title: Interhemispheric callosal transfer in adults with attention-deficit/hyperactivity disorder: an event-related potential study.
abstract: Although subtypes of attention-deficit/hyperactivity disorder have been recognized for some time, few studies have investigated neurophysiological differences that may reflect these. Here, adults with attention-deficit/hyperactivity disorder-inattentive type, attention-deficit/hyperactivity disorder-combined type and controls performed a simple reaction time laterality task (the Poffenberger) during 128-channel electroencephalography recording. Visual-evoked potentials were used to calculate interhemispheric transfer times. As expected for controls, mean right-to-left transfer time was faster than mean left-to-right transfer. No significant asymmetry was, however, found for clinical groups. Compared with controls, attention-deficit/hyperactivity disorder-combined participants demonstrated significantly faster left-to-right transfer, whereas attention-deficit/hyperactivity disorder-inattentive participants had significantly slower right-to-left transfer. These findings support the existence of functional differences between attention-deficit/hyperactivity disorder subtypes, and suggest that the right hemisphere dysfunction theory of attention-deficit/hyperactivity disorder may only be applicable to those without hyperactive symptoms.
authors.affiliation: Department of Psychology, Research Centre for Cognitive Neuroscience, University of Auckland, Auckland, New Zealand.
authors.forename: Mei Hsin Suzanne
authors.initials: MH
authors.lastname: Rolfe
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Kirk
authors.forename: Karen E
authors.initials: KE
authors.lastname: Waldie
mesh_terms: D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D003337:Corpus Callosum / Q000503:physiopathology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005074:Evoked Potentials, Visual / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology*; D009483:Neuropsychological Tests; D011930:Reaction Time / Q000502:physiology