title: Disentangling the adult attention-deficit hyperactivity disorder endophenotype: parametric measurement of attention.
abstract: Attention deficit hyperactivity disorder (ADHD) persists frequently into adulthood. The decomposition of endophenotypes by means of experimental neuro-cognitive assessment has the potential to improve diagnostic assessment, evaluation of treatment response, and disentanglement of genetic and environmental influences. We assessed four parameters of attentional capacity and selectivity derived from simple psychophysical tasks (verbal report of briefly presented letter displays) and based on a "theory of visual attention." These parameters are mathematically independent, quantitative measures, and previous studies have shown that they are highly sensitive for subtle attention deficits. Potential reductions of attentional capacity, that is, of perceptual processing speed and working memory storage capacity, were assessed with a whole report paradigm. Furthermore, possible pathologies of attentional selectivity, that is, selection of task-relevant information and bias in the spatial distribution of attention, were measured with a partial report paradigm. A group of 30 unmedicated adult ADHD patients and a group of 30 demographically matched healthy controls were tested. ADHD patients showed significant reductions of working memory storage capacity of a moderate to large effect size. Perceptual processing speed, task-based, and spatial selection were unaffected. The results imply a working memory deficit as an important source of behavioral impairments. The theory of visual attention parameter working memory storage capacity might constitute a quantifiable and testable endophenotype of ADHD.
authors.affiliation: Department of Psychology, Experimental Psychology/Neuro-Cognitive Psychology, Ludwig-Maximilians-University, Munich, Germany. finke@psy.lmu.de
authors.forename: Kathrin
authors.initials: K
authors.lastname: Finke
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schwarzkopf
authors.forename: Ulrich
authors.initials: U
authors.lastname: Müller
authors.forename: Thomas
authors.initials: T
authors.lastname: Frodl
authors.forename: Hermann J
authors.initials: HJ
authors.lastname: Müller
authors.forename: Werner X
authors.initials: WX
authors.lastname: Schneider
authors.forename: Rolf R
authors.initials: RR
authors.lastname: Engel
authors.forename: Michael
authors.initials: M
authors.lastname: Riedel
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Möller
authors.forename: Kristina
authors.initials: K
authors.lastname: Hennig-Fast
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D058068:Endophenotypes; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000503:physiopathology*; D008570:Memory, Short-Term; D008875:Middle Aged; D008959:Models, Neurological; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011582:Psychological Theory; D011930:Reaction Time / Q000502:physiology; D012680:Sensitivity and Specificity; D014794:Visual Fields / Q000502:physiology; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult