[Finger drop variant of Guillain-Barré syndrome: a case report].

We report the case of a 31-year-old man with a finger drop variant of Guillain-Barré syndrome (GBS). The patient visited a neurological clinic with complaints of difficulty in extending the fingers, which occurred seven days after he had fever and diarrhea. The physician who first saw the patient suspected posterior interosseous nerve palsy and referred him to our hospital. Neurological examination 35 days after the onset revealed distal weakness of the upper extremities, particularly in the bilateral extensor digitorum (Medical Research Council [MRC] scale 1/1 [right/left]). The left triceps surae muscle was also weak (MRC scale 5/4). Bilateral Achilles tendon reflexes were absent, but other neurological findings were normal. Cerebrospinal fluid examination showed albuminocytologic dissociation. Serum immunoglobulin G antibodies against GM1 were positive. Nerve conduction studies revealed reduced amplitude of compound muscle action potentials (CMAPs) without evidence of demyelination in the median, ulnar, radial, and tibial nerves. CMAP amplitude was most severely reduced in the radial nerve among the upper extremity nerves. We diagnosed the patient with acute motor axonal neuropathy. His symptoms gradually improved after treatment with intravenous immunoglobulin. When encountering acute finger drop, neurologists should consider the finger drop variant of GBS as a differential diagnosis.

Inducing Cortical Plasticity to Manipulate and Consolidate Subjective Time Interval Production.

OBJECTIVES: Time awareness may change depending on the mental state or disease conditions, although each individual perceives his/her own sense of time as stable and accurate. Nevertheless, the processes that consolidate altered duration production remain unclear. The present study aimed to manipulate the subjective duration production via memory consolidation through the modulation of neural plasticity. MATERIALS AND METHODS: We first performed false feedback training of duration or length production and examined the period required for natural recovery from the altered production. Next, persistent neural plasticity was promoted by quadripulse transcranial magnetic stimulation (QPS) over the right dorsolateral prefrontal cortex (DLPFC), temporoparietal junction (TPJ), and primary motor cortex (M1). We conducted the same feedback training in the individual and studied how the time course of false learning changed. RESULTS: We observed that altered duration production after false feedback returned to baseline within two hours. Next, immediate exposure to false feedback during neural plasticity enhancement revealed that in individuals who received QPS over the right DLPFC, but not over TPJ or M1, false duration production was maintained for four hours; furthermore, the efficacy persisted for at least one week. CONCLUSION: These findings suggest that, while learned altered duration production decays over several hours, QPS over the right DLPFC enables the consolidation of newly learned duration production.

[A case of polyneuropathy after COVID-19 vaccine].

A 43-year-old-woman developed paresthesia, weakness of limbs, dysphagia and deep sensory impairment 12 days after vaccination of Pfizer COVID-19 vaccine. Her deep tendon reflexes were absent and cerebrospinal fluid showed normal cell counts and protein level. Anti-ganglioside antibodies were negative, and F wave frequency was decreased in nerve conduction studies. We diagnosed her as immune mediated polyneuropathy caused by COVID-19 vaccine, and plasma exchange improved her symptoms. Compared with Guillain-Barré syndrome and polyneuropathy following COVID-19 infection and COVID-19 vaccination, deep sensory impairment was the most characteristic of this case. We supposed that non-antigen specific mechanism played an important role in the pathogenesis of this case.

Nerve ultrasound characteristics of immunoglobulin M neuropathy associated with anti-myelin-associated glycoprotein antibodies.

