B-cell Depletion Therapy in Pediatric Neuroinflammatory Disease.

PURPOSE OF REVIEW: B-cell depletion therapy, including anti-CD20 and anti-CD19 therapies, is increasingly used for a variety of autoimmune and conditions, including those affecting the central nervous system. However, B-cell depletion therapy use can be complicated by adverse effects associated with administration and immunosuppression. This review aims to summarize the application of anti-CD20 and anti-CD19 therapies for the pediatric neurologist and neuroimmunologist. RECENT FINDINGS: Most existing literature come from clinical trials with adult patients, although more recent studies are now capturing the effects of these therapies in children. The most common side effects include infusion related reactions and increased infection risk from immunosuppression. Several strategies can mitigate infusion related reactions. Increased infections due to persistent hypogammaglobulinemia can benefit from replacement immunoglobulin. B-cell depletion therapies can be safe and effective in pediatric patients. Anticipation and mitigation of common adverse effects through primary prevention strategies, close monitoring, and appropriate symptomatic management can improve safety and tolerability.

Isolated Psychiatric Symptoms in Children With Anti-N-Methyl-d Aspartate Receptor Encephalitis.

BACKGROUND: Isolated psychiatric symptoms can be the initial symptom of pediatric anti-N-methyl-d-aspartate (NMDA) receptor autoimmune encephalitis (pNMDARE). Here we report on the prevalence of isolated psychiatric symptoms in pNMDARE. We also assess whether initial neurodiagnostic tests (brain magnetic resonance imaging [MRI], electroencephalography [EEG], and/or cerebrospinal fluid [CSF] white blood cell count) are abnormal in children with isolated psychiatric symptoms and pNMDARE. METHODS: This multicenter retrospective cohort study from CONNECT (Conquering Neuroinflammation and Epilepsies Consortium) from 14 institutions included children under age 18 years who were diagnosed with pNMDARE. Descriptive statistics using means, medians, and comparisons for continuous versus discrete data was performed. RESULTS: Of 249 children included, 12 (5%) had only psychiatric symptoms without other typical clinical features of autoimmune encephalitis at presentation. All but one (11 of 12 = 92%) had at least one abnormal finding on initial ancillary testing: eight of 12 (67%) had an abnormal EEG, six of 12 (50%) had an abnormal MRI, and five of 12 (42%) demonstrated CSF pleocytosis. The single patient with a normal MRI, EEG, and CSF profile had low positive CSF NMDA antibody (titer of 1:1), and symptoms improved without immunotherapy. CONCLUSIONS: Isolated first-episode psychiatric symptoms in pNMDARE are uncommon, and the majority of children will exhibit additional neurodiagnostic abnormalities. Delaying immunotherapy in a child with isolated psychiatric symptoms and normal neurodiagnostic testing may be warranted while awaiting confirmatory antibody testing.

Analysis of Gender Discrepancies in Leadership Roles and Recognition Awards in the Child Neurology Society.

BACKGROUND AND OBJECTIVES: Gender disparities have been demonstrated across several medical specialties, including neurology. Although women have comprised most of the child neurology trainees since 2007, it is not apparent whether this demographic shift is reflected in the Child Neurology Society (CNS) awards and leadership. This study aimed to evaluate the differences in gender representation among leadership positions and award recipients within the CNS. The primary outcome measure was the total number of board of director (BOD) positions or awards given by gender each year. METHODS: A retrospective review of publicly available data was conducted on CNS members, post-training award recipients, and BOD positions, including nomination records, from 1972 to 2023. Data abstracted were restricted to gender to preserve member and nominee anonymity. Gender identification and consensus were determined through a combination of strategies and study members. Data analysis included descriptive statistics, Pearson χ2 test, and the exact binomial test to compare gender proportions and the probability of being underrepresented in awards, leadership, and nominations over time. Data are presented according to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines. RESULTS: From 1972 to 2023, women represented 29% (44/152) of the BOD positions and 26% (61/236) of post-training award recipients presented by the CNS. Despite the increase in the proportion of women in child neurology, the overall gap in gender representation in leadership positions remains broadly stable. Only 13% (4/32) of CNS presidents have been women, a significant underrepresentation (95% CI 2.3%-52%, p < 0.004), although the representation of women in nonpresidential positions increased from 2003 to 2023. Women are also underrepresented as overall awardees (95% CI 12%-38%, p < 0.00001) except for the Philip R. Dodge Young Investigator Award, which is an investigator-initiated application. DISCUSSION: Women remain underrepresented at the highest levels of recognition in child neurology despite representing most of the field. Reasons for disparities are known to be multifactorial and likely include gender bias and structural sexism. We present several discussion topics that seek to rationalize this disparity and provide suggestions for improving diversity, equity, and inclusion for leadership roles and awards.

