title: Behavioral consequences of aberrant alpha lateralization in attention-deficit/hyperactivity disorder.
abstract: 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<.001). These correlations were absent in the ADHD group.
  
  
  CONCLUSIONS
  Our results demonstrate that subjects with ADHD have a failure in sustaining hemispheric alpha lateralization when cued to the left, resulting in an attentional bias to the right visual hemifield. These findings suggest that aberrant modulations of alpha oscillations reflect attention problems in ADHD and might be related to the neurophysiological substrate of the disorder.
authors.affiliation: Centre for Cognitive Neuroimaging, Radboud University Medical Centre, Nijmegen NL-6500, The Netherlands. n.terhuurne@psy.umcn.nl
authors.forename: Niels
authors.initials: N
authors.lastname: ter Huurne
authors.forename: Marten
authors.initials: M
authors.lastname: Onnink
authors.forename: Cornelis
authors.initials: C
authors.lastname: Kan
authors.forename: Barbara
authors.initials: B
authors.lastname: Franke
authors.forename: Jan
authors.initials: J
authors.lastname: Buitelaar
authors.forename: Ole
authors.initials: O
authors.lastname: Jensen
mesh_terms: D000328:Adult; D000513:Alpha Rhythm / Q000502:physiology*; D001288:Attention / Q000502:physiology; D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology*; D001931:Brain Mapping; D003463:Cues; D004569:Electroencephalography; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D053798:Magnetocardiography; D008297:Male; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology*; D055815:Young Adult
keywords: ADHD; attention; bias; electroencephalography; magnetoencephalography (MEG); oscillations