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To date, no consensus exists on the key factors for diagnosing advanced Parkinson disease (APD). To obtain consensus on the definition of APD, we performed a prospective, multicenter, Spanish nationwide, 3-round Delphi study (CEPA study). An ad hoc questionnaire was designed with 33 questions concerning the relevance of several clinical features for APD diagnosis. In the first-round, 240 neurologists of the Spanish Movement Disorders Group participated in the study. The results obtained were incorporated into the questionnaire and both, results and questionnaire, were sent out to and fulfilled by 26 experts in Movement Disorders. Review of results from the second-round led to a classification of symptoms as indicative of “definitive,” “probable,” and “possible” APD. This classification was confirmed by 149 previous participating neurologists in a third-round, where 92% completely or very much agreed with the classification. Definitive symptoms of APD included disability requiring help for the activities of daily living, presence of motor fluctuations with limitations to perform basic activities of daily living without help, severe dysphagia, recurrent falls, and dementia. These results will help neurologists to identify some key factors in APD diagnosis, thus allowing users to categorize the patients for a homogeneous recognition of this condition.

The presence of mutations in glucocerebrosidase (GBA) gene is a known factor increasing the risk of developing Parkinson's disease (PD). Mutations carriers have earlier disease onset and are more likely to develop neuropsychiatric symptoms than other sporadic PD cases. These symptoms have primarily been observed in Parkinson's patients carrying the most common pathogenic mutations L444P and N370S. However, recent findings suggest that other variants across the gene may have a different impact on the phenotype as well as on the disease progression. We aimed to explore the influence of variants across GBA gene on the clinical features and treatment related complications in PD. In this study, we screened the GBA gene in a cohort of 532 well-characterised PD patients and 542 controls from southern Spain. The potential pathogeniticy of the identified variants was assessed using in-silico analysis and subsequently classified as benign or deleterious. As a result, we observed a higher frequency of GBA variants in PD patients (12.2% vs. 7.9% in controls, p = 0.021), earlier mean age at disease onset in GBA variant carriers (50.6 vs. 56.6 years; p = 0.013), as well as more prevalent motor and non-motor symptoms in patients carrying deleterious variants. In addition, we found that dopaminergic motor complications are influenced by both benign and deleterious variants. Our results highlight the fact that the impact on the phenotype highly depends on the potential pathogenicity of the carried variants. Therefore, the course of motor and non-motor symptoms as well as treatment-related motor complications could be influenced by GBA variants.

Quality of life (QoL) in people with Parkinson´s disease (PD) is commonly measured with the PD questionnaire-39 (PDQ-39), but its factor structure and construct validity have been questioned. To develop effective interventions to improve QoL, it is crucial to understand the connection between different PDQ-39 items and to assess the validity of PDQ-39 subscales. With a new approach based on network analysis using the extended Bayesian Information Criterion Graphical Least Absolute Shrinkage and Selection Operator (EBICglasso) followed by factor analysis, we mostly replicated the original PDQ-39 subscales in two samples of PD patients (total N = 977). However, model fit was better when the “ignored” item was categorized into the social support instead of the communication subscale. In both study cohorts, “depressive mood”, “feeling isolated”, “feeling embarrassed”, and “having trouble getting around in public/needing company when going out” were identified as highly connected variables. This network approach can help to illustrate the relationship between different symptoms and direct interventional approaches in a more effective manner.

There is increasing evidence that supports the role of the cerebellum in the pathophysiology of dystonia. We used transcranial magnetic stimulation to test the hypothesis that patients with cervical dystonia may have a disrupted cerebellar cortical connectivity at rest, and that cerebellar plasticity is altered too. We enrolled 12 patients with isolated cervical dystonia and 13 controls. A paired-pulse transcranial magnetic stimulation protocol was applied over the right cerebellum and the left primary motor area. Changes in the amplitude of motor evoked potentials were analysed. Continuous and intermittent Theta Burst Stimulation over the cerebellum was also applied. The effects of these repetitive protocols on cortical excitability, on intra-cortical circuits and on cerebellar cortical inhibition were analysed. In healthy subjects, but not in dystonic patients, a conditioning stimulus over the cerebellum was able to inhibit the amplitude of the motor evoked potentials from primary motor cortex. In healthy subjects continuous and intermittent cerebellar Theta Burst Stimulation were able to decrease and increase respectively motor cortex excitability. Continuous Theta Burst Stimulation was able to abolish the cerebellar cortical inhibition observed in basal condition. These effects were not observed in patients with cervical dystonia. Cerebellar cortical connectivity and cerebellar plasticity is altered at rest in patients with cervical dystonia.

