Increased glucosylsphingosine levels and Gaucher disease in GBA1-associated Parkinson's disease.

INTRODUCTION: Gaucher's disease (GD) is caused by biallelic mutations in the GBA1 gene, leading to reduced glucocerebrosidase (GCase) activity and substrate (glucosylceramide and glucosylsphingosine, GlcSph) accumulation. GBA1 variant carriers are at risk of Parkinson's disease (PD), but only those with biallelic mutations cross the threshold of GCase reduction, leading to substrate accumulation and GD. The link between GBA1 mutations, GD and PD is not fully understood. Here we aimed at reporting the results of a large PD population screening with dried blood spot tests for GD. METHODS: We measured GCase activity and GlcSph levels in 1344 PD patients with dried blood spot tests, and performed GBA1 genetic sequencing. RESULTS: While the GCase activity was reduced in GBA1-PD carriers compared to wild type PD, GlcSph was increased in GBA1-PD compared to GBA1-controls, regardless of the underlying type of GBA1 variant. 13.6 % and 0.4 % of PD patients had mono- or biallelic GBA1 mutations respectively. GCase deficiency, lipid accumulation and clinical manifestations of GD was detected in five PD patients with biallelic GBA1 mutations, of whom four had a risk combined with a GD causing variant. CONCLUSIONS: GlcSph appearing higher in PD may represent a reliable biomarker of the disease and deserves to be further investigated. This study highlights the importance of screening PD patients for possible underlying GD, which is a treatable condition that should not be missed. We diagnosed GD cases carrying a "risk" variant in one allele, which is an unprecedented finding deserving further investigation.

Personality and psychopathological characteristics in functional movement disorders.

INTRODUCTION: Aim of the present study was to assess personality and psychopathological characteristics in patients with functional movement disorders (FMDs) compared to patients with other neurological disorders (OND). METHODS: In this cross-sectional study, patients affected by clinically established FMDs and OND who attended the Neurologic Unit of the University-Hospital "Policlinico-San Marco" of Catania from the 1st of December 2021 to the 1st of June 2023 were enrolled. Personality characteristics were assessed with the Rorschach test coded according to Exner's comprehensive system and the Structured Clinical Interview for DSM-5 (SCID-II). RESULTS: Thirty-one patients with FMDs (27 women; age 40.2±15.5 years; education 11.7±3.2 years; disease duration 2.3±2.5 years) and 24 patients affected by OND (18 women; age 35.8±16.3 years; education 11.9±2.9 years; disease duration 3.4±2.8 years) were enrolled. At the Rorschach, FMDs presented a significantly higher frequency of Popular (P) and sum of all Human content codes (SumH>5) responses and avoidant coping than OND. CONCLUSION: FMDs presented "conformity behaviors", excessive interest in others than usual a maladaptive avoidant style of coping and a difficulty in verbalizing emotional distress. These psychopathological characteristics may favor the occurrence of FMDs.

CSF N-Glycomics Using High-Throughput UPLC-ESI Techniques in Alzheimer's Disease.

In this chapter, we will present a high-throughput method applied in our laboratory for the structural elucidation of the cerebrospinal fluid (CSF) N-glycome. This methodology is based on a commercial equipment developed by WATERS™ to speed up N-deglycosylation and N-glycan labeling of glycoproteins of pharmaceutical and biological interest such as monoclonal antibodies. This analytical kit is sold under the trade name of RapiFluor-MS (RFMS). We have slightly modified the methodology, increasing the glycosylation time and using a high-resolution mass analyzer for the analysis of CSF N-glycans, thus obtaining a high-throughput method (up to 96 samples simultaneously), mass accuracy better than 5 ppm, and the ability to separate and identify isomers.

CSF N-Glycomics Using MALDI MS Techniques.

In this chapter, we will present the methodology currently applied in our laboratory for the structural elucidation of the cerebrospinal fluid (CSF) N-glycome. N-glycans are released from denatured carboxymethylated glycoproteins by digestion with peptide-N-glycosidase F (PNGase F) and purified using both C18 Sep-Pak® and porous graphitized carbon (PGC) HyperSep™ Hypercarb™ solid phase extraction (SPE) cartridges. The glycan pool is subsequently permethylated to increase mass spectrometry sensitivity. Molecular assignments are performed through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) analysis considering either the protein N-linked glycosylation pathway or MALDI TOF MS/MS data. Each stage has been optimized to obtain high-quality mass spectra in reflector mode with an optimal signal-to-noise ratio up to m/z 4800. This method has been successfully adopted to associate specific N-glycome profiles to the early and the advanced phases of Alzheimer's disease (AD).

