title: Distractibility with advancing age and Parkinson's disease.
abstract: Focused attention can be compromised by the neurodegenerative processes associated with both healthy aging and Parkinson's disease (PD). Deficits in ignoring distractors with reflexive or overlearned response links have been attributed to impaired inhibition. The current research assessed whether similar deficits occur for distractors with recently learned arbitrary response associations, for which sensorimotor transformations are far less automatic and therefore considerably easier to resist. We used a selective attention task that evaluated distractibility and the use of distractor inhibition within the same context. The task involved stimuli that were arbitrarily assigned to responses based on a rule learned during the testing session. Performance showed that distraction increased with both healthy aging and PD. Moreover, these increases in distraction were accompanied by decreases in overt evidence of distractor inhibition, which appear to reflect at least in part a failure of reactive inhibition. Comparison of the deficits in the two groups indicates that the key difference reflects severity, rather than distinct symptoms, suggesting that they stem from neural changes associated with both aging and PD. These results demonstrate that aging- and PD-related hyper-distractibility and impaired inhibition during focused attention affect stimuli without prepotent response links, which implicates dopaminergic networks in the strategic control of arbitrary visuomotor transformations.
authors.affiliation: Department of Psychology and Brain Health and Repair Research Centre, University of Otago, New Zealand. liana@psy.otago.ac.nz
authors.forename: Liana
authors.initials: L
authors.lastname: Machado
authors.forename: Amy
authors.initials: A
authors.lastname: Devine
authors.forename: Natalie
authors.initials: N
authors.lastname: Wyatt
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000209:etiology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D007858:Learning; D008297:Male; D008609:Mental Status Schedule; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D013997:Time Factors; D055815:Young Adult