title: Atypical brain laterality in adults with ADHD during dichotic listening for emotional intonation and words.
abstract: Few studies directly examined the nature of hemispheric specialization and interaction in ADHD. The present experiment investigated left/right brain dynamics in unmedicated right handed adults with ADHD (n = 19) and in controls (n = 19), using a dichotic listening task to assess hemispheric differences in word and emotion recognition. We also assessed how focusing attention on a single ear modulated lateralized performance and affected cross-callosal interference effects. Analysis of variance indicated that ADHD subjects showed reduced left hemisphere specialization, were better at processing emotions, and worse at processing words compared to controls. These differences were eliminated during focused attention. Finally, during presumed right hemisphere processing of linguistic stimuli, subjects with ADHD showed reduced left hemisphere interference. We concluded that ADHD subjects demonstrated greater right hemisphere and reduced left hemisphere contribution during this task relative to controls. We posit that these hemispheric differences were due to management or use of available cognitive resources rather than inherent capacity.
authors.affiliation: Division of Child and Adolescent Psychiatry, UCLA Neuropsychiatric Institute and David Geffen School of Medicine, 760 Westwood Plaza, Room 48-270, Los Angeles, CA 90024, USA. sig@ucla.edu
authors.forename: T Sigi
authors.initials: TS
authors.lastname: Hale
authors.forename: Eran
authors.initials: E
authors.lastname: Zaidel
authors.forename: James J
authors.initials: JJ
authors.lastname: McGough
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Phillips
authors.forename: James T
authors.initials: JT
authors.lastname: McCracken
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D001288:Attention / Q000502:physiology; D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D004007:Dichotic Listening Tests; D004644:Emotions; D005260:Female; D007839:Functional Laterality; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008297:Male; D011930:Reaction Time / Q000502:physiology