INTRODUCTION/AIMS: Immunoglobulin M neuropathy associated with anti-myelin-associated glycoprotein antibody (IgM/anti-MAG) neuropathy typically presents with chronic, distal-dominant symmetrical sensory or sensorimotor deficits. Ultrasonographic studies of IgM/anti-MAG neuropathy are limited, and were all performed on Western populations. We aimed to characterize the nerve ultrasonographic features of IgM/anti-MAG neuropathy in the Japanese population and evaluate whether they differ from the findings of the common subtypes of chronic inflammatory demyelinating polyneuropathy (CIDP). METHODS: In this cross-sectional study, we retrospectively reviewed medical records and extracted the cross-sectional areas (CSAs) of C5-C7 cervical nerve roots and median and ulnar nerves of 6 IgM/anti-MAG neuropathy patients, 10 typical CIDP (t-CIDP) patients, 5 multifocal CIDP (m-CIDP) patients, and 17 healthy controls (HCs). RESULTS: Cervical nerve root CSAs were significantly larger at every examined site on both sides in IgM/anti-MAG neuropathy than in m-CIDP and HCs but were comparable to those in t-CIDP. Peripheral nerve enlargements were greatest at common entrapment sites (ie, wrist and elbow) in IgM/anti-MAG neuropathy, a pattern shared with t-CIDP but not with m-CIDP. The degree of nerve enlargement at entrapment sites compared to non-entrapment sites was significantly higher in IgM/anti-MAG neuropathy than in t-CIDP. DISCUSSION: Our study delineated the ultrasonographic features of IgM/anti-MAG neuropathy in the Japanese population and observed similar characteristics to those of t-CIDP, with subtle differences. Further studies comparing results from various populations are required to optimize the use of nerve ultrasound worldwide.

[COVID-19-associated Guillain-Barré syndrome in infectious period: a case report].

A 75-year-old man with a history of hypertension developed weakness and sensory disturbance in the extremities 1 week after upper respiratory tract infection and faced difficulty walking. Screening at the time of hospital admission revealed an incidental positive SARS-CoV-2 PCR test, and COVID-19 was diagnosed. Neurological findings showed dysarthria, dysphagia, absence of deep tendon reflexes in the extremities, distal-dominant muscle weakness, sensory disturbance, urinary retention and constipation. Nerve conduction studies showed prolonged distal latency, decreased conduction velocity, and poor F-wave response, leading to a diagnosis of COVID-19-associated Guillain-Barré syndrome (GBS). The patient was treated with intravenous immunoglobulin, and his neurological symptoms improved without the need of a ventilator. Anti-ganglioside autoantibodies were negative. The patient developed GBS during the infectious period of SARS-CoV-2 and was treated in the isolation ward by clinical staff with personal protective equipment. Because COVID-19-associated GBS can develop during the infectious period of SARS-CoV-2, it is important for neurologists to consider GBS and other neurological disorders as being potentially COVID-19-related, and to treat patients with COVID-19 accordingly.

Emerging Infection, Vaccination, and Guillain-Barré Syndrome: A Review.

Guillain-Barré syndrome (GBS) is an autoimmune disorder of the peripheral nervous system that typically develops within 4 weeks after infection. In addition to conventional infectious diseases with which we are familiar, emerging infectious diseases, such as Zika virus infection and coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have also been suggested to be associated with GBS. GBS is mainly categorized into a demyelinating subtype known as acute inflammatory demyelinating polyneuropathy (AIDP) and an axonal subtype known as acute motor axonal neuropathy (AMAN). Most patients who develop GBS after Zika virus infection or COVID-19 have AIDP. The concept of molecular mimicry between pathogens and human peripheral nerve components was established through studies of AMAN with anti-ganglioside GM1 antibodies occurring after Campylobacter jejuni infection. Although such mimicry between specific pathogens and myelin or Schwann cell components has not been clearly demonstrated in AIDP, a similarity of Zika virus and SARS-CoV-2 proteins to human proteins has been suggested. With the development of global commerce and travel, emerging infectious diseases will continue to threaten public health. From this viewpoint, the development of vaccines and antiviral drugs is important to prepare for and control emerging infectious diseases. Although a decrease in the number of patients after the 2015-2016 Zika epidemic increased the difficulty in conducting phase 3 trials for Zika virus vaccines, the efficacy and safety of new vaccines have recently been demonstrated for COVID-19. In general, vaccines can decrease the risk of infectious disease by stimulating the immune system, and discussions regarding an increased risk of autoimmune disorders, such as GBS, have been ongoing for many years. However, the risk of GBS is not considered a legitimate reason to limit the administration of currently available vaccines, as only a trivial association or no association with GBS has been demonstrated.

