title: Visuospatial working memory in ADHD patients, unaffected siblings, and healthy controls.
abstract: OBJECTIVE
  The aim of this study was to (a) test the usefulness of visuospatial working memory (VSWM) as an endophenotype for ADHD and (b) study the developmental trajectory of VSWM in ADHD.
  
  
  METHODS
  A total of 110 ADHD patients, 60 unaffected siblings, and 109 controls, aged 8 to 29 years, were assessed on VSWM functioning. Multilevel analyses were carried out to account for the correlation between measurements within families.
  
  
  RESULTS
  ADHD patients showed impaired VSWM performance compared with unaffected siblings and controls, with comparable performance between unaffected siblings and controls. Impaired VSWM in ADHD patients was not more pronounced on higher memory loads, signifying executive rather than storage deficits as an underlying mechanism. ADHD patients, unaffected siblings, and controls showed parallel developmental trajectories of VSWM.
  
  
  CONCLUSIONS
  Current findings question the usefulness of VSWM as a neurocognitive endophenotype for ADHD and provide unique insights into the developmental trajectory of VSWM in ADHD.
authors.affiliation: 1VU University Amsterdam, The Netherlands.
authors.forename: Hanneke
authors.initials: H
authors.lastname: van Ewijk
authors.forename: Dirk J
authors.initials: DJ
authors.lastname: Heslenfeld
authors.forename: Marjolein
authors.initials: M
authors.lastname: Luman
authors.forename: Nanda N
authors.initials: NN
authors.lastname: Rommelse
authors.forename: Catharina A
authors.initials: CA
authors.lastname: Hartman
authors.forename: Pieter
authors.initials: P
authors.lastname: Hoekstra
authors.forename: Barbara
authors.initials: B
authors.lastname: Franke
authors.forename: Jan K
authors.initials: JK
authors.lastname: Buitelaar
authors.forename: Jaap
authors.initials: J
authors.lastname: Oosterlaan
mesh_terms: D000293:Adolescent; D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000503:physiopathology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D055361:Multilevel Analysis; D009483:Neuropsychological Tests; D035781:Siblings / Q000523:psychology; D013028:Space Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: ADHD; WM; development; endophenotype; multilevel analysis; unaffected siblings; visuospatial working memory