title: Unexpected dual task benefits on cycling in Parkinson disease and healthy adults: a neuro-behavioral model.
abstract: BACKGROUND
  When performing two tasks at once, a dual task, performance on one or both tasks typically suffers. People with Parkinson's disease (PD) usually experience larger dual task decrements on motor tasks than healthy older adults (HOA). Our objective was to investigate the decrements in cycling caused by performing cognitive tasks with a range of difficulty in people with PD and HOAs.
  
  
  METHODS
  Twenty-eight participants with Parkinson's disease and 20 healthy older adults completed a baseline cycling task with no secondary tasks and then completed dual task cycling while performing 12 tasks from six cognitive domains representing a wide range of difficulty.
  
  
  RESULTS
  Cycling was faster during dual task conditions than at baseline, and was significantly faster for six tasks (all p<.02) across both groups. Cycling speed improved the most during the easiest cognitive tasks, and cognitive performance was largely unaffected. Cycling improvement was predicted by task difficulty (p<.001). People with Parkinson's disease cycled slower (p<.03) and showed reduced dual task benefits (p<.01) than healthy older adults.
  
  
  CONCLUSIONS
  Unexpectedly, participants' motor performance improved during cognitive dual tasks, which cannot be explained in current models of dual task performance. To account for these findings, we propose a model integrating dual task and acute exercise approaches which posits that cognitive arousal during dual tasks increases resources to facilitate motor and cognitive performance, which is subsequently modulated by motor and cognitive task difficulty. This model can explain both the improvement observed on dual tasks in the current study and more typical dual task findings in other studies.
authors.affiliation: Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, Florida, United States of America; Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Lori J P
authors.initials: LJ
authors.lastname: Altmann
authors.affiliation: Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, United States of America; Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, Florida, United States of America; Department of Kinesiology, Iowa State University, Ames, Iowa, United States of America.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Stegemöller
authors.affiliation: Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, Florida, United States of America; Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Audrey A
authors.initials: AA
authors.lastname: Hazamy
authors.affiliation: Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, Florida, United States of America; Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, Florida, United States of America; Department of Speech-Language Pathology, Midwestern University, Downers Grove, Illinois, United States of America.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Wilson
authors.affiliation: Department of Neurology and Neurosurgery, University of Florida, Gainesville, Florida, United States of America; Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Okun
authors.affiliation: Department of Neurology and Neurosurgery, University of Florida, Gainesville, Florida, United States of America; Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Nikolaus R
authors.initials: NR
authors.lastname: McFarland
authors.affiliation: Department of Neurology and Neurosurgery, University of Florida, Gainesville, Florida, United States of America; Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Aparna
authors.initials: A
authors.lastname: Wagle Shukla
authors.affiliation: Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, United States of America; Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Hass
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001642:Bicycling; D016022:Case-Control Studies; D003071:Cognition; D005081:Exercise Therapy; D006801:Humans; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology* / Q000523:psychology / Q000628:therapy; D013647:Task Performance and Analysis