Time Distortion in Parkinsonism.

Although animal studies and studies on Parkinson's disease (PD) suggest that dopamine deficiency slows the pace of the internal clock, which is corrected by dopaminergic medication, timing deficits in parkinsonism remain to be characterized with diverse findings. Here we studied patients with PD and progressive supranuclear palsy (PSP), 3-4 h after drug intake, and normal age-matched subjects. We contrasted perceptual (temporal bisection, duration comparison) and motor timing tasks (time production/reproduction) in supra- and sub-second time domains, and automatic versus cognitive/short-term memory-related tasks. Subjects were allowed to count during supra-second production and reproduction tasks. In the time production task, linearly correlating the produced time with the instructed time showed that the "subjective sense" of 1 s is slightly longer in PD and shorter in PSP than in normals. This was superposed on a prominent trend of underestimation of longer (supra-second) durations, common to all groups, suggesting that the pace of the internal clock changed from fast to slow as time went by. In the time reproduction task, PD and, more prominently, PSP patients over-reproduced shorter durations and under-reproduced longer durations at extremes of the time range studied, with intermediate durations reproduced veridically, with a shallower slope of linear correlation between the presented and produced time. In the duration comparison task, PD patients overestimated the second presented duration relative to the first with shorter but not longer standard durations. In the bisection task, PD and PSP patients estimated the bisection point (BP50) between the two supra-second but not sub-second standards to be longer than normal subjects. Thus, perceptual timing tasks showed changes in opposite directions to motor timing tasks: underestimating shorter durations and overestimating longer durations. In PD, correlation of the mini-mental state examination score with supra-second BP50 and the slope of linear correlation in the reproduction task suggested involvement of short-term memory in these tasks. Dopamine deficiency didn't correlate significantly with timing performances, suggesting that the slowed clock hypothesis cannot explain the entire results. Timing performance in PD may be determined by complex interactions among time scales on the motor and sensory sides, and by their distortion in memory.

Serum IgG anti-GD1a antibody and mEGOS predict outcome in Guillain-Barré syndrome.

OBJECTIVE: Approximately 15%-20% of patients with Guillain-Barré syndrome (GBS) are unable to walk independently at 6 months from the onset of neurological symptom. The modified Erasmus GBS outcome score (mEGOS) has been reported as a prognostic tool.Herein we investigated the association between a poor outcome, inability to walk independently at 6 months and presence of antiganglioside antibodies. METHODS: The clinical and serological data of 177 patients with GBS were retrospectively collected in Japan to assess the associations between a poor outcome and serum IgG antibodies against each ganglioside (GM1, GD1a, GalNAc-GD1a, GQ1b and GT1a). In addition, we investigated whether the combination of mEGOS and serum IgG antibodies against gangliosides is useful in predicting a poor outcome. RESULTS: The patients with IgG anti-GD1a antibodies more frequently showed poor outcomes than those without these antibodies (9 (36%) of 25 vs 8 (6%) of 127 patients, p<0.001). Particularly, 80% showed a poor outcome when they had both serum IgG anti-GD1a antibody and a high mEGOS of ≥10 on day 7 of admission. CONCLUSIONS: The combination of serum IgG anti-GD1a antibodies and a high mEGOS could help in making a more accurate prognosis of patients than mEGOS alone, especially for predicting poor outcomes.

[A case of antiphospholipid syndrome associated with recurrent brain infarction and diffuse hypertrophy of the arachnoid membrane].

