease course and quality of life. However, limited knowledge is available about cognitive abilities and NPS.

METHODS

Parkinson's Progression Markers Initiative (PPMI) is a multi-site study of early, untreated PD patients and healthy controls (HCs), the latter with normal cognition. At baseline, participants were assessed with a neuropsychological battery and for symptoms of depression, anxiety, impulse control disorders (ICDs), psychosis, and apathy.

RESULTS

Baseline data of 423 PD patients and 196 HCs yielded no between-group differences in demographic characteristics. Twenty-two percent of PD patients met the PD-recommended screening cutoff for CI on the Montral Cognitive Assessment (MoCA), but only 9% met detailed neuropsychological testing criteria for mild cognitive impairment (MCI)-level impairment. The PD patients were more depressed than HCs (P < 0.001), with twice as many (14% vs. 7%) meeting criteria for clinically significant depressive symptoms. The PD patients also experienced more anxiety (P < 0.001) and apathy (P < 0.001) than HCs. Psychosis was uncommon in PD (3%), and no between-group difference was seen in ICD symptoms (P = 0.51).

CONCLUSIONS

Approximately 10% of PD patients in the early, untreated disease state met traditional criteria of CI, which is a lower frequency compared with previous studies. Multiple dopaminergic-dependent NPS are also more common in these patients compared with the general population, but others associated with dopamine replacement therapy are not or are rare. Future analyses of this cohort will examine biological predictors and the course of CI and NPS. © 2015 International Parkinson and Movement Disorder Society.

Many Faces of Parkinson's Disease: Non-Motor Symptoms of Parkinson's Disease

Parkinson’s disease (PD) is a multi-systemic disorder that is characterized by a combination of motor and non-motor symptoms (NMS). The dopaminergic neurodegeneration of PD is involved in the genesis of NMS, but other conditions and side effects of levodopa are also associated with NMS. NMS can develop at all stage of PD and rapid eyeball movement sleep behavior disorder (RBD), constipation, depression, and olfactory dysfunction are considered prodromal signs of PD. Many NMS related with motor deficits and cognitive dysfunction. Some NMS including olfactory dysfunction, RBD and abnormal stereopsis are associated with presence of other NMS of PD. In addition, several NMS can be helpful to differentiate between idiopathic PD and other parkinsonian disorders. Early recognition and management of NMS in PD patients is important for preserving quality of life.

Precision medicine: Clarity for the clinical and biological complexity of Alzheimer's and Parkinson's diseases

The goal of precision medicine is to deliver optimally targeted and timed interventions tailored to an individual's molecular drivers of disease. This concept has wide currency in cancer care and in some diseases caused by monogenetic mutations, such as cystic fibrosis, and recently has been endorsed by the White House Office of Science and Technology for more widespread application in medicine. Here we describe our vision of how precision medicine can bring greater clarity to the clinical and biological complexity of the two most common neurodegenerative diseases, Alzheimer's disease and Parkinson's disease.

A systems approach identifies networks and genes linking sleep and stress: implications for neuropsychiatric disorders

Sleep dysfunction and stress susceptibility are comorbid complex traits that often precede and predispose patients to a variety of neuropsychiatric diseases. Here, we demonstrate multilevel organizations of genetic landscape, candidate genes, and molecular networks associated with 328 stress and sleep traits in a chronically stressed population of 338 (C57BL/6J × A/J) F2 mice. We constructed striatal gene co-expression networks, revealing functionally and cell-type-specific gene co-regulations important for stress and sleep. Using a composite ranking system, we identified network modules most relevant for 15 independent phenotypic categories, highlighting a mitochondria/synaptic module that links sleep and stress. The key network regulators of this module are overrepresented with genes implicated in neuropsychiatric diseases. Our work suggests that the interplay among sleep, stress, and neuropathology emerges from genetic influences on gene expression and their collective organization through complex molecular networks, providing a framework for interrogating the mechanisms underlying sleep, stress susceptibility, and related neuropsychiatric disorders.

