Optical Coherence Tomography Angiographic Follow-Up in a Case of Subacute Sclerosing Panencephalitis and Unilateral Necrotising Retinitis.

We present a 20-year-old woman who was diagnosed with subacute sclerosing panencephalitis (SSPE) 20 months after presenting with unilateral retinitis. At presentation, the patient had two inferotemporal macular lesions in her left eye. Corresponding to these areas, optical coherence tomography (OCT) showed hyporeflective spaces with loss of nearly all of the retinal layers. OCT-angiography (OCTA) demonstrated some flow deficit areas with a reduction in the vessel density. Her serum measles antibody titre was high (IgG >5000.0 mIU/ml). Twenty months later the macular lesions had diminished in size, and there was some focal retinal thinning with interruption of the ellipsoid zone. OCTA showed that the flow deficit areas were diminished in size together with the relatively improved perfusion density. Neurological examination disclosed myoclonic jerks. Neuropsychological assessment demonstrated impaired executive function, attention, and narrowed lexical fluency. Measles IgG antibody was high in the cerebrospinal fluid (>230.0 U/ml). Brain magnetic resonance imaging demonstrated bilateral, non-specific, small foci of T2 hyperintensity in the frontoparietal subcortical white matter and centrum semiovale. The present case is the first where OCTA findings of SSPE-related retinal lesions have been described.

TDP-43 pathology in subacute sclerosing panencephalitis.

Subacute sclerosing panencephalitis (SSPE) is a fatal, slowly progressive brain disorder caused by a mutated measles virus. Both subacute inflammatory and neurodegenerative mechanisms appear to play significant roles in the pathogenesis. TAR DNA-binding protein 43 (TDP-43) inclusions are a common co-pathology in several neurodegenerative disorders with diverse pathogenesis. In the present study, we examined brains of 16 autopsied SSPE patients for the presence of TDP-43 pathology and possible associations with tau pathology. Immunohistochemical staining identified TDP-43 inclusions in 31% of SSPE cases. TDP-43 pathology was widely distributed in the brains, most severely in the atrophied cerebral cortex (temporal and parietal), and most frequently as tangle- and thread-like neuronal cytoplasmic inclusions. It was associated with longer disease duration (>4 years) and tau pathology (all TDP-43-positive cases had tau-positive neurofibrillary tangles). This study demonstrates for the first time an association between TDP-43 pathology and SSPE. The co-occurrence of TDP-43 and tau aggregates and correlation with the disease duration suggest that both pathological proteins are involved in the neurodegenerative process induced by viral inflammation.

Neuroimaging Abnormalities in Patients with Subacute Sclerosing Panencephalitis : Prospective Follow-up Study.

OBJECTIVE: This study aimed to assess the neuroimaging abnormalities and their progression in patients with Subacute sclerosing panencephalitis (SSPE) and identify clinical predictors of these imaging findings. METHODS: This prospective observational study evaluated clinical and neuroimaging features in patients with SSPE. Patients were categorized using Dyken's criteria, Jabbour's staging system, and the definition of fulminant SSPE. They underwent comprehensive clinical assessments, cerebrospinal fluid examination, Electroencephalogram (EEG), and Magnetic Resonance Imaging (MRI) scans. Treatment involved intrathecal interferon­α and antiepileptic medications. Functional disability was assessed using the modified Barthel index. Follow-ups were performed at 6 months, including reassessment of Modified Barthel Index (MBI) and Jabbour's staging and EEG and MRI scans. RESULTS: The mean age was 13.9 ± 6.7 years, with males comprising 81.5% (44/54) of the cohort. Fulminant SSPE was noted in 33% (18/54) of cases. Disease duration before presentation varied significantly between fulminant and non-fulminant forms (p = 0.001). Neuroimaging abnormalities were more prevalent in JS III stage patients, with diffuse cerebral atrophy being a significant finding (p = 0.011). Basal ganglia involvement correlated with movement disorders. The 6­month follow-up showed increased cerebral atrophy (p = 0.004). Increasing disease duration was an independent predictor of cerebral atrophy. An Intercomplex interval (ICI) of more than 10 minutes correlated with normal neuroimaging, 10 patients died within the study period, 8 of whom had fulminant SSPE. CONCLUSION: Parieto-occipital White matter hyperintensity (WMH) is the most prevalent and sensitive neuroimaging finding for the diagnosis of SSPE. Despite interferon treatment, cerebral atrophy progressed in both aggressive and fulminant SSPE. Increasing disease duration is an independent predictor of cerebral atrophy.

