Immunological and therapeutic insights in autoimmune autonomic ganglionopathy: What is the position of apheresis in immunotherapy?

Autoimmune autonomic ganglionopathy (AAG) is characterized by various autonomic and extra-autonomic symptoms and is caused by autoantibodies against nicotinic acetylcholine receptors present in the autonomic ganglia (ganglionic acetylcholine receptor, gAChR), requiring immediate and aggressive intervention to prevent the exacerbation of symptoms. However, there is currently no internationally accepted standard of care for the immunotherapy of AAG, including apheresis. Although the rationale for the use of plasma exchange (PLEX) in AAG is strong, whereby pathogenic gAChR antibodies are removed, its overall impact on patient outcomes is not well-established. Based on previous case reports and small case series studies, we provide a comprehensive overview of the challenges and uncertainties surrounding the use of PLEX for the management of AAG and provide current practice recommendations to guide treatment decisions.

Autoimmune Autonomic Neuropathy: From Pathogenesis to Diagnosis.

Autoimmune autonomic ganglionopathy (AAG) is a disease of autonomic failure caused by ganglionic acetylcholine receptor (gAChR) autoantibodies. Although the detection of autoantibodies is important for distinguishing the disease from other neuropathies that present with autonomic dysfunction, other factors are important for accurate diagnosis. Here, we provide a comprehensive review of the clinical features of AAG, highlighting differences in clinical course, clinical presentation, and laboratory findings from other neuropathies presenting with autonomic symptoms. The first step in diagnosing AAG is careful history taking, which should reveal whether the mode of onset is acute or chronic, followed by an examination of the time course of disease progression, including the presentation of autonomic and extra-autonomic symptoms. AAG is a neuropathy that should be differentiated from other neuropathies when the patient presents with autonomic dysfunction. Immune-mediated neuropathies, such as acute autonomic sensory neuropathy, are sometimes difficult to differentiate, and therefore, differences in clinical and laboratory findings should be well understood. Other non-neuropathic conditions, such as postural orthostatic tachycardia syndrome, chronic fatigue syndrome, and long COVID, also present with symptoms similar to those of AAG. Although often challenging, efforts should be made to differentiate among the disease candidates.

Pathogenic role of anti-cN1A autoantibodies in sporadic inclusion body myositis.

BACKGROUND: Sporadic inclusion body myositis (sIBM) is an intractable muscle disease that frequently affects elderly people. Autoantibodies recognising cytosolic 5'-nucleotidase 1A (cN1A) were found in the sera of patients with sIBM. However, the pathogenic role of the autoantibodies remained unknown. This study investigated the pathogenic properties of the autoantibodies using active cN1A peptides immunisation. METHODS: Wild-type C57BL6 mice were injected with three different mouse cN1A peptides corresponding to the previously reported epitope sequences of human cN1A. After confirming the production of autoantibodies to the corresponding cN1A peptides in each group, changes in body weight, exercise capacity by treadmill test and histological changes in mice injected with cN1A peptides or controls were investigated. RESULTS: Autoantibodies against cN1A were detected in serum samples from mice injected with cN1A peptide. Some groups of mice injected with cN1A peptide showed significant weight loss and decreased motor activity. The number of myofibres with internal nuclei increased in all the peptide-injected groups, with surrounding or invading CD8-positive T cells into myofibres, abnormal protein aggregates and overexpression of p62 and LC3. CONCLUSIONS: Active cN1A peptide immunisation partially reproduced the clinical and histological aspects of sIBM in wild-type mice. The murine model demonstrates the pathogenic properties of anti-cN1A autoantibodies to cause sIBM-like histological changes.

Very late onset neuromyelitis optica spectrum disorders.

