REM sleep behavior disorder was associated with Parkinson's disease: a community-based study

A review of machine learning and deep learning algorithms for Parkinson's disease detection using handwriting and voice datasets

Parkinson's Disease (PD) is a prevalent neurodegenerative disorder with significant clinical implications. Early and accurate diagnosis of PD is crucial for timely intervention and personalized treatment. In recent years, Machine Learning (ML) and Deep Learning (DL) techniques have emerged as promis-ing tools for improving PD diagnosis. This review paper presents a detailed analysis of the current state of ML and DL-based PD diagnosis, focusing on voice, handwriting, and wave spiral datasets. The study also evaluates the effectiveness of various ML and DL algorithms, including classifiers, on these datasets and highlights their potential in enhancing diagnostic accuracy and aiding clinical decision-making. Additionally, the paper explores the identifi-cation of biomarkers using these techniques, offering insights into improving the diagnostic process. The discussion encompasses different data formats and commonly employed ML and DL methods in PD diagnosis, providing a comprehensive overview of the field. This review serves as a roadmap for future research, guiding the development of ML and DL-based tools for PD detection. It is expected to benefit both the scientific community and medical practitioners by advancing our understanding of PD diagnosis and ultimately improving patient outcomes.

Sex differences in rapid eye movement sleep behavior disorder: A systematic review and meta-analysis

Although rapid eye movement (REM) sleep behavior disorder (RBD) has been widely considered as a male-predominant parasomnia, the existing evidence for the sex difference in the risk of RBD in the general population was conflicting. The present study conducted a systematic review to explore the sex differences in the prevalence, comorbidities, clinical characteristics, and phenoconversion of RBD. One hundred thirty-five eligible studies were identified for the systematic review, and 133 were finally included in the meta-analysis. Males in the general population showed a trend for a higher risk of probable/possible RBD (pRBD), especially among the male older adults (aged ≥60). In the clinical populations, males showed a significantly higher risk of confirmed RBD, but not of pRBD. Among idiopathic RBD (iRBD) patients, males had a significantly earlier age onset of RBD compared with females. Male patients with Parkinson's disease (PD) had a higher risk of comorbid RBD. There was no significant sex difference in the risk of developing neurodegenerative diseases in iRBD patients. Large scale and prospective studies utilizing stringent diagnostic criteria for RBD are recommended to further verify the sex differences in RBD and to investigate the mechanism underlying the sex difference.

Effects of safinamide on REM sleep behavior disorder in Parkinson disease: A randomized, longitudinal, cross-over pilot study

BACKGROUND

Rapid Eye Movement sleep behavior disorder (RBD) is characterized by dream enactment and loss of muscle atonia during REM-sleep. RBD as a premotor feature occurred souvent in patients who develop Parkinson's disease. The glutamatergic, glycinergic, and GABA-ergic systems appear to play a crucial role in the pathogenesis of RBD.

METHODS

The present exploratory longitudinal cross-over study aimed to observe the effect of safinamide on RBD symptoms. Thirty patients with PD and RBD were randomized into two groups (15 subjects each), those that received for a period of 3-months safinamide (50 mg/die) in addition (Group A + ) or in absence (Group B - ) to the usual antiparkinsonian therapy. Patients exploring the clinical and video-polysomnographic changes occurred during this pharmacological therapy.

RESULTS

Twenty-two of 30 patients reported clear improvement in symptoms during safinamide treatment, and 16 were absolutely free from clinical RBD-symptoms at the end of the treatment. Eight patients reported slight improvement in RBD-symptoms. In 6/30 patients no substantial improvement was recorded about clinical RBD-symptoms had frightening dreams or from the bed after 1-week of treatment. In addition, after safinamide, the mean UPDRS-II and III scores decreased, while PDSS-2 score indicating an improvement in both motor symptoms and nocturnal sleep features. A significant reduction of sleep behavior disorder by questionnaire-Hong Kong-score (RBDQ-HS), mainly for two individual RBDQ-HK-items (dream related movements and failing out of bed) was registered.