Functional properties of measles virus proteins derived from a subacute sclerosing panencephalitis patient who received repeated remdesivir treatments.

Subacute sclerosing panencephalitis (SSPE) is a rare but fatal late neurological complication of measles, caused by persistent measles virus (MeV) infection of the central nervous system. There are no drugs approved for the treatment of SSPE. Here, we followed the clinical progression of a 5-year-old SSPE patient after treatment with the nucleoside analog remdesivir, conducted a post-mortem evaluation of the patient's brain, and characterized the MeV detected in the brain. The quality of life of the patient transiently improved after the first two courses of remdesivir, but a third course had no further clinical effect, and the patient eventually succumbed to his condition. Post-mortem evaluation of the brain displayed histopathological changes including loss of neurons and demyelination paired with abundant presence of MeV RNA-positive cells throughout the brain. Next-generation sequencing of RNA isolated from the brain revealed a complete MeV genome with mutations that are typically detected in SSPE, characterized by a hypermutated M gene. Additional mutations were detected in the polymerase (L) gene, which were not associated with resistance to remdesivir. Functional characterization showed that mutations in the F gene led to a hyperfusogenic phenotype predominantly mediated by N465I. Additionally, recombinant wild-type-based MeV with the SSPE-F gene or the F gene with the N465I mutation was no longer lymphotropic but instead efficiently disseminated in neural cultures. Altogether, this case encourages further investigation of remdesivir as a potential treatment of SSPE and highlights the necessity to functionally understand SSPE-causing MeV.IMPORTANCEMeasles virus (MeV) causes acute, systemic disease and remains an important cause of morbidity and mortality in humans. Despite the lack of known entry receptors in the brain, MeV can persistently infect the brain causing the rare but fatal neurological disorder subacute sclerosing panencephalitis (SSPE). SSPE-causing MeVs are characterized by a hypermutated genome and a hyperfusogenic F protein that facilitates the rapid spread of MeV throughout the brain. No treatment against SSPE is available, but the nucleoside analog remdesivir was recently demonstrated to be effective against MeV in vitro. We show that treatment of an SSPE patient with remdesivir led to transient clinical improvement and did not induce viral escape mutants, encouraging the future use of remdesivir in SSPE patients. Functional characterization of the viral proteins sheds light on the shared properties of SSPE-causing MeVs and further contributes to understanding how those viruses cause disease.

Subacute Sclerosing Panencephalitis in a 63-Year-Old Woman Presenting as Generalized Choreoathetosis.

The persistence of measles virus infection in childhood and early adolescence can rarely lead to a fatal progressive neurodegenerative disorder known as subacute sclerosing panencephalitis (SSPE), characterized by behavioral disturbances and intellectual disability followed by myoclonic jerks and occasional negative myoclonus. Movement disorders are rarely presenting manifestations in SSPE. We herein report a 63-year-old woman with generalized choreoathetosis as the presenting manifestation of stage-I SSPE. Our case was atypical for the patient's age and clinical presentation with generalized choreoathetosis and bilateral putaminal and caudate nucleus signal hyperintensity. Though highly uncommon, neurologists should keep SSPE as a differential diagnosis among patients with movement disorders. Measles-endemic countries should be more vigilant to the atypical and rare presentations of SSPE, such as generalized choreoathetosis.

Fatal subacute sclerosing panencephalitis in an 8-year-old male: a case report.

Subacute sclerosing panencephalitis (SSPE) is a chronic slow progressive neurodegenerative disease that is often associated with measles complications. The disease is characterized by seizures, behavioral changes, motor deficit and eventually death. In this case report we discuss the case of an 8-year-old male who developed SSPE and was presented to our hospital with a history of generalized tonic colonic convulsion followed by gait abnormality, episodes, abnormal behaviors, and cognitive regression. On clinical exploration, the child had a history of measles at 8 months of age and meningitis at 18 months. The electroencephalogram (EEG) investigation showed high amplitude spikes, with focal seizure and slowing, while the magnetic resonance imaging reveal signals synonymous with high fluid-attenuated inversion recovery (FLAIR), both of which are consistent with probable SSPE. The case was managed symptomatically; until his parents decided to take him back home, after which his condition deteriorated, and he sadly died. To the best of our knowledge, this is the first recorded case of SSPE in Mogadishu, Somalia. Hence, the need to further investigation to better understand the incidence of the disease in the population and propose better ways of managing the condition.