Nonmotor symptoms negatively affect health-related quality of life (HRQoL) in patients with Parkinson’s disease (PD). However, it is unknown which nonmotor symptoms are most commonly associated with HRQoL. Considering the complex interacting network of various nonmotor symptoms and HRQoL, this study aimed to reveal the network structure, explained HRQoL variance, and identify the nonmotor symptoms that primarily affect HRQoL. We included 689 patients with PD from the Cohort of Patients with Parkinson’s Disease in Spain (COPPADIS) study who were rated on the Nonmotor Symptoms Scale in Parkinson’s disease (NMSS) and the Parkinson´s Disease Questionnaire 39 (PDQ-39) at baseline. Network analyses were performed for the 30 items of the NMSS and both the PDQ-39 summary index and eight subscales. The nodewise predictability, edge weights, strength centrality, and bridge strength were determined. In PD, nonmotor symptoms are closely associated with the mobility, emotional well-being, cognition, and bodily discomfort subscales of the PDQ-39. The most influential nonmotor symptoms were found to be fatigue, feeling sad, hyperhidrosis, impaired concentration, and daytime sleepiness. Further research is needed to confirm whether influencing these non-motor symptoms can improve HRQoL.

Background Gilles de la Tourette Syndrome is a neurodevelopmental disorder that is caused by the interaction of environment with a complex genetic background. The genetic etiology of the disorder remains, so far, elusive, although multiple promising leads have been recently reported. The recent implication of the histamine decarboxylase (HDC) gene, the key enzyme in histamine production, raises the intriguing hypothesis of a possible role of histaminergic dysfunction leading to TS onset. Methods Following up on the finding of a nonsense mutation in a single family with TS, we investigated variation across the HDC gene for association with TS. As a result of a collaborative international effort, we studied a large sample of 520 nuclear families originating from seven European populations (Greek, Hungarian, Italian, Polish, German, Albanian, Spanish) as well as a sample collected in Canada. Results and Conclusions Interrogating 12 tagging SNPs (tSNP) across the HDC region, we find strong over-transmission of alleles at two SNPs (rs854150 and rs1894236) in the complete sample, as well as a statistically significant associated haplotypes. Analysis of individual populations also reveals signals of association in the Canadian, German and Italian samples. Our results provide strong support for the histaminergic hypothesis in TS etiology and point to a possible role of histamine pathways in neuronal development.

Peripheral inflammatory immune responses are thought to play a major role in the pathogenesis of Parkinson’s disease (PD). The neutrophil-to-lymphocyte ratio (NLR), a biomarker of systemic inflammation, has been reported to be higher in patients with PD than in healthy controls (HCs). The present study was aimed at determining if the peripheral inflammatory immune response could be influenced by the genetic background of patients with PD. We included a discovery cohort with 222 patients with PD (132 sporadic PD, 44 LRRK2 -associated PD (with p.G2019S and p.R1441G variants), and 46 GBA -associated PD), as well as 299 HCs. Demographic and clinical data were recorded. Leukocytes and their subpopulations, and the NLR were measured in peripheral blood. Multivariate lineal regression and post-hoc tests were applied to determine the differences among the groups. Subsequently, a replication study using the Parkinson’s Progression Markers Initiative cohort was performed which included 401 patients with PD (281 sPD patients, 66 LRRK2 -PD patients, 54 GBA -PD patients) and a group of 174 HCs. Patients with sporadic PD and GBA -associated PD showed a significantly lower lymphocyte count, a non-significantly higher neutrophil count and a significantly higher NLR than HCs. The peripheral inflammatory immune response of patients with LRRK2 -associated PD did not differ from HCs. Our study supports the involvement of a peripheral inflammatory immune response in the pathophysiology of sPD and GBA -associated PD. However, this inflammatory response was not found in LRRK2 -associated PD, probably reflecting different pathogenic inflammatory mechanisms.

