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Abstract Background The association between levodopa treatment and neuropathy in Parkinson's disease (PD) remains controversial, particularly when comparing the oral and intestinal administration routes. Objective To compare the electrophysiological and biochemical changes in patients receiving oral levodopa or levodopa/carbidopa intestinal gel (LCIG) and to determine their association with neuropathy development. Methods The current prospective cross-sectional study included 32 PD patients (18 oral and 14 LCIG). Demographic features, disease duration, Hoehn and Yahr (H&Y) stage, Unified Parkinson's Disease Rating Scale (UPDRS) scores, biochemical parameters (vitamin B12, folate, homocysteine), and electrophysiological values were recorded. Nerve conduction studies (NCSs) of the median, ulnar, peroneal, tibial, and sural nerves were performed unilaterally, using reference values from our neurophysiology laboratory. Results The LCIG group presented significantly higher doses of levodopa (p < 0.001), levodopa equivalent daily dose (LEDD; p < 0.001), and homocysteine levels (p = 0.002) compared with the oral group. Electrophysiological tests revealed significantly reduced motor amplitudes and sensory conduction velocities in the median, ulnar, tibial, and sural nerves in the LCIG group. The median and tibial F-wave latencies were prolonged in the LCIG group. Correlation analyses indicated significant associations involving homocysteine elevation and conduction abnormalities. Conclusion Patients receiving LCIG presented higher homocysteine levels and more frequent electrophysiological abnormalities than those on oral treatment, suggesting a higher risk of polyneuropathy. These findings highlight the importance of biochemical monitoring and individualized treatment strategies in advanced PD.

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Abstract Background Multiple sclerosis (MS) is an inflammatory and neurodegenerative disorder whose prevalence varies across Brazil (from 15–27 cases per 100 thousand inhabitants), and the absence of an extensive national study limits the understanding of MS epidemiology in a nation as diverse as Brazil. Objective To compare epidemiological data, including healthcare access, among people with MS across four Brazilian regions. Methods Data from 2,974 Brazilian MS patients in the Collaborative Latin American Database for Multiple Sclerosis (BRANDO) were analyzed. We assessed demographic and clinical outcomes, as well as healthcare access, to elucidate regional differences. Results The cohort was predominantly composed of female patients (72.5%) with MS onset at a mean age of 30.6 years. Regarding the regional differences, there was a lower predominance of female patients (68.7%; p = 0.003) in the Southeast, a higher rate of subjects of mixed ethnicity (p < 0.001) in the Midwest (40.3%) and Northeast (63.7%), higher scores on the Expanded Disability Status Scale (EDSS) in the Northeast (4.0; p < 0.001), a higher prevalence of relapsing-remitting MS (RRMS) in the Southeast and Midwest (87%; p < 0.001), while the Northeast presented (p < 0.001) the highest rates of primary progressive MS (PPMS) and secondary progressive MS (SPMS) (PPMS = 15.8%; SPMS = 18%). The Northeast presented the longest time (5.9 years; p < 0.01) from disease onset until MS diagnosis (range for the other regions = 1.9–3.7 years). And the Midwest showed the shortest time (2.1 years; p < 0.01) from disease onset until first access to disease-modifying therapies (DMTs; range for the other regions = 3.5–5.1 years). Conclusion The present is the first nationwide epidemiological study on people with MS in Brazil. It underscores regional epidemiological variations and differences in healthcare access, advocating for tailored approaches in MS management and research.

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Abstract Background The increasing screen time among the pediatric population is a detrimental factor for cognitive and psychosocial development, especially for children with autism spectrum disorder (ASD). However, there are still many questions regarding its negative effects on behavior and sleep in this population group and, as of the writing of this study, there are no specific recommendations regarding screen use for children with ASD. Objective To synthesize and analyze the current evidence on the association between screen exposure time, behavioral symptoms, and sleep disorders in ASD children. Methods The authors provided a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist adapted review of studies that examined the association between screen time and both autistic symptoms and sleep disturbances in this patient population. Results Research indicates that excessive screen use among ASD children, particularly in preschool-aged children, may be associated with significant behavioral, emotional, and sleep quality impacts. The screen time recommendations set by the World Health Organization for the general pediatric population could also be applied to these children, at least until new studies can clarify specific guidelines, taking their particularities into account. Conclusion This review article explores the current evidence on the association between excessive screen time and both autistic symptoms and sleep disturbances in ASD, underscoring the relevance of further clinical investigation.

