Multisite Study of Evoked Potentials in Rett Syndrome.

OBJECTIVE: The aim of the current study was to evaluate the utility of evoked potentials as a biomarker of cortical function in Rett syndrome (RTT). As a number of disease-modifying therapeutics are currently under development, there is a pressing need for biomarkers to objectively and precisely assess the effectiveness of these treatments. METHOD: Yearly visual evoked potentials (VEPs) and auditory evoked potentials (AEPs) were acquired from individuals with RTT, aged 2 to 37 years, and control participants across 5 sites as part of the Rett Syndrome and Related Disorders Natural History Study. Baseline and year 1 data, when available, were analyzed and the repeatability of the results was tested. Two syndrome-specific measures from the Natural History Study were used for evaluating the clinical relevance of the VEP and AEP parameters. RESULTS: At the baseline study, group level comparisons revealed reduced VEP and AEP amplitude in RTT compared to control participants. Further analyses within the RTT group indicated that this reduction was associated with RTT-related symptoms, with greater severity associated with lower VEP and AEP amplitude. In participants with RTT, VEP and AEP amplitude was also negatively associated with age. Year 1 follow-up data analyses yielded similar findings and evidence of repeatability of EPs at the individual level. INTERPRETATION: The present findings indicate the promise of evoked potentials (EPs) as an objective measure of disease severity in individuals with RTT. Our multisite approach demonstrates potential research and clinical applications to provide unbiased assessment of disease staging, prognosis, and response to therapy. ANN NEUROL 2021;89:790-802.

Biomarkers of hypercoagulability and inflammation in childhood-onset arterial ischemic stroke.

OBJECTIVE: To test the hypothesis that acute elevations of biomarkers of hypercoagulability and inflammation are common in children with arterial ischemic stroke (AIS), particularly among etiologic subtypes that carry an increased risk of recurrent stroke. STUDY DESIGN: In this prospective/retrospective institutional-based cohort study of acute childhood-onset AIS (n = 50) conducted between 2005 and 2009, D-dimer, factor VIII (FVIII) activity, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were serially evaluated at the time of clinical blood sampling. Patients were classified by stroke subtype as cardioembolic, moyamoya, non-moyamoya arteriopathy, or other. RESULTS: Both D-dimer and CRP were frequently elevated in acute childhood-onset AIS and exhibited a decreasing trend with time. Acute D-dimer levels were significantly higher in cardioembolic AIS compared with noncardioembolic AIS (median, 2.04 microg/mL [range 0.54-4.54 microg/mL] vs 0.32 microg/mL [0.22-3.18 microg/mL]; P = .002). At an optimal threshold of > or = 0.50 microg/mL, the sensitivity and specificity of D-dimer for cardioembolic subtype were 78% and 79%, respectively. CONCLUSIONS: Our findings identify D-dimer and CRP as candidate biomarkers for etiology and prognosis in childhood-onset AIS. Further studies should investigate the role of these and other biomarkers of hypercoagulability and inflammation in childhood-onset AIS.