Background Limited information is available on patients' experience living with Huntington’s disease (HD). The primary objective of this study was to assess the health-related quality of life and well being of patients with HD. Methods A non-interventional, cross-sectional study was conducted in 17 hospitals-based movement disorders units in Spain. Patients aged ≥ 18 years, genetically HD diagnosed [with a diagnostic confidence level score of 4, and an Independence Scale (IS) score ≥ 70] were included. The primary variables were the Huntington's Disease Health-related Quality of Life (HDQLIFE) scores and results of the Satisfaction with Life Scale (SWLS). Secondary outcomes include the Unified HD Rating Scale (UHDRS), Beck Hopelessness Scale (BHS), Stigma Scale for Chronic Illness (SSCI-8), Beck Depression Inventory-Fast Screen (BDI-FS) and Problem Behaviours Assessment for HD short Version (PBA-S). Results A total of 102 patients were included. The mean age (SD) was 53.1 (12.1) years and 56% were male. Most of the patients (99.0%) showed motor symptoms (87.3%), behavioural and psychiatric disturbances (59.8%), or cognitive impairment (20.6%). HDQLIFE domain score means (SD) includes concern with death and dying 45.97 (9.60) end-of-life planning 37.91 (8.84), and meaning and purpose 44.74 (9.05). SWLS score mean was 24.25 (7.33). Depressive symptoms were found in 37.4% of patients and moderate-to-severe feelings of hopelessness in 32.9%. The prevalence of stigma was 55.9% ( n  = 57). Conclusion HD impacted quality of life, with prevalent motor, psychiatric symptoms and cognitive impairment. Patient perspectives may provide complementary information to implement specific interventions.

Individual cognitive profiles of patients with Parkinson’s disease dementia (PDD) are highly heterogeneous, suggesting possible biological subtypes. We studied 75 PD patients who developed dementia in the course of the Parkinson’s Progression Markers Initiative study to investigate data-driven evidence for the existence of distinct cognitive subtypes of PDD. Using Ward’s hierarchical clustering on neuropsychological test data, we identified two distinct cognitive subtypes. Despite similar dementia severity (MoCA: 20.6 vs 20.0), cluster-A exhibited more pronounced memory deficits ( n  = 50), whereas cluster-B showed greater visuospatial impairments ( n  = 25). The subtypes did not differ in demographic, motor, or MRI-based neurodegeneration measures. However, the visuospatial-predominant cluster-B had a higher prevalence of GBA mutations ( p  = 0.003) and hallucinations ( p  = 0.009). No differences were found in APOE-ε4 prevalence or cerebrospinal fluid biomarkers of Alzheimer’s pathology. These findings reveal distinct memory-predominant and visuospatial-predominant PDD subtypes, which associate with different clinical and genetic features but are independent of comorbid Alzheimer’s pathology.

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor symptoms and heterogeneous cognitive impairments influenced by factors such as age, disease duration, and severity. Traditional neuropsychological assessments often fall short in capturing the multifaceted nature of PD-related cognitive dysfunction due to their reliance on single test metrics. This study provides empirical support for the implementation of domain-based cognitive assessments, structured in line with Movement Disorder Society recommendations, to provide a multidimensional evaluation of cognitive profiles in PD patients. Neuropsychological and clinical data were analyzed from 316 PD patients recruited from three Spanish hospitals-Hospital Clínico San Carlos (Madrid), the University Complejo Universitario de Santiago de Compostela (Galicia), and Hospital Virgen del Rocío (Sevilla)- and a control group of 96 older individuals, whose age difference from the PD group was statistically significant. Five cognitive domains were constructed, addressing attention/working memory, executive functions, memory, visuospatial abilities, and language, using composite z-scores derived from standardized neuropsychological tests. Latent Cluster Analysis identified three distinct cognitive profiles: (1) a fronto-striatal profile characterized by mild deficits in executive and attention functions and intact visuospatial abilities, (2) a posterior cortical profile marked by severe memory and visuospatial impairments but strong language performance, and (3) a preserved profile displaying mild deficits across multiple domains. Comparisons between PD clusters and controls revealed significant differences in cognitive trajectories, emphasizing the value of a domain-based approach for differentiating neurodegenerative patterns from normal aging. The findings highlight the potential of domain-based assessments to unify data across diverse samples, fostering standardized cross-cohort comparisons and facilitating large-scale research initiatives. By enabling methodological consistency, this approach provides a robust framework for advancing the understanding of cognitive dysfunctions in PD and improving clinical decision-making.