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Abstract Background Rapid eye movement (REM) sleep behavior disorder (RBD) is marked by abnormal behaviors during REM sleep and is associated with neurodegenerative diseases, such as Parkinson's disease. Early diagnosis is critical for managing these associations effectively. Objective To validate the Persian version of the RBD Screening Questionnaire (RBDSQ-PER) for Persian-speaking patients. Methods The study involved 171 participants from sleep centers associated with the Tehran University of Medical Sciences, including Parkinson's disease patients with RBD, individuals with obstructive sleep apnea, and healthy controls. The RBDSQ was translated into Persian following established linguistic validation protocols. Reliability and diagnostic utility were measured with Cronbach's alpha to determine internal consistency and the intraclass correlation coefficient. Results The RBDSQ-PER demonstrated a Cronbach's alpha and intraclass correlation coefficient of 0.847, indicating strong internal consistency. The analysis of the receiver operating characteristic curve established a cut-off score of 5.5, differentiating individuals with and without RBD with 100% sensitivity and 93% specificity. Conclusion The RBDSQ-PER is a reliable tool for screening in Persian-speaking populations, enhancing initial sleep assessments and guiding further diagnostic evaluations. Future research should consider broader patient groups to extend the questionnaire's applicability.

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Abstract Background Fatigue is a frequent and under-recognized symptom in adults with spinal muscular atrophy (SMA). Although motor scales can detect disease progression, they may be insufficiently sensitive over short observation periods, particularly in patients with slower progression. Objective To assess the prevalence and longitudinal course of fatigue in adult SMA patients using validated instruments. General perceived fatigue was assessed using the Fatigue Severity Scale (FSS), while the Modified Fatigue Impact Scale (MFIS) was used to evaluate multidimensional fatigue—comprising the physical, cognitive, and psychosocial domains. Additionally, we explored associations with motor function, neurophysiological parameters, and treatment status. Methods Twenty-five adults with genetically confirmed SMA were evaluated at baseline and after one year using the FSS and MFIS. Motor function was measured by the Hammersmith Functional Motor Scale – Expanded, Revised Upper Limb Module (RULM), and Motor Function Measurement (MFM); neurophysiological assessment included Compound Muscle Action Potential (CMAP), Motor Unit Number Index (MUNIX) and repetitive nerve stimulation. Patients were stratified by fatigue status and use of disease-modifying therapies. Results Significant fatigue (FSS > 4) was observed in 60% of patients at baseline and 56% at follow-up. After 1 year, the prevalence of fatigue was significantly lower in treated patients (33.3%) compared to untreated ones (75%; p = 0.04). The MFIS scores remained stable across the physical, cognitive, and psychosocial domains. No associations were found between fatigue severity and age, disease duration, motor scale scores, or neurophysiological parameters. Conclusion Fatigue is highly prevalent in adults with SMA and does not correlate with disease severity or motor/neurophysiological measures. Patients receiving disease-modifying therapies showed lower fatigue frequency, reinforcing the relevance of fatigue as a meaningful patient-reported outcome in this population.

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Abstract Background Alzheimer's disease (AD) is a progressive neurodegenerative condition causing cognitive decline. Given the aging population and increasing prevalence, understanding hospital morbidity patterns is crucial for improving prevention strategies and public health planning. Objective To analyze the epidemiological profile and temporal trend of AD hospitalizations in Brazil between 2012 and 2022. Methods The present mixed ecological study used data from the Hospital Information System of the Unified Health system. We calculated the frequencies for sex, age group, and skin color, along with the average length of stay and total costs. Simple linear regression was used for the temporal trend analysis across sex, age groups by sex, and regions. Results A higher proportion of hospitalizations was observed in females (65.80%), individuals aged 80 years or older (60.12%), and white individuals (49.06%). The average hospital stay was 21.6 days, with a total cost of R$ 23,306,587.01. The hospitalization trend was stable across both sexes, all age groups, and most regions (4.88/100 thousand hospitalizations), except for the Northeast, which showed a significant increase (β = 0.408; p < 0.001). Conclusion The profile of AD hospitalizations in Brazil is predominantly female, in individuals over 80 and white. While the trend remained stable nationally, there was an increase in the Northeast region. Additionally, a reduction in the average number of hospitalization days and hospital costs was observed throughout the period analyzed.

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Abstract Background Secondary headaches arise from underlying medical conditions and are associated with significant morbidity and mortality. Their diagnosis relies primarily on a comprehensive clinical history and a thorough physical examination, both aimed at identifying key warning signs. The SNNOOP10 mnemonic is a widely-recognized tool used to screen for potential secondary causes of headache. It consists of a structured checklist of 15 red flags, with validated sensitivity, specificity, and predictive values. However, the original English version may present challenges for healthcare providers who are non-native English speakers. Objective To introduce a culturally-adapted version of the SNNOOP10 mnemonic in Portuguese: "NÃO É PRIMÁRIA" ("IT IS NOT PRIMARY"). Methods The authors reorganized the SNNOOP10 red flags into "NÃO É PRIMÁRIA" by semantically grouping related items, assigning each letter to a corresponding clinical element and matching the original red flags into each letter of the new acronym. A comparative table and image were developed to ensure clarity. Results The new mnemonic covers all reorganized items of the SNNOOP10 adapted for Portuguese speakers. Conclusion "NÃO É PRIMÁRIA" is a practical mnemonic that adapts THE SNNOOP10 for Portuguese-speaking settings, based on clinical experience. It requires formal validation, and future studies should assess its diagnostic accuracy and applicability.

