Long-term neuropsychological outcome following pediatric anti-NMDAR encephalitis

Autoimmune Encephalitis

Autoimmune encephalitides (AE) constitute a broad group of inflammatory brain disorders characterized by prominent neuropsychiatric symptoms, frequently in association with autoantibodies against neural (neuronal or glial) antigens. The most frequent AE are anti-NMDA receptor encephalitis, acute disseminated encephalomyelitis (associated with MOG antibodies in 60% of patients), and limbic encephalitis (with several immunologic subtypes, anti-LGI1 encephalitis being the most frequent). The first 2 predominantly affect children and young adults, whereas limbic encephalitis usually affects patients older than 50 years. Despite the severity of symptoms, prompt diagnosis and treatment lead to substantial recovery in most patients.

Hippocampal dysfunction after autoimmune encephalitis depending on the antibody type

BACKGROUND

Comprehensive neurocognitive function analyses of autoimmune encephalitis (AE) patients, especially long-term ones, are rare. This study aims to measure cognitive function in patients diagnosed with AE.

METHODS

This case-control study included AE patients (n = 11) with antibodies against NMDA receptor (NMDAR) (n = 4), VGKC (n = 3), GAD (3), and one antibody-negative patient. The control group contained 12 pneumococcal meningo-encephalitis patients (PC). Subgroup analyses compared AE patients with and without NMDAR antibodies. Neurocognitive tests were performed to evaluate verbal and visual memory, face recognition, attentional capacity, incidental learning capacity, and overall cognitive function (Montreal cognitive assessment, MoCA). Limbic structural involvement was assessed through magnetic resonance imaging (MRI). Statistical analyses investigated correlations between antibody status, results of neurocognitive tests, and MRI findings.

RESULTS

Follow-up (AE vs. PC) was 33 (11-95) vs. 96 (26-132) months after diagnosis. Neurocognitive functions were normal in both AE and PC groups in all tests except face recognition, which was pathological in both groups. The overall/recognition/long-delay visual memory (p = 0.009/0.008/0.005) and incidental learning (p = 0.017) scores were significantly higher in NMDAR patients compared to non-NMDAR patients. Non-NMDAR patients with right-sided limbic MRI pathologies had significantly lower overall/recognition/long-delay visual memory (p = 0.006/0.044/0.024) and incidental learning (p = 0.009) scores compared to NMDAR patients.

CONCLUSIONS

We observed mainly normal neurocognitive functions after autoimmune and bacterial encephalitis. However, compared to NMDAR patients, patients with non-NMDAR autoimmune encephalitis showed a significant and material-specific association between a right-sided hippocampal lesion and limitations in figural-mnestic and incidental learning capacities. Neurocognitive functions in AE patients should be further evaluated prospectively and in more detail.

Patient-Reported Outcome Measures in NMDA Receptor Encephalitis

BACKGROUND AND OBJECTIVES

The characteristics of persistent long-term symptoms and their contribution to subjective quality of life remain unclear in patients with NMDAR encephalitis. In this study, we aimed to evaluate postacute neuropsychiatric symptoms, subjective cognitive complaints, and disease coping mechanisms and identify predictors of health-related quality of life (HRQoL) after N-methyl-D-aspartate receptor (NMDAR) encephalitis.

METHODS

This cross-sectional observational study investigated patients with NMDAR encephalitis in the postacute phase. Psychometric scales included assessment of neuropsychiatric symptoms (i.e., fatigue, sleep, anxiety, and depressive symptoms), HRQoL, everyday independence, metamemory (i.e., self-rated ability, satisfaction, and use of strategies), and coping strategies (i.e., self-efficacy, disease-related coping, and stress management).

RESULTS

A total of 50 patients (mean age 26.0 ± 10.1 years, 86% female) participated at a median of 4.15 (range 0.3-30.3) years after symptom onset. Patients reported significantly increased levels of anxiety (Beck Anxiety Inventory: 10.5 ± 7.7 [mean ± SD], 95% CI [8.32-12.71], p < 0.001) and depressive (Beck Depression Inventory-II: 11.4 ± 7.7 [9.22-13.62], p = 0.001) symptoms compared with the normative population. Both sleep problems (Pittsburgh Sleep Quality Index: 5.8 ± 3.0 [4.98-6.66], p < 0.001) and motor and cognitive fatigue (Fatigue Scale for Motor and Cognitive Function: 50.5 ± 23.1 [42.5-58.4], p < 0.001) were significantly more prevalent. Moreover, lower self-rated memory ability (Multifactorial Memory Questionnaire score: 54.6 ± 8.5 [52.1-57.1], p = 0.004) was associated with greater reliance on compensatory strategies and memory aids (r = -0.41, p = 0.004). Patients used significantly fewer cognitive coping strategies, such as relativization (11.7 ± 4.7 [10.3-13.1], p = 0.001), while depressive coping prevailed (49.1 ± 15.5 [44.5-53.8], p < 0.001). It is important to note that HRQoL was predicted by self-reported affective symptoms, self-efficacy, and coping behaviors in multivariable regression analyses, but not by acute disease severity or postacute physical disability.

DISCUSSION

Our findings show that persistent neuropsychiatric and subjective cognitive concerns explain a large part of the reduced quality of life in patients with NMDAR encephalitis. These findings have important implications for a patient-centered postacute care and the role of disease coping strategies in the neurorehabilitation of autoimmune encephalitis.

Long-Term Cognitive, Functional, and Patient-Reported Outcomes in Patients With Anti-NMDAR Encephalitis

BACKGROUND AND OBJECTIVES

Anti-NMDA receptor (anti-NMDAR) encephalitis generally manifests in young adults. Although 80%-90% returns to independence, the majority experience persistent cognitive and psychosocial difficulties. Studies have demonstrated that cognitive recovery may continue for years; the temporal trajectory is largely unknown, as are factors influencing cognitive/psychosocial recovery. Objectives were to (1) describe the cognitive recovery trajectory, (2) assess self-reported outcomes, (3) identify factors relating to outcome, and (4) explore the relation between cognitive and self-reported outcomes, and participation.

METHODS

We performed a large-scale cross-sectional and prospective cohort study. We addressed our nationwide cohort, provided they were (1) older than 16 years, (2) independent preillness, and (3) able to perform cognitive tests and/or self-report. Patients completed Patient-Reported Outcome Measures and neuropsychological assessments (memory, language, perception and construction, and attention and executive functions), and functional outcomes were established (modified Rankin Scale [mRS] score and return-to-work/-education). Outcomes were compared with references and between groups based on clinical characteristics and functional outcomes (T-tests for normalized data and nonparametric tests for patient-reported data). Recovery was visualized by plotting outcomes against time-of-assessment.

RESULTS

We included 92 patients (age 29 ± 2 years; 77% female). Cognitive scores improved with time-of-assessment, up to 36 months after diagnosis (R = 0.35, p = 0.022), with the most enhanced improvement in the first 6 months. This result could be reproduced in prospective patients (n = 12). Beyond 36 months (n = 44), 34% of patients had a persistent impairment (z-score <-1.5 SD) and 65% scored below-average (<-1 SD) in 1 or more cognitive domains, despite a "favorable" outcome measured by mRS (≤2) in the majority (91%). Most affected were memory (mean -0.67 ± 0.89 SD, p = 0.25) and language (-0.75 ± 1.06 SD, p = 0.23). Self-reported complaints remained in emotional well-being (mean 72 ± 25 SD vs norm 82 ± 33 SD, p < 0.001), social functioning (73 ± 26 SD vs 84 ± 22 SD, p < 0.001), energy levels (57 ± 19 SD vs 69 ± 19 SD, p < 0.001), and quality of life (0.85 ± 0.14 SD vs 0.93 ± 0.11 SD, p < 0.001). Many patients did not resume school/work (30%) or needed adjustments (18%). Resuming school/work related to processing speed (-0.14 ± 0.78 SD vs -0.84 ± 1.05 SD, p = 0.039) and well-being (EuroQol 5 Dimensions 5 Levels median 0.90 vs 0.81, p = 0.016).

DISCUSSION

Recovery from anti-NMDAR encephalitis may continue for 3 years, with risk of persisting cognitive deficits, notably in memory and language, and sequelae in social functioning, energy levels, and well-being. The frequently applied outcome measure mRS does not fully capture outcomes. Almost half of patients struggled resuming school/work, associated with cognitive deficits and well-being.

Recent advances in autoimmune encephalitis

Since the description of autoimmune encephalitis (AE) associated with N-methyl-D-aspartate receptor antibodies (anti-NMDARE) in 2007, more than 12 other clinical syndromes and antibodies have been reported. In this article, we review recent advances in pathophysiology, genetics, diagnosis pitfalls, and clinical phenotypes of AE associated with cell surface antibodies and anti-GAD associated neurological syndromes. Genetic studies reported human leukocyte antigen (HLA) associations for anti-LGI1, anti-Caspr2, anti-IgLON5, and anti-GAD. Follow-up studies characterized cognitive dysfunction, psychiatric symptoms, sleep disorders, and adaptative behavior dysfunction, mainly for anti-NMDARE. Late-onset anti-NMDARE and anti- GABA-B receptor (GABA-BR) encephalitis patients were described to have worse prognoses and different tumor associations. Additionally, the clinical spectrum of anti-LGI1, anti-AMPAR, anti-CASPR2, and anti-IgLON5 was expanded, comprising new differential diagnoses. The diagnostic criteria for AE were adapted to the pediatric population, and a diagnostic algorithm was proposed, considering potential mimics and misdiagnosis. We also review the limitations of commercial assays for AE and treatment recommendations, as well as clinical scales for short and long-term assessment of AE patients, along with cognitive evaluation.