A 55-year-old man presented with recurrent brain infarction which had increased multifocally mainly in the cerebral white matter over the course of one year. Antibodies associated with antiphospholipid syndrome (APS) were initially negative. The patient was admitted to our department because of the thickened meninges shown on gadolinium enhanced brain MRI, mimicking hypertrophic pachymeningitis. However, blood and cerebrospinal fluid analysis revealed no significant inflammatory changes. On histopathological examination of the biopsied meninges, the arachnoid membrane was thickened with fibrosis, and arachnoidal microvessels were enlarged without significant inflammatory changes. The dura mater was not thickened, and no inflammation or microvessel enlargement were revealed. Finally, serum IgG anticardiolipin antibody testing was positive twice at an interval of more than 12 weeks, confirming the diagnosis of APS. Since initiating antithrombotic therapy with warfarin, brain infarction has not recurred. Without inflammation in the arachnoid membrane, the congestion of blood flow caused by thrombosis of microvessels in the arachnoid membrane might have increased the thickness of the arachnoid membrane.

Novel SLC20A2 variant in a Japanese patient with idiopathic basal ganglia calcification-1 (IBGC1) associated with dopa-responsive parkinsonism.

Idiopathic basal ganglia calcification-1 (IBGC1) is an autosomal dominant disorder characterized by calcification in the basal ganglia, which can manifest a range of neuropsychiatric symptoms, including parkinsonism. We herein describe a 64-year-old Japanese IBGC1 patient with bilateral basal ganglia calcification carrying a novel SLC20A2 variant (p.Val322Glufs*92). The patient also presented with dopa-responsive parkinsonism with decreased dopamine transporter (DAT) density in the bilateral striatum and decreased cardiac 123I-meta-iodobenzylguanidine uptake.

Anti-ganglioside complex antibody profiles in a recurrent complicated case of GQ1b-seronegative miller fisher syndrome and Bickerstaff brainstem encephalitis: a case report.

BACKGROUND: Guillain-Barré syndrome (GBS), Miller Fisher syndrome (MFS) and Bickerstaff brainstem encephalitis (BBE) are a group of autoimmune neurological disorders (GBS spectrum disorder) that rarely recur. Recently, anti-ganglioside complex antibodies (GSC-Abs) were identified in patients with GBS spectrum disorder. However, there has been no case report describing GSC-Abs profiles in a recurrent case showing different phenotypes. CASE PRESENTATION: We report the case of a 33-year-old male patient with GQ1b-seronegative BBE-GBS after two prior episodes of MFS-GBS. Our patient showed ophthalmoplegia, ataxia, areflexia and a weakness of the extremities (MFS and GBS symptoms) in all episodes. In the episode reported here, our patient showed disturbed consciousness and an extensor response to cutaneous plantar stimulation was observed (BBE symptoms), with severe disability and requirement for artificial respiration management. GSC-Abs detected in previous episodes were also detected in the subsequent episodes, while new GSC-Abs emerged in each episode. Interestingly, whereas antibodies to GA1/GQ1b and GA1/GT1a, which are commonly identified in patients with GBS, MFS or BBE, appeared in all episodes, antibodies to GD1a/GD1b and GD1b/GT1b, which are predominantly associated with severe disability and the requirement for artificial respiration management in GBS, emerged for the first time in this episode. CONCLUSION: This study reports novel phenomena about the GSC-Abs profiles and its relationship with clinical features in a case with recurrent GBS spectrum disorder, showing different phenotypes in different episodes. Further studies are required to reveal the significance of the GSC-Abs profiles in recurrent GBS spectrum disorder.

[A New Aspect of Anti-Glycolipid Antibodies in Guillain-Barré Syndrome: Ca2+-Dependent Antibody in Fisher Syndrome-Related Disorders].

Anti-glycolipid antibodies are key to revealing the pathomechanisms of Guillain-Barré syndrome (GBS). There are correlations between the antigen specificities of the antibodies, clinical features, and preceding infectious agents. It has also been found that some glycoantigens are localized in human peripheral nervous tissues, corresponding to the clinical features. Antibody-detection methods are still evolving. The discovery of antibodies against glycolipid complexes expanded the horizon of anti-glycolipid research in GBS, which had started from isolated antigens. Recently, IgG antibodies against ganglioside GQ1b-related antigens that required Ca2+ cations in the antigen-antibody reaction (Ca2+-dependent anti-GQ antibody) have also been detected in patients with Fisher syndrome, or other related disorders, who were GQ1b-seronegative in conventional assays without adding Ca2+. It is suggested that Ca2+ interacts with disialosyl groups [NeuAc (a2-8) NeuAc (a2-)] in gangliosides, and that the Ca2+-dependent antibodies recognize the Ca2+-bound conformation of GQ1b.