Bilateral Vision Loss and Visual Hallucinations in Subacute Sclerosing Panencephalitis: A Case Report.

We report an interesting case of visual loss and visual hallucinations in a 37-year-old man. He presented with decreased vision in both eyes and visual hallucinations for the last one and a half months. He also had multiple focal to bilateral tonic-clonic seizures. On examination, there was no perception of light rays in both eyes. Fundus examination revealed disc oedema with peripapillary small haemorrhages in both eyes. Initially, the discs were hyperaemic, which turned pale in the subsequent examination at 1 month. Magnetic resonance imaging (MRI) of the brain revealed T2 hyperintensities in periventricular white matter and right fronto-parietal-occipital gray matter. His electroencephalogram showed intermittent slowing. His cerebrospinal fluid (CSF) examination showed five cells (all lymphocytes), protein 50 mg/dl, sugar 76 mg/dl (corresponding blood sugar 90 mg/dl). His CSF specimen was positive for anti-measles IgG antibodies. In conclusion, acute vision loss can rarely be the presenting symptom and, therefore, SSPE should also be considered in differential diagnoses of acute vision loss in measles-endemic regions.

Identical tau filaments in subacute sclerosing panencephalitis and chronic traumatic encephalopathy.

Subacute sclerosing panencephalitis (SSPE) occurs in some individuals after measles infection, following a symptom-free period of several years. It resembles chronic traumatic encephalopathy (CTE), which happens after repetitive head impacts or exposure to blast waves, following a symptom-free period. As in CTE, the neurofibrillary changes of SSPE are concentrated in superficial cortical layers. Here we used electron cryo-microscopy (cryo-EM) of tau filaments from two cases of SSPE to show that the tau folds of SSPE and CTE are identical. Two types of filaments were each made of two identical protofilaments with an extra density in the ß-helix region. Like in CTE, the vast majority of tau filaments were Type I, with a minority of Type II filaments. These findings suggest that the CTE tau fold can be caused by different environmental insults, which may be linked by inflammatory changes.

The Calm Before the Storm? An Unusual Case of Measles Retinopathy.

A 30-year-old male presented with sudden painless loss of vision in the right eye for the last two days. Slit-lamp examination of the right eye revealed a quiet anterior chamber and anterior vitreous. Fundus examination of the right eye revealed a large, focal retinitis lesion centered around the fovea, whereas examination of the left was unremarkable. He gave us a history of Measles at the age of 5 years but denied any history of systemic illness. Optical coherence tomography (OCT) revealed disruption of retinal architecture with ballooning of intact internal limiting membrane. His serology was negative for syphilis, human immunodeficiency virus and toxoplasmosis. Based on clinical suspicion, he was investigated by a neurologist. His electroencephalogram and Magnetic Resonance Imaging of brain were within normal limits, but high titres of anti-measles antibodies were found in serum and cerebrospinal fluid. The diagnosis of measles retinopathy should be considered in cases with focal necrotizing retinitis, even when classical findings of CNS involvement do not exist.

Immune-dysregulation in subacute sclerosing panencephalitis: An exploratory case-control study.

Subacute sclerosing panencephalitis (SSPE) is a chronic progressive neurological condition caused by a defective measles virus. It is postulated that immune-dysregulation might result in persistent infection (immune evasion) as well as initiation of autoimmune phenomenon (via natural killer cells) leading to panencephalitis. The primary objective of this case-control study was to analyse the pattern of immune dysregulation in cases with SSPE. The secondary objective was to assess the correlation between the measured immunological variables and disability/death at 6 months. This was an exploratory case-control study conducted at a tertiary-care referral-facility from January 2020 to September 2021. Thirty consecutive patients fulfilling the Dyken's criteria for SSPE and 30 age-and-sex-matched healthy controls were enrolled. Immunological profile constituted by lymphocyte subset analysis, immunoglobulin levels and complement levels were done in all cases and controls. Cases were staged as per Jabbour's system; disability was assessed using the modified Rankin Scale (mRS). Patients with SSPE had a mean age of 14.76 years (±6.9 years). There were 25 males and 5 females; 6.7% cases belonged to Jabbour's first stage, 40% to second stage and 53.3% to third stage. At least 1/4th had evidence of measles vaccination. Levels of absolute lymphocyte count, B-cells, T cells, helper T-cells, and cytotoxic T-cells were significantly higher in cases. IgG, IgM, and IgE levels were significantly higher while IgD levels were significantly lower in cases. At baseline, 13.3% of cases had a mRS score of 0-2 and 86.7% had a score of 3-6; at 6 months 10% had a mRS score 0-2 (favorable outcome) while 90% had a mRS score 3-6 (poor outcome). Higher IgE levels were found to correlate significantly with favorable outcome. Immune-dysregulation may play a significant role in shaping one's response to measles infection as well as in determining vaccine-efficacy.