Acute Bilateral Vocal Cord Paralysis in a Patient With Anti-Leucine-Rich Glioma-Inactivated 1 (LGI1) Limbic Encephalitis

Autoimmune encephalitis is a disorder characterized by an autoantibody-mediated process that leads to brain inflammation. It is associated with neurological symptoms including cognitive issues, psychiatric problems, seizures, and autonomic dysfunctions. Anti-leucine-rich glioma-inactivated 1 limbic encephalitis (anti-LGI1 LE) is a rare type of autoimmune LE with a unique presentation, comprising neuropsychiatric disturbances, sleep disorders, and faciobrachial dystonic seizures (FBDS). While the involvement of the larynx is seen in various other autoimmune and neurological diseases, it is not a known issue with anti-LGI1 LE. The purpose of this case report is to highlight an atypical symptom - acute bilateral vocal cord failure - that unexpectedly occurred in a patient with anti-LGI1 LE.

MRI findings in autoimmune encephalitis

Autoimmune encephalitis encompasses a spectrum of conditions characterized by distinct clinical features and magnetic resonance imaging (MRI) findings. Here, we review the literature on acute MRI changes in the most common autoimmune encephalitis variants. In N-methyl-D-aspartate (NMDA) receptor encephalitis, most patients have a normal MRI in the acute stage. When lesions are present in the acute stage, they are typically subtle and non-specific white matter lesions that do not correspond with the clinical syndrome. In some NMDA receptor encephalitis cases, these T2-hyperintense lesions may be indicative of an NMDA receptor encephalitis overlap syndrome with simultaneous co-existence of multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD) or myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Encephalitis with leucine-rich glioma-inactivated 1 (LGI1)-, contactin-associated protein-like 2 (CASPR2)- or glutamic acid decarboxylase (GAD)- antibodies typically presents as limbic encephalitis (LE) with unilateral or bilateral T2/fluid attenuated inversion recovery (FLAIR) hyperintensities in the medial temporal lobe that can progress to hippocampal atrophy. Gamma aminobutyric acid-B (GABA-B) receptor encephalitis also often shows such medial temporal hyperintensities but may additionally involve cerebellar lesions and atrophy. Gamma aminobutyric acid-A (GABA-A) receptor encephalitis features multifocal, confluent lesions in cortical and subcortical areas, sometimes leading to generalized atrophy. MRI is unremarkable in most patients with immunoglobulin-like cell adhesion molecule 5 (IgLON5)-disease, while individual case reports identified T2/FLAIR hyperintense lesions, diffusion restriction and atrophy in the brainstem, hippocampus and cerebellum. These findings highlight the need for MRI studies in patients with suspected autoimmune encephalitis to capture disease-specific changes and to exclude alternative diagnoses. Ideally, MRI investigations should be performed using dedicated autoimmune encephalitis imaging protocols. Longitudinal MRI studies play an important role to evaluate potential relapses and to manage long-term complications. Advanced MRI techniques and current research into imaging biomarkers will help to enhance the diagnostic accuracy of MRI investigations and individual patient outcome prediction. This will eventually enable better treatment decisions with improved clinical outcomes.

Predicting the future of autoimmune encephalitides

The concept that many neurologic and psychiatric disorders of unknown cause are immune-mediated has evolved fast during the past 20 years. The main contribution to the expansion of this field has been the discovery of antibodies that attack neuronal or glial cell-surface proteins or receptors, directly modifying their structure and function. These antibodies facilitate the diagnosis and prompt treatment of patients who often improve with immunotherapy. The identification of this group of diseases, collectively named "autoimmune encephalitides", was preceded by many years of investigations on other autoimmune CNS disorders in which the antibodies are against intracellular proteins, occur more frequently with cancer, and associate with cytotoxic T-cell responses that are less responsive to immunotherapy. Here, we first trace the recent history of the autoimmune encephalitides and address how to assess the clinical value and implement in our practice the rapid pace of autoantibody discovery. In addition, we review recent developments in the post-acute stage of the two main autoimmune encephalitides (NMDAR and LGI1) focusing on symptoms that are frequently overlooked or missed, and therefore undertreated. Because a better understanding of the pathophysiology of these diseases relies on animal models, we examine currently available studies, recognizing the existing needs for better and all-inclusive neuro-immunobiological models. Finally, we assess the status of biomarkers of disease outcome, clinical scales, current treatment strategies, and emerging therapies including CAR T-cell technology. Altogether, this overview is intended to identify gaps of knowledge and provide suggestions for improvement and insights for future research.

The immunology underlying CNS autoantibody diseases

The past two decades have seen a considerable paradigm shift in the way autoimmune CNS disorders are considered, diagnosed, and treated; largely due to the discovery of novel autoantibodies directed at neuroglial surface or intracellular targets. This approach has enabled multiple bona fide CNS autoantibody-associated diseases to thoroughly infiltrate the sphere of clinical neurology, facilitating advances in patient outcomes. This review focusses on the fundamental immunological concepts behind CNS autoantibody-associated diseases. First, we briefly review the broad phenotypic profiles of these conditions. Next, we explore concepts around immune checkpoints and the related B cell lineage. Thirdly, the sources of autoantibody production are discussed alongside triggers of tolerance failure, including neoplasms, infections and iatrogenic therapies. Penultimately, the role of T cells and leucocyte trafficking into the CNS are reviewed. Finally, biological insights from responses to targeted immunotherapies in different CNS autoantibody-associated diseases are summarised. The continued and rapid expansion of the CNS autoantibody-associated field holds promise for further improved diagnostic and therapeutic paradigms, ultimately leading to further improvements in patient outcomes.

Assessment of long-term psychosocial outcomes in N-methyl-D-aspartate receptor encephalitis - the SAPIENCE study protocol

BACKGROUND

N-methyl-D-aspartate-receptor (NMDAR) encephalitis is a rare neurological autoimmune disease with severe neuropsychiatric symptoms during the acute phase. Despite good functional neurological recovery, most patients continue to experience cognitive, psychiatric, psychological, and social impairments years after the acute phase. However, the precise nature and evolving patterns over time of these long-term consequences remain unclear, and their implications for the well-being and quality of life of predominantly young patients have yet to be thoroughly examined.

METHODS

SAPIENCE is a European multi-center (n = 3) prospective observational cohort study studying the long-term cognitive, psychiatric, psychological, and social outcome in patients with NMDAR encephalitis. The study consists of three interconnected levels. Level 1 comprises a qualitative interview and focus groups with patients and their caregivers. Level 2 consists of a condensed form of the interview, standardized questionnaires, and a detailed neuropsychological examination of patients. Level 3 involves an online survey that will be open to patients world-wide and explores patient-reported outcomes (PROMs), and patient-reported experiences (PREMs) in association with clinical and cognitive outcomes. Levels 1 to 3 will progressively contribute developing of structured interviews, survey questions, and treatment guidelines by informing one another.

DISCUSSION

SAPIENCE is an in-depth study of the long-term effects of NMDAR encephalitis and bridges the gap between standardized assessments and individual patient experiences, intending to improve patient care and to increase awareness of the psychosocial long-term consequences of the disease. Through collaboration of experts in clinical neurology and social and health psychology across Europe, SAPIENCE aims to create online assessment tools and formulate guidelines for patient-centered post-acute care that will help enhance the quality of life for patients and caregivers.

Innovation and optimization in autoimmune encephalitis trials: the design and rationale for the Phase 3, randomized study of satralizumab in patients with NMDAR-IgG-antibody-positive or LGI1-IgG-antibody-positive autoimmune encephalitis (CIELO)

Background

Autoimmune encephalitis (AIE) encompasses a spectrum of rare autoimmune-mediated neurological disorders, which are characterized by brain inflammation and dysfunction. Autoantibodies targeting the N-methyl-d-aspartic acid receptor (NMDAR) and leucine-rich glioma-inactivated 1 (LGI1) are the most common subtypes of antibody-positive AIE. Currently, there are no approved therapies for AIE. Interleukin-6 (IL-6) signaling plays a role in the pathophysiology of AIE. Satralizumab, a humanized, monoclonal recycling antibody that specifically targets the IL-6 receptor and inhibits IL-6 signaling, has demonstrated efficacy and safety in another autoantibody-mediated neuroinflammatory disease, aquaporin-4 immunoglobulin G antibody-positive neuromyelitis optica spectrum disorder, and has the potential to be an evidence-based disease modifying treatment in AIE.