De novo variants in immune regulatory genes in Down syndrome regression disorder.

BACKGROUND: Down Syndrome Regression Disorder (DSRD) is a rare and poorly understood disorder of the central nervous system, characterized by acute or subacute neuropsychiatric symptoms in previously healthy individuals with Down syndrome (DS). Many patients exhibit immunotherapy-responsiveness, indicative of immune dysregulation as a potential underlying etiology. While hypotheses are emerging regarding the role of interferon signaling in DSRD and other autoimmune conditions associated with DS, it is unclear why a small subset of individuals with DS develop DSRD. The aim of this study was to investigate genes of immune regulation in persons with DSRD. METHODS: This study included individuals with DSRD aged 10-30 years with trio exome sequencing performed during the diagnostic work up. Descriptive statistics and univariate analysis (Chi-square and Fisher's exact test) were used to describe and compare the characteristics of individuals with and without variants. RESULTS: Forty-one individuals with DSRD had trio exome sequencing results. Eight (20%) had heterozygous de novo variants of immune regulatory genes, with four variants being pathogenic or likely pathogenic (UNC13D, XIAP, RNASEH2A, and DNASE1L3). All genes harboring pathogenic variants were associated with interferon type-1 inflammatory response. Individuals harboring variants were more likely to have a preceding trigger (p = 0.03, 95% CI 1.21-97.06), rapid clinical decline in less than 1 month (p = 0.01, 95% CI 1.67-52.06), and MRI abnormalities (p < 0.001, 95% CI 4.89-527.71). DISCUSSION: A distinct subset of individuals with DSRD exhibited pathogenic variants in immune regulation genes associated with interferon-mediated inflammatory response, coinciding with previously established links between these genes and interferonopathies such as Aicardi-Goutieres syndrome. Our observations suggest that these variants might potentially contribute to the development of DSRD in individuals with DS.

Electroconvulsive therapy in N-methyl-d-aspartate receptor encephalitis: A retrospective cohort and scoping review of literature.

Neuropsychiatric symptoms in N-methyl-d-aspartate receptor encephalitis (NMDARE) have led some to pursue empiric trials of electroconvulsive therapy (ECT). A scoping review identified 39 patients diagnosed with NMDARE undergoing ECT. Separately, a retrospective cohort was reviewed to characterize 21 patients. Clinical improvement was attributed to ECT in 49% of patients in the scoping review and 19% of patients in the retrospective cohort; timing of immunotherapies was a confounding factor. Worsening of clinical course following ECT was reported in 28% of patients in the scoping review and 38% of patient in the retrospective review. There is currently insufficient data supporting a beneficial effect of ECT in NMDARE.

Effects of explainable artificial intelligence in neurology decision support.

