Abstract Background Sleep-disordered breathing (SDB) is increasingly recognized in myasthenia gravis (MG), yet potential differences in sleep respiratory patterns between antibody-defined MG subtypes remain poorly understood. We aimed to evaluate sleep disorders and polysomnographic characteristics in patients with acetylcholine receptor antibody–positive (AChR-MG) and muscle-specific tyrosine kinase antibody–positive (MuSK-MG) generalized MG. Methods Eighteen clinically stable MG patients (9 AChR-MG, 9 MuSK-MG) and 9 healthy controls underwent attended overnight polysomnography followed by the Multiple Sleep Latency Test (MSLT). Standardized sleep questionnaires and MG clinical scales were administered to assess sleep-related symptoms and disease severity. Results Obstructive sleep apnea was detected in 89% of AChR-MG and 78% of MuSK-MG patients. Both MG subgroups showed significantly higher apnea–hypopnea index values compared with controls (p < 0.05). Although overall AHI severity did not differ significantly between antibody groups, distinct respiratory patterns were observed. Respiratory events clustered predominantly during REM sleep in AChR-MG, whereas MuSK-MG patients exhibited more frequent events during NREM or supine sleep. Conclusions Sleep-disordered breathing appears to be common in MG, but polysomnographic patterns may differ according to antibody subtype. REM-predominant respiratory events in AChR-MG and NREM or positional predominance in MuSK-MG may reflect differences in muscle involvement between these subtypes. These findings suggest that antibody-specific mechanisms may influence nocturnal respiratory dysfunction in MG and highlight the importance of targeted sleep assessment in this population.

Objective: An agarose-based long-range polymerase chain reaction (PCR) assay was performed on patients with a preliminary diagnosis of Friedreich's ataxia (FA). It aimed to determine the repeat number in intron 1 of the FXN gene and to investigate the genotype-phenotype correlation. Patients and Methods: Nineteen cases participated in the study. Long-range PCR was performed under appropriate conditions using two custom-designed primer pairs (F1-R1 and F2-R2). The PCR products were run on an agarose gel, and guanine-adenine-adenine (GAA) repeat numbers were determined. Results: Biallelic GAA repeat expansions were detected in 6 patients. Four patients had typical FA. One had late-onset FA (LOFA). Another had very late-onset FA (VLOFA). All patients diagnosed with FA had ataxia and areflexia. The detected repeat numbers were approximately 190-1120 for F1-R1 and 170-1100 for F2-R2. The patient with LOFA had 190/1000 GAA repeats. The VLOFA patient Conclusion: An earlier clinical onset correlated with higher GAA repeats. An agarose-based long-range PCR assay is a quick, low-cost, and effective way to determine GAA repeats. This study shows it can diagnose the disease and identify carriers.

Introduction: Juvenile myasthenia gravis (JMG) is a rare autoimmune disorder with a variable clinical course and limited pediatric-specific treatment guidelines. Objective clinical scales, such as the Quantitative Myasthenia Gravis (QMG) Score and the Pediatric Myasthenia Gravis Quality of Life 15 (PM-QOL15), may support individualized management, but their role in routine practice remains underexplored. Methods: We retrospectively reviewed 10 seropositive JMG patients followed at a single tertiary neuromuscular clinic between 2014 and 2024. All patients underwent a systematic assessment with QMG at each visit, while PM-QOL15 was administered at the final visit. Clinical data, comorbidities, antibody status, treatment modalities, and outcomes were analyzed. Associations between treatment strategies, comorbidities, and scale scores were explored using appropriate statistical methods. Results: Seven patients (70%) underwent thymectomy, resulting in a reduction in mean QMG scores from 7.7 to 2.4, though residual relapses were observed. Chronic intravenous immunoglobulin (IVIG) therapy, administered to 70% of patients, did not significantly reduce relapse rates or steroid exposure and was associated with higher QMG scores in the second year, suggesting use in more severe phenotypes rather than therapeutic efficacy. Prolonged corticosteroid therapy did not improve remission time or relapse frequency and was complicated by major adverse effects in two patients. Timing of azathioprine initiation showed no significant correlation with relapse frequency. PM-QOL15 correlated strongly with mean QMG (r = 0.88, p < 0.001), reflecting cumulative disease burden. Patients with comorbidities required longer stabilization, although differences were not statistically significant. Conclusions: The routine integration of QMG and PM-QOL15 into follow-up may facilitate the earlier recognition of subclinical deterioration, provide objective measures of treatment response, and guide personalized management in JMG. Thymectomy showed benefit in selected patients, while the long-term roles of IVIG and corticosteroids remain uncertain. Larger multicenter prospective studies are warranted to confirm these findings and refine evidence-based strategies for pediatric JMG.