Macular Necrotizing Retinitis as a Presenting Feature of Atypical Fulminant SSPE: A Case Report.

Purpose: To report ocular findings in a case of atypical fulminant SSPECase report: A 20-year-old male who came with macular necrotising retinitis in both his eyes in absence of any neurological feature. Within a week the patient developed dystonic posturing and seizures. CSF examination revealed raised measles antibody titres and EEG was suggestive of SSPE. The patient succumbed to the disease within 35 days of presentation.Conclusion: SSPE can rarely have a rapidly progressive downhill course without typical neurological features and ophthalmic features which appear to be more consistent may help in clinching the diagnosis in these cases.

Association of NOD1 and NOD2 Polymorphisms With Susceptibility to Subacute Sclerosing Panencephalitis.

Background: Subacute sclerosing panencephalitis is a progressive neurodegenerative disease that is a late complication of measles infection. However, to date, the pathogenesis of subacute sclerosing panencephalitis is still not explained; both viral and host factors seem to be associated. The present study aimed to investigate the relationship between NOD1 and NOD2 gene variants and subacute sclerosing panencephalitis. Methods: The gene variants of NOD1 (rs2075820 and rs2075818) and NOD2 (R334Q and R334W) were explored in 64 subacute sclerosing panencephalitis patients and 70 controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: The frequencies of the AA genotype and A allele of rs2075820 (NOD1; c.796G>A) polymorphism were lower in patients compared with controls (P = .022 and .014, respectively). The presence of the A allele of rs2075820 may be considered as a protective factor for subacute sclerosing panencephalitis. There was a significant difference between the groups in rs2075818 (NOD1 G/C) polymorphism, and the CC genotype increased the risk of subacute sclerosing panencephalitis by 3.471-fold. The carriers of the C allele of rs2075818 (G/C) had a 1.855-fold susceptibility to subacute sclerosing panencephalitis (P = .018). The GC genotype might be associated with subacute sclerosing panencephalitis susceptibility in the patients compared with patients without having that haplotype (P = .03). Conclusions: Thus, we identified an association between subacute sclerosing panencephalitis and the rs2075820 (NOD1 G/A) and rs2075818 (NOD1 G/C) polymorphisms. These findings implicate a possible effect of this genetic polymorphism in susceptibility to subacute sclerosing panencephalitis, which needs to be confirmed in bigger populations.

Place of magistral preparations to continue the treatment if the drug is commercially stopped worldwide? A case report of a 10-year-old child with subacute sclerosing panencephalitis (SSPE) requiring inosiplex.

Subacute sclerosing panencephalitis (SSPE) is a late-onset and fatal viral disease caused by persistent infection of the central nervous system by measles virus (MeV). We present the case of a 10-year-old child from South Asia affected by SSPE, stabilized with a combination of intrathecal interferon-α2b (INF-α2b) injections and oral inosiplex and how we continued the treatment when inosiplex was commercially stopped worldwide.

Dissociations in white matter tracts and neuropsychological findings in a 17 years old patient with Subacute sclerosing panencephalitis.