OBJECTIVE: Artificial intelligence (AI)-based decision support systems (DSS) are utilized in medicine but underlying decision-making processes are usually unknown. Explainable AI (xAI) techniques provide insight into DSS, but little is known on how to design xAI for clinicians. Here we investigate the impact of various xAI techniques on a clinician's interaction with an AI-based DSS in decision-making tasks as compared to a general population. METHODS: We conducted a randomized, blinded study in which members of the Child Neurology Society and American Academy of Neurology were compared to a general population. Participants received recommendations from a DSS via a random assignment of an xAI intervention (decision tree, crowd sourced agreement, case-based reasoning, probability scores, counterfactual reasoning, feature importance, templated language, and no explanations). Primary outcomes included test performance and perceived explainability, trust, and social competence of the DSS. Secondary outcomes included compliance, understandability, and agreement per question. RESULTS: We had 81 neurology participants with 284 in the general population. Decision trees were perceived as the more explainable by the medical versus general population (P < 0.01) and as more explainable than probability scores within the medical population (P < 0.001). Increasing neurology experience and perceived explainability degraded performance (P = 0.0214). Performance was not predicted by xAI method but by perceived explainability. INTERPRETATION: xAI methods have different impacts on a medical versus general population; thus, xAI is not uniformly beneficial, and there is no one-size-fits-all approach. Further user-centered xAI research targeting clinicians and to develop personalized DSS for clinicians is needed.

Diagnostic Utility of MOG Antibody Testing in Cerebrospinal Fluid.

OBJECTIVE: The aim of this study was to assess the diagnostic utility of cerebrospinal fluid (CSF) myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) testing. METHODS: We retrospectively identified patients for CSF MOG-IgG testing from January 1, 1996, to May 1, 2023, at Mayo Clinic and other medical centers that sent CSF MOG-IgG for testing including: controls, 282; serum MOG-IgG positive MOG antibody-associated disease (MOGAD), 74; serum MOG-IgG negative high-risk phenotypes, 73; serum false positive MOG-IgG with alternative diagnoses, 18. A live cell-based assay assessed CSF MOG-IgG positivity (IgG-binding-index [IBI], ≥2.5) using multiple anti-human secondary antibodies and end-titers were calculated if sufficient sample volume. Correlation of CSF MOG-IgG IBI and titer was assessed. RESULTS: The pan-IgG Fc-specific secondary was optimal, yielding CSF MOG-IgG sensitivity of 90% and specificity of 98% (Youden's index 0.88). CSF MOG-IgG was positive in: 4/282 (1.4%) controls; 66/74 (89%) serum MOG-IgG positive MOGAD patients; and 9/73 (12%) serum MOG-IgG negative patients with high-risk phenotypes. Serum negative but CSF positive MOG-IgG accounted for 9/83 (11%) MOGAD patients, and all fulfilled 2023 MOGAD diagnostic criteria. Subgroup analysis of serum MOG-IgG low-positives revealed CSF MOG-IgG positivity more in MOGAD (13/16[81%]) than other diseases with false positive serum MOG-IgG (3/15[20%]) (p = 0.01). CSF MOG-IgG IBI and CSF MOG-IgG titer (both available in 29 samples) were correlated (Spearman's r = 0.64, p < 0.001). INTERPRETATION: CSF MOG-IgG testing has diagnostic utility in patients with a suspicious phenotype but negative serum MOG-IgG, and those with low positive serum MOG-IgG results and diagnostic uncertainty. These findings support a role for CSF MOG-IgG testing in the appropriate clinical setting. ANN NEUROL 2024;96:34-45.

The diagnostic workup of children with the radiologically isolated syndrome differs by age and by sex.

BACKGROUND: Cerebrospinal fluid (CSF) and spinal MRIs are often obtained in children with the radiologically isolated syndrome (RIS) for diagnosis and prognosis. Factors affecting the frequency and timing of these tests are unknown. OBJECTIVE: To determine whether age or sex were associated with (1) having CSF or spinal MRI obtained or (2) the timing of these tests. METHODS: We analyzed children (≤ 18 y) with RIS enrolled in an international longitudinal study. Index scans met 2010/2017 multiple sclerosis (MS) MRI criteria for dissemination in space (DIS). We used Fisher's exact test and multivariable logistic regression (covariates = age, sex, MRI date, MRI indication, 2005 MRI DIS criteria met, and race). RESULTS: We included 103 children with RIS (67% girls, median age = 14.9 y). Children ≥ 12 y were more likely than children < 12 y to have CSF obtained (58% vs. 21%, adjusted odds ratio [AOR] = 4.9, p = 0.03). Pre-2017, girls were more likely than boys to have CSF obtained (n = 70, 79% vs. 52%, AOR = 4.6, p = 0.01), but not more recently (n = 30, 75% vs. 80%, AOR = 0.2, p = 0.1; p = 0.004 for interaction). Spinal MRIs were obtained sooner in children ≥ 12 y (median 11d vs. 159d, p = 0.03). CONCLUSIONS: Younger children with RIS may be at continued risk for misdiagnosis and misclassification of MS risk. Consensus guidelines are needed.