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Abstract Since the 1960s, the pathophysiology of dystonia has been primarily attributed to dysfunction of the basal ganglia and their associated pathways. However, growing evidence from both basic and clinical research has highlighted the additional importance of the cerebellum, suggesting that dystonia arises from a motor-network dysfunction involving not only the basal ganglia, but also the cerebellum. Neuroimaging studies reinforce this concept, revealing structural and functional abnormalities in the cerebellum and its afferent pathways in patients with dystonia. Moreover, the dual involvement of the cerebellum and basal ganglia may help explain the frequent co-occurrence of dystonia in patients with ataxia and vice versa. The present review aims to integrate evidence from pathophysiology, clinical studies, genetics, and neuroimaging to underscore the crucial role of the cerebellum in the genesis of dystonia.

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Abstract The present narrative review delves into the multifaceted roles of the cerebellum, highlighting its significance beyond traditional motor functions to encompass cognitive and behavior-related processes, as evidenced by advancements in functional neuroimaging. We provide a comprehensive summary of the cerebellum's embryological development, intricate microanatomy, macroanatomy, and vascular anatomy of the cerebellum, revealing how these aspects contribute to its unique circuitry and operational capabilities. A non-systematic literature search was conducted using the PubMed database, focusing on landmark and recent studies addressing the embryology, anatomy, clinical correlations and radiological aspects of the cerebellum. Ultimately, this review underscores the cerebellum's complex structure and diverse function, advocating for a deeper understanding to improve diagnostic and therapeutic approaches for cerebellar disorders.

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Abstract For many decades, the cerebellum was regarded almost exclusively as a structure devoted to motor regulation, responsible for balance, coordination, and the fine-tuning of movement. This view began to change in the 1990s, when studies with patients with isolated cerebellar lesions revealed cognitive and affective disturbances that could not be solely explained by cortical dysfunction. Subsequent anatomical, neuroimaging, and clinical investigations demonstrated robust reciprocal connectivity between the cerebellum and prefrontal regions, while functional imaging confirmed cerebellar activation during cognitive tasks without any motor component. Cognitive impairment linked to cerebellar dysfunction is now recognized as a prominent feature of spinocerebellar ataxias, and it has also been reported in other major neurodegenerative disorders, including Huntington's disease, Parkinson's disease, and Alzheimer's disease. Therefore, the aim of the current narrative review is to synthesize and critically analyze the pathophysiological, neuropathological, genetic, clinical, and neuroimaging evidence that underscores the cerebellum's essential contributions to cognition.

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Abstract Cerebral amyloid angiopathy (CAA) is a small vessel disease characterized by the deposition of amyloid-beta in small cerebral vessels, which can lead to intracerebral hemorrhages and cognitive impairment. Rare variants, such as cerebral amyloid angiopathy-related inflammation (CAA-ri) and iatrogenic CAA (ICAA), may mimic other neurological conditions and challenge diagnosis in clinical practice. We present three cases that illustrate distinct CAA syndromes, along with CSF biomarker analysis. One patient experienced recurrent hemorrhagic strokes with a history of dural graft, raising concerns about amyloid transmission. Two patients presented with rapidly progressive dementia that fulfilled CAA-ri criteria. All cases exhibited decreased levels of CSF Aβ40 and Aβ42, with one showing elevated p-tau, suggesting comorbid Alzheimer's pathology. Cerebrospinal fluid biomarkers complement neuroimaging in the diagnosis of CAA, aiding in differentiation from other dementias. Early recognition and diagnosis of CAA-ri variants is crucial, because immunotherapy may improve outcomes. Further research is necessary to establish biomarker thresholds and their clinical applicability.

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Abstract Sir Isaac Newton is widely regarded as one of the greatest scientific minds in history, with seminal contributions across mathematics, physics—particularly optics—and the formulation of the law of universal gravitation. Less well known, however, is his extraordinary and rarely recognized contribution to the field of neurology: the early conceptualization of fiber decussation within the optic chiasm. Through his studies on light and vision, Newton proposed that optic nerve fibers cross at the chiasm—a hypothesis that would later be anatomically confirmed and provided the basis for understanding the classic patterns of visual field deficits.