Differentiated pattern of complement system activation between MOG-IgG-associated disease and AQP4-IgG-positive neuromyelitis optica spectrum disorder.

Background: Myelin oligodendrocyte glycoprotein antibody (MOG) immunoglobulin G (IgG)-associated disease (MOGAD) has clinical and pathophysiological features that are similar to but distinct from those of aquaporin-4 antibody (AQP4-IgG)-positive neuromyelitis optica spectrum disorders (AQP4-NMOSD). MOG-IgG and AQP4-IgG, mostly of the IgG1 subtype, can both activate the complement system. Therefore, we investigated whether the levels of serum complement components, regulators, and activation products differ between MOGAD and AQP4-NMOSD, and if complement analytes can be utilized to differentiate between these diseases. Methods: The sera of patients with MOGAD (from during an attack and remission; N=19 and N=9, respectively) and AQP4-NMOSD (N=35 and N=17), and healthy controls (N=38) were analyzed for C1q-binding circulating immune complex (CIC-C1q), C1 inhibitor (C1-INH), factor H (FH), C3, iC3b, and soluble terminal complement complex (sC5b-9). Results: In attack samples, the levels of C1-INH, FH, and iC3b were higher in the MOGAD group than in the NMOSD group (all, p<0.001), while the level of sC5b-9 was increased only in the NMOSD group. In MOGAD, there were no differences in the concentrations of complement analytes based on disease status. However, within AQP4-NMOSD, remission samples indicated a higher C1-INH level than attack samples (p=0.003). Notably, AQP4-NMOSD patients on medications during attack showed lower levels of iC3b (p<0.001) and higher levels of C3 (p=0.008), C1-INH (p=0.004), and sC5b-9 (p<0.001) compared to those not on medication. Among patients not on medication at the time of attack sampling, serum MOG-IgG cell-based assay (CBA) score had a positive correlation with iC3b and C1-INH levels (rho=0.764 and p=0.010, and rho=0.629 and p=0.049, respectively), and AQP4-IgG CBA score had a positive correlation with C1-INH level (rho=0.836, p=0.003). Conclusions: This study indicates a higher prominence of complement pathway activation and subsequent C3 degradation in MOGAD compared to AQP4-NMOSD. On the other hand, the production of terminal complement complexes (TCC) was found to be more substantial in AQP4-NMOSD than in MOGAD. These findings suggest a strong regulation of the complement system, implying its potential involvement in the pathogenesis of MOGAD through mechanisms that extend beyond TCC formation.

Serum neurofilament and glial fibrillary acidic protein in idiopathic and seropositive transverse myelitis.

BACKGROUND: Serum levels of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) reflect the disease activity and disability in central nervous system (CNS) demyelinating diseases. However, the clinical significance of NfL and GFAP in idiopathic transverse myelitis (iTM), an inflammatory spinal cord disease with unknown underlying causes, remains unclear. This study aimed to investigate NfL and GFAP levels in iTM and their association with the clinical parameters compared with those in TM with disease-specific antibodies such as anti-aquaporin 4 or myelin oligodendrocyte glycoprotein antibodies (sTM). METHODS: We collected serum and clinical data of 365 patients with CNS inflammatory diseases from 12 hospitals. The serum NfL and GFAP levels were measured in patients with iTM (n = 37) and sTM (n = 39) using ultrasensitive single-molecule array assays. Regression analysis was performed to investigate the associations between serum levels of NfL and GFAP and the clinical parameters such as higher EDSS scores (EDSS ≥ 4.0). RESULTS: Mean NfL levels were not significantly different between iTM (50.29 pg/ml) and sTM (63.18 pg/ml) (p = 0.824). GFAP levels were significantly lower in iTM (112.34 pg/ml) than in sTM (3814.20 pg/ml) (p = 0.006). NfL levels correlated with expanded disability status scale (EDSS) scores in sTM (p = 0.001) but not in iTM (p = 0.824). Disease duration also correlated with higher EDSS scores in sTM (p = 0.017). CONCLUSION: NfL levels and disease duration correlated with EDSS scores in sTM, and GFAP levels could be a promising biomarker to differentiate iTM from sTM.

Safety and Temporal Pattern of the Lymphocyte Count During Fingolimod Therapy in Patients With Multiple Sclerosis: Real-World Korean Experience.