Advanced Parkinson's disease treatment patterns in Italy: an observational study interim analysis.

BACKGROUND: Oral levodopa remains the mainstay of treatment for Parkinson's disease (PD). However, as PD progresses, response to treatment may fluctuate. Managing fluctuations can be demanding for clinicians and patients. There is a paucity of real-world studies reporting on PD management in patients with fluctuations in treatment response, especially in patients with advanced stages of PD. The multicentre, observational Parkinson's Disease Fluctuations treatment PAthway (PD-FPA) study describes the real-life management of response fluctuations in Italian patients with advanced PD. PATIENTS AND METHODS: PD-FPA had a retrospective and prospective phase; herein, retrospective results are presented. Ten Italian centres enrolled patients with a PD diagnosis from 10-15 years prior to study entry (T0) and who had ≥2-year history of fluctuations. Data on patient demographics, medical history, PD stage, fluctuation characteristics, symptoms, and prescribed treatments were collected at T0 and retrospectively (2 years prior to T0) via patient chart review/interview. RESULTS: Overall, 296 patients (60% male, mean age 68 years, 84% with Hoehn and Yahr scores 2-3) were enrolled. At T0, most patients (99.3%) were on oral levodopa therapy. All patients used dopaminergic medications; adjunctive medications included dopamine agonists (56%) and monoamine oxidase B (60%) and catechol-O-methyltransferase enzyme inhibitors (41%). At T0, 51% of patients had changed therapy, with response fluctuations being the most common reason (74%); wearing-off was the most common fluctuation (83%). CONCLUSION: This interim analysis of PD-FPA suggests that adequate levodopa dosing and adjunctive medications can stabilize advanced PD and provide patients with a good quality of life.

Patients with Parkinson's disease (PD) often exhibit fluctuations in their response to oral levodopa; however, real-world studies on the management of these fluctuations are lacking. This planned interim analysis of the real-world, multicentre, observational PD Fluctuations treatment Pathway (PD-FPA) study found that adequate levodopa dosing and adjunctive medications can stabilize Italian patients with advanced PD and improve their quality of life.

Elderly Onset of Functional Motor Disorders: Clinical Correlates from the Italian Registry.

BACKGROUND: Functional motor disorders (FMD) are a frequent neurological condition affecting patients with movement disorders. Commonly described in younger adults, their manifestation can be also associated to an elderly onset. OBJECTIVE: To assess the prevalence and describe the clinical manifestations of FMD with elderly and younger onset and their relationship with demographical and clinical variables. METHODS: We recruited patients with a "clinically definite" diagnosis of FMD from the Italian Registry of FMD. Patients underwent extensive clinical assessments. For elderly onset, we set a chronological cut-off at 65 years or older according to WHO definition. Multivariate regression models were implemented to estimate adjusted odds ratio of elderly FMD onset related to clinical characteristics. RESULTS: Among the 410 patients, 34 (8.2%) experienced elderly-onset FMD, with a mean age at onset of 70.9 years. The most common phenotype was tremor (47.1%), followed by gait disorders, weakness, and dystonia (29.4%, 23.5%, 14.7%, respectively). Eleven elderly patients had a combined phenomenology: 9 exhibited two phenotypes, 2 had three phenotypes. Weakness was isolated in 3/8 patients and combined with another phenotype in 5/8, manifesting as paraplegia (n = 4); upper limb diplegia (n = 2), hemiparesis/hemiplegia (n = 1), and tetraparesis/tetraplegia (n= 1). Non-motor and other functional neurological disorders occurred more frequently in the younger group (89.1%) than the elderly (73.5%). Neurological and non-neurological comorbidities were more prevalent in the elderly group (82.4%) as opposed to the younger (32.7%). In a multivariate regression analysis, elderly-onset FMD was significantly associated with neurological comorbidities, including parkinsonism (OR 6.73) and cerebrovascular diseases (OR 5.48). CONCLUSIONS: These results highlight the importance of achieving an accurate diagnosis of FMD in the elderly, as it is crucial for effectively managing FMD symptoms and addressing neurological comorbidities.

Retinal Thickness in Essential Tremor and Early Parkinson Disease: Exploring Diagnostic Insights.