CV2/CRMP5-antibody-related Paraneoplastic Optic Neuropathy Associated with Small-cell Lung Cancer.

A 61-year-old woman who had smoked for 41 years developed subacute dizziness, ataxic gait, opsoclonus, and right visual impairment. She had right optic disc swelling and optic nerve gadolinium enhancement on magnetic resonance imaging. She had small-cell lung cancer (SCLC), with CV2/collapsin response mediator protein (CRMP) 5 and HuD antibodies in her serum and cerebrospinal fluid. She was diagnosed with paraneoplastic optic neuropathy (PON) accompanied by paraneoplastic opsoclonus-ataxia syndrome. Her symptoms improved after removing the SCLC. Classical PON is rare in Japan. We recommend assaying for CV2/CRMP5 antibodies and searching for cancer in elderly patients with subacute painless visual impairment.

Markers for Guillain-Barré syndrome with poor prognosis: a multi-center study.

Guillain-Barré syndrome (GBS) is an acute monophasic neuropathy. Prognostic tools include the modified Erasmus GBS outcome score (mEGOS), Erasmus GBS respiratory insufficiency score (EGRIS), and the increase in serum IgG levels (ΔIgG) 2 weeks after intravenous immunoglobulin (IVIg) treatment. Given that proportions of GBS subtypes differ between Western countries and Japan, the usefulness of these tools in Japan or other countries remains unknown. We enrolled 177 Japanese patients with GBS from 15 university hospitals and retrospectively obtained mEGOS and EGRIS for all and ΔIgG status for 79 of them. High mEGOS scores on admission or on day 7 were significantly associated with poorer outcomes (unable to walk independently at 6 months). High EGRIS scores (≥5 points) were associated with an increased risk for mechanical ventilation. Patients with ΔIgG <1,108 mg/dl had significantly poorer outcomes. We suggest that mEGOS, EGRIS, and ΔIgG in GBS are clinically relevant in Japan.

IgG4 anti-neurofascin155 antibodies in chronic inflammatory demyelinating polyradiculoneuropathy: Clinical significance and diagnostic utility of a conventional assay.

We aimed to validate the diagnostic utility of enzyme-linked immunosorbent assay (ELISA) for the detection of anti-neurofascin (NF) 155 antibody in 191 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Human NF155-based ELISA clearly distinguished between anti-NF155 antibody-positive and -negative sera. Fifteen CIDP patients (8%) were IgG4 anti-human NF155 antibody-positive, which were confirmed by western blot, cell-based assay and immunohistochemical study. None of disease controls or healthy subjects had positive results. Clinical presentation of IgG4 anti-NF155 antibody-positive patients was consistent with those in previous reports. This ELISA combined with determination of the IgG4 subclass is useful in screening for anti-NF155 antibodies.

Cancer association as a risk factor for anti-HMGCR antibody-positive myopathy.

OBJECTIVE: To show cancer association is a risk factor other than statin exposure for anti-3-hydroxy-3-methylglutaryl coenzyme A reductase autoantibody-positive (anti-HMGCR Ab+) myopathy. METHODS: We analyzed the clinical features and courses of 33 patients (23 female and 10 male) with anti-HMGCR Ab+ myopathy among 621 consecutive patients with idiopathic inflammatory myopathies. RESULTS: Among the 33 patients, 7 (21%) were statin-exposed and 26 were statin-naive. In relation with cancer, there were 12 patients (statin-exposed, n = 4) with cancers detected within 3 years of myopathy diagnosis (cancer association), 3 patients (all statin-naive) with cancers detected more than 3 years before myopathy diagnosis (cancer history), 10 cancer-free patients followed up for more than 3 years (all statin-naive), and 8 patients without cancer detection but followed up for less than 3 years (statin-exposed, n = 3). Therefore, 12 patients with cancer association (36%) formed a larger group than that of 7 statin-exposed patients (21%). Among 12 patients with cancer association, 92% had cancer detection within 1 year of myopathy diagnosis (after 1.3 years in the remaining patient), 83% had advanced cancers, and 75% died of cancers within 2.7 years. Of interest, 1 patient with cancer history had sustained increase in creatine kinase level over 12 years from cancer removal to the development of weakness. CONCLUSIONS: Patients with cancer association formed a large group with poor prognosis in our series of patients with anti-HMGCR Ab+ myopathy. The close synchronous occurrence of cancers and myopathies suggested that cancer association is one of the risk factors for developing anti-HMGCR Ab+ myopathy.