BACKGROUND AND PURPOSE: Fingolimod (FTY) inhibits lymphocyte egress from lymphoid organs to cause lymphopenia, but the clinical implications of FTY-induced lymphopenia are not fully understood. We aimed to determine the frequency and severity of lymphopenia during FTY treatment among Korean patients with multiple sclerosis (MS), and its association with infections. METHODS: We retrospectively reviewed the medical records of patients with MS treated using FTY from 12 referral centers in South Korea between March 2013 and June 2021. Patients were classified according to their nadir absolute lymphocyte count (ALC) during treatment: grade 1, 800-999/µL; grade 2, 500-799/µL; grade 3, 200-499/µL; and grade 4, <200/µL. RESULTS: FTY treatment was administered to 69 patients with a median duration of 18 months (range=1-169 months), with 11 patients being treated for ≥7 years. During FTY treatment, mean ALCs were reduced after the first month (653.0±268.9/µL, mean±standard deviation) (p<0.0001) and remained low during treatment lasting up to 84 months. During follow-up, 41 (59.4%) and 7 (10.1%) patients developed grade-3 and grade-4 lymphopenia, respectively. No significant difference was found in age at FTY initiation, sex, baseline ALC, body mass index, or prior disease-modifying treatment between patients with and without grade-4 lymphopenia. Infections were observed in 11 (15.9%) patients, and the frequencies of patients with and without grade-4 lymphopenia were similar. CONCLUSIONS: FTY treatment induced grade-4 lymphopenia in 10% of South Korean patients with MS, but did not appear to be associated with an increased infection risk.

Serum Peptide Immunoglobulin G Autoantibody Response in Patients with Different Central Nervous System Inflammatory Demyelinating Disorders.

Previous efforts to discover new surrogate markers for the central nervous system (CNS) inflammatory demyelinating disorders have shown inconsistent results; moreover, supporting evidence is scarce. The present study investigated the IgG autoantibody responses to various viral and autoantibodies-related peptides proposed to be related to CNS inflammatory demyelinating disorders using the peptide microarray method. We customized a peptide microarray containing more than 2440 immobilized peptides representing human and viral autoantigens. Using this, we tested the sera of patients with neuromyelitis optica spectrum disorders (NMOSD seropositive, n = 6; NMOSD seronegative, n = 5), multiple sclerosis (MS, n = 5), and myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD, n = 6), as well as healthy controls (HC, n = 5) and compared various peptide immunoglobulin G (IgG) responses between the groups. Among the statistically significant peptides based on the pairwise comparisons of IgG responses in each disease group to HC, cytomegalovirus (CMV)-related peptides were most clearly distinguishable among the study groups. In particular, the most significant differences in IgG response were observed for HC vs. MS and HC vs. seronegative NMOSD (p = 0.064). Relatively higher IgG responses to CMV-related peptides were observed in patients with MS and NMOSD based on analysis of the customized peptide microarray.

Comparison of MOG and AQP4 antibody seroprevalence in Korean adults with inflammatory demyelinating CNS diseases.

We aimed to compare seroprevalence of anti-myelin oligodendrocyte glycoprotein (MOG) and anti-aquaporin-4 (AQP4) antibodies in Korean adults with inflammatory demyelinating diseases (IDDs) of the central nervous system (CNS), based on a multicenter nationwide database. Sera were analyzed using a live cell-based assay for MOG and AQP4 antibodies. Of 586 Korean adults with IDDs of the CNS, 36 (6.1%) and 185 (31.6%) tested positive for MOG and AQP4 antibodies, respectively. No participant showed double positivity. Seroprevalence of MOG antibodies was about five times lower than that of AQP4 antibodies in a large cohort of Korean adults with IDDs of the CNS.

Apolipoprotein E ε4 Is Associated With the Development of Incident Dementia in Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy Patients With p.Arg544Cys Mutation.

BACKGROUND AND PURPOSE: To identify clinical, laboratory, and magnetic resonance imaging (MRI) features in predicting incident stroke and dementia in Korean patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). MATERIALS AND METHODS: We enrolled 87 Korean CADASIL patients who had undergone baseline clinical, laboratory, and MRI examinations between March 2012 and February 2015. The primary outcome of this study is the occurrence of stroke and dementia during the study period. The occurrence of incident stroke was confirmed by neuroimaging study, and dementia was defined by the diagnostic and statistical manual of mental disorders, fourth edition, criteria. RESULTS: Of the 87 patients, 57.5% were men, and the mean age was 63 ± 13 years (range 34-90 years), and 82 patients (94.3%) had p.Arg544Cys mutation. During an average follow-up of 67 months (interquartile range: 53-69 months), incident stroke occurred in 14 of 87 patients (16.1%) and incident dementia in 7 of 70 non-demented patients (10.0%). In adjusted analysis, increased systolic blood pressure was associated with increased risk of incident stroke [for every 10-mmHg increase; hazard ratio, 1.44 (1.02-2.03)]. Apolipoprotein E ε4 genotype was associated with an increased risk of incident dementia [hazard ratio, 10.70 (1.27-89.88)]. CONCLUSION: In this study, apolipoprotein E ε4 genotype was associated with the development of incident dementia, and higher blood pressure was associated with increased risk of incident stroke in CADASIL patients with predominant p.Arg544Cys mutation.