BACKGROUND: Essential tremor (ET) represents a heterogeneous condition which may overlap with Parkinson disease (PD) even at early stages, by sharing some subtle clinical aspects. Longstanding ET demonstrated also higher risk of developing PD, especially with a Tremor-dominant (TD-PD) phenotype. Therefore, differential diagnosis between ET and early PD could be quite challenging. Optical coherence tomography (OCT) has been recognized as a reliable tool to assess the retina as a proxy of neurodegeneration. We aimed to explore the possible role of retinal assessment in differential diagnosis between ET and early PD. METHODS: Macular layers and peripapillary retinal nerve fiber layer (RNFL) thickness among ET, early PD, and healthy controls (HCs) were assessed using OCT. RESULTS: Forty-two eyes from 23 ET, 41 eyes from 21 early PD, and 33 eyes from 17 HCs were analyzed. Macular RNFL, ganglion cell layer, inner plexiform layer, and inner nuclear layer were thinner in PD as compared with ET and even more in HCs. Differences between ET and PD were more evident when considering the TD-PD subgroup, especially for RNFL. Among ET patients, thickness of the inner macular layers showed negative linear relationship with both age at onset and disease duration. Peripapillary temporal quadrant thinning was found in ET compared with HCs. CONCLUSIONS: Macular inner retina was thinner in patients with ET and early PD compared with HCs. These findings suggest that the retinal assessment may have a utility in the differential diagnosis between ET and PD.

Real-world use of Safinamide in motor fluctuating Parkinson's disease patients in Italy.

INTRODUCTION: Safinamide is a recent antiparkinsonian drug that modulates both dopaminergic and glutamatergic systems with positive effects on motor and nonmotor symptoms of Parkinson's disease (PD). Here, we aimed to describe the efficacy and safety of safinamide in the Italian PD patients in real-life conditions. METHODS: We performed a sub-analysis of the Italian cohort of the SYNAPSES study, a multi-country, multi-center, retrospective-prospective cohort observational study, designed to investigate the use of safinamide in routine clinical practice. Patients received for the first time a treatment with safinamide and were followed up for 12 months. The analysis was conducted on the overall population and in subgroups of interest: i) patients > 75 years, ii) patients with relevant comorbidities and iii) patients affected by psychiatric symptoms. RESULTS: Italy enrolled 616/1610 patients in 52 centers, accounting for 38% of the entire SYNAPSES cohort. Of the patients enrolled, 86.0% were evaluable at 12 months, with 23.3% being > 75 years, 42.4% with psychiatric conditions and 67.7% with relevant comorbidities. Safinamide was effective on motor symptoms and fluctuations as measured through the Unified PD rating scale III and IV scores, and on the total score, without safety issues in none of the subgroups considered. CONCLUSION: The SYNAPSES data related to Italian patients confirms the good safety profile of safinamide even in special groups of patients. Motor fluctuations and motor impairment improved at the follow-up suggesting the significant role of safinamide in managing motor symptoms in PD patients.

Neuroanatomical findings in isolated REM sleep behavior disorder and early Parkinson's disease: a Voxel-based morphometry study.

Isolated rapid eye movement (REM) sleep behavior disorder (iRBD) is a parasomnia characterized by loss of physiological atonia of skeletal muscles with abnormal behaviors arising during REM sleep. RBD is often the early manifestation of neurodegenerative diseases, particularly alpha-synucleinopathies, such as Parkinson's disease (PD). Both structural and functional neuroimaging studies suggest that iRBD might share, or even precede, some of the features commonly found in PD, although without a definitive conclusion. Aim of the study is to evaluate the presence of structural abnormalities involving cortical and subcortical areas in PD patients with RBD and iRBD. Patients with video-polysomnographic (VPSG)-confirmed iRBD, and patients with a diagnosis of PD were recruited. In all PD patients, the presence of probable RBD was assessed during the follow-up visits (PD/pRBD). A group of healthy controls (HC) subjects was also recruited. Each subject underwent a structural brain MRI using a 3-D T1-weighted spoiled gradient echo sequence. Twenty-three patients with iRBD, 24 PD/pRBD, and 26 HC were enrolled. Voxel-based morphometry-AnCOVA analysis revealed clusters of grey matter changes in iRBD and PD/pRBD compared to HC in several regions, involving mainly the frontal and temporal regions. The involvement of cortical brain structures associated to the control of sleep cycle and REM stage both in PD/pRBD and iRBD might suggest the presence of a common structural platform linking iRBD and PD, although this pattern may not underlie exclusively RBD-related features. Further longitudinal studies are needed to clarify the patterns of changes occurring at different time points of RBD-related neurodegeneration.

