The correlation of quantitative EEG &influence of heavy metal levels in children with Autism spectrum disorder

Objectives:To correlate the pathogenesis of autism spectrum disorder(ASD) with mean blood levels of mercury(Hg), other heavy/essential metal & further validation byquantitativeEEG. Methods:This is a prospective cross-sectional study, 180 children (aged 3-12years)diagnosed as per the DSM-5 and180 age matched controls having developmental profile(DP3) with standard score more than 84 were recruited. Blood sampleswere collected in EDTA metal-freetubes, were processed for Inductively-Coupled-Plasma-Mass-Spectroscopy.EEG was recorded from 128electrodes using an Electrical Geodesics(EGI) high-density EEGsystem(Netstation) & digitized @ 1000Hz. Impedance was kept below 50kΩ. EEG was recorded at 0.1-Hz high-pass/100Hz low-pass filtering & 50Hz notch. Results:ASD subjects (153boys/27girls, 6.5±1.6years, Childhood Autism Rating Scale (CARS): 36.59±2.38, Developmental Quotient (DQ):59.94±5.86) had significantly higher levels: Mercury(Hg), Chromium(Cr), Manganese(Mn) (p=0.01 for all three); Selenium(Se) &lead(Pb) (p=0.001). The spectral power of gamma(γ), beta(β), lower alpha1(lα1), theta(θ)& coherence ofγ, lα1, during eyes-closed condition was significantly (p < 0.0005) lower & the spectral power of θ& coherence of lα1, θ, δ, was significantly lower (p < 0.0005) during eyes-open condition in ASD compared to controls. γ band had positive correlation with Cr, Zinc (Zn), Pb & negative correlation with Nickel(Ni). β band had positive correlation with Fe, Se, Ni, Pb & negative correlation with Copper, Mn, Arsenic. Conclusions: The findings of this study showed impaired coherence pattern in children with ASD during attention task. ASD children have different qEEG correlates, as well as, significantly higher blood Hg, Cr, Mn, Se& Pb levels as compared controls.
Keywords: Autism Spectrum Disorder, Heavy metals, Quantitative EEG