CONCLUSIONS

This pilot study indicated that safinamide is well tolerated and improves RBD-symptom in parkinsonian.

Prevalence of idiopathic REM behavior disorder: a systematic review and meta-analysis

STUDY OBJECTIVES

To provide an overall estimate of the prevalence of idiopathic REM Sleep Behavior Disorder (iRBD).

METHODS

Two investigators have independently searched the PubMed and Scopus databases for population-based studies assessing the prevalence of iRBD. Data about type of diagnosis (polysomnographic diagnosis, defined iRBD [dRBD]; clinical diagnosis, probable RBD [pRBD]), continent, age range of the screened population, quality of the studies, sample size, screening questionnaires, and strategies have been gathered. A random-effect model was used to estimate the pooled prevalence. Heterogeneity was investigated with subgroup analysis and meta-regression.

RESULTS

From 857 articles found in the databases, 19 articles were selected for the systematic review and meta-analysis. According to the type of diagnosis, five studies identified dRBD cases given a pooled prevalence of 0.68% (95% confidence interval [CI] 0.38-1.05) without significant heterogeneity (Cochran's Q p = 0.11; I2 = 46.43%). Fourteen studies assessed the prevalence of pRBD with a pooled estimate of 5.65% (95% CI 4.29-7.18) and a significant heterogeneity among the studies (Cochran's Q p < 0.001; I2 = 98.21%). At the subgroup analysis, significant differences in terms of prevalence were present according to the quality of the studies and, after removing two outlaying studies, according to the continents and the screening questionnaire used. Meta-regression did not identify any significant effect of the covariates on the pooled estimates.

CONCLUSION

Prevalence estimates of iRBD are significantly impacted by diagnostic level of certainty. Variations in pRBD prevalence are due to methodological differences in study design and screening questionnaires employed.

Recent Progress in Non-motor Features of Parkinson's Disease with a Focus on Circadian Rhythm Dysregulation

Parkinson's disease (PD) is the second most common neurodegenerative disease, which manifests with both motor and non-motor symptoms. Circadian rhythm dysregulation, as one of the most challenging non-motor features of PD, usually appears long before obvious motor symptoms. Moreover, the dysregulated circadian rhythm has recently been reported to play pivotal roles in PD pathogenesis, and it has emerged as a hot topic in PD research. In this review, we briefly introduce the circadian rhythm and circadian rhythm-related genes, and then summarize recent research progress on the altered circadian rhythm in PD, ranging from clinical features to the possible causes of PD-related circadian disorders. We believe that future comprehensive studies on the topic may not only help us to explore the mechanisms of PD, but also shed light on the better management of PD.

Increased rapid eye movement density in Chinese patients with Parkinson's disease and RBD

OBJECTIVE

Impaired rapid eye movement sleep is common among patients with Parkinson's disease (PD). However, information on rapid eye movement density (REM) among PD patients is currently lacking. The current study sought to characterize REM density in PD patients and to examine the associations between REM density sleep parameters and clinical manifestations.

PARTICIPANTS AND METHODS

We retrospectively recruited 172 PD patients. All participants were assessed with a two-night polysomnography, and REM density was calculated. Clinical assessments were completed in PD patients before polysomnography.

RESULTS

Rapid eye movement sleep behavior disorder (RBD) was observed in 93 patients (54.1%). The disease duration, UPDRS part III score, Hoehn and Yahr (H-Y) stage, and HAMA, HAMD, PDQ-39 scores, and REM density in the Parkinson's disease patients with rapid eye movement sleep behavior disorder (RBD) were significantly higher than in the patients without RBD (P < 0.05). However, NREM sleep stage 3 time (N3 time) and percentage of N3 time of total sleep time (N3%) were significantly lower in the RBD patients than in the patients without RBD (P < 0.05). The forward binary logistic regression model showed that REM density, UPDRS-III score, and N3 sleep time were associated with RBD in the PD patients.