Effectiveness of telerehabilitation plus virtual reality (Tele-RV) in cognitive e social functioning: A randomized clinical study on Parkinson's disease.

INTRODUCTION: Telemedicine could represent an emerging and innovative approach to support cognitive and behavioral rehabilitation reducing the overload of healthcare facilities, favoring home care therapy. The present study aimed to assess the potential efficacy of Tele-VR apps in enhancing cognitive performance and improving social skills in patients with Parkinson's disease (PD). METHODS: Thirty-four patients with PD were included in the study. Patients were assigned to one of the following treatment groups: Experimental Group 1 (EG1) underwent a Tele-VR program using two cognitive rehabilitation applications (app) on smartphones (Neuronation-Brain Training and Train your Brain); Experimental Group 2 (EG2) received a Tele-VR program through one cognitive rehabilitation app (Neuronation-Brain Training) and one socio-cognitive rehabilitation App (The Sims) on smartphones; Active Control Group (aCG) performed a conventional training using pencil and paper exercises (Not-VR). RESULTS: At the end of the study, the aCG and EG1 presented an improvement in the executive, attentional and visuospatial cognitive domains. Mood and subjective memory also improved in the EG1. Moreover, in the EG2 group, a significant improvement was found in all cognitive domains, including social cognition skills (theory of mind). The inter-group comparison showed that both EG1 and EG2 had significantly greater improvements than aCG in MoCA score. Finally, both EG1 and EG2 showed a higher improvement in the FAB score, as compared to the aCG. CONCLUSION: Rehabilitation with smartphone apps could be more useful than conventional rehabilitation in improving cognitive and social cognition skills in patients with PD. Combining cognitive and social cognition training could improve the cognitive and affective domains, also aiding in the long-term maintenance of cognitive outcomes.

Cerebrospinal fluid neurofilament light chains predicts early disease-activity in Multiple Sclerosis.

BACKGROUND: Among biomarkers of axonal damage, neurofilament light chains (NFL) seem to play a major role, representing a promising and interesting tool in Multiple Sclerosis (MS). Our aim was to explore the predictive role of cerebrospinal fluid (CSF) NFL in patients with a recent diagnosis of MS, naïve to any MS therapy. METHODS: We retrospectively collected data of patients diagnosed with MS, referred to the Neurology Clinic of the University-Hospital G. Rodolico of Catania between January 1st 2005 and December 31st 2015. All patients underwent CSF collection at the time of MS diagnosis and were followed-up for at least three years afterwards. NFL levels were measured in CSF samples with Simoa NFLight advantage kit at the CRESM (University Hospital San Luigi Gonzaga, Orbassano, Torino). NFL levels were expressed as LogNFL. Symbol Digit Modalities test (SDMT) was performed at baseline, at 1-year and at 3-year follow-up. Multivariate logistic regression analysis was performed to investigate LogNFL as a potential risk factor of different clinical outcomes. RESULTS: 244 MS patients (230 relapsing-remitting, RRMS; 94.3 %), with a mean age at diagnosis of 37.0 ± 11.1 years, were recruited. LogNFL did not correlate neither with EDSS score at diagnosis and at subsequent follow-up up to 12 years, nor with SDMT performed at diagnosis, at 1 year and at 3 years. LogNFL were an independent factor for the occurrence of at least one relapse during the first two years after MS diagnosis (OR = 2.75; 95 % CI 1.19-6.31; p = 0.02) and for the occurrence of gadolinium-enhanced (Gd+) lesions during the first 2 years from diagnosis at brain and spine MRI scans (OR = 3.45, 95 % CI 1.81-6.57; p < 0.001). CONCLUSION: The detection of CSF NFL at the time of MS diagnosis can be a useful support to predict the two-year risk of clinical and radiological relapses, thus affecting therapeutic choices in the very early phases of the disease.

A dynamic interpretation of κFLC index for the diagnosis of multiple sclerosis: a change of perspective.