Leptomeningeal Enhancement in Pediatric Anti-Myelin Oligodendrocyte Glycoprotein Antibody Disease, Multiple Sclerosis, and Neuromyelitis Optica Spectrum Disorder.

BACKGROUND: Anti-myelin oligodendrocyte glycoprotein (MOG) antibody disease (MOGAD) is a type of acquired demyelinating disease that is distinct from multiple sclerosis (MS) and aquaporin-4 antibody neuromyelitis optica spectrum disorder (AQP4-NMOSD). Leptomeningeal enhancement (LME) has been reported in children and adults with MOGAD, and in adults with MS and AQP4-NMOSD, but less is known about LME in pediatric-onset MS (POMS) and pediatric AQP4-NMOSD. Here we compare the rates of LME in children with MOGAD, POMS, and AQP4-NMOSD. METHODS: A retrospective chart review was performed in patients with MOGAD, POMS, and AQP4-NMOSD who presented to our institution. Clinical characteristics, imaging features, and relapsing data were included. Descriptive statistics were used, including chi-square or Fischer exact test, to compare proportions. The Benjamini-Hochberg procedure was used to correct for multiple comparisons. RESULTS: A total of 42 children were included: 16 with POMS, six with AQP4-NMOSD, and 20 with MOGAD. Brain LME was only observed in the MOGAD group (six of 20 = 30%) when compared with zero (0%) POMS and AQP4-NMOSD (P = 0.012). Relapsing disease occurred in nine of 20 (45%), but LME did not associate with relapse. CONCLUSIONS: LME is only observed in pediatric MOGAD and not in POMS or pediatric AQP4-NMOSD. LME did not predict relapses in MOGAD. Further work is needed to determine the clinical significance of LME in pediatric MOGAD.

Cerebrospinal fluid cytokines in COVID-19: a review and meta-analysis.

INTRODUCTION: Neurological involvement can occur in patients with SARS-CoV-2 infections, resulting in coronavirus disease 2019 (COVID-19). Cytokine alterations are associated with neurological symptoms in COVID-19. We performed a review of cytokines in the cerebrospinal fluid (CSF) of patients with COVID-19. METHODS: Two reviewers independently searched PubMed for all relevant articles published prior to November 11, 2022. Active SARS-CoV-2 infection and CSF cytokine analyses were required for inclusion. RESULTS: Three-hundred forty-six patients with COVID-19 and 356 controls from 28 studies were included. SARS-CoV-2 PCR was positive in the CSF of 0.9% (3/337) of patients with COVID-19. Thirty-seven different cytokines were elevated in the CSF of patients with COVID-19 when compared to controls and the standards set forth by individual assays used in each study. Of the 37 cytokines, IL-6 and IL-8 were most commonly elevated. CSF IL-6 is elevated in 60%, and CSF IL-8 is elevated in 51% of patients with COVID-19. CONCLUSION: Levels of several inflammatory cytokines are elevated in the CSF of patients with COVID-19, and SARS-CoV-2 PCR is often not isolated in the CSF of patients with COVID-19. Many patients with COVID-19 have neurological symptoms and given the cytokine elevations in the absence of detectable viral RNA in cerebrospinal fluid; further study of the CSF cytokine profiles and pathogenesis of neurological symptoms in COVID-19 is needed.

Immunotherapy responsiveness and risk of relapse in Down syndrome regression disorder.