CONCLUSIONS

Our results confirm the high prevalence of RBD in patients with PD. Increased REM density was the main risk factor of RBD.

Rapid Eye Movement Sleep Behavior Disorder and Neurodegenerative Diseases: An Update

Rapid eye movement sleep behavior disorder (RBD) is a sleep behavior disorder characterized by abnormal behaviors and loss of muscle atonia during rapid eye movement (REM) sleep. RBD is generally considered to be associated with synucleinopathies, such as Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), and usually precedes years before the first symptom of these diseases. It is believed that RBD predicts the neurodegeneration in synucleinopathy. However, increasing evidences have shown that RBD is also found in non-synucleinopathy neurodegenerative diseases, including Alzheimer’s disease (AD), Huntington’s disease (HD), amyotrophic lateral sclerosis (ALS), etc. Sleep disturbance such as RBD may be an early sign of neurodegeneration in these diseases, and also serve as an assessment of cognitive impairments. In this review, we updated the clinical characteristics, diagnosis, and possible mechanisms of RBD in neurogenerative diseases. A better understanding of RBD in these neurogenerative diseases will provide biomarkers and novel therapeutics for the early diagnosis and treatment of the diseases.

Motor function and the probability of prodromal Parkinson's disease in older adults

BACKGROUND

Identification and characterization of Parkinson's disease (PD) in its prodromal stage is crucial.

OBJECTIVE

The objective of this study was to investigate the association between motor function and the probability of prodromal PD in a community-dwelling older population.

METHODS

We used data from a population-based cohort of older adults (HELIAD study). Subjective motor function was evaluated with a 12-item motor symptoms questionnaire and objective motor function indirectly with a physical activity questionnaire and two gait speed tests. The probability of prodromal PD was calculated according to the Movement Disorder Society research criteria for n = 1731 without PD. Regression multiadjusted models were used to investigate the associations between each motor measure and prodromal PD probability.

RESULTS

For each unit increase in motor symptoms score and for each kcal/kg/day lower energy expenditure (corresponding to 20 minutes of light walking/day for a 75-kg man) there was a 27% and 3% higher probability for prodromal PD, respectively (P < 0.001). Having at least one subjective motor symptom increased the odds of having possible/probable prodromal PD (n = 49; P < 0.05). Including subjective and indirect motor variables in the same model showed that both (symptoms and physical activity) contributed significantly to the model (P < 0.01). Excluding subthreshold parkinsonism from the calculation showed that gait speed less than 0.8 m/s was also associated with a higher prodromal PD probability score (P < 0.001).

CONCLUSIONS

Subjective motor symptoms as well as simple objective motor measures of physical activity or gait speed are associated with a higher probability of prodromal PD in older adults. These data may serve to enable the early identification of prodromal PD cohorts, particularly if they are confirmed in longitudinal studies. © 2019 International Parkinson and Movement Disorder Society.

Higher probability of prodromal Parkinson disease is related to lower cognitive performance

OBJECTIVE

Given the limited information on cognitive function before Parkinson disease (PD) clinical onset in the general population, we sought to assess prodromal PD (pPD) probability and relate it to detailed cognitive performance in a community cohort.

METHODS

In a population-based cohort of 1,629 dementia-free and PD-free participants ≥65 years of age in Greece, we assessed probability of pPD according to the International Parkinson and Movement Disorder Society's criteria. Clinical cognitive diagnoses (cognitively unimpaired, mild cognitive impairment [MCI], dementia) considering neuropsychological testing and functional status were assigned in consensus conferences. Cognitive performance in 5 cognitive domains was assessed by a detailed neuropsychological battery and summarized in the form of z scores. We investigated associations between pPD probability (and its individual constituents) and cognitive outcomes.