BACKGROUND AND PURPOSE: Neuromyelitis optica spectrum disorder (NMOSD) often presents in the elderly with an insidious onset of symptoms and aggressive progression. There have been anecdotal cases of very late onset (VLO)-NMOSD, but case series reports are rare. The aim of this retrospective study was to clarify the clinical features of VLO-NMOSD. METHODS: According to the age at onset, we classified patients with NMOSD into three subgroups: ≤49 years, early onset NMOSD (EO-NMOSD); 50-69 years, late onset NMOSD (LO-NMOSD); and ≥70 years, VLO-NMOSD. We evaluated the clinical characteristics, magnetic resonance imaging (MRI) findings, laboratory data, and immunotherapies of the groups. RESULTS: Overall, 12 men and 64 women with a median (interquartile range) age at onset and duration of disease of 42.0 (29.0-55.8) years and 70.0 (16.3-143.0) months, respectively, were included. Eight (11%) patients had VLO-NMOSD, 22 (29%) had LO-NMOSD, and 46 (61%) had EO-NMOSD. Patients with EO-NMOSD had a significantly longer interval between episodes as well as time between the first symptom and diagnosis of NMOSD than did those with VLO-NMOSD and LO-NMOSD (p = 0.046). Optic neuritis and nerve lesions on MRI were significantly less frequent in patients with VLO-NMOSD than in those with LO-NMOSD and EO-NMOSD (p = 0.002 and p = 0.028, respectively). In contrast, patients with VLO-NMOSD had higher nadir Expanded Disability Status Scale and Nurick scale scores and a significantly longer spinal lesion length than did those with LO-NMOSD and EO-NMOSD (p = 0.029, p = 0.049, and p = 0.032, respectively). CONCLUSIONS: Patients with VLO-NMOSD tend to develop severe myelitis with long cord lesions but not optic neuritis.

A comprehensive analysis of the clinical characteristics and laboratory features in 179 patients with autoimmune autonomic ganglionopathy.

The clinical importance of autoantibodies against the ganglionic acetylcholine receptor (gAChR) remains to be fully elucidated. We aimed to identify the clinical characteristics of autoimmune autonomic ganglionopathy (AAG) in patients with gAChR autoantibodies. For this cohort investigation, serum samples were obtained from patients with AAG between 2012 and 2018 in Japan. We measured the levels of autoantibodies against gAChRα3 and gAChRß4 and evaluated clinical features, as well as assessing the laboratory investigation results among the included patients. A total of 179 patients tested positive for antibodies, including 116 gAChRα3-positive, 13 gAChRß4-positive, and 50 double antibody-positive patients. Seropositive AAG patients exhibited widespread autonomic dysfunction. Extra-autonomic manifestations including sensory disturbance, central nervous system involvement, endocrine disorders, autoimmune diseases, and tumours were present in 118 patients (83%). We observed significant differences in the frequencies of several autonomic and extra-autonomic symptoms among the three groups. Our 123I-metaiodobenzylguanidine myocardial scintigraphy analysis of the entire cohort revealed that the heart-to-mediastinum ratio had decreased by 80%. The present study is the first to demonstrate that patients with AAG who are seropositive for anti-gAChRß4 autoantibodies exhibit unique autonomic and extra-autonomic signs. Decreased cardiac uptake occurred in most cases, indicating that 123I- metaiodobenzylguanidine myocardial scintigraphy may be useful for monitoring AAG. Therefore, our findings indicate that gAChRα3 and gAChRß4 autoantibodies cause functional changes in postganglionic fibres in the autonomic nervous system and extra-autonomic manifestations in seropositive patients with AAG.

Anti-Kir4.1 Antibodies in Multiple Sclerosis: Specificity and Pathogenicity.

