Low Cost Screening for Features of Prodromal Parkinson’s Disease in General Medical Practice in Italy

Who to Enroll in Parkinson Disease Prevention Trials? The Case for Composite Prodromal Cohorts

Significant progress has been made in expanding our understanding of prodromal Parkinson disease (PD), particularly for recognition of early motor and nonmotor signs and symptoms. Although identification of these prodromal features may improve our understanding of the earliest stages of PD, they are individually insufficient for early disease detection and enrollment of participants in prevention trials in most cases because of low sensitivity, specificity, and positive predictive value. Composite cohorts, composed of individuals with multiple co-occurring prodromal features, are an important resource for conducting prodromal PD research and eventual prevention trials because they are more representative of the population at risk for PD, allow investigators to evaluate the efficacy of an intervention across individuals with varying prodromal feature patterns, are able to produce larger sample sizes, and capture individuals at different stages of prodromal PD. A key challenge in identifying individuals with prodromal disease for composite cohorts and prevention trial participation is that we know little about the natural history of prodromal PD. To move toward prevention trials, it is critical that we better understand common prodromal feature patterns and be able to predict the probability of progression and phenoconversion. Ongoing research in cohort studies and administrative databases is beginning to address these questions, but further longitudinal analyses in a large population-based sample are necessary to provide a convincing and definitive strategy for identifying individuals to be enrolled in a prevention trial.

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.

Prevalence of isolated RBD in the city of Catania, Italy: a population-based study

STUDY OBJECTIVES

Few studies have analyzed the prevalence of isolated REM sleep behavior disorder (RBD) giving different estimates. Aim of the study was to estimate the prevalence of isolated RBD in the city of Catania.

METHODS

A three-stage design was adopted. Participants attending the cabinets of General Practitioners in the city of Catania were screened with the RBD1Q questionnaire (Stage I). Positive participants were interviewed by phone and if suspected of RBD, were invited for clinical examination by a movement disorders specialist and a sleep specialist (Stage II). After the clinical examination, patients diagnosed as probable isolated RBD (pRBD) were invited to undergo a video polysomnography (VPSG) (Stage III) to confirm the diagnosis of definite RBD (dRBD).

RESULTS

A total of 1,524 participants have been screened. Of these, 220 (14.4%) screened positive. One-hundred-forty-three of them were further screened by phone, of whom 75 were suspected RBD. Thirty-six patients were diagnosed as pRBD giving a prevalence of 2.36% (95%CI 1.71-3.25). Twelve pRBD agreed to a VPSG and, of these, four were diagnosed as dRBD giving a prevalence of 0.26% (95%CI 0.07-0.67). Prevalence adjusted by non-participants was 3.48% (95%CI 2.67-4.52) and 1.18% (95%CI 0.45-1.37) for pRBD and dRBD respectively.

CONCLUSIONS

Prevalence of both pRBD and dRBD in Italy is comparable to the estimates reported in literature, confirming that isolated RBD has a low prevalence in the general population.