RESULTS

The median probability of pPD was 1.81% (0.2%-96.7%). Participants with MCI had higher probability of pPD compared to those with normal cognition (p < 0.001). Higher probability of pPD was related to lower performance in all cognitive domains (memory, language, executive, attention, and visuospatial function) (p < 0.001). Lower cognitive performance was further associated with certain nonmotor markers of pPD, such as daytime somnolence, depression, urinary dysfunction, constipation, and subthreshold parkinsonism (p < 0.001).

CONCLUSIONS

Higher probability of pPD was associated with lower cognitive performance in all domains and higher probability of MCI. This may reflect a widespread pathologic process although future studies are warranted to infer causality. These results suggest to clinicians that they should assess cognition early, and to researchers that they should further look into the possible mechanisms that may underlie this observation.

Parkinsonism Risk Factors in Salt Lake City, Utah: A Community-Based Study

BACKGROUND

The prevalence of dream enactment behavior and other risk factors for a parkinsonian disorder is not well documented.

METHODS

A survey on prevalence of parkinsonism risk factors was designed using two validated instruments (REM behavior disorder single item question, bowel movement frequency for constipation) and three exploratory instruments (for hallucinations, cognitive and olfactory complaints.) It was sent by mail and email to patients aged 50 and over at two University of Utah community clinics in Salt Lake City. A total of 7888 unique patients were sent the survey, and 1607 responses were recorded (response rate 20%). Those whose age was missing (n = 117) or less than 50 years (n = 10) were excluded from the analysis.

RESULTS

Of the 1406 without personal diagnosis of neurodegenerative disease 62.7% were female, and median age was 63. Family history (FH) of Parkinson's disease was endorsed by 9%, constipation (defined as a bowel movement less than once per day) by 19%, mild cognitive complaints (MCI) 15.8%, dream enactment 13.7%, subjective hyposmia or anosmia 18.2%, and at least one potential psychotic symptom in 37.6%. Multivariable logistic regression showed male gender, mild cognitive complaints, hearing voices, and at least one potentially psychotic symptom to be significantly associated with dream enactment.

CONCLUSIONS

This survey shows that dream enactment, a strong predictor of risk for synucleinopathy, is relatively common in the older population; because such individuals rarely come to medical attention of a sleep clinic, such survey research may be useful to identify and recruit at-risk individuals for trials aimed at preventing neurodegenerative disease.

Non-motor features of Parkinson's disease in a nested case-control study of US men

BACKGROUND

Several non-motor features may individually contribute to identify prodromal Parkinson's disease (PD), but little is known on how they interact.

METHODS

We conducted a case-control study nested within the Health Professionals Follow-up Study in a large cohort of men age 40-75 at recruitment in 1986. Cases (n=120) had confirmed PD, were<85 in January 2012, returned a 2012 questionnaire with questions on probable rapid eye movement sleep behaviour disorder (RBD) and constipation sent to all cohort participants and completed in 2014 the Brief Smell Identification Test and a questionnaire assessing parkinsonism and other non-motor PD features (including depressive symptoms, excessive daytime sleepiness, impaired colour vision and body pain). Controls (n=6479) met the same criteria as cases, except for the PD diagnosis.

RESULTS

Concurrent constipation, probable RBD and hyposmia were present in 29.3% of cases and 1.1% of controls, yielding an age-adjusted OR of 160(95%CI 72.8to353) for three features versus none. The odds of PD increased exponentially with additional non-motor features (OR for 6-7 features versus none: 1325; 95%CI333to5279). Among men without PD, the number of non-motor features was associated with odds of parkinsonism (OR for 6-7 features versus none: 89; 95%CI21.2to375). We estimated that in a population with a prodromal PD prevalence of 2%, concurrent constipation, probable RBD and hyposmia would have a maximum sensitivity of 29% and a positive predictive value (PPV) of 35%. The PPV could increase up to 70% by including additional features, but with sharply decreased sensitivity.

CONCLUSIONS

Concurrent constipation, probable RBD and hyposmia are strongly associated with PD. Because these features often precede motor symptoms and their co-occurrence could provide an efficient method for early PD identification.

