Electroencephalography and externalizing behavior: A meta-analysis

Systematic overview of neuroanatomical differences in ADHD: Definitive evidence

“…The previous assumption has also been identified in simultaneous EEG/fMRI evaluation where a high arousal pattern (decreased delta and theta with increased alpha and beta) might be associated with this brain network (Hlinka, Alexakis, Diukova, Liddle, & Auer, 2010;Rudo-Hutt, 2015) and other fMRI resting-state results (Konrad & Eickhoff, 2010;Paloyelis et al, 2007;Posner et al, 2014;Yeo et al, 2011).…”

“…In terms of coherence (calculated as the cross-correlation in the frequency domain between two EEG time points, measured simultaneously at different scalp locations), ADHD showed frontal hypercoherence (Sigi Hale et al, 2000;Tye et al, 2011) thought to indicate reduced cortical differentiation (Tye et al, 2011;Willis & Weiler, 2005). This fact supported both interpretations since this hypercoherence is relative to slow waves in the frontal region and this lower cortical differentiation tends to normalize with increasing age (Loo & Makeig, 2012;Rudo-Hutt, 2015;Tye et al, 2011;Willis & Weiler, 2005).…”

“…These EEG results supported two previous ADHD interpretations: low cortical arousal and delayed cortical maturation. The low cortical arousal interpretation was supported by the frontal increase of slow wave pattern (delta and theta), decrease of fast wave pattern (alpha e beta) and increased theta/beta ratio (Castellanos & Acosta, 2002;Loo & Makeig, 2012;Rudo-Hutt, 2015;Sigi Hale et al, 2000;Tannock, 1998;Tye, McLoughlin, Kuntsi, & Asherson, 2011;Willis & Weiler, 2005). In terms of coherence (calculated as the cross-correlation in the frequency domain between two EEG time points, measured simultaneously at different scalp locations), ADHD showed frontal hypercoherence (Sigi Hale et al, 2000;Tye et al, 2011) thought to indicate reduced cortical differentiation (Tye et al, 2011;Willis & Weiler, 2005).…”

“…Different EEG frequencies have also been implicated in specific mental/physiological states consistent with ADHD: delta waves with deep sleep; theta with the intake of sensory information, spatial memory and positively associated with low arousal; alpha waves with wakeful relaxation, possibly with a synchronization of neuronal processes across the brain, negative association with arousal and positive association with externalizing behavior; beta waves with working memory, mental activation and focus; gamma waves with alertness and sensory stimulation; and theta/beta ratio with a negative association to reaction time (Loo & Makeig, 2012;Rudo-Hutt, 2015). The hippocampus has also been implicated with the theta rhythm and thalamo-cortical circuits with alpha rhythm (Willis & Weiler, 2005) Therefore, the NAA findings indicating frontal hyperactivation are not consistent with previous EEG results.…”

“…However, these EEG results are consistent with the fMRI results of a frontal hypoactivation and posterior hyperactivation tendency. EEG findings are mostly based on a resting state with eyes open and closed (Loo & Makeig, 2012;Rudo-Hutt, 2015;Tye et al, 2011), but functional state is also possible (Willis & Weiler, 2005), so it is expected that some EEG results might represent a combination of both states. This EEG/fMRI consistency might also be due to the fact that both techniques have decades of investigation and MRS results related to ADHD are in the early stages, which may explain the inconsistent findings.…”