BACKGROUND: Previous studies attempted to define the best threshold for κ free light chains (κFLC) index, confirming higher sensitivity (Se) but less specificity (Sp) compared with IgG oligoclonal bands (OCB) for the diagnosis of MS. OBJECTIVE: To evaluate the diagnostic accuracy of different κFLC index intervals in a miscellaneous cohort of neurological patients, proposing a procedural flowchart for MS diagnosis. METHODS: We analyzed data from 607 patients diagnosed with MS (179), CIS (116), other inflammatory (94) or non-inflammatory neurological diseases (218). Measures of diagnostic accuracy were reported for different potential thresholds of κFLC index, and for IgG OCB and IgG index. Binary logistic regression was to used to calculate the odds of being diagnosed with MS based on each increase of κFLC index. RESULTS: CSF IgG OCB showed 72.2% Se (CI 95% 68.4-75.7) and 95.2% Sp (CI 95% 93.1-96.7) in discriminating between MS/CIS and controls, with an AUC of 0.84 (CI 95% 0.80-0.87). The highest diagnostic accuracy was reported for κFLC index cut-off of 5.0 (Se = 85.4%, Sp = 90.4%, AUC = 0.88), while a threshold of 11.0 exhibited higher Sp (95.5%, 95% CI 93.1-97.1) than IgG OCB. AUCs for all thresholds between 4.25 and 6.6 were not significantly different from each other, but were significantly higher than the AUC of IgG OCB (p < 0.05). The odds of being diagnosed with MS/CIS increased by 17.1% for each unit increase of κFLC index (OR = 1.17; 95% CI 1.12-1.23; p < 0.001). CONCLUSION: κFLC index performed better than CSF IgG OCB in supporting the diagnosis of MS/CIS, with the advantage of being a cost-effective and quantitative analysis.

Gender differences in non-motor fluctuations in Parkinson's disease.

Non-motor symptoms (NMS) and Non-motor fluctuations (NMF) in Parkinson's Disease (PD) are common, involving several domains and affecting quality of life. Aim of the study is to estimate the burden of NMF in PD patients and to evaluate the possible gender effect. PD patients fulfilling the MDS-PD diagnostic criteria attending the "Parkinson's Disease and Movement Disorders Centre" of the University of Catania were evaluated using the Non-Motor Fluctuations Assessment (NoMoFA) Questionnaire. NoMoFA items were also grouped into the following domains: cognitive, mood, sleep/fatigue, dysautonomia, hallucination/perception and miscellaneous domains were identified. One-hundred and twenty-one patients with PD (67 men, 55.4%; mean age 70.2 ± 8.9 years, disease duration 8.3 ± 4.6 years) were evaluated. All PD patients reported at least one NMS, whereas 87 (71.9%) also reported NMF. "Feel sluggish or had low energy levels" (47.2%) along with "Feel excessively sleepy during the day" (40.0%) were the most common NMF reported in the whole sample. The majority of PD patients reported the presence of NMF during the OFF state (79, 65.3%). At multivariate analysis, NMF were positively associated with the female gender (adjusted OR 3.13; 95%CI 1.21-8.11 p-value 0.01). Women with PD had higher NMF scores especially in depression/anxiety, sleep/fatigue and dysautonomia domains. Our study reported the presence of a gender-related pattern in the frequency of NMS and NMF in PD patients, with female gender associated with a higher risk of developing NMF, highlighting the need for personalized treatment strategies when addressing NMF.

Brain linear measurements for differentiating normal pressure hydrocephalus from Alzheimer's disease: an exploratory study.

BACKGROUND AND PURPOSE: Easy and reliable tools for the differential diagnosis between idiopathic normal pressure hydrocephalus (iNPH) and Alzheimer's disease (AD) are needed. MATERIALS AND METHODS: In this cross-sectional study iNPH and AD patients referred to the Neurology Unit of the University of Catania from 1 January 2020 to 1 December 2022 were enrolled. The following brain linear measurements (BLMs) were calculated: Evan's index (EI), the parieto-occipital ratio (POR) and the temporal ratio (TR). For each index, sensitivity, specificity and the area under the curve (AUC) were calculated. Moreover, a cumulative index, the BLM index, was also considered. RESULTS: Fifty patients (25 iNPH and 25 AD) were enrolled. In differentiating iNPH from AD, EI had the highest AUC (0.956), POR had the highest specificity (100%) whilst TR had the highest sensitivity (92%). The BLM index differentiated iNPH and AD with a sensitivity of 96%, a specificity of 92% and an AUC of 0.963 with an optimal cut-off value of 0.303. CONCLUSION: Evan's index, POR and TR may be useful in the differential diagnosis between iNPH and AD. At an individual level, the BLM index represents a valid and reliable tool to achieve an accurate differentiation between these two conditions.

