title: Are factors related to dual-task performance in people with Parkinson's disease dependent on the type of dual task?
abstract: BACKGROUND
  Impaired dual-task performance significantly impacts upon functional mobility in people with Parkinson's disease (PD). The aim of this study was to identify determinants of dual-task performance in people with PD in three different dual tasks to assess their possible task-dependency.
  
  
  METHODS
  We recruited 121 home-dwelling patients with PD (mean age 65.93 years; mean disease duration 8.67 years) whom we subjected to regular walking (control condition) and to three dual-task conditions: walking combined with a backwards Digit Span task, an auditory Stroop task and a Mobile Phone task. We measured dual-task gait velocity using the GAITRite mat and dual-task reaction times and errors on the concurrent tasks as outcomes. Motor, cognitive and descriptive variables which correlated to dual-task performance (p < 0.20) were entered into a stepwise forward multiple linear regression model.
  
  
  RESULTS
  Single-task gait velocity and executive function, tested by the alternating intake test, was significantly associated with gait velocity during the Digit Span (R(2) = 0.65; p < 0.001), the Stroop (R(2) = 0.73; p < 0.001) and the Mobile Phone task (R(2) = 0.62; p < 0.001). In addition, disease severity proved correlated to gait velocity during the Stroop task. Age was a surplus determinant of gait velocity while using a mobile phone.
  
  
  CONCLUSIONS
  Single-task gait velocity and executive function as measured by a verbal fluency switching task were independent determinants of dual-task gait performance in people with PD. In contrast to expectation, these factors were the same across different tasks, supporting the robustness of the findings. Future study needs to determine whether these factors predict dual-task abnormalities prospectively.
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, Neuromotor Rehabilitation Research Group, Leuven, Belgium.
authors.forename: Carolien
authors.initials: C
authors.lastname: Strouwen
authors.affiliation: Radboud University Medical Center, Nijmegen Centre for Evidence Based Practice, Department of Neurology, Nijmegen, The Netherlands.
authors.forename: Esther A L M
authors.initials: EA
authors.lastname: Molenaar
authors.affiliation: Radboud University Medical Center, Nijmegen Centre for Evidence Based Practice, Department of Neurology, Nijmegen, The Netherlands.
authors.forename: Samyra H J
authors.initials: SH
authors.lastname: Keus
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, Neuromotor Rehabilitation Research Group, Leuven, Belgium.
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Münks
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, Neuromotor Rehabilitation Research Group, Leuven, Belgium.
authors.forename: Elke
authors.initials: E
authors.lastname: Heremans
authors.affiliation: University Hospitals Leuven, Department of Neurology, Leuven, Belgium; KU Leuven, Department of Neurosciences, Leuven, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Vandenberghe
authors.affiliation: Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Nijmegen, The Netherlands.
authors.forename: Bastiaan R
authors.initials: BR
authors.lastname: Bloem
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, Neuromotor Rehabilitation Research Group, Leuven, Belgium. Electronic address: Alice.Nieuwboer@faber.kuleuven.be.
authors.forename: Alice
authors.initials: A
authors.lastname: Nieuwboer
mesh_terms: D000368:Aged; D040421:Cell Phone; D056344:Executive Function / Q000502:physiology*; D005260:Female; D005684:Gait; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology* / Q000534:rehabilitation*; D011597:Psychomotor Performance / Q000502:physiology*; D057190:Stroop Test
keywords: Cognition; Dual task; Gait; Parkinson's disease; Prediction