title: Different motor tasks impact differently on cognitive performance of older persons during dual task tests.
abstract: BACKGROUND
  Dual task paradigm states that the introduction of a second task during a cognitive or motor performance results in a decreased performance in either task. Treadmill walk, often used in clinical applications of dual task testing, has never been compared to overground walk, to ascertain its susceptibility to interference from a second task. We compared the effects of overground and treadmill gait on dual task performance.
  
  
  METHODS
  Gait kinematic parameters and cognitive performance were obtained in 29 healthy older adults (mean age 75 years, 14 females) when they were walking freely on a sensorized carpet or during treadmill walking with an optoelectronic system, in single task or dual task conditions, using alternate repetition of letters as a cognitive verbal task.
  
  
  RESULTS
  During overground walking, speed, cadence, step length stride length, and double support time (all with P value<0.001) and cognitive performance (number of correct words, P<0.001) decreased substantially from single to dual task testing. When subjects walked at a fixed speed on the treadmill, cadence decreased significantly (P=0.005), whereas cognitive performance remained unaffected.
  
  
  CONCLUSIONS
  Both motor and cognitive performances decline during dual task testing with overground walking. Conversely, cognitive performance remains unaffected in dual task testing on the treadmill. In the light of current dual task paradigm, these findings may have relevant implication for our understanding of motor control, as they suggest that treadmill walk does not involve brain areas susceptible to interference from the introduction of a cognitive task.
authors.affiliation: Research Unit of Medicine of Aging, Department of Experimental and Clinical Medicine, University of Florence, Italy. david.simoni@unifi.it
authors.forename: David
authors.initials: D
authors.lastname: Simoni
authors.forename: Gaia
authors.initials: G
authors.lastname: Rubbieri
authors.forename: Marco
authors.initials: M
authors.lastname: Baccini
authors.forename: Lucio
authors.initials: L
authors.lastname: Rinaldi
authors.forename: Dimitri
authors.initials: D
authors.lastname: Becheri
authors.forename: Tatiana
authors.initials: T
authors.lastname: Forconi
authors.forename: Enrico
authors.initials: E
authors.lastname: Mossello
authors.forename: Samanta
authors.initials: S
authors.lastname: Zanieri
authors.forename: Niccolò
authors.initials: N
authors.lastname: Marchionni
authors.forename: Mauro
authors.initials: M
authors.lastname: Di Bari
mesh_terms: D000203:Activities of Daily Living; D000368:Aged / Q000502:physiology*; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D003071:Cognition / Q000502:physiology*; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D013647:Task Performance and Analysis; D014705:Verbal Behavior / Q000502:physiology*; D016138:Walking / Q000502:physiology
keywords: Dual task; Gait; Motor control; Overground walking; Treadmill walking