Objectives

CIELO will evaluate the efficacy, safety, pharmacodynamics, and pharmacokinetics of satralizumab compared with placebo in patients with NMDAR-immunoglobulin G antibody-positive (IgG+) or LGI1-IgG+ AIE.

Study design

CIELO (NCT05503264) is a prospective, Phase 3, randomized, double-blind, multicenter, basket study that will enroll approximately 152 participants with NMDAR-IgG+ or LGI1-IgG+ AIE. Prior to enrollment, participants will have received acute first-line therapy. Part 1 of the study will consist of a 52-week primary treatment period, where participants will receive subcutaneous placebo or satralizumab at Weeks 0, 2, 4, and every 4 weeks thereafter. Participants may continue to receive background immunosuppressive therapy, symptomatic treatment, and rescue therapy throughout the study. Following Part 1, participants can enter an optional extension period (Part 2) to continue the randomized, double-blind study drug, start open-label satralizumab, or stop study treatment and continue with follow-up assessments.

Endpoints

The primary efficacy endpoint is the proportion of participants with a ≥1-point improvement in the modified Rankin Scale (mRS) score from study baseline and no use of rescue therapy at Week 24. Secondary efficacy assessments include mRS, Clinical Assessment Scale of Autoimmune Encephalitis (CASE), time to rescue therapy, sustained seizure cessation and no rescue therapy, Montreal Cognitive Assessment, and Rey Auditory Verbal Learning Test (RAVLT) measures. Safety, pharmacokinetics, pharmacodynamics, exploratory efficacy, and biomarker endpoints will be captured.

Conclusion

The innovative basket study design of CIELO offers the opportunity to yield prospective, robust evidence, which may contribute to the development of evidence-based treatment recommendations for satralizumab in AIE.

Examining cognition and brain networks using magnetoencephalography in paediatric autoimmune encephalitis and acute disseminated encephalomyelitis: a preliminary study

Paediatric autoimmune encephalitis, including acute disseminated encephalomyelitis, are inflammatory brain diseases presenting with cognitive deficits, psychiatric symptoms, seizures, MRI and EEG abnormalities. Despite improvements in disease recognition and early immunotherapy, long-term outcomes in paediatric autoimmune encephalitis remain poor. Our aim was to understand functional connectivity changes that could be associated with negative developmental outcomes across different types of paediatric autoimmune encephalitis using magnetoencephalography. Participants were children diagnosed with paediatric autoimmune encephalitis at least 18 months before testing and typically developing children. All completed magnetoencephalography recording at rest, T1 MRI scans and neuropsychology testing. Brain connectivity (specifically in delta and theta) was estimated with amplitude envelope correlation, and network efficiency was measured using graph measures (global efficiency, local efficiency and modularity). Twelve children with paediatric autoimmune encephalitis (11.2 ± 3.5 years, interquartile range 9 years; 5M:7F) and 12 typically developing controls (10.6 ± 3.2 years, interquartile range 7 years; 8M:4F) participated. Children with paediatric autoimmune encephalitis did not differ from controls in working memory (t(21) = 1.449; P = 0.162; d = 0.605) but had significantly lower processing speed (t(21) = 2.463; P = 0.023; Cohen's d = 1.028). Groups did not differ in theta network topology measures. The paediatric autoimmune encephalitis group had a significantly lower delta local efficiency across all thresholds tested (d = -1.60 at network threshold 14%). Theta modularity was associated with lower working memory (β = -0.781; t(8) = -2.588, P = 0.032); this effect did not survive correction for multiple comparisons (P(corr) = 0.224). Magnetoencephalography was able to capture specific network alterations in paediatric autoimmune encephalitis patients. This preliminary study demonstrates that magnetoencephalography is an appropriate tool for assessing children with paediatric autoimmune encephalitis and could be associated with cognitive outcomes.

Autoimmune Encephalitis

OBJECTIVE

This article focuses on the clinical features and diagnostic evaluations that accurately identify patients with ever-expanding forms of antibody-defined encephalitis. Forms of autoimmune encephalitis are more prevalent than infectious encephalitis and represent treatable neurologic syndromes for which early immunotherapies lead to the best outcomes.

LATEST DEVELOPMENTS

A clinically driven approach to identifying many autoimmune encephalitis syndromes is feasible, given the typically distinctive features associated with each antibody. Patient demographics alongside the presence and nature of seizures, cognitive impairment, psychiatric disturbances, movement disorders, and peripheral features provide a valuable set of clinical tools to guide the detection and interpretation of highly specific antibodies. In turn, these clinical features in combination with serologic findings and selective paraclinical testing, direct the rationale for the administration of immunotherapies. Observational studies provide the mainstay of evidence guiding first- and second-line immunotherapy administration in autoimmune encephalitis and, whereas these typically result in some clinical improvements, almost all patients have residual neuropsychiatric deficits, and many experience clinical relapses. An improved pathophysiologic understanding and ongoing clinical trials can help to address these unmet medical needs.

ESSENTIAL POINTS

Antibodies against central nervous system proteins characterize various autoimmune encephalitis syndromes. The most common targets include leucine-rich glioma inactivated protein 1 (LGI1), N-methyl-d-aspartate (NMDA) receptors, contactin-associated proteinlike 2 (CASPR2), and glutamic acid decarboxylase 65 (GAD65). Each antibody-associated autoimmune encephalitis typically presents with a recognizable blend of clinical and investigation features, which help differentiate each from alternative diagnoses. The rapid expansion of recognized antibodies and some clinical overlaps support panel-based antibody testing. The clinical-serologic picture guides the immunotherapy regime and offers valuable prognostic information. Patient care should be delivered in conjunction with autoimmune encephalitis experts.

A systematic review of the epidemiology of pediatric autoimmune encephalitis: disease burden and clinical decision-making

Background

Autoimmune encephalitis (AIE) comprises a group of rare, immune system-mediated conditions. Clinical manifestations among children are not well-characterized, and there are challenges in testing and diagnosis. This can result in treatment delays, which has been found to correlate with poorer long-term outcomes. This challenge is exacerbated by the scarcity of epidemiological reporting of AIE. The objective of this systematic literature review (SLR) was to identify studies reporting epidemiological data on AIE in children.

Methods

MEDLINE, Embase, the Cochrane Library, and the University of York Centre for Reviews and Dissemination (CRD) were searched in May 2023 for studies reporting on the epidemiology of AIE in children. These were supplemented with additional searches of conference proceedings, gray literature, and the reference lists of identified SLRs. Quality of studies was assessed using a modified version of the Joanna Briggs Institute (JBI) Checklist for Prevalence Studies.

Results

Forty-three publications reporting on 41 unique studies were included. Nine studies reported incidence estimates of different subtypes of AIE, with only one reporting the incidence of overall AIE in children ≤ 18 years, estimated at 1.54 per million children per year in the Netherlands. Three studies reported the incidence of pediatric N-methyl-D-aspartate receptor (NMDAR)-AIE [in United Kingdom (UK), Hong Kong, and Denmark]. The other studies reported incidence data for selected populations.

Conclusion

This SLR highlights a paucity of epidemiology data for AIE in children, which is likely reflective of difficulties in testing and diagnosis. There is a clear need for further research and awareness of these challenges in clinical practice to avoid treatment delays and improve patient outcomes. A deeper understanding of the epidemiology of AIE will help determine the worldwide burden of disease and inform research, health policies and clinical decision-making.

Brazilian consensus recommendations on the diagnosis and treatment of autoimmune encephalitis in the adult and pediatric populations

BACKGROUND

 Autoimmune encephalitis (AIE) is a group of inflammatory diseases characterized by the presence of antibodies against neuronal and glial antigens, leading to subacute psychiatric symptoms, memory complaints, and movement disorders. The patients are predominantly young, and delays in treatment are associated with worse prognosis.

OBJECTIVE

 With the support of the Brazilian Academy of Neurology (Academia Brasileira de Neurologia, ABN) and the Brazilian Society of Child Neurology (Sociedade Brasileira de Neurologia Infantil, SBNI), a consensus on the diagnosis and treatment of AIE in Brazil was developed using the Delphi method.

METHODS

 A total of 25 panelists, including adult and child neurologists, participated in the study.

RESULTS

 The panelists agreed that patients fulfilling criteria for possible AIE should be screened for antineuronal antibodies in the serum and cerebrospinal fluid (CSF) using the tissue-based assay (TBA) and cell-based assay (CBA) techniques. Children should also be screened for anti-myelin oligodendrocyte glucoprotein antibodies (anti-MOG). Treatment should be started within the first 4 weeks of symptoms. The first-line option is methylprednisolone plus intravenous immunoglobulin (IVIG) or plasmapheresis, the second-line includes rituximab and/or cyclophosphamide, while third-line treatment options are bortezomib and tocilizumab. Most seizures in AIE are symptomatic, and antiseizure medications may be weaned after the acute stage. In anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis, the panelists have agreed that oral immunosuppressant agents should not be used. Patients should be evaluated at the acute and postacute stages using functional and cognitive scales, such as the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the Modified Rankin Scale (mRS), and the Clinical Assessment Scale in Autoimmune Encephalitis (CASE).