Mediterranean diet adherence is related to reduced probability of prodromal Parkinson's disease

BACKGROUND

The International Parkinson and Movement Disorder Society recently introduced a methodology for probability score calculation for prodromal PD.

OBJECTIVES

To assess the probability of prodromal PD in an older population and investigate its possible association with Mediterranean diet adherence.

METHODS

Data from a population-based cohort study of older adults (HEllenic Longitudinal Investigation of Aging and Diet) in Greece were used. Probability of prodromal PD was calculated according to International Parkinson and Movement Disorder Society research criteria. A detailed food frequency questionnaire was used to evaluate dietary intake and calculate Mediterranean diet adherence score, ranging from 0 to 55, with higher scores indicating higher adherence.

RESULTS

Median probability of prodromal PD was 1.9%, ranging from 0.2 to 96.7% in 1,731 PD-free individuals aged ≥ 65 (41% male). Lower probability for prodromal PD (P < 0.001) in the higher Mediterranean diet adherence groups was noted, driven mostly by nonmotor markers of prodromal PD, depression, constipation, urinary dysfunction, and daytime somnolence. Each unit increase in Mediterranean diet score was associated with a 2% decreased probability for prodromal PD (P < 0.001). Compared to participants in the lowest quartile of Mediterranean diet adherence, those in the highest quartile were associated with a ∼21% lower probability for prodromal PD.

CONCLUSIONS

Adherence to the Mediterranean diet is associated with lower probability of prodromal PD in older people. Further studies are needed to elucidate the potential causality of this association, potential relation of the Mediterranean diet to delayed onset or lower incidence of PD, as well as the underlying neurobiological mechanisms. © 2018 International Parkinson and Movement Disorder Society.

Stroke and Coronary Artery Disease Are Associated With Parkinson’s Disease

Background: The relationship between vascular disease and Parkinson’s disease (PD) is controversial. We performed a cross-sectional study to investigate the association of two common vascular diseases (stroke and coronary artery disease [CAD]) with Parkinson’s disease. Methods: We identified 63 and 62 PD cases in two population-based cohorts (Malu rural community and Wuliqiao urban community) and collected information of PD and non-PD by means of questionnaires. Logistic regression analysis was used to investigate the association between stroke, coronary artery disease and PD, after adjusting for age, sex, hypertension, diabetes mellitus, hypercholesterolemia, smoking status, alcohol consumption, tea consumption and body mass index. Results: After adjustment for potential confounders, we found that CAD and stroke were associated with PD in the Malu rural community (CAD: odds ratio [OR]=7.11, 95% confidence intervals [CI]: 3.09-16.40, p<0.001; stroke: OR=6.77, 95% CI: 3.09-14.81, p<0.001) and stroke was associated with PD in the Wuliqiao urban community (OR=2.58, 95% CI: 1.36-4.89, p=0.004), especially in women. In a subgroup analysis of PD with age- and sex-matched controls, the results were similar in the Malu rural community (CAD: OR=12.72, 95% CI: 2.92-55.32, p=0.001; stroke: OR=6.26, 95% CI: 1.83-21.42, p=0.003), whereas in the Wuliqiao urban community the results were different in that CAD (but not stroke) was found to be associated with PD (CAD: OR=2.44, 95% CI: 1.09-5.47, p=0.03; stroke: OR=1.79, 95% CI: 0.77-4.17, p=0.18). Conclusions: Our study suggested that stroke and CAD are associated with PD in two Chinese population-based cohorts, indicating a probable vascular component in the pathogenesis of PD.

