Influence of RBD onset on the clinical characteristics of Parkinson's disease patients: a retrospective study

Potential Risk Factors for Psychosis in Parkinson's Disease: A Review of Cohort and Case-Control Studies

BACKGROUND

Among neuropsychiatric sequelae of Parkinson's disease (PD), psychosis may have the most adverse impacts on prognosis and quality of life.

OBJECTIVES

To summarize and critically review the literature on potential risk factors for psychosis in PD, with particular focus on potentially modifiable risk factors.

METHODS

We conducted a literature review using PubMed and EMBASE. We included articles if: (1) the study population was comprised of patients with PD, (2) the presence of psychosis was systematically ascertained through clinician diagnosis, clinical outcome assessments and/or administrative data, and (3) potential risk factors were examined prior to the onset of psychosis.

RESULTS

Twenty-six studies (15 prospective cohort, 10 retrospective cohort, 1 retrospective case-control) of 21 patient cohorts (n = 15,535 unique patients) were included in the review. Ten studies included minor phenomena in their definition of psychosis. The most consistent potential risk factors for psychosis were sleep disturbances, particularly rapid eye movement sleep behavior disorder and autonomic dysfunction. Potentially modifiable risk factors for psychosis included excessive daytime sleepiness and exposure to anticholinergic medications and levodopa. Possible biomarkers for psychosis in PD included reduced striatal dopamine transporter binding on imaging and mutations in the GBA gene.

CONCLUSIONS

Several studies have identified potentially modifiable risk factors for the development of psychosis in PD. Future studies should utilize consistent, validated definitions of psychosis and focus on increasing understanding of, and developing interventions for, potentially modifiable risk factors for psychosis in patients with PD.

Investigation of nonmotor symptoms and their clinical correlates in patients with Parkinson's disease

BACKGROUND

In this study, we aimed to investigate the clinical features of a large group of patients with Parkinson's disease (PD), paying particular attention to the nonmotor symptom (NMS) load. Secondly, we aimed to investigate the clinical correlates of NMSs using the results of various clinical assessments.

METHODS

Data from all PD patients who visited our movement disorders clinic between January 2023 and March 2024 were retrospectively reviewed. We included the data of all patients whose information regarding clinical features and extensive scale results were available.

RESULTS

Overall, we included data from 285 PD patients with a mean age of 64.5 ± 10.0 years (F/M = 119/166). The median scores of the MDS-UPDRS subparts were 9 for MDS-UPDRS-1 and 30 for MDS-UPDRS-3 (off). The median NMSS score was 38 (range: 229), and 46% of the patients had severe to very severe disease in terms of NMS burden. The regression analyses revealed the MDS-UPDRS 3 score, FES-I score, and RBD (0.9772 + 0.453*MDS-UPDRS 3 + 0.724 * FES-I + 15.192*RBD) as predictors of the NMS scale.

CONCLUSIONS

We found a very high NMS burden in our PD cohort. Remarkably, RBD, motor stage, and concern about falling were found to correlate with NMS load.

Behavioral disorders in Parkinson disease: current view

Patients with Parkinson disease (PD) frequently experience several behavioral symptoms, such as anxiety, apathy, irritability, agitation, impulsive control and obsessive-compulsive or REM sleep behavior disorders, which can cause severe psychosocial problems and impair quality of life. Occurring in 30-70% of PD patients, these symptoms can manifest at early stages of the disease, sometimes even before the appearance of classic motor symptoms, while others can develop later. Behavioral changes in PD show distinct patterns of brain atrophy, dopaminergic and serotonergic deterioration, altered neuronal connectivity in frontostriatal, corticolimbic, default mode and other networks due to a cascade linking molecular pathologies and deficits in multiple behavior domains. The changes suggest a multi-system neurodegenerative process in the context of a specific α-synucleinopathy inducing a variety of biochemical and functional changes, the neurobiological basis and clinical relevance of which await further elucidation. This paper is intended to review the recent literature with focus on the main behavioral disturbances in PD patients, their epidemiology, clinical features, risk factors, animal models, neuroimaging findings, pathophysiological backgrounds, and treatment options of these deleterious lesions.