CONCLUSION

 The present study provides tangible evidence for the effective management of AIE patients within the Brazilian healthcare system.

Functional connectivity changes of the hippocampal subregions in anti-N-methyl-D-aspartate receptor encephalitis

The hippocampus plays an important role in the pathophysiological mechanism of Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. Nevertheless, the connection between the resting-state activity of the hippocampal subregions and neuropsychiatric disorders in patients remains unclear. This study aimed to explore the changes in functional connectivity (FC) in the hippocampal subregions of patients with anti-NMDAR encephalitis and its association with clinical symptoms and cognitive performance. Twenty-three patients with anti-NMDAR encephalitis and 23 healthy controls (HC) were recruited. All participants underwent resting-state functional magnetic resonance imaging (rs-fMRI) scans and completed clinical cognitive scales. Based on the Brainnetome Atlas, the rostral (anterior) and caudal (posterior) hippocampi of both the left and right hemispheres were selected as regions of interest (ROIs) for FC analysis. First, a one-sample t-test was used to observe the whole-brain connectivity distribution of hippocampal subregions within the patient and HC groups at a threshold of p < 0.05. The two-sample t-test was used to compare the differences in hippocampal ROIs connectivity between groups, followed by a partial correlation analysis between the FC values of brain regions with statistical differences and clinical variables. This study observed that the distribution of whole-brain functional connectivity in the rostral and caudal hippocampi aligned with the connectivity differences between the anterior and posterior hippocampi. Compared to the HC group, the patients showed significantly decreased FC between the bilateral rostral hippocampus and the left inferior orbitofrontal gyrus and between the right rostral hippocampus and the right cerebellum. However, a significant increase in FC was observed between the right rostral hippocampus and left superior temporal gyrus, the left caudal hippocampus and right superior frontal gyrus, and the right caudal hippocampus and left gyrus rectus. Partial correlation analysis showed that FC between the left inferior orbitofrontal gyrus and the right rostral hippocampus was significantly negatively correlated with the California Verbal Learning Test (CVLT) and Brief Visuospatial Memory Test (BVMT) scores. The FC between the right rostral hippocampus and the left superior temporal gyrus was negatively correlated with BVMT scores. FC abnormalities in the hippocampal subregions of patients with anti-NMDAR encephalitis were associated with cognitive impairment, emotional changes, and seizures. These results may help explain the pathophysiological mechanisms and clinical manifestations of anti-NMDAR encephalitis and NMDAR dysfunction-related diseases such as schizophrenia.

Anti-NMDAR encephalitis in a child with long impaired consciousness and persistent antibodies: a case report and mini review

We described a challenging case of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis in a young girl. Despite enduring months of reduced consciousness with ongoing antibody presence, she ultimately exhibited remarkable improvement within a 5-year follow-up period. Additionally, we conducted a concise review of relevant literature on anti-NMDAR encephalitis, with a specific focus on anti-NMDAR antibodies. Our findings enhance the clinical comprehension of anti-NMDAR encephalitis and offer valuable insights to clinicians for its management.

Very Long-Term Functional Outcomes and Dependency in Children With Anti-NMDA Receptor Encephalitis

OBJECTIVES

To assess the daily function of children with anti-N-methyl-d-aspartate receptor encephalitis (NMDARe) after a minimal follow-up of 5 years.

METHODS

Patients 18 years and younger by the time of disease onset, whose serum and CSF were studied in our center between 2013 and 2017, were included in the study. Patients' daily life function was assessed by their physicians using a 15-domain question format (Liverpool Outcome Score).

RESULTS

Of 76 patients, 8 (11%) died and 68 were followed for a mean of 7.1 years (SD 1.5 years, range: 5.0-10.1). Three outcome patterns were identified: full recovery (50; 73%); behavioral and school/working deficits (12; 18%); and multidomain deficits (6; 9%) involving self-care ability, behavioral-cognitive impairment, and seizures. Younger age of disease onset was significantly associated with multidomain deficits (OR 1.6, 95% CI 1.02-2.4, p = 0.04), particularly in children younger than 6 years, among whom 8 of 23 (35%) remained sociofamiliar dependent.

DISCUSSION

After a minimal follow-up of 5 years, most children with NMDARe had substantial or full functional recovery, but approximately one-fifth remained with behavioral and school/working deficits. The younger the patient at disease onset, the more probable it was to remain with multidomain deficits and dependent on sociofamiliar support.

Fatigue predicts quality of life after leucine-rich glioma-inactivated 1-antibody encephalitis

Patient-reported quality-of-life (QoL) and carer impacts are not reported after leucine-rich glioma-inactivated 1-antibody encephalitis (LGI1-Ab-E). From 60 patients, 85% (51 out of 60) showed one abnormal score across QoL assessments and 11 multimodal validated questionnaires. Compared to the premorbid state, QoL significantly deteriorated (p < 0.001) and, at a median of 41 months, fatigue was its most important predictor (p = 0.025). In total, 51% (26 out of 51) of carers reported significant burden. An abbreviated five-item battery explained most variance in QoL. Wide-ranging impacts post-LGI1-Ab-E include decreased QoL and high caregiver strain. We identify a rapid method to capture QoL in routine clinic or clinical trial settings.

Disease course and psychosocial outcome for children and adolescents with anti-N-methyl-D-aspartate receptor encephalitis

OBJECTIVES

Explore psychosocial outcome and impact of persisting deficits on quality of life (QoL) and global functioning after anti-N-methyl-D-aspartate receptor encephalitis (anti-NMDARE) in children and adolescents.

METHODS

Four female patients (age 7-16y) and their caregivers participated in the study. Information was collected from the medical records and the caregivers via a questionnaire. Both the patients and their caregivers were interviewed by means of the structured clinical interview for DSM-5 disorders, junior version (SCID-5 junior). CGAS and mRS scores were defined and the Pediatric Quality of Life Inventory (PedsQL) was used to assess quality of life of patients and caregivers.

RESULTS AND CONCLUSION

After the acute phase of the disease patients go through a post-acute phase in which several persisting physical, cognitive and psychiatric symptoms gradually resolve during the following months to a year. In long-term follow up these symptoms partly resolved, but deficits persisted on several domains. Psychiatric symptoms, fatigue and mild cognitive deficits were present in three out of four patients at current assessment. In three patients their academic trajectory was altered. These deficits can have an impact on the quality of life and the global functioning of the patients and caregivers.

Criminality in patients with autoimmune encephalitis: A case series

BACKGROUND AND PURPOSE

Despite it being an immunotherapy-responsive neurological syndrome, patients with autoimmune encephalitis (AE) frequently exhibit residual neurobehavioural features. Here, we report criminal behaviours as a serious and novel postencephalitic association.

METHODS

This retrospective cohort study included 301 AE patients. Five of who committed crimes underwent direct assessments and records review alongside autoantibody studies.

RESULTS

Five of 301 patients (1.7%) with AE exhibited criminal behaviours, which included viewing child pornography (n = 3), repeated shoplifting, and conspiracy to commit murder. All five were adult males, with LGI1 autoantibodies (n = 3), CASPR2 autoantibodies, or seronegative AE. None had evidence of premorbid antisocial personality traits or psychiatric disorders. Criminal behaviours began a median of 18 months (range = 15 months-12 years) after encephalitis onset. At the time of crimes, two patients were immunotherapy-naïve, three had been administered late immunotherapies (at 5 weeks-4 months), many neurobehavioural features persisted, and new obsessive behaviours had appeared. However, cognition, seizure, and disability measures had improved, alongside reduced autoantibody levels.

CONCLUSIONS

Criminal behaviours are a rare, novel, and stigmatizing residual neurobehavioural phenotype in AE, with significant social and legal implications. With caution towards overattribution, we suggest they occur as part of a postencephalitis limbic neurobehavioural syndrome.

Clinical characteristics of Chinese pediatric patients positive for anti-NMDAR and MOG antibodies: a case series

Introduction

The cases of MOG-AD (MOG antibody-associated disorder) and anti-NMDAR encephalitis overlapping syndrome (MNOS) are rare, especially among pediatric patients, and their clinical understanding is limited. This study aimed to investigate the clinical manifestations, imaging findings, treatments, and prognosis of Chinese pediatric patients who tested positive for anti-NMDAR and MOG antibodies.

Methods

This retrospective study enrolled 10 MNOS pediatric patients, 50 MOG-AD (anti-NMDAR antibody-negative), and 81 anti-NMDAR encephalitis (MOG antibody-negative) pediatric patients who were admitted from July 2016 to June 2022 and used their clinical data for comparison.

Results

The MNOS patients had a significantly lower incidence of psycho-behavioral abnormalities and involuntary movements than anti-NMDAR antibody (+)/MOG antibody (-) patients and had a significantly higher incidence of sleep disorders, seizures, and psycho-behavioral abnormalities than MOG antibody (+)/anti-NMDAR antibody (-) patients. The MNOS patients had a significantly higher incidence of MRI abnormalities than the anti-NMDAR antibody (+)/MOG antibody (-) patients, while there was no significant difference in the incidence between the MNOS patients and the MOG antibody (+)/anti-NMDAR antibody (-) patients. No significant difference was seen in the initial mRS score between the three groups of patients. The anti-NMDAR antibody (+)/MOG antibody (-) patients had a higher rate of admission to the ICU, a longer length of in-hospital stay, and a higher rate of introduction to second-line treatment than the other two groups of patients. No significant difference was seen in the mRS score at the last follow-up and in the disease recurrence rate between the three groups. All these patients respond well to immunosuppressive therapy.