Nonmotor symptoms in healthy Ashkenazi Jewish carriers of the G2019S mutation in the LRRK2 gene

BACKGROUND

The asymptomatic carriers of the Leucine rich repeat kinase 2 (LRRK2) G2019S mutation represent a population at risk for developing PD. The aim of this study was to assess differences in nonmotor symptoms between nonmanifesting carriers and noncarriers of the G2019S mutation.

METHODS

Two hundred fifty-three subjects participated in this observational cross-sectional multicenter study. Standard questionnaires assessing anxiety, depression, cognition, smell, nonmotor symptoms, and rapid eye movement (REM) sleep behavior were administered. Analyses were adjusted for age, sex, family relations, education, and site.

RESULTS

One hundred thirty-four carriers were identified. Carriers had higher nonmotor symptoms score on the Nonmotor symptoms (NMS) questionnaire (P = 0.02). These findings were amplified in carriers older than age 50 y, with higher nonmotor symptoms scores and trait anxiety scores (P < 0.03).

CONCLUSIONS

In this cross-section study, carriers of the G2019S LRRK2 mutation endorsed subtle nonmotor symptoms. Whether these are early features of PD will require a longitudinal study. © 2015 International Parkinson and Movement Disorder Society.

Parkinson risk in idiopathic REM sleep behavior disorder: preparing for neuroprotective trials

OBJECTIVE

To precisely delineate clinical risk factors for conversion from idiopathic REM sleep behavior disorder (RBD) to Parkinson disease, dementia with Lewy bodies, and multiple system atrophy, in order to enable practical planning and stratification of neuroprotective trials against neurodegenerative synucleinopathy.

METHODS

In a 10-year prospective cohort, we tested prodromal Parkinson disease markers in 89 patients with idiopathic RBD. With Kaplan-Meier analysis, we calculated risk of neurodegenerative synucleinopathy, and using Cox proportional hazards, tested the ability of prodromal markers to identify patients at higher disease risk. By combining predictive markers, we then designed stratification strategies to optimally select patients for definitive neuroprotective trials.

RESULTS

The risk of defined neurodegenerative synucleinopathy was high: 30% developed disease at 3 years, rising to 66% at 7.5 years. Advanced age (hazard ratio [HR] = 1.07), olfactory loss (HR = 2.8), abnormal color vision (HR = 3.1), subtle motor dysfunction (HR = 3.9), and nonuse of antidepressants (HR = 3.5) identified higher risk of disease conversion. However, mild cognitive impairment (HR = 1.8), depression (HR = 0.63), Parkinson personality, treatment with clonazepam (HR = 1.3) or melatonin (HR = 0.55), autonomic markers, and sex (HR = 1.37) did not clearly predict clinical neurodegeneration. Stratification with prodromal markers increased risk of neurodegenerative disease conversion by 200%, and combining markers allowed sample size reduction in neuroprotective trials by >40%. With a moderately effective agent (HR = 0.5), trials with fewer than 80 subjects per group can demonstrate definitive reductions in neurodegenerative disease.

CONCLUSIONS

Using stratification with simply assessed markers, it is now not only possible, but practical to include patients with RBD in neuroprotective trials against Parkinson disease, multiple system atrophy, and dementia with Lewy bodies.

Evolution of prodromal clinical markers of Parkinson disease in a GBA mutation-positive cohort

IMPORTANCE

Numerically, the most important genetic risk factor for the development of Parkinson disease (PD) is the presence of a glucocerebrosidase gene (GBA) mutation.

OBJECTIVE

To evaluate longitudinally and clinically a GBA mutation-positive cohort and the evolution of the prodromal features of PD.

