title: Hyperactivity in boys with attention-deficit/hyperactivity disorder (ADHD): a ubiquitous core symptom or manifestation of working memory deficits?
abstract: Hyperactivity is currently considered a core and ubiquitous feature of attention-deficit/hyperactivity disorder (ADHD); however, an alternative model challenges this premise and hypothesizes a functional relationship between working memory (WM) and activity level. The current study investigated whether children's activity level is functionally related to WM demands associated with the domain-general central executive and subsidiary storage/rehearsal components using tasks based on Baddeley's (Working memory, thought, and action. New York: Oxford University Press 2007) WM model. Activity level was objectively measured 16 times per second using wrist- and ankle-worn actigraphs while 23 boys between 8 and 12 years of age completed control tasks and visuospatial/phonological WM tasks of increasing memory demands. All children exhibited significantly higher activity rates under all WM relative to control conditions, and children with ADHD (n = 12) moved significantly more than typically developing children (n = 11) under all conditions. Activity level in all children was associated with central executive but not storage/rehearsal functioning, and higher activity rates exhibited by children with ADHD under control conditions were fully attenuated by removing variance directly related to central executive processes.
authors.affiliation: Department of Psychology, University of Central Florida, Orlando, FL, USA. mrapport@mail.ucf.edu
authors.forename: Mark D
authors.initials: MD
authors.lastname: Rapport
authors.forename: Jennifer
authors.initials: J
authors.lastname: Bolden
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kofler
authors.forename: Dustin E
authors.initials: DE
authors.lastname: Sarver
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Raiker
authors.forename: R Matt
authors.initials: RM
authors.lastname: Alderson
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications* / Q000503:physiopathology / Q000523:psychology*; D002648:Child; D003071:Cognition; D006801:Humans; D006948:Hyperkinesis / Q000503:physiopathology / Q000523:psychology*; D008297:Male; D008569:Memory Disorders / Q000503:physiopathology / Q000523:psychology*; D009483:Neuropsychological Tests; D011597:Psychomotor Performance; D011930:Reaction Time; D012720:Severity of Illness Index; D013028:Space Perception; D013647:Task Performance and Analysis; D014706:Verbal Learning; D014796:Visual Perception