The glial cells in the central nervous system express diverse inward rectifying potassium channels (Kir). They express multiple Kir channel subtypes that are likely to have distinct functional roles related to their differences in conductance, and sensitivity to intracellular and extracellular factors. Dysfunction in a major astrocyte potassium channel, Kir4.1, appears as an early pathological event underlying neuronal phenotypes in several neurological diseases. The autoimmune effects on the potassium channel have not yet been fully described in the literature. However, several research groups have reported that the potassium channels are an immune target in patients with various neurological disorders. In 2012, Srivastava et al. reported about Kir4.1, a new immune target for autoantibodies in patients with multiple sclerosis (MS). Follow-up studies have been conducted by several research groups, but no clear conclusion has been reached. Most follow-up studies, including ours, have reported that the prevalence of Kir4.1-seropositive patients with MS was lower than that in the initial study. Therefore, we extensively review studies on the method of antibody testing, seroprevalence of MS, and other neurological diseases in patients with MS. Finally, based on the role of Kir4.1 in MS, we consider whether it could be an immune target in this disease.

Ganglionic Acetylcholine Receptor Antibodies and Autonomic Dysfunction in Autoimmune Rheumatic Diseases.

Autonomic neuropathy has been reported in autoimmune rheumatic diseases (ARD) including Sjögren's syndrome, systemic sclerosis, rheumatoid arthritis, and systemic lupus erythematosus. However, the pathophysiological mechanism underlying autonomic dysfunction remains unknown to researchers. On the other hand, autoimmune autonomic ganglionopathy (AAG) is an acquired immune-mediated disorder, which causes dysautonomia that is mediated by autoantibodies against ganglionic acetylcholine receptors (gAChRs). The purpose of this review was to describe the characteristics of autonomic disturbance through previous case reports and the functional tests used in these studies and address the importance of anti-gAChR antibodies. We have established luciferase immunoprecipitation systems to detect antibodies against gAChR in the past and determined the prevalence of gAChR antibodies in various autoimmune diseases including AAG and rheumatic diseases. Autonomic dysfunction, which affects lower parasympathetic and higher sympathetic activity, is usually observed in ARD. The anti-gAChR antibodies may play a crucial role in autonomic dysfunction observed in ARD. Further studies are necessary to determine whether anti-gAChR antibody levels are correlated with the severity of autonomic dysfunction in ARD.

Trousseau's syndrome triggered by an immune checkpoint blockade in a non-small cell lung cancer patient.

PD-1 blockade therapy activates T cells by blocking the interaction between PD-1 and PD-L1 and promotes IFN-γ and Th1 cytokine production. In turn, IFN-γ and Th1 cytokines produced by activated T cells promote TF synthesis in monocytes/macrophages, which results in hypercoagulability leading to thrombosis.

Inflammatory myopathy associated with PD-1 inhibitors.

OBJECTIVE: To characterize the inflammatory myopathy associated with programmed cell death 1 inhibitors (PD-1 myopathy). METHODS: We studied 19 Japanese patients with PD-1 myopathy (13 men and 6 women, mean age 70 years), who were referred to Keio University. As control groups, we used 68 patients with anti-signal recognition particle antibodies, 51 patients with anti-aminoacyl transfer RNA synthetase antibodies and 460 healthy subjects. RESULTS: In regard to muscle-disease severity, 10 patients showed a mild form of disease and 9 patients showed a severe form. Non-small cell lung cancer was the most common underlying cancer. PD-1 inhibitor consisted of 11 nivolumab and 8 pembrolizumab. PD-1 myopathy occurred 29 days on average after the first administration of PD-1 inhibitor. The initial manifestation of muscle weakness was ptosis in 10 patients, 15 patients had ptosis, 13 diplopia, 8 facial muscle weakness, 10 bulbar symptoms, 13 limb weakness, 14 neck weakness, 4 cardiac involvement, 6 respiratory involvement and 16 myalgia. Ocular, facial, cardiac and respiratory involvement and myalgia were more frequently observed than controls. Serum creatine kinase was increased to 5247 IU/L on average. Autoantibodies related to inflammatory myopathy were negative, while anti-striational antibodies were found in 13 (68%) patients. HLA-C*12:02 alleles were more frequently detected than healthy controls. Muscle pathology was characterized by multifocal necrotic myofibers with endomysial inflammation and expression of MHC class I. Immunosuppressive therapy with corticosteroids was generally effective for muscle weakness. CONCLUSIONS: Based on our clinical, histological and immunological findings, PD-1 myopathy is a discrete subset of inflammatory myopathy.

