title: Frontal brain asymmetry in adult attention-deficit/hyperactivity disorder (ADHD): extending the motivational dysfunction hypothesis.
abstract: OBJECTIVE
  Attention-deficit/hyperactivity disorder (ADHD) involves motivational dysfunction, characterized by excessive behavioral approach tendencies. Frontal brain asymmetry in the alpha band (8-13 Hz) in resting-state electroencephalogram (EEG) represents a neural correlate of global motivational tendencies, and abnormal asymmetry, indicating elevated approach motivation, was observed in pediatric and adult patients. To date, the relation between ADHD symptoms, depression and alpha asymmetry, its temporal metric properties and putative gender-specificity remain to be explored.
  
  
  METHODS
  Adult ADHD patients (n=52) participated in two resting-state EEG recordings, two weeks apart. Asymmetry measures were aggregated across recordings to increase trait specificity. Putative region-specific associations between asymmetry, ADHD symptoms and depression, its gender-specificity and test-retest reliability were examined.
  
  
  RESULTS
  ADHD symptoms were associated with approach-related asymmetry (stronger relative right-frontal alpha power). Approach-related asymmetry was pronounced in females, and also associated with depression. The latter association was mediated by ADHD symptoms. Test-retest reliability was sufficient.
  
  
  CONCLUSIONS
  The association between reliably assessable alpha asymmetry and ADHD symptoms supports the motivational dysfunction hypothesis. ADHD symptoms mediating an atypical association between asymmetry and depression may be attributed to depression arising secondary to ADHD. Gender-specific findings require replication.
  
  
  CONCLUSIONS
  Frontal alpha asymmetry may represent a new reliable marker of ADHD symptoms.
authors.affiliation: Klinikum Bayreuth, Department of Neurology, Hohe Warte 8, 95445 Bayreuth, Germany; Otto-Friedrich-University of Bamberg, Department of Physiological Psychology, Bamberg, Germany. Electronic address: pmkeune@gmail.com.
authors.forename: Philipp M
authors.initials: PM
authors.lastname: Keune
authors.affiliation: Institute of Psychology, Department of Clinical Psychology, Eberhard Karls University, Tübingen, Schleichstraße 4, 72076 Tübingen, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Wiedemann
authors.affiliation: Institute of Psychology, Department of Clinical Psychology, Eberhard Karls University, Tübingen, Schleichstraße 4, 72076 Tübingen, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Schneidt
authors.affiliation: Institute of Psychology, Department of Clinical Psychology, Eberhard Karls University, Tübingen, Schleichstraße 4, 72076 Tübingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schönenberg
mesh_terms: D000328:Adult; D000513:Alpha Rhythm / Q000502:physiology; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis* / Q000503:physiopathology*; D003863:Depression / Q000175:diagnosis / Q000503:physiopathology; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009042:Motivation / Q000502:physiology
keywords: Adult attention-deficit/hyperactivity disorder (ADHD); Depression; EEG alpha asymmetry; Electroencephalogram (EEG); Gender difference; Test–retest reliability