The present multimodal diffusion tensor imaging and neuropsychological study investigated the integrity of the white matter fascicles in a 17 years-old patient diagnosed with subacute sclerosing panencephalitis (SSPE). A brief neuropsychological testing showed that word and pseudoword repetition, naming, semantic and phonological fluency, long-term memory, working memory were impaired. A review of the literature on Diffusion weighted imaging (DWI) and Diffusion Tensor Imaging (DTI) evidenced that, studies investigating the integrity of white matter in this condition being a rare disease, are very few. Significant differences (p < 0.05) were found between the fractional anisotropy (FA) values of the controls and the patient in the Superior Longitudinal fasciculus, the Inferior Longitudinal Fasciculus, the Inferior Fronto-Occipital Fasciculus, the Uncinate Fasciculus, and the Arcuate Fasciculus with lower values in the patient. No differences were found for the corticospinal tract. The number of streamlines was significantly lower in the patient, compared to controls, for the left Superior Longitudinal fasciculus, and for the left Uncinate fasciculus while for all the other fascicles, the number did not significantly differ from controls. DTI results were consistent with the patient's cognitive profile showing impairments at repetition, at tasks tapping lexical-semantics and long-term memory / retrieval. Diffusion tensor imaging results indicate that there were diffuse alterations of the degree of anisotropic diffusion along the white matter tracts distributed in posterior-anterior direction. Differently, a selective sparing of this measure was observed along the white matter tract distributed in inferior-superior direction (the corticospinal fascicle).

Spectral Domain Optical Coherence Tomography Findings of Subacute Sclerosing Panencephalitis Presenting with Macular Necrotizing Retinitis: A Case Report.

PURPOSE: To report the fundus photographs and spectral domain optical coherence tomography (SD-OCT) findings of a patient with subacute sclerosing panencephalitis (SSPE) presenting merely with ocular symptoms. CASE REPORT: A 20-year-old patient presented with sudden loss of vision in the left eye (LE). Fundus photograph showed a yellow lesion in the macula and SD-OCT showed increased reflectivity of the inner retinal layers. Disorganization of the necrotizing retinal layers in the LE gradually progressed to the atrophic retina. Then, visual complaints began in the right eye (RE) accompanied by neurological symptoms. SD-OCT revealed the inner and outer plexiform layers edema and interruption of the ellipsoid zone in RE. Fundus photographs showed macular atrophy for both eyes on the day patient died. CONCLUSION: This case report demonstrates the SD-OCT findings of SSPE retinitis with close follow-up from the acute retinitis to the total atrophic macula. These unique findings may be considered as characteristical for the diagnosis.

The EEG Features of Four Cases of Subacute Sclerosing Panencephalitis in North China : SSPE EEG Features.

Objective. To analyze the EEG features of four subacute sclerosing panencephalitis cases in North China. Methods. We retrospectively analyzed the EEG features in four patients with subacute sclerosing panencephalitis and 12 patients in control group from North China. Results. The periodic long-interval diffuse discharges were found in all of the four cases with subacute sclerosing panencephalitis. The morphology and component of periodic complexes were varied in different patients and different wakefulness states. Some EEG parameter settings help to identify periodic long-interval diffuse discharges including the slowed sweep speed, decreased sensitivity and reduced number of montages. In each patient with subacute sclerosing panencephalitis, the periodic long-interval diffuse discharges associated with two types of brief episodes (1:1) during awake period were found and none of the patients in the control group had this EEG pattern. The score system based on the periodic discharges and brief episodes also shows that all the patients with SSPE reached score 5 while none of the patients in the control group has a score greater than 3, which suggests that this EEG pattern may have diagnostic value. Conclusions. In subacute sclerosing panencephalitis, the morphology and component of periodic long-interval diffuse discharges were varied in different patients and different wakefulness states. Specific EEG parameter settings help to identify periodic long-interval diffuse discharges. Periodic long-interval diffuse discharges associated with two types of brief episodes (1:1) during awake period may strongly suggest the diagnosis of subacute sclerosing panencephalitis.

A Comprehensive Investigation of the Current Subacute Sclerosing Panencephalitis (SSPE) Treatment Options to Improve Patient Quality of Life.

Subacute sclerosing panencephalitis (SSPE) is a progressive, disabling, and deadly neurological disorder related to measles (rubeola) infection occurring primarily in children. The slow but persistent viral infection occurs in children or young adults and affects their central nervous system (CNS). There have been plenty of reports on SSPE throughout the world, but it is considered a rare disease in developed countries. This research focuses on comparing the current treatments available to prolong the life of patients for over three years after the onset of SSPE. The goal was to identify possible patterns or trends among the treatments in order to find the best possible method to lengthen a patient's life. The results indicated that interferon alpha, inosine pranobex, and ribavirin display the most effective treatment plan and indicate the most potential in discovering a more effective therapeutic for SSPE.