Novel anti-suprabasin antibodies may contribute to the pathogenesis of neuropsychiatric systemic lupus erythematosus.

Neuropsychiatric systemic lupus erythematosus (NPSLE) is often difficult to diagnose and distinguish from other diseases, because no NPSLE-specific antibodies have been identified. We developed a novel proteomic strategy for identifying and profiling antigens in immune complexes in the cerebrospinal fluid (CSF), and applied this strategy to 26 NPSLE patients. As controls, we also included 25 SLE patients without neuropsychiatric manifestations (SLE), 15 with relapsing remitting multiple sclerosis (MS) and 10 with normal pressure hydrocephalus (NPH). We identified immune complexes of suprabasin (SBSN) in the CSF of the NPSLE group. The titer of anti-SBSN antibodies was significantly higher in the CSF of the NPSLE group compared to those of the SLE, MS and NPH groups. Microarray data showed that the senescence and autophagy pathways were significantly changed in astrocytes exposed to anti-SBSN antibodies. Our findings indicate that SBSN could be a novel autoantibody for the evaluation of suspected NPSLE.

Pathomechanisms of anti-cytosolic 5'-nucleotidase 1A autoantibodies in sporadic inclusion body myositis.

OBJECTIVE: Sporadic inclusion body myositis (sIBM), an intractable progressive muscle disease, frequently occurs in older persons. sIBM pathogenesis may involve protein degradation dysfunction and immune abnormalities. Autoantibodies recognizing cytosolic 5'-nucleotidase 1A (cN1A) were found in plasma and serum from sIBM patients. However, whether anti-cN1A autoantibodies play a pathogenic role in sIBM is controversial. This study investigated the pathogenic properties of anti-cN1A autoantibodies in sIBM pathogenesis. METHODS: We developed a cell-based assay to detect anti-cN1A autoantibodies, which we found in serum from patients with neuromuscular diseases including sIBM. We also investigated the clinicopathological differences between sIBM patients with and without the autoantibodies. We used passive in vitro and in vivo immunization models to evaluate the pathogenic role of the autoantibodies. RESULTS: Of 67 patients with sIBM, 24 (35.8%) possessed anti-cN1A autoantibodies as determined via our cell-based assay. In the anti-cN1A-positive group, the percentage of patients with hepatitis C virus antibodies was significantly lower and the mean area of type 2 myofibers was significantly smaller compared with the autoantibody-negative group. In the in vitro passive immunization model, p62/SQSTM1 significantly increased in anti-cN1A-positive sIBM immunoglobulin G (IgG)-supplemented cells. In the in vivo passive immunization model, anti-cN1A-positive sIBM IgG-injected mice demonstrated p62/SQSTM1-positive sarcoplasmic aggregates in myofibers, associated with macrophage infiltration. INTERPRETATION: Our cell-based assay is useful for anti-cN1A autoantibodies detection. Patients with anti-cN1A autoantibodies demonstrated unique clinicopathological features. In vitro and in vivo passive immunization model results suggest that anti-cN1A autoantibodies may affect protein degradation in myofibers. Ann Neurol 2017;81:512-525.

Ganglionic acetylcholine receptor autoantibodies in patients with autoimmune diseases including primary biliary cirrhosis.