Down syndrome regression disorder (DSRD) is a clinical symptom cluster consisting of neuropsychiatric regression without an identifiable cause. This study evaluated the clinical effectiveness of IVIg and evaluated clinical characteristics associated with relapse after therapy discontinuation. A prospective, multi-center, non-randomized, observational study was performed. Patients met criteria for DSRD and were treated with IVIg. All patients underwent a standardized wean-off therapy after 9-12 months of treatment. Baseline, on-therapy, and relapse scores of the Neuropsychiatric Inventory Total Score (NPITS), Clinical Global Impression-Severity (CGI-S), and the Bush-Francis Catatonia Rating Scale (BFCRS) were used to track clinical symptoms. Eighty-two individuals were enrolled in this study. Patients had lower BFCRS (MD: -6.68; 95% CI: -8.23, -5.14), CGI-S (MD: -1.27; 95% CI: -1.73, -0.81), and NPITS scores (MD: -6.50; 95% CI: -7.53, -5.47) while they were on therapy compared to baseline. Approximately 46% of the patients (n = 38) experienced neurologic relapse with wean of IVIg. Patients with neurologic relapse were more likely to have any abnormal neurodiagnostic study (χ2 = 11.82, P = 0.001), abnormal MRI (χ2 = 7.78, P = 0.005), and abnormal LP (χ2 = 5.45, P = 0.02), and a personal history of autoimmunity (OR: 6.11, P < 0.001) compared to patients without relapse. IVIg was highly effective in the treatment of DSRD. Individuals with a history of personal autoimmunity or neurodiagnostic abnormalities were more likely to relapse following weaning of immunotherapy, indicating the potential for, a chronic autoimmune etiology in some cases of DSRD.

COVID-19 and the Pandemic-Related Aspects in Pediatric Demyelinating Disorders.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also known as Coronavirus-19 (COVID-19) infection, has been associated with several neurological symptoms, including acute demyelinating syndromes (ADS). There is a growing body of literature discussing COVID-19 and demyelinating conditions in adults; however, there is less published about COVID-19 demyelinating conditions in the pediatric population. This review aims to discuss the impact of COVID-19 in pediatric patients with central nervous system ADS (cADS) and chronic demyelinating conditions. We reviewed PubMed, Google Scholar, and Medline for articles published between December 1, 2019 and October 25, 2022 related to COVID-19 and pediatric demyelinating conditions. Of 56 articles reviewed, 20 cases of initial presentation of ADS associated with COVID-19 were described. The most commonly described cADS associated with COVID-19 infection in children was Acute Disseminated Encephalomyelitis followed by Transverse Myelitis. Cases of Myelin Oligodendrocyte Glycoprotein Antibody Disease, Neuromyelitis Optica Spectrum Disorder, and Multiple Sclerosis are also described. The risk of severe COVID-19 in pediatric patients with demyelinating conditions appears low, including in patients on disease modifying therapies, but studies are limited. The pandemic did affect disease modifying therapies in ADS, whether related to changes in prescriber practice or access to medications. COVID-19 is associated with ADS in children and the COVID-19 pandemic has impacted pediatric patients with demyelinating conditions in various ways.

Antibody response to SARS-CoV-2 vaccination or infection in a prospective cohort of children with neuroinflammatory diseases.

INTRODUCTION: Immune medications affect antibody responses to SARS-CoV-2 vaccination in adults with neuroinflammatory disorders, but little is known about antibody responses in children with neuroinflammation and on immune treatments. Here we measure antibody levels in response to SARS-CoV-2 vaccination in children receiving anti-CD20 monoclonal antibodies, or fingolimod. METHODS: Children under 18 years of age with pediatric-onset neuroinflammatory disorders who received at least two mRNA vaccines were included. Plasma samples were assayed for SARS-CoV-2 antibodies (spike, spike receptor binding domain-RBD, nucleocapsid) and neutralization antibodies. RESULTS: Seventeen participants with pediatric onset neuroinflammatory diseases were included: 12 multiple sclerosis, one neuromyelitis optica spectrum disorder, two MOG-associated disease, and two autoimmune encephalitis. Fourteen were on medications (11 on CD20 monoclonal antibodies-mAbs, one on fingolimod, one on steroids, one on intravenous immunoglobulin) and three were untreated. Nine patients also had pre-vaccination samples available. All participants had seropositivity to spike or spike RBD antibodies except for those receiving CD20 mAbs. However, this proportion was higher in children than in an adult MS patient cohort. The most significant contributor to antibody levels was duration of DMT. CONCLUSION: SARS-CoV-2 antibodies are decreased in children on CD20 monoclonal antibodies than on other treatments. Treatment duration associated with vaccination responses.