DESIGN, SETTING, AND PARTICIPANTS

Participants in a study of the etiology and prodrome of PD were reevaluated in this clinic-based 2-year follow-up report. Patients with type 1 Gaucher disease (GD) and heterozygous GBA mutation carriers were recruited in 2010 from the Lysosomal Storage Disorder Unit at the Royal Free Hospital, London, England. Thirty patients who previously received a diagnosis of type 1 GD, 28 heterozygous GBA mutation carriers, and 26 genetically unrelated controls were included. Exclusion criteria included a diagnosis of PD or dementia for both the patients with GD and the GBA mutation carriers and any existing neurological disease for the controls.

MAIN OUTCOMES AND MEASURES

Assessment was performed for clinical markers using standardized scales for hyposmia, rapid eye movement sleep behavior disorder, depression, autonomic dysfunction, cognitive function, and parkinsonian motor signs (using the Unified Parkinson's Disease Rating Scale motor subscale [UPDRS part III]).

RESULTS

Over 2 years, depression scores were significantly worse for heterozygous carriers (mean baseline, 0.65; mean follow-up, 2.88; P = .01), rapid eye movement sleep behavior disorder scores were significantly worse for patients with GD (mean baseline, 0.93; mean follow-up, 2.93; P < .001) and heterozygotes (mean baseline, 0.10; mean follow-up, 2.30; P < .001), and UPDRS part III scores were significantly worse for patients with GD (mean baseline, 4.29; mean follow-up, 7.82; P < .001) and heterozygotes (mean baseline, 1.97; mean follow-up, 4.50; P < .001). For controls, there was a small but significant deterioration in the UPDRS part II (activities of daily living) score (mean baseline, 0.00; mean follow-up, 0.58; P = .006). At 2 years, olfactory and cognitive assessment scores were lower in patients with GD and heterozygotes compared with controls, but they did not differ significantly from baseline. When the results from the patients with GD and the heterozygotes were combined, a significant deterioration from baseline was observed, as reflected in the Rapid Eye Movement Sleep Behaviour Disorder Questionnaire (mean baseline, 0.51; mean follow-up, 2.63; P < .001), Beck Depression Inventory (mean baseline, 1.72; mean follow-up, 4.44; P = .002), and UPDRS part II (mean baseline, 0.88; mean follow-up, 2.01; P < .001) and part III scores (mean baseline, 3.09; mean follow-up, 6.10; P < .001) (all P < .01), and at 2 years, significant differences in University of Pennsylvania Smell Identification Test, Unified Multiple System Atrophy Rating Scale, Mini-Mental State Examination, Montreal Cognitive Assessment, and UPDRS part II and part III scores were observed between patients with GD/heterozygotes and controls (all P < .05).

CONCLUSIONS AND RELEVANCE

This study indicates that, as a group, GBA mutation-positive individuals show a deterioration in clinical markers consistent with the prodrome of PD. Within this group of individual, 10% appear to be evolving at a more rapid rate.

Accelerometer-based quantitative analysis of axial nocturnal movements differentiates patients with Parkinson's disease, but not high-risk individuals, from controls

INTRODUCTION

There is a need for prodromal markers to diagnose Parkinson's disease (PD) as early as possible. Knowing that most patients with overt PD have abnormal nocturnal movement patterns, we hypothesised that such changes might occur already in non-PD individuals with a potentially high risk for future development of the disease.

METHODS

Eleven patients with early PD (Hoehn & Yahr stage ≤2.5), 13 healthy controls and 33 subjects with a high risk of developing PD (HR-PD) were investigated. HR-PD was defined by the occurrence of hyperechogenicity of the substantia nigra in combination with prodromal markers (eg, slight motor signs, olfactory dysfunction). A triaxial accelerometer was used to quantify nocturnal movements during two nights per study participant. Outcome measurements included mean acceleration, and qualitative axial movement parameters, such as duration and speed.

RESULTS

Mean acceleration of nocturnal movements was lower in patients with PD compared to controls. Frequency and speed of axial movements did not differ between patients with PD and controls, but mean size and duration were lower in PD. The HR-PD group did not significantly differ from the control group in any of the parameters analysed.