Exploring the relation between REM sleep behavior disorder onset and striatal dopaminergic dysfunction in Parkinson's Disease

BACKGROUND

The α-Synuclein Origin and Connectome (SOC) model recently proposed two different Parkinson's Disease (PD) phenotypes clinically based on the relationship between REM sleep behavior disorder (RBD) and motor symptoms' onset: a "body first" phenotype and a "brain first" phenotype in which RBD precedes or may follow the motor onset, respectively. A higher burden of non-motor symptoms as well as a more symmetrical clinical presentation have also been predicted in the body-first phenotype. This point has been poorly assessed through semi-quantitative striatal dopaminergic functional imaging to date.

OBJECTIVES

To explore the relation between RBD onset and striatal dysfunction in PD.

METHODS

PD patients were retrospectively enrolled and clinical follow-up data were gathered. Presence and onset of probable RBD were evaluated classifying patients into PD-RBDpre (onset before motor symptoms), PD-RBDpost (onset after motor symptoms) and PD-RBD-. Semi-quantitative 123I-FP-CIT-DAT-SPECT imaging was performed at baseline. Mean putamen and caudate-specific binding ratios (SBR) and asymmetry index (AI) were computed.

RESULTS

Fifty-six PD patients were enrolled (10 PD-RBDpre, 19 PD-RBDpost and 27 PD-RBD-). A more symmetrical motor impairment, higher mild cognitive impairment (MCI) prevalence, lower caudate SBR and lower putamen AI were found in PD-RBDpre. A negative trend in MCI prevalence as well as a positive trend in both caudate SBR and putamen AI were found across PD-RBDpre, PD-RBDpost and PD-RBD-.

CONCLUSIONS

Different patterns of striatal dopaminergic dysfunction and cognitive impairment based on RBD onset were unraveled, supporting the SOC model's predictions.

Quantitative EEG in Parkinson's disease: when REM sleep behavior disorder onset really matters

Parkinson's Disease (PD) body-first subtype is characterized by prodromal autonomic symptoms and REM sleep behavior disorder (RBD), symmetric dopaminergic degeneration, and increased risk of dementia. On the other hand, the PD brain-first subtype has fewer non-motor symptoms and a milder motor phenotype. The temporal relationship between RBD onset and motor symptoms onset may differentiate these two subtypes. We aimed to investigate electrocortical differences between brain-first and body-first PD patients. PD patients with an available routinely collected EEG were retrospectively selected. RBD was diagnosed using the RBD screening questionnaire (≥ 6). According to the onset of RBD patients were classified into PD-RBDpre (RBD onset before motor symptoms) and PD-RBDpost (RBD onset after motor symptoms). Patients without RBD were classified as PD-RBD-. Presence of Mild Cognitive Impairment (MCI) was diagnosed according to the MDS criteria. EEG Spectral analysis was performed in resting state by computing the Power Spectral Density (PSD) of site-specific signal epochs for the common frequency bands (delta, theta, alpha, beta). Thirty-eight PD-RBD-, 14 PD-RBDpre and 31 PD-RBDpost patients were recruited. Comparing both global and site-specific absolute values, we found a significant trend toward beta band reduction going from PD-RBD-, PD-RBDpost and PD-RBDpre. No significant differences were found between PD-RBDpost and PD-RBD- patients. PD-RBDpre patients may represent a different subset of patients as compared to patients without RBD, while patients with later onset have intermediate EEG spectral features. Quantitative EEG may provide new hints in PD subtyping.

Cortical Macro- and Microstructural Changes in Parkinson's Disease with Probable Rapid Eye Movement Sleep Behavior Disorder

BACKGROUND

Evidence regarding cortical atrophy patterns in Parkinson's disease (PD) with probable rapid eye movement sleep behavior disorder (RBD) (PD-pRBD) remains scarce. Cortical mean diffusivity (cMD), as a novel imaging biomarker highly sensitive to detecting cortical microstructural changes in different neurodegenerative diseases, has not been investigated in PD-pRBD yet.

OBJECTIVES

The aim was to investigate cMD as a sensitive measure to identify subtle cortical microstructural changes in PD-pRBD and its relationship with cortical thickness (CTh).

METHODS

Twenty-two PD-pRBD, 31 PD without probable RBD (PD-nonpRBD), and 28 healthy controls (HC) were assessed using 3D T1-weighted and diffusion-weighted magnetic resonance imaging on a 3-T scanner and neuropsychological testing. Measures of cortical brain changes were obtained through cMD and CTh. Two-class group comparisons of a general linear model were performed (P < 0.05). Cohen's d effect size for both approaches was computed.