Discussion

In the presence of psycho-behavioral abnormalities, sleep disorders, and frequent seizures in MOG-AD patients or demyelinating symptoms of the central nervous system or demyelinating lesions on head MRI in anti-NMDAR encephalitis patients, the coexistence of MOG and anti-NMDAR antibodies should be considered and would suggest a diagnosis of MNOS for these patients. Immunotherapy is effective among these patients and should be given possibly earlier.

Neuropsychological Testing in Autoimmune Encephalitis: A Scoping Review

BACKGROUND AND OBJECTIVES

Identifying optimal methods for evaluation and monitoring of cognitive outcomes in AE is important for clinical care and research. This scoping review aimed to evaluate neuropsychological tests (NPT) that are most frequently impaired in AE cohorts to provide recommendations for a standardized NPT battery for AE outcome.

METHODS

PubMed search for studies examining NPT in patients with AE was conducted on June 9, 2023. Studies were screened for inclusion/exclusion criteria as follows: at least 1 NPT, individual NPT test scores with comparison with healthy controls or normative data and neural-IgG status, total sample size ≥5, and English manuscript available.

RESULTS

The search yielded 5,393 studies, of which 3,359 were screened, 107 were full text reviewed, and 32 met inclusion/exclusion criteria, anti-NMDA-R (k = 18), anti-LGI1 (k = 10), anti-GABAB-R (k = 2), anti-GAD-65 (k = 4), and anti-CASPR2 (k = 3). The cognitive domains most frequently impaired were visual and verbal episodic memory, attention/working memory, processing speed, and aspects of executive functions.

DISCUSSION

Given the dearth of literature examining NPT in AE in combination with small sample sizes and methodological differences, more research in this area is needed. However, we provide recommendations for a test battery to be used in future studies, with the aim of standardizing research in this area. Based on the available literature, we recommend the use of comprehensive NPT batteries, spanning all cognitive domains. The highest yield measures may include the tests of (1) visual and verbal learning/memory, (2) basic and sustained attention, (3) processing speed, and (4) executive functions.

Antibody Investigations in 2,750 Children With Suspected Autoimmune Encephalitis

OBJECTIVES

To assess the frequency and types of neuronal and glial (neural) antibodies in children with suspected autoimmune encephalitis (AE).

METHODS

Patients younger than 18 years with suspected AE other than acute disseminated encephalomyelitis, whose serum or CSF samples were examined in our center between January 1, 2011, and April 30, 2022, were included in this study. Samples were systematically examined using brain immunohistochemistry; positive immunostaining was further investigated with cell-based assays (CBA), immunoblot, or live neuronal immunofluorescence.

RESULTS

Of 2,750 children, serum or CSF samples of 542 (20%) showed brain immunoreactivity, mostly (>90%) against neural cell surface antigens, and 19 had antibodies only identified by CBA. The most frequent targets were N-methyl-d-aspartate receptor (NMDAR, 76%) and myelin oligodendrocyte glycoprotein (MOG, 5%), followed by glutamic acid decarboxylase 65 (2%) and γ-aminobutyric acid A receptor (2%). Antibodies against other known cell surface or intracellular neural antigens (altogether 6% of positive cases) and unknown antigens (9%) were very infrequent.

DISCUSSION

The repertoire of antibodies in children with AE is different from that of the adults. Except for NMDAR and MOG antibodies, many of the antibodies included in diagnostic panels are rarely positive and their up-front testing in children seems unneeded.

Clinical Outcome Assessments in Encephalitis: A Systematic Review

BACKGROUND AND OBJECTIVES

Most patients with encephalitis experience persisting neurocognitive and neuropsychiatric sequelae in the years following this acute illness. Reported outcomes are often based on generic clinical outcome assessments that rarely capture the patient perspective. This may result in an underestimation of disease-specific sequelae. Disease-specific clinical outcome assessments can improve clinical relevance of reported outcomes and increase the power of research and trials. There are no patient-reported outcome measures (PROMs) developed or validated specifically for patients with encephalitis. The primary objective of this systematic literature review was to identify PROMs that have been developed for or validated in patients with encephalitis.

METHODS

We performed a systematic review of the literature published from inception until May 2023 in 3 large international databases (MEDLINE, EMBASE and Cochrane libraries). Eligible studies should have developed or validated a PROM in patients with encephalitis or encephalopathy. Methodologic quality was evaluated using the Consensus-based Standards for the selection of health status Measurement Instruments study design checklist for PROMs.

RESULTS

We identified no disease-specific PROMs developed or validated for patients with encephalitis. We identified one study on the development and validation of a disease-specific PROM for hepatic encephalopathy, although this disease course is substantially different to that of patients with encephalitis. The methodologic quality of the included study was generally rated as "doubtful." We identified 30 PROMs that have been applied in 46 studies on encephalitis or encephalopathy, although not validated in these populations. The most commonly applied PROMs for measuring Health-Related Quality of Life were the Medical Outcomes Study Short Form-36 and the Sickness Impact Profile. Emotional well-being was often assessed with the Beck Depression Inventory (BDI-II). Sporadically, PROMs were applied to address other aspects of outcome including daily functioning and sleep quality.

DISCUSSION

This systematic review confirms a critical gap in clinical outcome assessments in patients with encephalitis, failing to identify a validated measuring tool for detecting neurocognitive, functional, and health status. It is therefore essential to develop and/or validate disease-specific PROMs for the population with encephalitis to capture relevant information for patient management and clinical trials about the effects of disease that are at risk of being overlooked.

Antibodies to neural cell surface and synaptic proteins in paraneoplastic neurologic syndromes

Among patients with paraneoplastic neurologic syndromes (PNS), emphasis has historically been placed on neural antibodies against intracellular proteins that have a strong association with malignancy. Because of the intracellular location of their antigenic targets, these antibodies are typically considered to be non-pathogenic surrogate markers of immune cell-mediated neural injury. Unfortunately, patients with these antibodies often have suboptimal response to immunotherapy and poor prognosis. Over the last two decades, however, dramatic advancements have been made in the discovery and clinical characterization of neural antibodies against extracellular targets. These antibodies are generally considered to be pathogenic, given their potential to directly alter antigen structure or function, and patients with these antibodies often respond favorably to prompt immunotherapy. These antibodies also associate with tumors and may thus occur as PNS, albeit more variably than neural antibodies against intracellular targets. The updated 2021 PNS diagnostic criteria, which classifies antibodies as high-risk, intermediate-risk, or lower-risk for an associated cancer, better clarifies how neural antibodies against extracellular targets relate to PNS. Using this recently created framework, the clinical presentations, ancillary test findings, oncologic associations, and treatment responses of syndromes associated with these antibodies are discussed.

The Impact of Neuroimmunologic Disease and Developing Nervous System

Over the last two decades, neuroimmunologic disorders of childhood have been increasingly described, phenotyped, and treated. These disorders remain rare in the general population and while sharing common therapeutic interventions due to their immune pathophysiology, are heterogeneous with regard to presentation and risk of recurrence. As such, the impact of these disorders on the developing brain has come into the forefront of emerging research in pediatric neuroimmunology. Investigations into the singular impact of monophasic disease on long-term development and the impact of early and aggressive disease-modifying therapy in relapsing conditions are quickly becoming areas of ripe investigation as the field's most optimal way to treat and monitor these conditions over time. Although critically important in evaluating the developing brain, research has been heterogeneous among these diseases and limited by small cohort size. This narrative review details the role of common neuroimmunologic disorders in long-term neurological and cognitive outcomes in children as they develop.

Long-term outcomes and health-related quality of life in patients with autoimmune encephalitis: An observational study

Autoimmune encephalitis (AE) subacutely causes severe and multiple symptoms; however, most patients achieve neurologically favorable outcomes. Despite the substantial recovery in motor function, persistent impairments in mental/social aspects lasting for several years have been recognized, and its potential effect on health-related quality of life (HRQOL) has been argued. To urgently evaluate the long-term effects of AE on patients' HRQOL, we investigated patient-oriented long-term outcomes and assessed the HRQOL of patients with AE. Data of patients who were diagnosed with probable/definite AE, defined by Graus AE criteria 2016, and treated at our hospital between January 2011 and October 2020 were retrospectively retrieved. Their long-term (≥2 years) outcomes, which included various sequelae and handicaps in social activities such as returning to previous work/school life through structured interview forms, were evaluated, and the HRQOL was assessed using Neuro-QOL battery. We identified 32 patients who met the Graus AE criteria 2016 and eventually enrolled 21 patients in the study. The median interval between disease onset and survey period was 63 (25-156) months, and 43% of the patients had persistent neuropsychiatric symptoms, including memory disorders, personality changes, and seizures. No more than 71% returned to their previous work/school life. Although most of the patients had global QOL within normal limits, 48% had social QOL under normal limits. Patients with sequelae were significantly less likely to return to previous work/school and had worse global/social quality of life than patients without sequelae. In conclusion, nearly half of patients with AE had social QOL under normal limits 5 years after onset. The difficulty in returning to work/school and a worse HRQOL were notable in patients with sequelae.