OBJECTIVES: Autonomic dysfunction is closely associated with autoimmune diseases (AID) including primary biliary cirrhosis (PBC). The objective of this study was to determine the prevalence of anti-ganglionic (nicotinic) acetylcholine receptor (gAChR) antibodies in patients with AID. METHODS: We determined the presence of gAChR antibodies in serum samples from 146 patients (systemic lupus erythematosus [SLE] = 32; rheumatoid arthritis [RA] = 43; systemic sclerosis [SSc] = 38; PBC= 33) without information regarding autonomic symptoms, as well as 34 patients with other neurological diseases [OND], and 73 healthy controls [HC]. We specifically analyzed sera for anti-gAChRα3 and -ß4 antibodies using the luciferase immunoprecipitation system (LIPS) assay. RESULTS: LIPS assay detected anti-gAChRα3 and -ß4 antibodies in the sera from patients with SLE (12.5%, 4/32), RA (18.6%, 8/43), SSc (13.2%, 5/38), PBC (9.1%, 3/33), OND (2.9%, 1/34), and HC (0.0%, 1/73). There were no significant correlations between the levels of anti-gAChRα3 and -ß4 antibodies, and the total titers of autoantibodies in AID. CONCLUSIONS: The results demonstrated a significant prevalence of anti-gAChR antibodies in patients with AID, which is independent of the production of other autoantibodies in patients with autoimmune diseases. These anti-gAChR antibodies could mediate the autonomic dysfunction involved in the autoimmune mechanisms of AID.

Myasthenic symptoms in anti-low-density lipoprotein receptor-related protein 4 antibody-seropositive amyotrophic lateral sclerosis: two case reports.

BACKGROUND: Myasthenic symptoms can be present in patients with amyotrophic lateral sclerosis (ALS). These symptoms have been considered to be caused by the degeneration of distal motor neurons and the neuromuscular junction (NMJ). Recent studies suggested that antibody to low-density lipoprotein receptor-related protein 4 (LRP4) was a pathogenic agent of myasthenia gravis (MG), and it was also detected in ALS patients. CASE PRESENTATION: Patient 1: A 58-year-old Japanese man developed progressive weakness and subsequent myasthenic symptoms including oculomotor disturbance. Clinical examination and electrophysiological studies confirmed upper and lower motor neuron involvement and NMJ dysfunction, and anti-LRP4 antibody was detected in his serum. A series of immunotherapies, including steroid pulse therapy, intravenous immunoglobulin, and plasmapheresis, was performed, and the myasthenic symptoms partially improved. The titer of anti-LRP4 antibody subsequently decreased. However, the therapeutic effect was transient, and ALS symptoms progressed. His clinical findings fulfilled the criteria of probable ALS using the Awaji criteria. Patient 2: A 74-year-old Japanese man suffered from progressive weakness of all limbs and dropped head in the evening. He complained of diplopia with a lateral horizontal gaze. Probable ALS was diagnosed because of the upper and lower motor neuron signs, whereas anti-LRP4 antibody was detected. Several immunotherapies were administered, and the myasthenic symptoms partially responded to each therapy. However, the truncal muscle weakness progressed, and he died of respiratory failure. CONCLUSION: We report two anti-LRP4 antibody-seropositive ALS patients with myasthenia who were not typical of ALS patients, and showed partial responses to immunotherapies. The anti-LRP4 antibody-seropositive status may influence developing ALS and cause additional ALS symptoms.

Insights from the ganglionic acetylcholine receptor autoantibodies in patients with Sjögren's syndrome.

OBJECTIVE: It is not known whether autonomic neuropathy is a feature of Sjögren's syndrome (SS) or whether it is related to circulating antiganglionic acetylcholine receptor (gAChR) antibodies. The goal of the present study was to investigate the autonomic dysfunction in patients with SS and the associations between autonomic dysfunction, anti-gAChR antibodies, and clinical features of SS. METHODS: (1) The first observational study tested for the presence of gAChR antibodies in the serum samples from 39 patients with SS (absent information regarding autonomic symptoms) and healthy volunteers. (2) In the second study, serological and clinical data from 10 Japanese patients diagnosed with SS were reviewed. These patients showed autonomic dysfunction, and luciferase immunoprecipitation systems (LIPS) test was conducted to detect anti-α3 and anti-ß4 gAChR antibodies. (3) In the final analysis, we combined the data of seropositive SS patients with autonomic symptom from the first study with all of the patients from the second study, and analyzed the clinical features. RESULTS: (1) The LIPS assay revealed that anti-gAChRα3 and anti-gAChRß4 antibodies were detected in the sera from patients with SS (23.1%, 9/39). Five of nine SS patients had autonomic symptoms. (2) Anti-α3 and anti-ß4 gAChR antibodies were also detected in 80.0% (8/10) of patients with SS with autonomic symptoms. Six of the ten patients were diagnosed as having SS after neurological symptoms developed. These seropositive patients had predominant and severe autonomic symptoms and were diagnosed with autonomic neuropathy. (3) Thirteen of fifteen SS patients with autonomic symptoms (86.7%) were seropositive for anti-gAChR antibodies, and we confirmed sicca complex, orthostatic hypotension, upper and lower gastrointestinal (GI) symptoms, and bladder dysfunction at high rates. CONCLUSION: The present results suggest the possibility of anti-gAChR antibodies aiding the diagnostics of SS with autonomic dysfunction.