Paretic knee extensor strength, gait velocity, and fat mass are major determinants of peak aerobic capacity in subacute stroke: observational cohort study.

The purpose of this study is to investigate major determinants of peak aerobic capacity in subacute stroke patients among body composition, balance function, walking capacity, and lower limb muscular strength. This was a retrospective observational cohort study. Eighty-three subacute stroke patients were enrolled and their medical records were retrospectively reviewed in the study (47 males; mean age: 62.95 ± 13.9 years). Gait capacity was assessed by gait velocity (10 m walk velocity:10MWV) and gait endurance (6 min walk distance:6MWD). Balance function was evaluated with Berg Balance Scale (BBS). The isometric muscular strengths of bilateral knee extensors were measured with an isokinetic dynamometer. Cardiovascular fitness was evaluated with an expired gas analyzer. In backward linear regression analyses, paretic isometric extensor strength (p < 0.001), fat mass (p = 0.005) and 10MWV (p < 0.001) are significantly correlated with peak aerobic capacity (adjusted R2 = 0.499) in all patients. Our results confirmed that paretic knee extensor strength, gait velocity, and fat mass were major determinants of peak aerobic capacity in subacute stroke. Therefore, therapeutic approaches should focus on improving gait velocity and paretic knee extensor strength in the early stages of recovery from stroke.

Serum FAM19A5 in neuromyelitis optica spectrum disorders: Can it be a new biomarker representing clinical status?

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) targets astrocytes and elevates the levels of astrocyte-injury markers during attacks. FAM19A5, involved in reactive gliosis, is secreted by reactive astrocytes following central nervous system (CNS) damage. OBJECTIVE: To investigate the significance of serum FAM19A5 in patients with NMOSD. METHODS: We collected clinical data and sera of 199 patients from 11 hospitals over 21 months. FAM19A5 levels were compared among three groups: NMOSD with positive anti-aquaporin-4 antibody (NMOSD-AQP4), other CNS demyelinating disease, and healthy controls. RESULTS: The median serum FAM19A5 level was higher in the NMOSD-AQP4 (4.90 ng/mL (3.95, 5.79)) than in the other CNS demyelinating (2.35 ng/mL (1.83, 4.07), p < 0.001) or healthy control (1.02 ng/mL (0.92, 1.14), p < 0.001) groups. There were significant differences in the median serum FAM19A5 levels between the attack and remission periods (5.89 ng/mL (5.18, 6.98); 4.40 ng/mL (2.72, 5.13), p < 0.001) in the NMOSD-AQP4 group. Sampling during an attack (p < 0.001) and number of past attacks (p = 0.010) were independently associated with increased serum FAM19A5. CONCLUSION: Serum FAM19A5 was higher in patients with NMOSD-AQP4 and correlated with clinical characteristics. Thus, serum FAM19A5 may be a novel clinical biomarker for NMOSD-AQP4.

Low serum vitamin D levels in patients with myasthenia gravis.

Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disease. Vitamin D has important roles both in the autoimmune response and in skeletal muscles. We investigated the levels of 1,25-dihydroxy vitamin D [1,25(OH)2D] and 25-hydroxy vitamin D [25(OH)D] in patients with MG and healthy subjects. MG patients were classified by disease stage, age of onset and treatment status whether or not to taking immunosuppressive agents. MG patients had lower plasma 25(OH)D levels (mean, 18.8 ±â€¯8.4 ng/mL) than healthy controls (26.3 ±â€¯6.1 ng/mL) (p < .05). 1,25(OH)2D levels showed slightly high in MG patients than healthy controls, but had no significant difference between two groups. In addition, no significant differences were observed between two groups divided by clinical characteristics. Serum 25(OH)D levels significantly lower in patients with MG compared with healthy controls. We recommend monitoring of vitamin D status in patients with MG to avoid direct negative effects on the muscles or autoimmune response.