Turning and Sitting in Early Parkinsonism: Differences Between Idiopathic Normal Pressure Hydrocephalus Associated with Parkinsonism and Parkinson's Disease.

Background: Differential diagnosis between idiopathic normal pressure hydrocephalus (iNPH) associated with parkinsonism (iNPH-P) and Parkinson's disease (PD) may prove difficult when evaluating patients with early parkinsonism. The objective of this study was to evaluate differences in mobility during standardized tasks between iNPH-P and PD. Methods: We selected 21 iNPH-P and 21 pharmacologically untreated PD patients. They all performed the instrumented Timed Up and Go test at the time of diagnosis. Results: Turning tasks showed longer duration and lower speed in iNPH-P than in PD. Vertical variation in acceleration during the sit-to-stand phase was lower in iNPH-P patients, whereas the duration of the stand-to-sit phase was longer. On walking, iNPH-P showed smaller stride length and a longer gait cycle duration. In multivariate analysis adjusting for age and cognitive status as potential confounders, average angular speed on turning before sitting was the discriminating parameter between the two groups. Conclusions: Patients with iNPH-P showed specific abnormal mobility performances with respect to untreated PD, specifically during the turning-to-sitting transition.

Subclinical involvement of eye movements detected by video-based eye tracking in myasthenia gravis.

BACKGRO UND: Ocular abnormalities in myasthenia gravis (MG) are characterized by severely limited movements and rapid saccades. Data about eye motility of MG patients whose ocular movements are apparently normal are lacking. Our study assessed the eye movement parameters in MG patients without clinical eye motility dysfunctions and investigated the effects of neostigmine administration on the eye motility in these patients. MATERIALS: In this longitudinal study, we screened all patients diagnosed with MG referring to the Neurologic Clinic of the University of Catania between October 1, 2019, and June 30, 2021. Ten age- and sex-matched healthy controls were enrolled. Patients underwent eye movement recording using the EyeLink1000 Plus® eye tracker at baseline and after 90 min from the intramuscular administration of neostigmine (0.5 mg). RESULTS: A total of 14 MG patients with no clinical signs of ocular motor dysfunction (64.3% men, with a mean age of 50.4 ± 14.4 years) were enrolled. At baseline, saccades in MG patients showed slower velocities and longer latencies compared to controls. Moreover, the fatigue test induced a reduction in saccadic velocity and an increase in latencies. After neostigmine administration, the ocular motility analysis showed shorter saccadic latencies and a significant improvement of velocities. CONCLUSIONS: Eye motility is impaired even in MG patients with no clinical evidence of ocular movement disturbance. Video-based eye tracking may detect subclinical involvement of eye movements in patients with MG.

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

INTRODUCTION: In Parkinson's disease (PD), rapid eye movement (REM) sleep behavior disorder (RBD) might either precede the appearance of motor symptoms, or develop during the disease course. PD patients with RBD are characterized by a higher burden of cognitive impairment and hallucinations. However, few studies have analyzed the clinical characteristics of PD patients according to the timeline of RBD onset. METHODS: PD patients have been retrospectively enrolled. Presence and onset of probable RBD (pRBD) has been evaluated using RBD Screening Questionnaire (score ≥ 6). Presence of Mild Cognitive Impairment (MCI) at baseline has been evaluated using the MDS criteria level II. Presence of motor complications and hallucinations has been evaluated at a 5-year follow-up. RESULTS: A total of 115 PD patients (65 men, 56.5%; mean age 62.5 ± 9.7 years; mean disease duration 3.7 ± 3.9 years) have been enrolled. Out of these, 63 fulfilled the diagnosis of pRBD (54.8%) with 21 (33.3%) reporting the RBD onset before the onset of the motor symptoms (PD-RBDpre), and 42 (66.7%) after the motor symptoms (PD-RBDpost). At enrolment presence of MCI was associated with PD-RBDpre patients (OR 5.04; 95% CI 1.33-19.05; p value 0.02). At follow-up, a higher risk of developing hallucinations was also associated with PD-RBDpre (OR 4.68; 95% CI 1.24-17.63; p = 0.022). CONCLUSIONS: PD patients with RBD occurring before the onset of motor symptoms represent a subgroup of patients with a more severe cognitive phenotype and with a higher risk of developing hallucinations along the disease course, with significant implications in terms of prognostic stratification and therapeutic approach.