Atypical psychiatric presentation of relapsing anti-N-methyl-D-aspartate receptor encephalitis in childhood

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune encephalitis caused by antibodies (Ab) against the GluN1 subunit of the NMDAR. The disease typically presents with a combination of psychiatric and neurological symptoms. Presentation solely with psychiatric symptoms is rare, especially in childhood. After treatment substantial recovery with mild or no residual symptoms is seen in most cases in both children and adults. Relapse occurs in 10%-25% of patients, with recurrent episodes presenting less severe than initial presentation in most cases. We herein describe a child with a pure psychiatric presentation of anti-NMDAR encephalitis. Diagnosis and treatment was delayed because of the atypical presentation. The child relapsed several times and severe residual psychiatric symptoms persisted after recovery. This case illuminates the need to consider the diagnosis of anti-NMDAR encephalitis in both adults and children with an atypical psychiatric presentation. It also demonstrates the need for a multidisciplinary approach and brings attention to the possible severe impact of the disease on long-term psychosocial functioning.

Olfactory dysfunction after autoimmune encephalitis depending on the antibody type and limbic MRI pathologies

Objective

Patients' olfactory function after autoimmune encephalitis (AE) involving limbic structures may be impaired. This study aimed to characterize olfactory function in patients after autoimmune encephalitides.

Methods

A case-control study was performed including 11 AE patients with antibodies against NMDAR (n = 4), GAD (n = 3), VGKC (n = 3) and antibody-negative AE (n = 1) and a control group of 12 patients with pneumococcal meningo-encephalitis (PC). In subgroup analyses, AE patients with and without NMDAR-antibodies were compared. Olfactory function was assessed using the Sniffin Sticks test and the resulting TDI-score (threshold, discrimination, identification). Involvement of limbic structures was evaluated on imaging data (MRI). Statistical analyses were performed to test for correlations of TDI-score and MRI results.

Results

The overall olfactory function of the AE-group and the PC-group was comparable (mean TDI 32.0 [CI 27.3-36.7], 32.3 [CI 28.5-36.0)]. The proportions of hyposmic patients were similar compared to the general population. However, AE patients of the non-NMDAR group had significantly lower TDI-scores (28.9 ± 6,8) than NMDAR patients (37.4 ± 3.5) (p = 0.046) and a significantly lower discrimination capability than the NMDAR patients (9.9 ± 2.0 vs. 14.5 ± 0.6) (p = 0.002). The non-NMDAR patients had significantly more limbic MRI pathologies (6/7) compared to the NMDAR patients (0/4) (p = 0.015). Furthermore, a correlation between limbic MRI pathologies and worse capability of smelling discrimination was found (p = 0.016, r = -0.704, n = 11).

Conclusion

Our results indicate that patients with NMDAR autoimmune encephalitis have normal long term olfactory function. However, patients with non-NMDAR autoimmune encephalitis appear to have a persistently impaired olfactory function, probably mediated by encephalitic damage to limbic structures.

Autoimmune encephalitis: recent clinical and biological advances

In 2015, we wrote a review in The Journal of Neurology summarizing the field of autoantibody-associated neurological diseases. Now, in 2023, we present an update of the subject which reflects the rapid expansion and refinement of associated clinical phenotypes, further autoantibody discoveries, and a more detailed understanding of immunological and neurobiological pathophysiological pathways which mediate these diseases. Increasing awareness around distinctive aspects of their clinical phenotypes has been a key driver in providing clinicians with a better understanding as to how these diseases are best recognized. In clinical practice, this recognition supports the administration of often effective immunotherapies, making these diseases 'not to miss' conditions. In parallel, there is a need to accurately assess patient responses to these drugs, another area of growing interest. Feeding into clinical care are the basic biological underpinnings of the diseases, which offer clear pathways to improved therapies toward enhanced patient outcomes. In this update, we aim to integrate the clinical diagnostic pathway with advances in patient management and biology to provide a cohesive view on how to care for these patients in 2023, and the future.

Brain rhythmic abnormalities in convalescent patients with anti-NMDA receptor encephalitis: a resting-state EEG study

Objective

Anti-N-methyl-D-aspartate receptor encephalitis (anti-NMDARE) is autoimmune encephalitis with a characteristic neuropsychiatric syndrome and persistent cognition deficits even after clinical remission. The objective of this study was to uncover the potential noninvasive and quantified biomarkers related to residual brain distortions in convalescent anti-NMDARE patients.

Methods

Based on resting-state electroencephalograms (EEG), both power spectral density (PSD) and brain network analysis were performed to disclose the persistent distortions of brain rhythms in these patients. Potential biomarkers were then established to distinguish convalescent patients from healthy controls.

Results

Oppositely configured spatial patterns in PSD and network architecture within specific rhythms were identified, as the hyperactivated PSD spanning the middle and posterior regions obstructs the inter-regional information interactions in patients and thereby leads to attenuated frontoparietal and frontotemporal connectivity. Additionally, the EEG indexes within delta and theta rhythms were further clarified to be objective biomarkers that facilitated the noninvasive recognition of convalescent anti-NMDARE patients from healthy populations.

Conclusion

Current findings contributed to understanding the persistent and residual pathological states in convalescent anti-NMDARE patients, as well as informing clinical decisions of prognosis evaluation.

MRI Features and Their Association With Outcomes in Children With Anti-NMDA Receptor Encephalitis

OBJECTIVES

How brain MRI lesions associate with outcomes in pediatric anti-NMDA receptor encephalitis (pNMDARE) is unknown. In this study, we correlate T2-hyperintense MRI brain lesions with clinical outcomes in pNMDARE.

METHODS

This was a multicenter retrospective cohort study from 11 institutions. Children younger than 18 years with pNMDARE were included. One-year outcomes were assessed by the modified Rankin Score (mRS) with good (mRS ≤2) and poor (mRS ≥3) outcomes.

RESULTS

A total of 175 pNMDARE subjects were included, with 1-year mRS available in 142/175 (81%) and 60/175 (34%) had abnormal brain MRIs. The most common T2-hyperintense lesion locations were frontal, temporal, and parietal. MRI features that predicted poor 1-year outcomes included abnormal MRI, particularly T2 lesions in the frontal and occipital lobes. After adjusting for treatment within 4 weeks of onset, improvement within 4 weeks, and intensive care unit admission, MRI features were no longer associated with poor outcomes, but after multiple imputation for missing data, T2 frontal and occipital lesions associated with poor outcomes.

DISCUSSION

Abnormal frontal and occipital lesions on MRI may associate with 1-year mRS in pNMDARE. MRI of the brain may be a helpful prognostication tool that should be examined in future studies.

Evaluation, Treatment, and Outcomes of Viral and Autoimmune Encephalitis in Children

Viral encephalitis and autoimmune encephalitis are currently the most common causes of encephalitis. Determining the causative agent is helpful in initiating medical treatment that may help reduce long-term sequelae. Cerebrospinal fluid, neuroimaging, serologic, and electroencephalogram in combination with clinical manifestations play a role in determining the cause of the encephalitis. Although motor dysfunction tends to improve, there is a significant risk of long-term neurologic and cognitive sequelae. These persistent deficits that occur in childhood indicate the importance for ongoing rehabilitative services to maximize functional skills, improve cognitive deficits, and assist with community integration.

Long-term effects of anti-N-methyl-d-aspartate receptor encephalitis on quality of life

Background

Patients with anti-N-methyl-d-aspartate receptor encephalitis (NMDARE) usually achieve neurologically favorable outcomes in the post-acute-phase. Even when motor function recovers, many patients experience numerous non-motor sequelae and cannot resume their pre-NMDARE lives even years later. Additionally, the needs of patients with NMDARE may impose a severe caregiver burden. Unfortunately, few studies have comprehensively examined patients recovering from NMDARE. We investigated the long-term effects of NMDARE on patients' quality of life (QOL).

Methods

Data collected via structured self-reported questionnaires included clinical features, long-term outcomes, and QOL. These questionnaires were administered to adult members of the Japanese Anti-NMDARE Patients' Association. We used the NeuroQOL battery to assess QOL in physical, mental, and social domains. Raw NeuroQOL scores were converted to T-scores for comparison with controls.

Results

Twenty-two patients completed the questionnaire. The median interval between disease onset and questionnaire response was 78  months. Forty-six percent of patients reported persistent sequelae, with only 73% able to resume prior work/school activities. Although patients' Global QOL was similar to controls, patients with NMDARE had significantly worse social QOL. Patients with worse social QOL had more frequent sequelae than those with better social QOL. Furthermore, patients with persistent sequelae had significantly worse Global QOL than those without sequelae and controls.