Accuracy of Rating Scales and Clinical Measures for Screening of Rapid Eye Movement Sleep Behavior Disorder and for Predicting Conversion to Parkinson's Disease and Other Synucleinopathies

Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by repeated episodes of REM sleep-related vocalizations and/or complex motor behaviors. Definite diagnosis of RBD is based on history and polysomnography, both of which are less accessible due to the lack of trained specialists and high cost. While RBD may be associated with disorders like narcolepsy, focal brain lesions, and encephalitis, idiopathic RBD (iRBD) may convert to Parkinson's disease (PD) and other synucleinopathies in more than 80% of patients and it is to date the most specific clinical prodromal marker of PD. Identification of individuals at high risk for development of PD is becoming one of the most important topics for current PD-related research as well as for future treatment trials targeting prodromal PD. Furthermore, concomitant clinical symptoms, such as subtle motor impairment, hyposmia, autonomic dysfunction, or cognitive difficulties, in subjects with iRBD may herald its phenoconversion to clinically manifest parkinsonism. The assessment of these motor and non-motor symptoms in iRBD may increase the sensitivity and specificity in identifying prodromal PD subjects. This review evaluates the diagnostic accuracy of individual rating scales and validated single items for screening of RBD and the role and accuracy of available clinical, electrophysiological, imaging, and tissue biomarkers in predicting the phenoconversion from iRBD to clinically manifest synucleinopathies.

Relationships between Rapid Eye Movement Sleep Behavior Disorder and Neurodegenerative Diseases: Clinical Assessments, Biomarkers, and Treatment

OBJECTIVE

Rapid eye movement sleep behavior disorder (RBD) is characterized by dream enactment and loss of muscle atonia during rapid eye movement sleep. RBD is closely related to α-synucleinopathies including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Many studies have investigated the markers of imaging and neurophysiological, genetic, cognitive, autonomic function of RBD and their predictive value for neurodegenerative diseases. This report reviewed the progress of these studies and discussed their limitations and future research directions.

DATA SOURCES

Using the combined keywords: "RBD", "neurodegenerative disease", "Parkinson disease", and "magnetic resonance imaging", the PubMed/MEDLINE literature search was conducted up to January 1, 2018.

STUDY SELECTION

A total of 150 published articles were initially identified citations. Of the 150 articles, 92 articles were selected after further detailed review. This study referred to all the important English literature in full.

RESULTS

Single-nucleotide polymorphisms in SCARB2 (rs6812193) and MAPT (rs12185268) were significantly associated with RBD. The olfactory loss, autonomic dysfunction, marked electroencephalogram slowing during both wakefulness and rapid eye movement sleep, and cognitive impairments were potential predictive markers for RBD conversion to neurodegenerative diseases. Traditional structural imaging studies reported relatively inconsistent results, whereas reduced functional connectivity between the left putamen and substantia nigra and dopamine transporter uptake demonstrated by functional imaging techniques were relatively consistent findings.

CONCLUSIONS

More longitudinal studies should be conducted to evaluate the predictive value of biomarkers of RBD. Moreover, because the glucose and dopamine metabolisms are not specific for assessing cognitive cognition, the molecular metabolism directly related to cognition should be investigated. There is a need for more treatment trials to determine the effectiveness of interventions of RBD on preventing the conversion to neurodegenerative diseases.

Idiopathic REM sleep behavior disorder in the elderly Spanish community: a primary care center study with a two-stage design using video-polysomnography

OBJECTIVE

To examine the presence and characteristics of idiopathic REM sleep behavior disorder (IRBD) in a representative Caucasian sample from the elderly community of Lleida, Spain, attending primary care centers.

METHODS

Participants were individuals aged 60 years or older who underwent routine visits in two primary care centers. They underwent a two-stage study; a validated screening single question for IRBD diagnosis (RBD1Q) followed by, in those who endorsed positive answer, clinical assessment by a neurologist plus video-polysomnography (V-PSG).