The Impacts of Influenza Infection and Vaccination on Exacerbation of Myasthenia Gravis.

BACKGROUND AND PURPOSE: Upper respiratory infection (URI), including influenza, may exacerbate the symptoms of myasthenia gravis (MG), which is an autoimmune disease that causes muscle weakness. There is also concern that the influenza vaccine may trigger or worsen autoimmune diseases. The objective of this study was to determine the impacts of influenza infection and vaccination on symptom severity in MG patients. METHODS: Patients diagnosed with MG were enrolled from 10 university-affiliated hospitals between March and August 2015. Subjects completed a questionnaire at the first routine follow-up visit after enrolling in the study. The patient history was obtained to determine whether a URI had been experienced during the previous winter, if an influenza vaccination had been administered before the previous winter, and whether their MG symptoms were exacerbated during or following either a URI or vaccination. Influenza-like illness (ILI) was defined and differentiated from the common cold as a fever of ≥38°C accompanied by a cough and/or a sore throat. RESULTS: Of the 258 enrolled patients [aged 54.1±15.2 years (mean±SD), 112 men, and 185 with generalized MG], 133 (51.6%) had received an influenza vaccination and 121 (46.9%) had experienced a common cold (96 patients) or ILI (25 patients) during the analysis period. MG symptoms were aggravated in 10 (40%) patients after ILI, whereas only 2 (1.5%) experienced aggravation following influenza vaccination. The rate of symptom aggravation was significantly higher in patients experiencing an ILI (10/25, 40%) than in those with the common cold (15/96, 15.6%, p=0.006). CONCLUSIONS: The results of this study suggest that the potential risk of aggravating autoimmune disease is higher for ILI than for influenza vaccination, which further suggests that influenza vaccination can be offered to patients with MG.

A multicenter prospective observational study on the safety and efficacy of tacrolimus in patients with myasthenia gravis.

INTRODUCTION: Several clinical studies using tacrolimus revealed reasonable therapeutic mechanisms and efficacy in patients with myasthenia gravis (MG). However, long-period studies in a large number of patients with MG are limited; therefore, the aim of this study was to investigate the therapeutic efficacies and safety of tacrolimus in patients with MG during a 12-month follow-up period. METHODS: Tacrolimus was administered to 150 patients with MG who were recruited based on the inclusion criteria. Fifteen medical centers in Korea participated in this study. The efficacy of tacrolimus was assessed using MG composite scales (MGCS) and the prednisolone-sparing effect. And the adverse drug reactions (ADRs) of tacrolimus were monitored in each patient from the beginning of tacrolimus treatment to the end of the follow-up period. RESULTS: After starting tacrolimus, the 32 patients were affected by ADRs, and consequentially 134 patients of the enrolled patients were followed up for 12months. They showed that the mean prednisolone dosage significantly decreased (6.1±7.6mg/day), compared to that in the baseline (11.3±9.5mg/day), and MGCS significantly improved after 12months of tacrolimus treatment, compared to that at the baseline. CONCLUSIONS: Our study showed that tacrolimus would be an effective immunosuppressant as an initial therapeutic agent in patients with MG; in addition, it showed tolerable safety profiles during the 12-month follow-up evaluation.

NUDT15 p.R139C variant is common and strongly associated with azathioprine-induced early leukopenia and severe alopecia in Korean patients with various neurological diseases.

Azathioprine (AZA)-induced leukopenia is a relatively common complication in Korean patients. In addition to variation in TPMT (thiopurine S-methyltransferase), the NUDT15 p.R139C variant was recently identified to have a strong association with AZA-induced leukopenia. We investigated these associations in Korean patients undergoing AZA treatment with various neurological diseases. Among 84 enrolled patients, 20 (23.8%; 7 early, 13 late) exhibited leukopenia. The NUDT15 p.R139C variant was associated with leukopenia (OR: 11.844, 95% CI 3.984-36.024, p=1.327 × 10-5). The allelic frequency of NUDT15 p.R139C was as high as 10.7% and the frequency of the C/C, C/T, and T/T genotypes was 84.5, 10.7, and 5.9%, respectively. All T/T homozygous patients (5/5) developed early severe-grade leukopenia (white blood cells <1000mm-3) and severe alopecia. NUDT15 p.R139C was strongly associated with early leukopenia and severe alopecia (OR for early leukopenia: 107.624, 95% CI 18.857-614.250, p=1.403 × 10-7, OR for severe alopecia: 77.152, 95% CI 17.378-342.526, p=1.101 × 10-8). The sensitivity and specificity for predicting AZA-induced early leukopenia were 85.7% and 92.2%, respectively. Therefore, the NUDT15 p.R139C variant is common and strongly associated with AZA-induced early leukopenia and severe alopecia in Korean patients with various neurological diseases.