Conclusion

Patients with NMDARE had worse social QOL than controls. Given the adverse effects of disease sequelae on QOL, treatment strategies that minimize sequelae during the acute-phase may improve patients' QOL, even years post-disease onset.

Retrospective Pediatric Cohort Study Validates NEOS Score and Demonstrates Applicability in Children With Anti-NMDAR Encephalitis

BACKGROUND AND OBJECTIVES

Anti-N-methyl-D-aspartate receptor encephalitis (NMDARE) is the most common form of autoimmune encephalitis in children and adults. Although our understanding of the disease mechanisms has progressed, little is known about estimating patient outcomes. Therefore, the NEOS (anti-NMDAR Encephalitis One-Year Functional Status) score was introduced as a tool to predict disease progression in NMDARE. Developed in a mixed-age cohort, it currently remains unclear whether NEOS can be optimized for pediatric NMDARE.

METHODS

This retrospective observational study aimed to validate NEOS in a large pediatric-only cohort of 59 patients (median age of 8 years). We reconstructed the original score, adapted it, evaluated additional variables, and assessed its predictive power (median follow-up of 20 months). Generalized linear regression models were used to examine predictability of binary outcomes based on the modified Rankin Scale (mRS). In addition, neuropsychological test results were investigated as alternative cognitive outcome.

RESULTS

The NEOS score reliably predicted poor clinical outcome (mRS ≥3) in children in the first year after diagnosis (p = 0.0014) and beyond (p = 0.036, 16 months after diagnosis). A score adapted to the pediatric cohort by adjusting the cutoffs of the 5 NEOS components did not improve predictive power. In addition to these 5 variables, further patient characteristics such as the "Herpes simplex virus encephalitis (HSE) status" and "age at disease onset" influenced predictability and could potentially be useful to define risk groups. NEOS also predicted cognitive outcome with higher scores associated with deficits of executive function (p = 0.048) and memory (p = 0.043).

DISCUSSION

Our data support the applicability of the NEOS score in children with NMDARE. Although not yet validated in prospective studies, NEOS also predicted cognitive impairment in our cohort. Consequently, the score could help identify patients at risk of poor overall clinical outcome and poor cognitive outcome and thus aid in selecting not only optimized initial therapies for these patients but also cognitive rehabilitation to improve long-term outcomes.

Anti-LGI1 encephalitis with initiating symptom of seizures in children

Background

Anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis is infrequently reported but more and more recognizable in children. Here we give detailed description of the clinical features and long-term outcome of three cases of childhood onset anti-LGI1 encephalitis.

Methods

Three anti-LGI1 encephalitis patients were hospitalized in the Department of Pediatrics at Qilu Hospital of Shandong University. Data about the clinical manifestations, treatments and long-term follow-up outcomes were described in detail.

Results

Case 1 showed an adolescent girl with initiating symptom of acute-onset frequent focal seizures. Her serum LGI1-antibody test was positive, and she had a good response to antiseizure medication (ASM) and IVIG. Case 2 showed a preschool-age boy with long-period refractory focal seizures and recent behavioral change. Both serum and cerebrospinal fluid (CSF) tests of LGI1-antibody were positive, and the MRI showed progressive atrophy in the left hemisphere. The symptoms got improved after receiving second-line immunotherapy initially but there are still the sequelae of drug-resistant epilepsy and mild to moderate intellectual disability. Case 3 showed an adolescent boy with initiating symptom of acute-onset frequent focal seizures. Both serum and CSF tests of LGI1-antibody were positive, and he had a good response to immunotherapy. By analyzing all literature-reported 19 pediatric cases, we found pediatric anti-LGI1 encephalitis is more common in female and adolescent. Seizures and behavioral changes were the most common symptoms. CSF pleocytosis and LGI1-antibodies results were mostly negative. Most patients showed good response to immunotherapy.

Conclusion

Childhood onset anti-LGI1 encephalitis is a heterogeneous clinical syndrome, ranging from typical limbic encephalitis to isolating focal seizures. It is important to test autoimmune antibodies when encountering similar cases and repeat antibody testing if necessary. Timely recognition leads to earlier diagnosis and more rapid initiation of effective immunotherapy and potentially better outcomes.

The Leading Role of Brain and Abdominal Radiological Features in the Work-Up of Anti-NMDAR Encephalitis in Children: An Up-To-Date Review

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis (NMDARe) is the most common cause of nonviral encephalitis, mostly affecting young women and adolescents with a strong female predominance (F/M ratio of around 4:1). NMDARe is characterized by the presence of cerebrospinal fluid (CSF) antibodies against NMDARs, even though its pathophysiological mechanisms have not totally been clarified. The clinical phenotype of NMDARe is composed of both severe neurological and neuropsychiatric symptoms, including generalized seizures with desaturations, behavioral abnormalities, and movement disorders. NMDARe is often a paraneoplastic illness, mainly due to the common presence of concomitant ovarian teratomas in young women. Abdominal ultrasonography (US) is a key imaging technique that should always be performed in suspected patients. The timely use of abdominal US and the peculiar radiological features observed in NMDARe may allow for a quick diagnosis and a good prognosis, with rapid improvement after the resection of the tumor and the correct drug therapy.

Neuroinflammatory syndromes in children

PURPOSE OF REVIEW

Neuropsychiatric symptoms due to paediatric neuroinflammatory diseases are increasingly recognized and reported. Psychiatrists are crucial in front-lines identification, diagnosis and care of individuals with disorders such as autoimmune encephalitis and management of long-term neurobehavioral sequelae. This review summarizes recent literature on autoimmune and post-infectious encephalitis, discusses special considerations in children with neurodevelopmental conditions and presents a paradigm for evaluation and management.

RECENT FINDINGS

There is a growing body of evidence on neuropsychiatric symptom burdens of paediatric neuroinflammatory diseases. A particular development is the evolution of diagnostic and treatment guidelines for conditions such as autoimmune encephalitis, which take into account phenotypes of acute, short-term and long-term sequelae. Interest in inflammatory sequelae of viral illness, such as SARS-CoV-2, in children remains in early development.

SUMMARY

Neuroimmunological disease data are constantly evolving. New recommendations exist for multiple common neuroimmunological disorders with behavioural, emotional, cognitive and neurological sequelae. Anti-NMDA receptor encephalitis now has well-recognized patterns of symptom semiology, diagnostic and treatment recommendations, and outcome patterns. Recognizing psychiatric symptoms heralding autoimmune brain disease and understanding neuropsychiatric sequelae are now a crucial skill set for paediatric psychiatrists. Exploration of inflammatory features of other diseases, such as genetic syndromes, is a burgeoning research area.

Cerebrospinal fluid proteomics indicates immune dysregulation and neuronal dysfunction in antibody associated autoimmune encephalitis

Autoimmune Encephalitis (AE) spans a group of non-infectious inflammatory conditions of the central nervous system due to an imbalanced immune response. Aiming to elucidate the pathophysiological mechanisms of AE, we applied an unsupervised proteomic approach to analyze the cerebrospinal fluid (CSF) protein profile of AE patients with autoantibodies against N-methyl-d-aspartate receptor (NMDAR) (n = 9), leucine-rich glioma-inactivated protein 1 (LGI1) (n = 9), or glutamate decarboxylase 65 (GAD65) (n = 8) compared to 9 patients with relapsing-remitting multiple sclerosis as inflammatory controls, and 10 patients with somatic symptom disorder as non-inflammatory controls. We found a dysregulation of the complement system, a disbalance between pro-inflammatory and anti-inflammatory proteins on the one hand, and dysregulation of proteins involved in synaptic transmission, synaptogenesis, brain connectivity, and neurodegeneration on the other hand to a different extent in all AE subtypes compared to non-inflammatory controls. Furthermore, elevated levels of several proteases and reduction in protease inhibitors could be detected in all AE subtypes compared to non-inflammatory controls. Moreover, the different AE subtypes showed distinct protein profiles compared to each other and inflammatory controls which may facilitate future identification of disease-specific biomarkers. Overall, CSF proteomics provides insights into the complex pathophysiological mechanisms of AE, including immune dysregulation, neuronal dysfunction, neurodegeneration, and altered protease function.

Neuropsychological functioning in children and adolescents with anti-NMDA receptor encephalitis (anti-NMDARE)

The objective of this study was to describe neuropsychological functioning and associated medical features in pediatric patients with anti-NMDA receptor encephalitis (anti-NMDARE). Retrospective data were collected from electronic medical records and neuropsychological reports of 15 children and adolescents with cerebral spinal fluid antibody-confirmed anti-NMDARE who were 7-21 years old at the time of the neuropsychological evaluation. The median time between treatment initiation for anti-NMDARE and neuropsychological testing was 228 days (IQR 431, range 41-927). Consistent with the limited literature, this pediatric sample with anti-NMDARE generally had average IQs, but had scores falling in the low average range on tests of verbal and visual memory as well as aspects of executive functioning (set shifting and phonemic verbal fluency). Other relative weaknesses were observed in visuo-constructional ability and reading comprehension. Future prospective studies are needed to replicate these data and explore disease and treatment variables that reduce or exacerbate the risk for neuropsychological sequelae, while longitudinal analyses are required to better characterize academic, vocational, and social outcomes.