Oral corticosteroid therapy and present disease status in myasthenia gravis.

INTRODUCTION: The aim of this study was to elucidate the effectiveness of oral prednisolone (PSL) according to dosing regimen in 472 patients with myasthenia gravis (MG). METHODS: We compared the clinical characteristics and PSL treatment between 226 patients who achieved minimal manifestations (MM) or better and 246 patients who remained improved (I) or worsened, according to the MG Foundation of America postintervention status. RESULTS: Achievement of MM or better at peak PSL dose (odds ratio 12.25, P < 0.0001) and combined use of plasma exchange/plasmapheresis (PE/PP) and/or intravenous immunoglobulin (IVIg) (odds ratio 1.92, P = 0.04) were associated positively, and total PSL dose during the past year (odds ratio 0.17, P = 0.03) was associated negatively with present MM or better status. CONCLUSIONS: Higher PSL dose and longer PSL treatment do not ensure better outcome. In the absence of a good response, the PSL dose should be decreased by combining with modalities such as PE/PP or IVIg.

Health-related quality-of-life and treatment targets in myasthenia gravis.

INTRODUCTION: The aim of this study was to determine factors affecting health-related quality of life (HRQOL) and to propose appropriate treatment targets for patients with myasthenia gravis (MG). METHODS: We evaluated 640 consecutive patients with MG seen at 11 neurological centers. Two-year follow-up data were obtained for 282 patients. Correlations between detailed clinical factors and the Japanese version of the 15-item MG-specific QOL scale score were analyzed. RESULTS: In a cross-sectional analysis of 640 MG patients, multivariate regression revealed that disease severity, as evaluated by the MG Composite (P<0.0001), total dose of oral prednisolone during the last year (P=0.002), and Cushingoid appearance index (P=0.0004), showed significant negative effects on HRQOL, but the quantitative MG score and current prednisolone dose did not. CONCLUSIONS: Achieving minimal manifestations (MM) status or better with prednisolone ≤ 5 mg/day was found to exert a major positive impact on HRQOL in both the cross-sectional and 2-year follow-up patient samples and can be recommended as a treatment target.

Quality of life in purely ocular myasthenia in Japan.

BACKGROUND: Since there has been no conclusive evidence regarding the treatment of ocular myasthenia, treatment guidelines were recently issued by the European Federation of Neurological Societies/European Neurological Society (EFNS/ENS). However, the therapeutic outcomes concerning the quality-of-life (QOL) of patients with ocular myasthenia are not yet fully understood. METHODS: We investigated the therapeutic outcomes of patients with purely ocular myasthenia in a multicenter cross-sectional survey in Japan. To evaluate the severity of ocular symptoms, we used the ocular-quantitative MG (QMG) score advocated by Myasthenia Gravis Foundation of America. We used the Japanese translated version of the MG-QOL15, a self-appraised scoring system. RESULTS: Of 607 myasthenia gravis (MG) patients with an observation-duration of illness ≥ 2 years, the cases of 123 patients (20%) were limited to ocular muscles (purely ocular myasthenia). During the entire clinical course, 81 patients experienced both ptosis and diplopia, 36 had ptosis alone, and six had diplopia alone. Acetyl-cholinesterase inhibitors and prednisolone were used in 98 and 52 patients, respectively. Treatment improved ocular symptoms, with the mean reduction in ocular-QMG score of 2.3 ± 1.8 points. However, 47 patients (38%) failed to gain minimal manifestation or a better status. Patients with unfavorable outcomes also self-reported severe QOL impairment. Multivariate analyses showed that the pretreatment ocular-QMG score was associated with unfavorable outcomes, but not associated with the patient's QOL. CONCLUSION: A treatment strategy designed in accord with a patient's ocular presentation must be considered in order to improve ocular symptoms and the patient's QOL.