Arterial Stiffness in Subacute Stroke: Changing Pattern and Relationship with Functional Recovery.

BACKGROUND: To examine changing patterns in arterial stiffness and functional outcome in patients with subacute stroke, and to determine which parameter shows a strong correlation with the reversal of arterial stiffness, during a 3-month period of comprehensive rehabilitation therapy. METHODS: This descriptive, observational cohort study enrolled 60 patients (43 male and 17 female; average age, 62.7 years), and all received conventional rehabilitation therapy, during a 3-month period. Brachial-ankle pulse wave velocity (baPWV) was measured as an index of arterial stiffness. Functional assessments included the 6-minute walk test (6MWT), Fugl-Meyer Assessment of hemiparetic upper and lower limbs, the functional ambulatory category, the Berg balance scale, the Korean Mini-Mental Status Examination, and the Korean-Modified Barthel Index. All measurements were conducted at baseline and 1 and 3 months after stroke onset. RESULTS: Rehabilitation therapy resulted in a statistically significant improvement in baPWV since 3 months post stroke. Another functional outcome measure showed statistically significant improvements since 1 month after rehabilitation. Multivariable linear regression analysis revealed that a change in baPWV was significantly correlated with changes in the 6MWT. CONCLUSIONS: Three months of comprehensive rehabilitation therapy led to statistically significant improvements in arterial stiffness and functional outcomes during the subacute phase of stroke. Thus, the comprehensive rehabilitation focused on improving gait endurance would be warranted in subacute stroke patients.

Bilateral Adduction Palsy in a Patient with Myotonic Dystrophy Type 1.

Myotonic dystrophy type 1 (DM1) is caused by CTG repeat expansion in the DMPK gene in chromosome 19q13.3. External ophthalmoplegia is a rare manifestation in DM1. We report a DM1 patient confirmed by the presence of 650 CTG triplet expansions in the DMPK gene and had limitation of adduction gaze bilaterally. Brain MRI showed bilateral medial rectus muscles atrophy. Our patient provides additional evidence of ocular motor muscle involvement in DM1.

B-cell-activating factor is elevated in serum of patients with myasthenia gravis.

INTRODUCTION: Myasthenia gravis (MG) is a B-cell-mediated autoimmune disease. B-cell-activating factor (BAFF) is a major factor in B-cell development and activation. In this study we investigated serum BAFF levels in MG patients. METHODS: We compared the serum BAFF levels of 20 MG patients with gender-matched healthy controls. We assayed serum concentrations of BAFF and anti-acetylcholine receptor antibody (AChR) titers. RESULTS: Serum BAFF levels of MG patients with AChR antibodies were significantly higher than those of healthy controls. A significant positive correlation was observed between serum BAFF levels and anti-AChR antibody titers. BAFF values did not correlate with disease severity. CONCLUSIONS: BAFF may play a major role in the pathogenesis of MG, and it may provide a potential target for therapy in patients with MG. Muscle Nerve 54: 1030-1033, 2016.

Both binding and blocking antibodies correlate with disease severity in myasthenia gravis.

Myasthenia gravis (MG) is an autoimmune disease associated with antibodies directed to the postsynaptic muscle components of the neuromuscular junction. The heterogeneous nature of the acetylcholine receptor (AChR) antibody response had led to the categorization of AChR antibodies into 3 types: binding, blocking, and modulating antibodies. The purpose of this study is to compare the AChR antibodies' type with the clinical severity of MG patients. The patients enrolled in the study had been tested for both binding and blocking antibodies and had disease duration exceeding 2 years since diagnosis. The patients were divided into five main classes by the Myasthenia Gravis Foundation of America clinical classification. Again, the enrolled patients were divided into ocular and generalized group. We compared the type and titer of antibodies and the thymus status between the ocular and generalized group. Thirty-five patients met the inclusion criteria. Of these, 16 patients (47 %) had both blocking and binding AChR antibodies, 11 patients (31 %) had only binding antibodies, and 8 patients (22 %) had only blocking antibodies. By defined clinical classification, the ocular and generalized groups included 10 and 25 patients, respectively. Sixteen patients in the generalized group possessed both AChR antibodies, with the remaining patients displaying only the binding antibody. All the patients with only blocking antibody were classified into ocular group. Use of binding and blocking antibodies' tests may, therefore, be more helpful in predicting the prognosis and diagnoses of MG patient.