Clinical analysis of 173 pediatric patients with antibody-mediated autoimmune diseases of the central nervous system: a single-center cohort study

Background

Antibody-mediated disorders of the central nervous system (CNS) have seen a gradual rise in their incidence and prevalence. This retrospective observational study aimed to investigate the clinical characteristics and short-term prognosis of children with antibody-mediated CNS autoimmune diseases at Hunan Children's Hospital.

Methods

We collected the clinical data of 173 pediatric patients diagnosed with antibody-mediated CNS autoimmune diseases between June 2014 and June 2021 and analyzed their demographics, clinical features, imaging and laboratory data, treatment, and prognosis.

Results

A total of 187 patients tested positive for anti-neural antibodies and 173 patients were finally diagnosed with antibody-mediated CNS autoimmune diseases after excluding the 14 false-positive cases through clinical phenotypic evaluation and follow-up of treatment outcomes. Of the 173 confirmed patients, 97 (56.06%) were positive for anti-NMDA-receptor antibody, 48 (27.75%) for anti-MOG antibody, 30 (17.34%) for anti-GFAP antibody, 5 (2.89%) for anti-CASPR2 antibody, 3 (1.73%) for anti-AQP4 antibody, 2 (1.16%) for anti-GABABR antibody, and 1 (0.58%) for anti-LGI1antibody. Anti-NMDAR encephalitis was the most commonly seen among the patients, followed by MOG antibody-associated disorders and autoimmune GFAP astrocytopathy. Psycho-behavioral abnormalities, seizures, involuntary movements, and speech disorder were the most common clinical presentations of anti-NMDAR encephalitis, while fever, headache, and disturbance of consciousness or vision were the most seen among patients with MOG antibody-associated disorders or autoimmune GFAP astrocytopathy. The coexistence of multiple anti-neural antibodies was detected in 13 patients, among which 6 cases had coexistent anti-NMDAR and anti-MOG antibodies (including 1 case with anti-GFAP antibody also), 3 cases had coexistent anti-NMDAR and anti-GFAP antibodies, 3 cases had coexistent anti-MOG and anti-GFAP antibodies, 1 case had coexistent anti-NMDAR and anti-CASPR2 antibodies, and 1 case had coexistent anti-GABABR and anti-CASPR2 antibodies. All the survivors were followed up for at least 12 months; 137 recovered completely, 33 had varying sequelae, and 3 died; 22 had one or more relapses.

Conclusion

Antibody-mediated CNS autoimmune diseases occur in children of all ages. Most such pediatric patients have a good response to immunotherapy. Despite the low mortality rate, some survivors have a non-negligible risk of developing relapses.

Anti-NMDAR encephalitis with seizure-like activity and hemiplegia - a case report and literature review

Background

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis accounts for the vast majority of cases of autoimmune encephalitis. Its common clinical symptoms are psychiatric symptoms, behavioral dysfunction, seizures, speech impairment, cognitive impairment, movement disorders, decreased consciousness, and autonomic instability. This report was aimed to provide evidence for anti-NMDAR encephalitis with seizure-like activity, based on the clinical presentations, brain magnetic resonance imaging (MRI), and electroencephalogram (EEG) recordings.

Case presentation

We report a 11-year-old girl who suffered epigastric pain after vigorous physical activity. She felt weakness of the muscles. She had syncope only once and urinary incontinence on the way to the hospital and vomited at the arrival. The entire procedure lasted approximately 15 min. The next night she had recurrent headache attacks along with irritability, like someone “tapping” to the right occipital region. She experienced numbness in the left upper limbs and shallowing of the frontal lines on the left side. Holter monitoring showed normal findings, but brain MRI, EEG recording, and cerebrospinal fluid (CSF) antibody testing showed abnormal results. The patient was finally diagnosed with anti-NMDAR encephalitis. After treatment with glucocorticoids and acyclovir, she fully recovered and was discharged from the hospital.

Conclusions

Although the patient presented with pain and impaired limb movements, she did not have respiratory or (and) circulatory failure, and the symptoms entirely resolved. Early accurate diagnosis and timely treatment are essential for patients with anti-NMDAR encephalitis.

Long-term outcome of paediatric anti-N-methyl-D-aspartate receptor encephalitis

AIM

To study long-term clinical and cognitive outcomes of patients with anti-N-methyl-d-aspartate receptor encephalitis (NMDAR-E), an acute autoimmune neurological disease with severe acute presentations.

METHOD

In this French multicentre retrospective observational cohort study, patients no older than 18 years with a follow-up of at least 2 years were included. Data from clinical and cognitive assessments were collected.

RESULTS

Eighty-one patients were included (57 females, 24 males; median age 10 years 7 months [range 1-18 years], median follow-up 40 months [range 25-53 months]). At last follow-up, 35 patients (45%) had cognitive impairment, 48 (70%) had academic difficulties, and 65 (92%) needed rehabilitation. Seventy-one patients (88%) had a modified Rankin Scale score of no more than 2. A higher number of symptoms at diagnosis was associated with cognitive impairment (p = 0.01), while an abnormal electroencephalogram at diagnosis increased the risk of academic difficulties (p = 0.03).

INTERPRETATION

Although most children with NMDAR-E seemed to recover from motor disabilities, more than 45% had cognitive and academic difficulties. The initial severity of symptoms seems to have an impact on cognition and academic performances.

Younger Age at Onset Is Associated With Worse Long-term Behavioral Outcomes in Anti-NMDA Receptor Encephalitis

BACKGROUND AND OBJECTIVES

Anti-NMDA receptor encephalitis (anti-NMDARE) is one of the most common causes of encephalitis. It typically presents in adolescence and young adulthood, but little is known about its potential long-term consequences across the lifespan. Adaptive behavior describes an individual's ability to respond and adapt to environmental demands and unanticipated changes in daily routines. In this study, we evaluate the relationship between features from clinical presentation, including age, and long-term adaptive behavior in participants with anti-NMDARE.

METHODS

Cross-sectional informant-reported data were collected between 2017 and 2019 from 41 individuals/caregivers of individuals with anti-NMDARE treated at 3 major academic hospitals. Neurologic disability was assessed by record review using the modified Rankin Scale (mRS). Functional outcomes were assessed using the validated Adaptive Behavior Assessment System, Third Edition (ABAS-3).

RESULTS

The mean age at the time of study enrollment was 23.4 years (SD 17.0 years), and the mean time from symptom onset to study enrollment was 4.0 years. Seventeen participants were aged <12 years at symptom onset, 19 participants were aged 12-30 years, and 5 participants were aged >30 years. Mean ABAS-3 scores at study enrollment for all participants were in the average range (mean general adaptive composite standard score 92.5, SD 18.7). Individuals aged <12 years at symptom onset had lower mean ABAS-3 scores and were in the below average range compared with those aged 12-30 years at symptom onset, whose mean scores were in the average range (87 vs 99, p < 0.05). Similar differences were seen in 3 of the individual subscales (functional academics, health and safety, and self-care). There were no significant differences in mRS scores between age groups (p > 0.05).

DISCUSSION

Although anti-NMDARE is associated with an overall favorable outcome, younger age at onset associates with worse long-term adaptive behavior despite no differences in neurologic disability. These findings suggest that the disease may have distinct consequences on the early developing brain. Future studies should evaluate behavioral recovery and quality of life after anti-NMDARE and identify additional factors associated with differential recovery.

A systematic review and quantitative synthesis of the long-term psychiatric sequelae of pediatric autoimmune encephalitis

BACKGROUND

Long-term neuropsychiatric sequelae of autoimmune encephalitis (AE) remain understudied, particularly in pediatric-onset AE. We aimed to synthesize the published data on ongoing psychiatric symptoms in pediatric-onset AE.

METHODS

The Pubmed, PyscINFO, Web of Science databases were searched from their inception years to August 23, 2021, and 29 studies were identified and analyzed. We also performed a quantitative synthesis of available patient data from the 29 studies combined with a cohort of anti-NMDA receptor (NMDAR) AE from our institution to examine the associations between acute treatment course and long-term psychiatric outcome.

RESULTS

At long-term follow up, 52.4% of the cases with pediatric-onset AE had any persistent symptom and 36.0% had at least one psychiatric symptom. Pooled data found that 36.3% of pediatric-onset anti-NMDAR AE had ongoing psychiatric symptoms. Using a univariate logistic regression analysis, we found that abnormal initial EEG, use of certain immunotherapies, and persistent cognitive impairments were associated with ongoing psychiatric symptoms.

LIMITATIONS

Limitations of the existing literature included a significant paucity of outcomes measured using consistent, objective methods. Limitations of the systematic review included the wide variability among the studies reviewed, which rendered a meta-analysis impossible and beyond the scope of the paper.

CONCLUSION

Chronic psychiatric and behavioral problems remain present in one-third of children months to years after onset of AE. Larger scaled prospective observational studies with a consistent standardized battery of testing are needed to examine impact of specific clinical features and immunotherapies on long-term mental health outcomes.