EEG coherence in girls with Attention-Deficit/Hyperactivity Disorder: Stimulant effects in good responders

Assessment of ADHD Through Electroencephalographic Measures of Functional Connectivity

“…Over the past 15 years, the study of EEG FC in ADHD using coherence has been carried out primarily by researchers of the Brain & Behaviour Research Institute and Department of Psychology at the University of Wollongong in Australia, who have studied coherence, both intra-and interhemispheric, by planned contrast and by considering short, medium and long distances between electrodes. They have reported that ADHD subjects, compared to healthy controls, present higher intrahemispheric coherences in short/medium distances in delta, theta and beta frequency bands [7][8][9][53][54][55], reduced laterality in the theta band [8,53,55,56] and increased frontal interhemispheric values in the delta and theta bands [8,9,[53][54][55]. Coherence results found from our group [4] indicate, in agreement with previous results, that for certain pairs of channels at short (e.g., C3-C4, O1-O2) and medium (e.g., C3-T4, T3-C4, O1-C4) interhemispheric distances, FC was clearly greater for the ADHD group than for controls, whereas for large interhemispheric distances (e.g., Fp1-O2), the reverse was true during both EC and EO.…”

“…In fact, [60] have found that it reduces the alterations found in EEG coherence profiles in children with ADHD; in contrast, other authors have found neither that MPH ingestion produces changes in the EEG coherence of ADHD, nor that the coherence profile comes closer to that of the controls after treatment [53]. In another study, [56] reported a change in the profile of EEG coherence after MPH ingestion in girls with ADHD and specifically an increase in the delta band between intrahemispheric cortical areas at short distances, resulting in a reduction of the differences between the ADHD and control groups. In [55], the authors reported that ADHD boys showing good response to MPH differed from those unresponsive to the drug, in that MPH produced greater intrahemispheric coherence (shorter and medium distances) in the delta band of the ADHD good response group.…”

Increased theta coherence during Chinese reading

“…Coherence values were transformed using Fisher's z-transform. Following published literature (Barry et al, 2002(Barry et al, , 2004(Barry et al, , 2006(Barry et al, , 2009Clarke et al, 2005Clarke et al, , 2007Clarke et al, , 2008Dupuy et al, 2008), the means were inversetransformed for reporting. The coherence values were grouped into (i) intrahemispheric short-range (between adjacent electrodes pairs, such as F1-F3, F2-F4) or (ii) intrahemispheric long-range (at least one electrode was in between, such as F1-C1, F2-C2) coherence Coben et al, 2008).…”

“…The coherence values were grouped into (i) intrahemispheric short-range (between adjacent electrodes pairs, such as F1-F3, F2-F4) or (ii) intrahemispheric long-range (at least one electrode was in between, such as F1-C1, F2-C2) coherence Coben et al, 2008). The interhemispheric coherences were separately calculated within FT8, T3-T4, TP7-TP8), and (vi) parietal/occipital (P1-P2, P3-P4, P5-P6, P7-P8, PO3-PO4, PO5-PO6, PO7-PO8, O1-O2) cortical regions (Coben et al, 2008;Dupuy et al, 2008).…”

“…The examination of temporal synchronization of neuronal activities during various cognitive tasks by calculating coherence between two EEG signals has provided useful information about underlying cortical coupling and connectivity between distinct brain regions (Weiss and Mueller, 2003;Clarke et al, 2005Clarke et al, , 2007Clarke et al, , 2008Barry et al, 2009). Research suggests that high EEG coherence indicates strong structural or functional connection between cortical regions (Fein et al, 1988;Thatcher et al, 2008) and is associated with various cognitive tasks, such as memory (Klimesch, 1999;Sauseng et al, 2005), language (Weiss and Mueller, 2003), intelligence (Thatcher et al, 2005), and brain disorder, such as Autistic Spectrum Disorder (Coben et al, 2008), Attention-Deficit/Hyperactivity Disorder (Barry et al, 2002(Barry et al, , 2004(Barry et al, , 2006Dupuy et al, 2008), and Alzheimer's disease (Hogan et al, 2003;van der Hiele et al, 2007).…”