CONCLUSIONS

Compared with controls, patients with PD had an overall decreased mean acceleration, as well as smaller and shorter nocturnal axial movements. These changes did not occur in our potential HR-PD individuals, suggesting that relevant axial movement alterations during sleep have either not developed or cannot be detected by the means applied in this at-risk cohort.

Predictors for mild parkinsonian signs: a prospective population-based study

OBJECTIVE

Mild parkinsonian signs (MPS) are common in the elderly population and are associated with a wide range of adverse health outcomes, including incident Parkinson's disease (PD). We aimed to prospectively evaluate potential risk factors for incident MPS.

METHODS

Participants of the population-based Bruneck Study representative for the general elderly community underwent a baseline assessment of substantia nigra (SN)-echogenicity with transcranial sonography, olfactory function with the Sniffin' Sticks identification test and vascular risk according to the Framingham risk score as well as a baseline and 5-year follow-up neurological examination. MPS were defined according to established criteria based on the entire motor section of the Unified PD Rating Scale. Participants with PD at baseline or follow-up and subjects with MPS at baseline were excluded. A logistic regression analysis adjusted for age and sex was used to detect risk factors for incident MPS in the remaining 393 participants.

RESULTS

SN-hyperechogenicity and hyposmia were related to the development of MPS with odds ratios of 2.0 (95%CI, 1.1-3.7) and 1.6 (95%CI, 1.0-2.7), respectively, while increased vascular risk was not. Having both, SN-hyperechogenicity and hyposmia, was associated with an odds ratio of 3.0 (95%CI, 1.2-7.7) for incident MPS. Among the various motor domains, increased SN-echogenicity predicted the development of bradykinesia and rigidity, whereas diminished olfactory function predicted the development of impaired axial motor function.

CONCLUSIONS

In addition to their established roles as risk factors for PD, SN-hyperechogenicity and hyposmia are associated with an increased risk for MPS in the general elderly community.

Do subjective memory complaints herald the onset of mild cognitive impairment in Parkinson disease?

BACKGROUND

Longitudinal studies on healthy participants have shown that subjective memory impairment (defined as subjective cognitive complaints with normal cognitive objective performance) might be a strong predictor of mild cognitive impairment (MCI). Parkinson disease (PD) also manifests cognitive disturbances, but whether subjective memory complaints may predict the development of MCI in PD has not yet been explored.

METHODS

We prospectively screened newly diagnosed, untreated patients with PD in order to evaluate whether subjective memory complaints may predict development of MCI over a 2-year follow-up evaluation.

RESULTS

We enrolled 76 de novo untreated patients with PD. Of the 76 patients, 23 (30.3%) complained memory issues. Among the patients cognitively unimpaired at baseline, those with subjective complaints were more likely to develop MCI at follow-up. The regression model confirmed that presence of subjective memory complaints at baseline was an independent predictor of development of MCI at follow-up.

DISCUSSION

This is the first prospective study to explore the relationship between subjective and objective cognitive deficits in newly diagnosed, untreated patients. Our results provide preliminary evidence that subjective memory complaints might predict future development of MCI.

Constipation is reduced by beta-blockers and increased by dopaminergic medications in Parkinson's disease

BACKGROUND

Constipation is one of most frequent non-motor symptoms of Parkinson's disease (PD) and it may precede the clinical diagnosis of PD by years, with negative effects on quality of life. In contrast to motor features, levodopa is ineffective and possibly detrimental on constipation. Treatment of constipation in PD is non-specific and frequently unsuccessful. Stemming from a clinical observation of unexpected relief of bothersome constipation, abdominal bloating and pain after treatment with the beta-blocker carvedilol in one patient, we have evaluated the association between the use of beta-blockers and the presence of constipation in a large, unselected PD cohort.

