Conservative method for vertical electrooculogram attenuation based on local suppression of ongoing EEG artifact templates.

Eye movement during blinking can be a significant artifact in Event-Related Potentials (ERP) analysis. Blinks produce a positive potential in the vertical electrooculogram (VEOG), spreading towards the posterior direction. Two methods are frequently used to suppress VEOGs: linear regression to subtract the VEOG signal from the electroencephalogram (EEG) and Independent Component Analysis (ICA). However, some information is lost in both. The present algorithm (1) statistically identifies the position of VEOGs in the frontopolar channels; (2) performs EEG averaging for each channel, which results in 'blink templates'; (3) subtracts each template from the respective EEG at each VEOG position, only when the linear correlation index between the template and the segment is greater than a chosen threshold L. The signals from twenty subjects were acquired using a behavioral test and were treated using FilterBlink for subsequent ERP analysis. A model was designed to test the method for each subject using twenty copies of the EEG signal from the subject's mid-central channel (with nearly no VEOG) representing the EEG channels and their respective blink templates. At the same 200 equidistant time points (marks), a signal (2.5 sinusoidal cycles at 1050 ms emulating an ERP) was mixed with each model channel and the respective blink template of that channel, between 500 to 1200 ms after each mark. According to the model, VEOGs interfered with both ERPs and the ongoing EEG, mainly on the anterior medial leads, and no significant effect was observed on the mid-central channel (Cz). FilterBlink recovered approximately 90% (Fp1) to 98% (Fz) of the original ERP and EEG signals for L = 0.1. The method reduced the VEOG effect on the EEG after ERP and blink-artifact averaging in analyzing real signals. The method is straightforward and effective for VEOG attenuation without significant distortion in the EEG signal and embedded ERPs.

Willingness of Brazilian caregivers in having their children and adolescents vaccinated against Covid-19.

BACKGROUND: The vaccination of children and adolescents for the prevention of Covid-19 is important to:decrease in deaths and hospitalizations, prevent multisystem inflammatory syndrome, avoid long-term complications and decrease the suspension of on-site classes. Despite of these benefits, some studies have shown that some caregivers are still hesitancy. METHODS: This is a voluntary and anonymous online survey conducted from November 17 to December 14, 2021, in Brazil, through a free-of-charge platform with a link provided on social networks. A bivariate analysis was conducted with the independent variables, with vaccine hesitancy as the outcome variable, and a multivariate logistic model was used to calculated adjusted odds ratios. RESULTS: The sample included 15,297 respondents. Approximately 13.3 % (2,028) of the caregivers were hesitant to vaccinate their children and adolescents against Covid-19 in at least one age group. The vaccination hesitanty rate of caregivers of children aged 0-4 years, 5-11 years and adolescents were 16 %, 13 %, 15 %, respectively. The principal factors associated with vaccine hesitancy were the following: belief that they need to wait longer, belief that children that had natural infection doesn't need to vaccinate and belief that vaccine has long term adverse effects. INTERPRETATION: The present study showed that the willingness of caregivers to have their children and adolescents vaccinated in Brazil is high compared to data from adult and pediatric international studies. This study provides a profile of the hesitant caregivers considering their perspectives and beliefs regarding vaccines that can help the elaboration of strategies to increase vaccine adherence.

Auditory brainstem function in microcephaly related to Zika virus infection.

OBJECTIVE: To study the effect of prenatal Zika virus (ZV) infection on brainstem function reflected in brainstem auditory evoked potentials (BAEPs). METHODS: In a cross-sectional study in 19 children (12 girls) with microcephaly related to ZV infection, aged between 12 and 62 weeks, the brainstem function was examined through BAEPs. The latencies of wave peaks I, III, and V of the left and right ears (n = 37) were standardized according to normative data, and compared between them by 2-tailed t test. The confounding variables (cephalic perimeter at the born and chronological age) were correlated with the normalized latencies using Pearson test. RESULTS: All patients showed, in general, clear waveforms, with latencies within 3 SDs of the normative values. However, statistically increased latencies of waves I and III (I > III, p = 0.031) were observed, relative to wave V (p < 0.001), the latter being closer to respective normative value. The latency of wave I was observed to increase with age (r = 0.45, p = 0.005). The waves, in turn, did not depend on cephalic perimeter. CONCLUSIONS: These results are consistent with the functional normality of the brainstem structure and its lack of correlation with microcephaly, suggesting that the disruption produced by the ZV infection does not act in the cell proliferation phase, but mostly in the processes of neuronal migration and differentiation in the telencephalon.