Objective: Obstructive sleep apnea (OSA) is a sleep disorder accompanied by intermittent hypoxia. Neuromuscular transmission (NT) is known to be disturbed under chronic hypoxia. In this descriptive study, it has been aimed to test NT under intermittent hypoxia in OSA. Methods: Thirty-nine newly diagnosed OSA patients without any comorbidities or conditions that alter NT were included in the study. Jitter analysis was performed using a concentric needle electrode. Results: The mean jitter value of 39 OSA patients was 25.9 ± 3.7 μs. When compared to the mean reference jitter values, patients in the present study had significantly higher jitter (p < 0.001). Seven (17.9%) patients met the electrophysiological criteria for NT failure. Conclusion: The authors propose that intermittent hypoxia can be the trigger for NT failure in OSA. The interaction between increased oxidative stress and disturbed mitochondrial functions may also contribute.

Myasthenia Gravis (MG) is an autoimmune disease known to be often associated with thymic pathologies. This study aimed to evaluate the clinical, serological and electrophysiological data of patients with thymic pathology in terms of possible accompanying MG.

Background and Aims: This study aimed to identify the clinical characteristics and electrodiagnostic subtypes of Guillain-Barre syndrome (GBS) in Istanbul. Methods: Patients with GBS were prospectively recruited between April 2019 and March 2022 and two electrodiagnostic examinations were performed on each patient. The criteria of Ho et al., Hadden et al., Rajabally et al., and Uncini et al. were compared for the differentiation of demyelinating and axonal subtypes, and their relations with anti-ganglioside antibodies were analyzed. Results: One hundred seventy-seven patients were included, 69 before the coronavirus disease 2019 pandemic (April 2019-February 2020) and 108 during the pandemic (March 2020-March 2022), without substantial changes in monthly frequencies. As compared with the criteria of Uncini et al., demyelinating GBS subtype diagnosis was more frequent according to the Ho et al. and Hadden et al. criteria (95/162, 58.6% vs. 110/174, 63.2% and 121/174, 69.5%, respectively), and less frequent according to Rajabally et al.'s criteria (76/174, 43.7%). Fourteen patients' diagnoses made using Rajabally et al.'s criteria were shifted to the other subtype with the second electrodiagnostic examination. Of the 106 analyzed patients, 22 had immunoglobulin G anti-ganglioside antibodies (14 with the axonal subtype). They had less frequent sensory symptoms (54.5% vs. 83.1%, p = 0.009), a more frequent history of previous gastroenteritis (54.5% vs. 22.9%, p = 0.007), and a more severe disease as compared with those without antibodies. Interpretation: Serial electrodiagnostic examinations are more helpful for accurate subtype diagnosis of GBS because of the dynamic pathophysiology of the disease. We observed no significant increase in GBS frequency during the pandemic in this metropolis.