RESULTS

Of 539 individuals (56.4% women, mean age 72.86 ± 8.20 years), 28 (5.2%) endorsed positively the RBD1Q. Four of these 28 refused further assessments. Four of the 24 remaining subjects underwent clinical assessment but refused V-PSG. Of the 20 who underwent clinical assessment plus V-PSG, REM sleep was not recorded in four (20%, all four taking antidepressants). V-PSG ruled out RBD in 12 subjects who had obstructive sleep apnea (n = 9), periodic limb movement disorder in sleep (n = 2) and normal sleep (n = 1). IRBD was diagnosed in four individuals giving an estimated prevalence of 0.74% (95% CI = 0.29-1.89). They were three men and one woman between 74 and 82 years of age who never reported dream-enacting behaviors to their doctors because they thought they represented a normal phenomenon despite suffering sleep-related injuries. These patients had history of violent sleep behaviors with an interval between estimated RBD onset and V-PSG of 4.5 ± 4.2 years.

CONCLUSIONS

IRBD is not uncommon in the elderly community and its demographic and clinical profile is similar to those diagnosed in sleep centers.

Predictive markers for early conversion of iRBD to neurodegenerative synucleinopathy diseases

OBJECTIVE

To determine the predictive value of clinical assessment and dopamine transporter (DAT) uptake for the early development of neurodegenerative synucleinopathy diseases from idiopathic REM sleep behavior disorder (iRBD) over 5 years in a Chinese population.

METHODS

Forty-three patients with iRBD were administered clinical assessment tests, and 35 were examined by DAT-SPECT imaging during 2011. Cox proportional hazard and Kaplan-Meier analyses were used to evaluate the predictive value of the markers in a follow-up study over 5 years.

RESULTS

Eighteen patients (41.9%) developed neurodegenerative synucleinopathy diseases after a median of 4.1 years of prospective follow-up (median interval of 10.5 years from the estimated onset of iRBD symptoms). Patients with higher scores on the Nonmotor Symptom Questionnaire (hazard ratio [HR] 3.11, 95% confidence interval [CI] 1.15-8.40, p = 0.026) and Scale for Outcomes in Parkinson Disease-Autonomic questionnaire (HR 4.46, 95% CI 1.64-12.10, p = 0.003) were more likely to develop neurodegenerative synucleinopathy diseases. Furthermore, the population with decreased ^99mTc-TRODAT-1 binding in the left striatum (HR 2.7, 95% CI 1.02-7.14, p = 0.046) and putamen (HR 3.23, 95% CI 1.16-8.33, p = 0.024) had a relatively higher risk of developing neurodegenerative synucleinopathy diseases.

CONCLUSIONS

Our findings elucidate the predictive value of autonomic dysfunction and DAT uptake in identifying patients with iRBD at a high risk of progressing into neurodegenerative synucleinopathy diseases and could form a basis for future disease-prevention trials.

Meta-analysis on the prevalence of REM sleep behavior disorder symptoms in Parkinson's disease

Background

Our study was aimed to evaluate the risk of a selected non-motor symptom, namely rapid eye movement behavior disorder (RBD) symptoms, among patients with newly diagnosed Parkinson disease compared with health controls.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for meta-analysis and Cochrane manual were followed. Studies on RBD symptoms and PD were searched using PubMed, Embase, Web of Science and Cochrane library databases. All studies were published before August 3^rd, 2016. Eligible studies were those that reported a prevalence of RBD symptoms among newly diagnosed PD and health control. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by random-effected models. Heterogeneity across studies was assessed using Cochran Q and I² statistics.

Results

We identified eight studies including 2462 PD patients and 3818 health controls. The overall prevalence of RBD symptoms in PD was 582/2462 (23.6%) compared to 131/3818 (3.4%) in control. And the pooled OR was 5.69 (95% CI 3.60 to 9.00; p = 0.001) with a moderate heterogeneity I² = 70.5%. After excluding the study of low weight, the overall polled OR was 3.54 (95% CI 2.77 to 4.52; p < 0.00001) and the heterogeneity was completely eliminated (I² = 0%).

Conclusions

RBD symptoms are common non-motor symptoms of PD, and people with PD are at a higher risk of developing RBD. Further studies are needed to understand the natural history of RBD symptoms in PD and its etiological and clinical implications.