RESULTS

PD-pRBD patients showed higher cMD than PD-nonpRBD patients in the left superior temporal, superior frontal, and precentral gyri, precuneus cortex, as well as in the right middle frontal and postcentral gyri and paracentral lobule (d > 0.8), whereas CTh did not detect significant differences. PD-pRBD patients also showed increased bilateral posterior cMD in comparison with HCs (d > 0.8). These results partially overlapped with CTh results (0.5 < d < 0.8). PD-nonpRBD patients showed no differences in cMD when compared with HCs but showed cortical thinning in the left fusiform gyrus and lateral occipital cortex bilaterally (d > 0.5).

CONCLUSIONS

cMD may be more sensitive than CTh displaying significant cortico-structural differences between PD subgroups, indicating this imaging biomarker's utility in studying early cortical changes in PD. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Brain-first vs. body-first Parkinson's disease: An update on recent evidence

We recently proposed a new disease model of Parkinson's disease - the a-Synuclein Origin site and Connectome model. The model posits that the initial pathology starts either in the olfactory bulb or amygdala leading to a brain-first subtype, or in the enteric nervous system leading to a body-first subtype. These subtypes should be distinguishable early in the disease course on a range of imaging, clinical, and neuropathological markers. Here, we review recent original human studies, which tested the predictions of the model. Molecular imaging studies were generally in agreement with the model, whereas structural imaging studies, such as MRI volumetry, showed conflicting findings. Most large-scale clinical studies were supportive, reporting clustering of relevant markers of the body-first subtype, including REM-sleep behavior disorder, constipation, autonomic dysfunction, neuropsychiatric symptoms, and cognitive impairment. Finally, studies of a-synuclein deposition in antemortem and postmortem tissues revealed distribution of pathology, which generally supports the model.

Predictors for early-onset psychotic symptoms in patients newly diagnosed with Parkinson's disease without psychosis at baseline: A 5-year cohort study

AIMS

To investigate the risk factors for early-onset psychosis in Parkinson's disease (PD) in a cohort of patients from the Parkinson's Progression Markers Initiative.

METHODS

Longitudinal data on motor and non-motor features, dopamine transporter (DAT) imaging, and cerebrospinal fluid (CSF) measurements were collected. The survival probability of psychotic symptoms, potential risk factors for psychosis development over a 5-year follow-up period, and the performance of the prediction model were evaluated.

RESULTS

Among the 338 newly diagnosed patients with PD, 83 developed psychotic symptoms. Gastrointestinal autonomic dysfunction, presence of probable rapid-eye-movement sleep behavior disorder, and the ratio Aβ42: total-tau could independently predict onset of psychosis in PD (hazard ratio (HR) = 1.157, 95% confidence interval (CI) 1.022-1.309, p = 0.021, HR = 2.596, 95% CI 1.287-5.237, p = 0.008, and HR = 0.842, 95% CI 0.723-0.980, p = 0.027, respectively). The combined model integrating baseline clinical predictors, DAT imaging, and CSF measurements achieved better sensitivity than the clinical predictors alone (area under the curve = 0.770 [95% CI 0.672-0.868] vs. 0.714 [95% CI 0.625-0.802], p = 0.098).

CONCLUSION

We identified clinical and CSF predictors of early-onset psychosis in patients with PD. Our study provides evidence and implications for prognostic stratification and therapeutic approaches for PD psychosis.

REM Behavior Disorder: Implications for PD Therapeutics

PURPOSE

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia that occurs during REM sleep, characterized by REM sleep without atonia (RSWA) and dream enactment behavior (DEB). RBD is associated with several diseases and medications but most notably is a prodromal feature of synucleinopathies, including Parkinson's disease (PD). This article reviews RBD, its treatments, and implications for PD therapeutics.

RECENT FINDINGS

Recent research recognizes RBD as a prodromal marker of PD, resulting in expansion of basic science and clinical investigations of RBD. Current basic science research investigates the pathophysiology of RBD and explores animal models to allow therapeutic development. Clinical research has focused on natural history observation, as well as potential RBD treatments and their impact on sleep and phenoconversion to neurodegenerative disease. RBD serves as a fresh access point to develop both neuroprotective and symptomatic therapies in PD. These types of investigations are novel and will benefit from the more established basic science infrastructure to develop new interventions.