The spectrum of anti-GQ1B antibody syndrome: beyond Miller Fisher syndrome and Bickerstaff brainstem encephalitis.

INTRODUCTION: Since the initial identification of Miller Fisher syndrome (MFS) and Bickerstaff brainstem encephalitis (BBE),significant milestones have been achieved in understanding these diseases.Discoveries of common serum antibodies (IgG anti-GQ1b), antecedent infections, neurophysiological data, andneuroimaging suggested a shared autoimmune pathogenetic mechanism rather than distinct pathogenesis, leadingto the hypothesis that both diseases are part of a unified syndrome, termed "Fisher-Bickerstaff syndrome". The subsequent identification of atypical anti-GQ1b-positive forms expanded the classification to a broader condition known as "Anti-GQ1b-Antibody syndrome". METHODS: An exhaustive literature review was conducted, analyzing a substantial body of research spanning from the initialdescriptions of the syndrome's components to recent developments in diagnostic classification and researchperspectives. RESULTS: Anti-GQ1b syndrome encompasses a continuous spectrum of conditions defined by a common serological profilewith varying degrees of peripheral (PNS) and central nervous system (CNS) involvement. MFS and BBE represent theopposite ends of this spectrum, with MFS primarily affecting the PNS and BBE predominantly involving the CNS.Recently identified atypical forms, such as acute ophthalmoparesis, acute ataxic neuropathy withoutophthalmoparesis, Guillain-Barré syndrome (GBS) with ophthalmoparesis, MFS-GBS and BBE-GBS overlap syndromes,have broadened this spectrum. CONCLUSION: This work aims to provide an extensive, detailed, and updated overview of all aspects of the anti-GQ1b syndromewith the intention of serving as a stepping stone for further shaping thereof. Special attention was given to therecently identified atypical forms, underscoring their significance in redefining the boundaries of the syndrome.

Longitudinal change of energy expenditure, body composition and dietary habits in Progressive Supranuclear Palsy patients.

INTRODUCTION: Alterations in metabolic status, body composition, and food intake are present in all neurodegenerative diseases. Aim of this study was to detect the progression of these changes in Progressive Supranuclear Palsy (PSP). METHODS: We conducted a longitudinal study of 15 patients with PSP. The assessments were performed at baseline (T0) and after 7(IQR = 5) months of follow-up (T1). We collected anthropometric measures including body weight, height, body mass index and waist circumference, metabolic parameters through indirect calorimeters, body composition using bioimpedance analysis, and dietary habits with a validated questionnaire. PSP-rating scale (PSP-rs) was used to evaluate disease severity and dysphagia. RESULTS: The majority of patients (66.66%) presented PSP-Richardson Syndrome and 33.33% the other variant syndromes of the disease. At T1 there was a decrease in intake of total daily calories (p < 0.001), proteins (p < 0.001), fibers (p = 0.001), calcium (p = 0.008), iron (p < 0.001), zinc (0.034), vitamin E (p = 0.006) and folates (p = 0.038) compared to T0. No other changes were found. As for T1 data, no significant differences were shown according to disease phenotypes or the presence of clinically significant dysphagia for solids. CONCLUSIONS: Within a mid-term follow up, PSP patients presented reduced caloric and proteins intake regardless the presence of dysphagia. The PSP-rs is likely not adequate to assess dysphagia, which should be investigated by specific clinical scales or instrumental examinations. With the goal of maintaining adequate nutritional status, the administration of protein and vitamin supplements should be considered even in the absence of dysphagia evidenced by the rating scales.

Anti-pan-neurofascin nodopathy: cause of fulminant neuropathy.

Autoimmune nodopathies are inflammatory diseases of the peripheral nervous system with clinical and neurophysiological peculiar characteristics. In this nosological category, we find patients with autoantibodies against Neurofascin 140/186 and 155, Contactin1, and Caspr1 directed precisely towards nodal and paranodal structures. These antibodies are extremely rare and cause severe clinical symptoms. We describe the clinical case of a patient with autoimmune nodopathy caused by the coexistence of anti-neurofascin (NF) 186/140 and 155, characterized by progressive weakness in all limbs leading to tetraplegia, involving cranial nerves, and respiratory insufficiency. Response to first-line treatments was good followed by rapid dramatic clinical relapse. There are few reported cases of anti-pan NF neuropathy in the literature, and they present a clinical phenotype similar to our patient. In these cases, early recognition of clinical red flags of nodopathies and serial neurophysiological studies can facilitate the diagnosis. However, the severe clinical relapse suggests a possible early use of immunosuppressive therapies for this rare category of patients.

Miller Fisher syndrome: an updated narrative review.