Ca(2+)-dependent anti-GQ1b antibody in GQ1b-seronegative Fisher syndrome and related disorders.

Although serum IgG anti-ganglioside GQ1b antibody is the most specific biomarker for Fisher syndrome and its related disorders (FS-RD), 10%-30% of the patients are still negative in conventional assays ("GQ1b-seronegative") and the relationship between GQ1b-seropositive and -seronegative patients has been unclear. Some molecules require Ca(2+) cations to interact with their ligands (Ca(2+)-dependency). Here we have investigated whether Ca(2+)-dependency is also present in anti-GQ1b antibodies in FS-RD, especially in the GQ1b-seronegative patients and show that IgG antibodies against GQ1b-related antigens (isolated GQ1b and GQ1b-containing complexes) are detected Ca(2+)-dependently in the majority of GQ1b-seronegative patients with FS-RD. The Ca(2+)-dependent antibodies might react specifically with GQ1b-Ca(2+) conformation. This is the first demonstration of disease-related Ca(2+)-dependent antibodies in neurological field. GQ1b-related pathology would be involved in FS-RD more extensively than previously revealed.

Anti-TIF1-γ antibody and cancer-associated myositis: A clinicohistopathologic study.

OBJECTIVE: We aimed to analyze the clinical and histopathologic features of cancer-associated myositis (CAM) in relation to anti-transcriptional intermediary factor 1 γ antibody (anti-TIF1-γ-Ab), a marker of cancer association. METHODS: We retrospectively studied 349 patients with idiopathic inflammatory myopathies (IIMs), including 284 patients with pretreatment biopsy samples available. For the classification of IIMs, the European Neuromuscular Center criteria were applied. Patients with CAM with (anti-TIF1-γ-Ab[+] CAM) and without anti-TIF1-γ-Ab (anti-TIF1-γ-Ab[-] CAM) were compared with patients with IIM without cancers within and beyond 3 years of myositis diagnosis. RESULTS: Cancer was detected in 75 patients, of whom 36 (48%) were positive for anti-TIF1-γ-Ab. In anti-TIF1-γ-Ab(+) patients with CAM, cancers were detected within 1 year of myositis diagnosis in 35 (97%) and before 1 year of myositis diagnosis in 1. All the anti-TIF1-γ-Ab(+) patients with CAM satisfied the dermatomyositis (DM) criteria, including 2 possible DM sine dermatitis cases, and were characterized histologically by the presence of perifascicular atrophy, vacuolated fibers (VFs), and dense C5b-9 deposits on capillaries (dC5b-9). In contrast, 39 anti-TIF1-γ-Ab(-) patients with CAM were classified into various subgroups, and characterized by a higher frequency of necrotizing autoimmune myopathy (NAM). Notably, all 7 patients with CAM classified into the NAM subgroup were anti-TIF1-γ-Ab(-) and exhibited no dC5b-9 or VFs. CONCLUSIONS: CAM includes clinicohistopathologically heterogeneous disease entities. Among CAM entities, anti-TIF1-γ-Ab(+) CAM has characteristically shown a close temporal association with cancer detection and the histopathologic findings of dC5b-9 and VFs, and CAM with NAM is a subset of anti-TIF1-γ-Ab(-) CAM.