This consensus statement by a panel of neurology experts aimed to provide a practical and implementable guidance document to assist clinicians with the best clinical practice in terms of diagnosis, treatment, and monitoring of late-onset Pompe disease (LOPD). The participating experts consider the clinical suspicion of LOPD by the physician to be of utmost importance in the prevention of diagnostic and therapeutic delay in LOPD patients. A diagnostic algorithm is proposed to facilitate the diagnosis of LOPD in patients presenting with unexplained proximal/axial weakness (with or without respiratory symptoms) or restrictive respiratory insufficiency with hyperCKemia and/or exercise intolerance as the red flag symptoms/signs that raise the index of suspicion for LOPD diagnosis. The diagnosis is based on the subsequent use of dried blood spot (DBS) assay, and the DBS assay can be confirmed by acid alpha-glucosidase (GAA) tissue analysis in leukocytes, fibroblasts, or muscle fibers and/or genetic mutation analysis. Accordingly, experts consider increased awareness among physicians about potential presenting characteristics with a high index of suspicion for LOPD to be crucial to suspect and consider LOPD in the differential diagnosis, while strongly suggesting the use of a diagnostic algorithm combined with DBS assay and confirmatory tests in the timely diagnosis of LOPD and implementation of best practice patterns.

BackgroundDespite the primary myelin-related pathophysiology, small fiber neuropathy (SFN) and axonal degeneration are also considered to be involved and associated with disabling symptoms and impaired quality of life in chronic inflammatory demyelinating polyneuropathy (CIDP). Demonstration of SFN usually requires complex or invasive investigations.ObjectsIn vivo corneal confocal microscopy (IVCCM) has evolved as a non-invasive, easily applied method for quantification of small fiber involvement in peripheral nerve disorders. We aimed to investigate the potential role of IVCCM in CIDP.MethodsIn this cross-sectional study, 15 patients with CIDP underwent assessment with clinical disability scales, neuropathic pain (NP) and autonomic symptom questionnaires, nerve conduction studies, and IVCCM. IVCCM parameters were analyzed and compared to those from 32 healthy controls.ResultsCorneal nerve fiber density (CNFD) and corneal nerve fiber length (CNFL) were significantly decreased in the CIDP group, compared to those in controls (p = 0.03 and p = 0.024, respectively). Langerhans cells and fiber tortuosity were increased in CIDP patients (p = 0.005 and p = 0.001, respectively). IVCCM parameters were significantly lower in patients with NP compared to those in patients without NP.ConclusionIVCCM shows promise as a non-invasive complementary biomarker in the assessment of demyelinating polyneuropathies, providing insights into the potential pathophysiology of these non-length-dependent neuropathies.

Introduction Muscle weakness and easy fatigability are the clinical hallmarks of myasthenia gravis (MG). However, fatigue perception, which can be seen quite often in myasthenic patients, and its effect on the quality of life, irrespective of motor deficit, has not been elucidated yet. The aim is to evaluate the frequency of fatigue in myasthenic patients with nearly full muscle strength and the effect of fatigue on quality of life by assessing its correlation with other symptoms. Methods Fifty-three patients with ocular or mild generalized MG in remission or minimal manifestations completed the questionnaires measuring the severity of MG and quality of life (MG Composite Scale and MG-Activities of Daily Living Profile). Both patient group and control group (53 healthy volunteers)completed the scales assessing fatigue [Fatigue Assessment Scale (FAS) and Fatigue Impact Scale (FIS)], depression [Beck Depression Inventory (BDI)] and sleep (Epworth Sleepiness Scale). Disease severity was assessed using MG Foundation of America (MGFA) and MGFA Post-Intervention Status classifications. Results FAS, FIS physical and BDI scores were significantly higher in patients compared to the control group ( p = 0.003, p = 0.001, and p = 0.003, respectively) and fatigue was associated with depression and daytime sleepiness. Inpatient group, depressive symptoms and daytime sleepiness were higher in females ( p = 0.019 and p = 0.013). The mean values of FIS total and cognitive scores were higher in patients with generalized MG ( p = 0.033 and p = 0.045). Fatigue scores correlated with motor signs. Discussion Fatigue can be seen in MG independently from muscle weakness and is an important symptom worsening the quality of life.