Apathy/depression, but not subjective fatigue, is related with cognitive dysfunction in patients with multiple sclerosis.

BACKGROUND: Cognitive impairment could affect quality of life for patients with multiple sclerosis (MS), and cognitive function may be correlated with several factors such as depression and fatigue. This study aimed to evaluate cognitive function in Japanese patients with MS and the association between cognitive function and apathy, fatigue, and depression. METHODS: The Brief Repeatable Battery of Neuropsychological tests (BRB-N) was performed in 184 Japanese patients with MS and 163 healthy controls matched for age, gender, and education. The Apathy Scale (AS), Fatigue Questionnaire (FQ), and Beck Depression Inventory Second Edition (BDI-II) were used to evaluate apathy, fatigue, and depression, respectively. Student's t-test was used to compare MS patients and healthy controls. Correlations between two factors were assessed using the Pearson correlation test, and multiple regression analysis was used to evaluate how much each factor affected the BRB-N score. RESULTS: In all BRB-N tests, patients with MS scored significantly lower than controls, and the effect size of symbol digit modalities test was the highest among the 9 tests of the BRB-N. Patients with MS had higher AS (p < 0.001), FQ (p < 0.0001), and BDI-II (p < 0.0001) scores than controls. In patients with MS, scores on most of the BRB-N tests correlated with scores on the AS and BDI-II; however, there was little correlation between scores on the BRB-N tests and those on the FQ. CONCLUSIONS: Cognitive function was impaired, particularly information-processing speed, and decreased cognitive function was correlated with apathy and depression in Japanese patients with MS. Despite the association between cognitive variables and depression/apathy, cognitive function was impaired beyond the effect of depression and apathy. However, subjective fatigue is not related with cognitive impairment. Taken together, this suggests that different therapeutic approaches are needed to improve subjective fatigue and cognition, and thereby quality of life, in patients with MS.

Spinal cord stimulation for intractable pain evaluated by a collision study using somatosensory evoked potentials: a preliminary report.

OBJECTIVE: Appropriate stimulation of the dorsal column is required in order to achieve optimal control over pain by way of spinal cord stimulation (SCS). In this study, we objectively evaluated changes in somatosensory evoked potentials (SEPs) during a collision test in order to investigate whether paresthetic sensation or amount of pain reduction was correlated with the degree of dorsal column stimulation. MATERIALS AND METHODS: We studied 12 patients with intractable pain who underwent permanent SCS implantation. SEP collision was examined while recording the cortical SEP components elicited by posterior tibial nerve stimulation. A positive collision effect was observed when the SEP amplitude was clearly reduced by the SCS. RESULTS: Based on the SEP collision findings, the effects of SCS were classified into four patterns: positive collision with pain reduction (Type 1), positive collision without pain reduction (Type 2), negative collision with pain reduction (Type 3), and negative collision without pain reduction (Type 4). Type 1 was observed for well-known diseases in which SCS was very effective, whereas Type 2 was seen in poor candidates for dorsal column stimulation. Patients with poststroke pain exhibited various patterns including types 1, 2, and 3. One patient showed Type 4 patterning, and we recommended further SCS trials before the abandonment of SCS therapy for this patient. CONCLUSIONS: We show that SEP collision is useful for evaluating the degree of dorsal column stimulation needed as well as in considering factors related to differences between responders and nonresponders to SCS therapy.