Identification of a novel nonsense mutation in the rod domain of GFAP that is associated with Alexander disease.

Alexander disease (AxD) is an astrogliopathy that primarily affects the white matter of the central nervous system (CNS). AxD is caused by mutations in a gene encoding GFAP (glial fibrillary acidic protein). The GFAP mutations in AxD have been reported to act in a gain-of-function manner partly because the identified mutations generate practically full-length GFAP. We found a novel nonsense mutation (c.1000 G>T, p.(Glu312Ter); also termed p.(E312*)) within a rod domain of GFAP in a 67-year-old Korean man with a history of memory impairment and leukoencephalopathy. This mutation, GFAP p.(E312*), removes part of the 2B rod domain and the whole tail domain from the GFAP. We characterized GFAP p.(E312*) using western blotting, in vitro assembly and sedimentation assay, and transient transfection of human adrenal cortex carcinoma SW13 (Vim(+)) cells with plasmids encoding GFAP p.(E312*). The GFAP p.(E312*) protein, either alone or in combination with wild-type GFAP, elicited self-aggregation. In addition, the assembled GFAP p.(E312*) aggregated into paracrystal-like structures, and GFAP p.(E312*) elicited more GFAP aggregation than wild-type GFAP in the human adrenal cortex carcinoma SW13 (Vim(+)) cells. Our findings are the first report, to the best of our knowledge, on this novel nonsense mutation of GFAP that is associated with AxD and paracrystal formation.

Lying-down nystagmus and head-bending nystagmus in horizontal semicircular canal benign paroxysmal positional vertigo: are they useful for lateralization?

BACKGROUND: Lateralization of horizontal semicircular canal benign paroxysmal positional vertigo (HSC-BPPV) is very important for successful repositioning. The directions of lying-down nystagmus (LDN) and head-bending nystagmus (HBN) have been used as ancillary findings to identify the affected sites. This retrospective study was performed to evaluate the lateralizing values of LDN and HBN using clinical and laboratory findings for lateralizing probabilities in patients with HSC-BPPV. METHODS: For 50 HSC-BPPV patients with asymmetric direction-changing horizontal nystagmus (DCHN) during the head-rolling test (HRT) using Frenzel goggles, the directions of LDN and HBN were evaluated and compared to those determined by video-oculography. Directional LDN was defined as the contralesional direction of nystagmus in geotropic types and the ipsilesional direction in apogeotropic types. Directional HBN was defined as the opposite direction relative to directional LDN. We also analyzed LDN and HBN in 14 patients with a history of ipsilesional peripheral vestibulopathy, caloric abnormality or conversion from other types of BPPV (such as probable localized HSC-BPPV, pro-BPPV). RESULTS: LDN and HBN were seen in 68% (34/50) and 76% (38/50) of patients, respectively. Of these, 19 (55.9%), and 28 (73.7%) patients showed directional LDN and HBN, respectively. The proportion of patients with directional LDN and HBN was much smaller among the pro-BPPV patients (4/12 for LDN, 3/10 for HBN). CONCLUSIONS: LDN and HBN did not seem to predict lateralization in patients with HSC-BPPV. To improve the prediction of lateralization of HSC-BPPV, it is necessary to modify the maneuvers used to elicit LDN or HBN, especially in cases of symmetric DCHN during HRT.

Comparison between Flail Arm Syndrome and Upper Limb Onset Amyotrophic Lateral Sclerosis: Clinical Features and Electromyographic Findings.

Flail arm syndrome (FAS), an atypical presentation of amyotrophic lateral sclerosis (ALS), is characterized by progressive, predominantly proximal, weakness of upper limbs, without involvement of the lower limb, bulbar, or respiratory muscles. When encountering a patient who presents with this symptomatic profile, possible diagnoses include upper limb onset ALS (UL-ALS), and FAS. The lack of information regarding FAS may make differential diagnosis between FAS and UL-ALS difficult in clinical settings. The aim of this study was to compare clinical and electromyographic findings from patients diagnosed with FAS with those from patients diagnosed with UL-ALS. To accomplish this, 18 patients with FAS and 56 patients with UL-ALS were examined. Significant differences were observed between the 2 groups pertaining to the rate of fasciculation, patterns of predominantly affected muscles, and the Medical Research Council scale of the weakest muscle. The presence of upper motor neuron signs and lower motor neuron involvement evidenced through electromyography showed no significant between-group differences.