Introduction: Miller Fisher syndrome (MFS) is considered a rare variant of Guillain-Barré syndrome (GBS), a group of acute-onset immune-mediated neuropathies characterized by the classic triad of ataxia, areflexia, and ophthalmoparesis. The present review aimed to provide a detailed and updated profile of all aspects of the syndrome through a collection of published articles on the subject, ranging from the initial description to recent developments related to COVID-19. Methods: We searched PubMed, Scopus, EMBASE, and Web of Science databases and gray literature, including references from the identified studies, review studies, and conference abstracts on this topic. We used all MeSH terms pertaining to "Miller Fisher syndrome," "Miller Fisher," "Fisher syndrome," and "anti-GQ1b antibody." Results: An extensive bibliography was researched and summarized in the review from an initial profile of MFS since its description to the recent accounts of diagnosis in COVID-19 patients. MFS is an immune-mediated disease with onset most frequently following infection. Anti-ganglioside GQ1b antibodies, detected in ~85% of patients, play a role in the pathogenesis of the syndrome. There are usually no abnormalities in MFS through routine neuroimaging. In rare cases, neuroimaging shows nerve root enhancement and signs of the involvement of the central nervous system. The most consistent electrophysiological findings in MFS are reduced sensory nerve action potentials and absent H reflexes. Although MFS is generally self-limited and has excellent prognosis, rare recurrent forms have been documented. Conclusion: This article gives an updated narrative review of MFS with special emphasis on clinical characteristics, neurophysiology, treatment, and prognosis of MFS patients.

Measurement of visual acuity with a digital eye chart: optotypes, presentation modalities and repeatability

Purpose: Digital or computerised eye charts are becoming standard in the examination of visual acuity. Each instrument allows the selection of different optotypes, presentation modalities, and crowding. The aim of this study was to examine the differences in visual acuity (VA) measurement using a digital eye chart, comparing different optotypes and procedures, together with an evaluation of the repeatability of the measurement.MethodsTwo groups of 52 participants aged between 18 and 31 years participated in the study. In the first experiment, VA thresholds were measured using LEA Symbols, Tumbling E, and Landolt Rings in monocular and binocular conditions using single line presentation and QUEST presentation. In the second experiment, we have compared all modalities of presentation together with a paper eye-chart and test the repeatability.ResultsThe results showed that thresholds for LEA Symbols are low. The modality of presentation affects these thresholds. For Landolt Rings and Tumbling E, the QUEST procedure gave significantly better thresholds than line presentation, while this difference was absent for LEA Symbols. In comparing all modalities of presentation, single letter and line presentation showed similar values, slightly better than block presentation. Paper eye-charts showed better values of VA. Repeatability and agreement were good for all presentations, but best for QUEST.ConclusionsThe QUEST modality of presentation provides a better threshold than line presentation except for LEA Symbols. Examiners using digital eye charts must take into account that not all modalities of presentation and optotypes are equivalent and give different VA thresholds. Specific thresholds need to be used for each optotype and presentation modality. (AU)

Measurement of visual acuity with a digital eye chart: optotypes, presentation modalities and repeatability.

PURPOSE: Digital or computerised eye charts are becoming standard in the examination of visual acuity. Each instrument allows the selection of different optotypes, presentation modalities, and crowding. The aim of this study was to examine the differences in visual acuity (VA) measurement using a digital eye chart, comparing different optotypes and procedures, together with an evaluation of the repeatability of the measurement. METHODS: Two groups of 52 participants aged between 18 and 31 years participated in the study. In the first experiment, VA thresholds were measured using LEA Symbols, Tumbling E, and Landolt Rings in monocular and binocular conditions using single line presentation and QUEST presentation. In the second experiment, we have compared all modalities of presentation together with a paper eye-chart and test the repeatability. RESULTS: The results showed that thresholds for LEA Symbols are low. The modality of presentation affects these thresholds. For Landolt Rings and Tumbling E, the QUEST procedure gave significantly better thresholds than line presentation, while this difference was absent for LEA Symbols. In comparing all modalities of presentation, single letter and line presentation showed similar values, slightly better than block presentation. Paper eye-charts showed better values of VA. Repeatability and agreement were good for all presentations, but best for QUEST. CONCLUSIONS: The QUEST modality of presentation provides a better threshold than line presentation except for LEA Symbols. Examiners using digital eye charts must take into account that not all modalities of presentation and optotypes are equivalent and give different VA thresholds. Specific thresholds need to be used for each optotype and presentation modality.

Landau damping and coherent structures in narrow-banded 1+1 deep water gravity waves.

We study the modulational instability in surface gravity waves with random phase spectra. Starting from the nonlinear Schrödinger equation and using the Wigner-Moyal transform, we study the stability of the narrow-banded approximation of a typical wind-wave spectrum, i.e., the JONSWAP spectrum. By performing numerical simulations of the nonlinear Schrödinger equation we show that in the unstable regime, the nonlinear stage of the modulational instability is responsible for the formation of coherent structures. Furthermore, a Landau-type damping, due to the incoherence of the waves, whose role is to provide a stabilizing effect against the modulational instability, is both analytically and numerically discussed.