Behavioral consequences of aberrant alpha lateralization in attention-deficit/hyperactivity disorder

Background: Attention-deficit/hyperactivity disorder (ADHD) is characterized by problems in directing and sustaining attention. Recent findings suggest that alpha oscillations (8-12 Hz) are crucially involved in gating information between brain regions when allocating attention. The current study investigates whether aberrant modulation of alpha oscillations contributes to attention problems in ADHD patients. Methods: Magnetoencephalographic signals were recorded in adults with ADHD (n = 17) and healthy control subjects (n = 18) while they performed a visuospatial attention task. Cues directed attention to the left or right visual hemifield with an 80% validity with respect to the upcoming target. Results: Unlike the control group, subjects with ADHD showed a higher accuracy for invalidly cued right targets compared with invalidly cued left targets (p =.04). This coincided with an inability of the ADHD subjects to sustain the posterior hemispheric alpha lateralization in the period before the target for the left cue condition (p =.011). Furthermore, the control group showed a strong correlation between the degree of alpha lateralization and the magnitude of the cueing effect assessed in terms of accuracy (rs =.71, p =.001) and reaction times (rs =-.81, p