METHODS

Retrospective review of the medical records of every patient with a diagnosis of PD seen in the Movement Disorders clinic at Cedars-Sinai Medical Center from October 2010 to April 2014.

RESULTS

341 medical records with a primary diagnosis of PD were reviewed, 336 of which contained information about constipation. Overall, 205/336 patients (61%) reported constipation. Among the 66 subjects treated with beta-blockers at the time of the encounter of record, only 28 (42.4%) reported constipation. By comparison, among the 270 subjects not treated with beta-blockers, 177 (65.5%) had constipation (χ(2) test p value = 0.001). Multivariate logistic analysis showed an odds ratio (OR) of 0.293 for beta-blockers (95% C.I. 0.161-0.535, p = 0.0001), 2.287 for levodopa (95% C.I. 1.271-4.117, p = 0.006) and 1.805 for dopamine agonists (95% C.I. 1.039-3.136, p = 0.036).

CONCLUSIONS

Beta-blockers are associated with a lower risk of constipation, while dopaminergic treatments appear to increase risk of constipation.

Instrumented functional reach test differentiates individuals at high risk for Parkinson's disease from controls

The functional reach (FR) test as a complex measure of balance including limits of stability has been proven to differentiate between patients with Parkinson’s disease (PD) and controls (CO). Recently, it has been shown that the instrumentation of the FR (iFR) with a wearable sensor may increase this diagnostic accuracy. This cross-sectional study aimed at investigating whether the iFR has the potential to differentiate individuals with high risk for PD (HRPD) from CO, as the delineation of such individuals would allow for, e.g., early neuromodulation. Thirteen PD patients, 13 CO, and 31 HRPD were investigated. HRPD was defined by presence of an enlarged area of hyperechogenicity in the mesencephalon on transcranial sonography and either one motor sign or two risk and prodromal markers of PD. All participants were asked to reach with their right arm forward as far as possible and hold this position for 10 s. During this period, sway parameters were assessed with an accelerometer (Dynaport, McRoberts) worn at the lower back. Extracted parameters that differed significantly between PD patients and CO in our cohort [FR distance (shorter in PD), anterior–posterior and mediolateral acceleration (both lower in PD)] as well as JERK, which has been shown to differentiate HRPD from CO and PD in a previous study, were included in a model, which was then used to differentiate HRPD from CO. The model yielded an area under the curve of 0.77, with a specificity of 85%, and a sensitivity of 74%. These results suggest that the iFR can contribute to an assessment panel focusing on the definition of HRPD individuals.

Olfactory identification in LRRK2 G2019S mutation carriers: a relevant marker?

Objective

Olfactory impairment is a potential marker for impending phenoconversion to Parkinson disease (PD) that may precede the development of disease by several years. Because of low specificity, it may be of greater predictive value in those with genetic mutations and its potential as a marker for developing LRRK2 PD should be evaluated.

Methods

We examined olfactory identification in 126 LRRK2 G2019S mutation carriers with PD, 125 mutation carriers not manifesting PD, 126 noncarriers with idiopathic PD, 106 noncarrier family members without PD, and 35 unrelated controls. We compared olfactory performance and performed mixture modeling to identify possible subgroups of olfactory performance in LRRK2 PD and nonmanifesting carriers.

Results

Adjusting for sex, age, cognitive score, site, and smoking history, LRRK2 PD had better olfactory scores compared to idiopathic PD (mean olfaction difference: −3.7, P < 0.001), and both LRRK2 PD and idiopathic PD had worse olfaction than controls (−12.8, −9.1, both P < 0.001). LRRK2 PD were less likely to be hyposmic than idiopathic PD (54.8% vs. 80.2%, P < 0.001). Nonmanifesting carriers and noncarrier family members did not differ. Mixture model analysis identified three classes in the LRRK2 PD and nonmanifesting carriers, suggesting that there are subgroups with poor olfactory identification in both LRRK2 PD and nonmanifesting carriers.