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.

Sleep Characteristics in Pediatric Anti-N-methyl-d-aspartate (NMDA) Receptor Encephalitis: A Retrospective Cohort Study.

Background: Rates of sleep problems in children with anti-N-methyl-d-aspartate (NMDA) receptor encephalitis are unknown. Methods: We used a retrospective observational cohort database of children with a diagnosis of NMDA receptor encephalitis at a single freestanding institution. One-year outcomes were assessed with the pediatric modified Rankin Score (mRS), with 0 to 2 as good and 3 or greater as poor outcome. Results: Ninety-five percent (39/41) of children with NMDA receptor encephalitis had sleep dysfunction at onset; 34% (11/32) reported sleep problems at 1 year. Sleep problems at onset and propofol use were not associated with poor outcomes at 1 year. Poor sleep at 1 year correlated with mRS scores (range 2-5) at 1 year. Discussion: High rates of sleep dysfunction occur in children with NMDA receptor encephalitis. Persistent sleep problems at 1 year may correlate with outcomes as assessed by mRS at 1 year. Further studies comparing the relationship of poor sleep with outcomes in NMDA receptor encephalitis are needed.

The Neutrophil-to-Lymphocyte Ratio and the Monocyte-to-Lymphocyte Ratio Predict Expanded Disability Status Scale Score at One Year in Pediatric Neuromyelitis Optica Spectrum Disorder but not in Multiple Sclerosis.

BACKGROUND: The neutrophil-to-lymphocyte ratio (NLR) and monocyte-to-lymphocyte ratio (MLR) are inflammatory biomarkers that may predict disease course in neuroinflammatory diseases. We examine whether NLR or MLR at the time of the first attack predicts longitudinal disease outcomes in pediatric neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS). METHODS: Clinical data were collected retrospectively at a single institution. NLR (ratio of percent neutrophils to percent lymphocytes) and MLR (ratio of percent monocytes to percent lymphocytes) were calculated in the complete blood cell count at the time of presentation before treatments. Expanded Disability Status Scale (EDSS) score and time to next relapse were used as the outcome assessments. RESULTS: Twenty-eight patients with MS and eight patients with aquaporin-4-positive NMOSD were included. For NMOSD, NLR at presentation associated with EDSS at six months (P = 0.003) and one year (P = 0.032) even when adjusting for age at presentation. MLR associated with EDSS at six months (P = 0.0203) and EDSS at one year (P = 0.0079). However, NLR and MLR did not predict EDSS scores in MS. MLR and NLR did not predict time to next relapse or did not associate with magnetic resonance imaging activity in MS and NMOSD. Changes in MLR and NLR were observed with disease-modifying therapies but did not predict disease activity. CONCLUSIONS: NLR and MLR associated with six-month and one-year EDSS in children with NMOSD but not in MS. Future studies should explore whether changes in NLR and MLR could predict disease activity or treatment efficacy.

Review of Machine Learning and Artificial Intelligence (ML/AI) for the Pediatric Neurologist.

Artificial intelligence (AI) and a popular branch of AI known as machine learning (ML) are increasingly being utilized in medicine and to inform medical research. This review provides an overview of AI and ML (AI/ML), including definitions of common terms. We discuss the history of AI and provide instances of how AI/ML can be applied to pediatric neurology. Examples include imaging in neuro-oncology, autism diagnosis, diagnosis from charts, epilepsy, cerebral palsy, and neonatal neurology. Topics such as supervised learning, unsupervised learning, and reinforcement learning are discussed.