Preliminary seroprevalence study of neurotropic virus antibodies in Nodding syndrome.

Nodding syndrome (NS) is a mostly East African pediatric epileptiform encephalopathy of unknown etiology that shares some clinical features with measles-associated subacute sclerosing panencephalitis (SSPE) and progressive rubella panencephalitis. Two independent studies in northern Uganda identified an association between NS and prior measles infection, while an earlier study in South Sudan found an inverse association. We report preliminary serologic analyses of antibodies to measles (MV), rubella (RV), HSV-1, and CMV viruses in northern Ugandan children with NS and Household (HC) and Community (CC) Controls. Only MV-positive titers were significantly different (3-fold and > 2-fold) in NS relative to HC and HC + CC, respectively. While these results are consistent with greater prior measles infection in Ugandan persons with NS, further studies are needed to determine whether Measles virus (MV) plays any role in the etiology and pathogenesis of NS. Resolving this issue will be invaluable for the thousands of children at risk for this devastating yet often neglected condition.

Subacute Sclerosing Panencephalitis (SSPE): Experience from a Tertiary-Care Pediatric Center.

Introduction Subacute sclerosing panencephalitis (SSPE) is a devastating neurodegenerative disease occurring as a complication of measles infection that is still prevalent in low-resource countries. Clinical and electrographical variability in SSPE can lead to diagnostic delays. Methods Children diagnosed with SSPE in a tertiary care pediatric hospital in India in a period of 8 years were included in the study. The diagnosis was established on the basis of Dyken's criteria. The demographic data, clinical presentations, investigations, treatment approaches, and outcomes were reviewed and recorded. Results Thirty-four patients were included in the analysis. Average age at symptom onset was 7 years, 5 months. Majority of the children were not vaccinated for measles. Most patients (80%) presented with stage 2 of illness. Nearly 25% presented with atypical clinical features. Myoclonus was the most predominant feature seen after diagnosis. Electroencephalography (EEG) was the most useful investigation for suspecting the diagnosis. All patients showed deterioration in neurological status with time and 20% died during follow-up. Conclusion Atypical presentations of SSPE must be recognized in areas with high incidence to institute timely treatment and establish prognosis. EEG findings were found to be the most important indicator for diagnosis. Measles eradication will pave the way for elimination of this dreaded disease.

Diagnostic reference value of antibody levels measured using enzyme immunoassay for subacute sclerosing panencephalitis.

High measles-specific antibody titers in the cerebrospinal fluid (CSF) have important diagnostic significance for subacute sclerosing panencephalitis (SSPE), a progressive neurological disorder caused by measles virus variants. However, the diagnostic reference value of antibody levels and the usefulness of the CSF/serum ratio measured using enzyme immunoassays (EIAs) for SSPE diagnosis remain unclear. To facilitate SSPE diagnosis using EIAs, measles immunoglobulin G (IgG) titers in the CSF and serum of patients with and without SSPE were measured and their CSF/serum antibody ratios evaluated. Serum and CSF antibody levels were compared among three patients with SSPE (59 paired samples), 37 non-SSPE patients, and 2618 patients of unknown backgrounds. Of the 59 paired samples from three patients with SSPE, 56 paired samples (94.9%) showed CSF measles IgG levels ≥0.5 IU/mL and a CSF/serum ratio ≥0.05, whereas non-SSPE cases showed CSF measles IgG levels <0.1 IU/mL and a CSF/serum ratio <0.03. Of the 2618 CSF samples with unknown backgrounds, 951 showed measurable IgG levels with EIA, with a CSF/serum ratio peak of 0.005-0.02, with a 90th percentile of 0.05. Assuming the SSPE criteria as CSF measles IgG ≥0.5 IU/mL and a CSF/serum ratio ≥0.05, only 20 samples (0.8%) with unknown backgrounds were categorized as having SSPE. Conversely, assuming the non-SSPE criteria as CSF measles IgG <0.1 IU/mL and a CSF/serum ratio <0.03, 2403 samples (92%) with unknown backgrounds were categorized as not having SSPE. In conclusion, high CSF/serum ratios (≥0.05) and high measles CSF IgG levels (≥0.5 IU/mL) may be useful for diagnosing SSPE.