Interpretation

Therefore, olfactory identification deficit is less likely to be an obligate feature in LRRK2 PD than idiopathic PD, and while a relevant marker in some, a subset of carriers who eventually phenoconvert may proceed directly to PD without prior impaired olfaction.

Comparison of sleep and other non-motor symptoms between SWEDDs patients and de novo Parkinson's disease patients

BACKGROUND

SWEDDs (Scans Without Evidence of Dopaminergic Deficits) was defined from a series of pharmaceutical trials on Parkinson's disease (PD). Non-motor features including sleep-related problems are common even in early-stage PD patients; however, little is known about the burden of the non-motor symptoms in SWEDDs patients.

METHODS

The Non-motor Symptoms Assessment Scale (NMSS), revised version of the Parkinson's Disease Sleep Scale (PDSS-2), Epworth Sleepiness Scale (ESS), and EuroQol 5-Dimension (EQ-5D) were applied to evaluate 17 SWEDDs patients and 28 de novo PD patients. The presence of clinically probable rapid eye movement sleep behavior disorder (cpRBD) was assessed using the International Classification of Sleep Disorders-Revised (ICSD-R) criteria.

RESULTS

The total NMSS score for the SWEDDs group was significantly lower than for the de novo PD group (p = 0.032). The most distinct difference was in taste or smell change (p < 0.000). Prevalence of cpRBD was higher in de novo PD patients than in SWEDDs patients (p = 0.030), though no significant differences in the PDSS-2 total score (p = 0.496) or the ESS score (p = 0.517) were found. The SWEDDs patients did not significantly differ from the de novo PD patients with regard to quality of life, as measured by the EQ-5D index score (p = 0.177).

CONCLUSIONS

The patients with SWEDDs have less non-motor problems than newly diagnosed untreated PD patients. Given the difficulty distinguishing between SWEDDs and early PD, identifying some of non-motor symptoms, such as RBD or olfactory impairment, could aid clinicians in their work.

Prediction of Parkinson's disease subsequent to severe depression: a ten-year follow-up study

Major depressive disorder (MDD) has been associated with an increased risk of subsequent Parkinson's disease (PD) in case-control and cohort studies. However, depression alone is unlikely to be a useful marker of prodromal PD due to its low specificity. In this longitudinal observational study, we assessed whether the presence of other potential markers of prodromal PD predicts the subsequent development of PD in MDD patients. Of 57 patients with severe MDD but no diagnosis of PD who underwent a structured interview, olfactory and motor investigation and transcranial sonography at baseline, 46 (36 women; mean age 54.9 ± 11.7 years) could be followed for up to 11 (median, 10) years. Three patients (2 women; age 64, 65 and 70 years) developed definite PD after 1, 7, and 9 years, respectively. The combined finding of mild asymmetric motor slowing, idiopathic hyposmia, and substantia nigra hyperechogenicity predicted subsequent PD in all patients who could be followed for longer than 1 year. Out of the whole study cohort, only the subjects with subsequent PD presented with the triad of asymmetric motor slowing, idiopathic hyposmia, and substantia nigra hyperechogenicity in combination with at least two out of four reportable risk factors (family history of PD, current non-smoker, non-coffee drinker, constipation) at baseline investigation. Post-hoc analysis revealed that additional rating of eye and eye-lid motor abnormalities might further improve the prediction of PD in larger cohorts. Findings of this pilot-study suggest that MDD patients at risk of subsequent PD can be identified using an inexpensive non-invasive diagnostic battery.

Parkinson disease and smoking revisited: ease of quitting is an early sign of the disease

OBJECTIVE

To assess whether being able to quit smoking is an early marker of Parkinson disease (PD) onset rather than tobacco being "neuroprotective," we analyzed information about ease of quitting and nicotine substitute use.