Purpose: To determine the diagnostic utility of brain magnetic resonance imaging (MRI) findings in patients with idiopathic intracranial hypertension (IIH) and to investigate the significance of evaluating radiological findings together with neurological and ophthalmological data in the diagnosis of IIH. Materials and Methods: All consecutive patients diagnosed with IIH in our tertiary neuro-ophthalmology center between January 1, 2018 and March 15, 2020, were included in the study. The clinical, radiological, and ophthalmological findings of IIH patients were compared with the control group with similar demographic characteristics. Results: A total of 98 patients, 49 cases and 49 controls, were included in the study. Lateral ventricular index had the highest area under the curve (AUC) value (0.945) for prediction of disease group followed by sella height category (AUC = 0.915) and optic nerve tortuosity (AUC = 0.855) According to the multivariate model we developed, caudate index (OR = 0.572, 95% CI 0.329-0.996), lateral ventricle index (OR = 3.969, 95% CI 1.851-8.509) and bilateral optic nerve tortuosity (OR = 22,784, 95% CI 2.432-213.450) were significant predictors for disease group. Conclusion: Tortuosity in the optic nerve, lateral ventricular index and caudate index can be used as MRI parameters supporting the diagnosis of IIH in clinically suspicious cases. A holistic approach to the clinical and radiological findings of the cases in the diagnosis of IIH can prevent overdiagnosis and enable early correct diagnosis.

Background The aim of this study was to establish reference jitter values for the voluntary activated sternocleidomastoid (SCM) muscle using a concentric needle electrode (CNE). Methods The study included 39 healthy participants (20 female and 19 male) aged 18-77 y. Jitter was expressed as the mean consecutive difference (MCD) of 80-100 consecutive discharges. Filters were set at 1 and 10 kHz. The mean MCDs for all participants were pooled, and the mean value +2.5 SD was accepted as the upper limit for the mean MCD. The upper limit for individual MCD was calculated using +2.5 SD of the upper 10th percentile MCD for individual participants. Results Mean age of the participants was 45 +/- 14.5 y. Mean MCD was 16.20 +/- 2.23 mu s (range: 12-21 mu s), and the upper limit of normal for mean MCD was 21.8 mu s. The mean value for 823 individual jitters was 23.3 +/- 4.61 mu s (range: 6.6-36.9 mu s), and the upper limit of normal for each individual jitter was 34.6 mu s. Conclusions The present findings indicate that upper normal limit for mean MCD is 22 mu s and for individual data it is 35 mu s.

Muscle weakness and easy fatigability is the clinical hallmark of myasthenia gravis (MG). However, the opinion has emerged that physical and mental "fatigue" can be seen in MG.

Thursday, April 30April 14, 2020Free AccessTransthyretin Familial Amyloid Polyneuropathy (TTR-FAP): A Database Analysis (3987)Cagdas Erdogan, Ayse Oytun Bayrak, Kayihan Uluc, Necdet Karli, Filiz Koc, Serefnur Ozturk, Ihsan Sukru Sengun, … Show All … , Yaprak Secil, Melih Tutuncu, Mehmet Ali Akalin, Hilmi Uysal, Sevim Erdem Ozdamar, and Yesim Parman Show FewerAuthors Info & AffiliationsApril 14, 2020 issue94 (15_supplement)https://doi.org/10.1212/WNL.94.15_supplement.3987 Letters to the Editor

Mucin glycopeptides were isolated from rat small intestinal mucosa after reduction/alkylation, trypsin digestion and gel chromatography. The oligosaccharides were released by using alkaline-NaBH4, separated into neutral and acidic species and permethylated. The derivatized mixtures were analysed with fast atom bombardment mass spectrometry and gas chromatography-mass spectrometry using thin film columns. Permethylated neutral oligosaccharides with up to seven sugars could be chromatographed and detected with mass spectrometry. The complex mixture revealed was partly due to the linkage GalNAc being substituted at both position 3 and 6. The approach will be very useful when analysing small amounts of mucins and mucin fragments.