METHODS

For this case-control study, we identified 1,808 patients with PD diagnosed between 1996 and 2009 from Danish registries, matched 1,876 population controls on sex and year of birth, and collected lifestyle information. We estimated odds ratios and 95% confidence intervals with logistic regression adjusting for matching factors and confounders.

RESULTS

Fewer patients with PD than controls ever established a smoking habit. Among former smokers, those with greater difficulty quitting or using nicotine substitutes were less likely to develop PD, with the risk being lowest among those reporting "extremely difficult to quit" compared with "easy to quit." Nicotine substitute usage was strongly associated with quitting difficulty and duration of smoking, i.e., most strongly among current smokers, followed by former smokers who had used nicotine substitutes, and less strongly among former smokers who never used substitutes.

CONCLUSIONS

Our data support the notion that patients with PD are able to quit smoking more easily than controls. These findings are compatible with a decreased responsiveness to nicotine during the prodromal phase of PD. We propose that ease of smoking cessation is an aspect of premanifest PD similar to olfactory dysfunction, REM sleep disorders, or constipation and suggests that the apparent "neuroprotective" effect of smoking observed in epidemiologic studies is due to reverse causation.

Alpha-synuclein mutations impair axonal regeneration in models of Parkinson's disease

The dopaminergic (DAergic) nigrostriatal tract has an intrinsic regenerative capacity which can be impaired in Parkinson's disease (PD). Alpha-synuclein (aSyn) is a major pathogenic component in PD but its impact on DAergic axonal regeneration is largely unknown. In this study, we expressed pathogenic variants of human aSyn by means of recombinant adeno-associated viral vectors in experimental paradigms of DAergic regeneration. In a scratch lesion model in vitro, both aSyn(A30P) and aSyn(A53T) significantly reduced DAergic neurite regeneration and induced loss of TH-immunopositive cells while aSyn(WT) showed only minor cellular neurotoxic effects. The striatal density of TH-immunopositive axons in the striatal 6-OHDA lesion mouse model was attenuated only by aSyn(A30P). However, striatal expression levels of the regeneration marker GAP-43 in TH-immunopositive fibers were reduced by both aSyn(A30P) and aSyn(A53T), but not by aSyn(WT), which was associated with an activation of the ROCK signaling pathway. Nigral DAergic cell loss was only mildly enhanced by additional overexpression of aSyn variants. Our findings indicate that mutations of aSyn have a strong impact on the regenerative capacity of DAergic neurons, which may contribute to their pathogenic effects.

Prodromal symptoms and early detection of Parkinson's disease in general practice: a nested case-control study

BACKGROUND

Timely diagnosis of Parkinson's disease (PD), facilitating early intervention, depends largely on the GP's awareness of early symptomatology. For general practice, it is unknown which prodromal symptoms (symptoms preceding the typical motor symptoms of PD) demand the GP's alertness.

OBJECTIVE

To assess prodromal symptoms that should alert the GP to the possibility of PD in primary care patients.

METHODS

A nested case-control study was carried out in a population of approximately 12000 patients registered in the Continuous Morbidity Registration database affiliated with the University of Nijmegen in the Netherlands. The database pools subject data from four primary care practices. The subjects comprised all 86 patients diagnosed with PD between 1972 and 2007, and 78 controls, matched by sex, age, socioeconomic status and primary care practice. The primary measures of outcome were the prodromal symptoms presenting in the two years prior to the diagnosis of PD. The number (and type) of referrals and diagnostic tests were also assessed.

RESULTS

In the two-year period prior to diagnosis, PD patients more often presented with functional somatic symptoms, constipation, hyperhidrosis and sleep disorders than controls. Patients also more frequently experienced more than one prodromal symptom and were more often referred within the primary care team or to a medical specialist.

CONCLUSIONS

Prodromal symptoms of PD are encountered in general practice. GPs should be alert when patients present with multiple prodromal symptoms in a two-year period, especially considering the benefits of early intervention, and the future possibilities for disease-modifying therapy.