title: Age-related changes in prefrontal activity during walking in dual-task situations: a fNIRS study.
abstract: BACKGROUND
  Previous studies suggest that the human gait is under control of higher-order cognitive processes, located in the frontal lobes, such that an age-related degradation of cognitive capabilities has a negative impact on gait.
  
  
  METHODS
  Using functional Near-Infrared-Spectroscopy (fNIRS) we investigate the frontocortical hemodynamic correlates of dual-task walking in two conditions. 15 young and 10 older individuals walked on a treadmill while completing concurrent tasks that had either visual (checking) or verbal-memory (alphabet recall) demands. We compared subjects' motor performance, as well as their prefrontal activity in single- and dual-task walking.
  
  
  RESULTS
  Our behavioral data partly confirm previous accounts on higher dual-task costs in stepping parameters (i.e., decreased step duration) in old age, particularly with a visual task and negative dual-task cost (i.e., improved performance) during the verbal task in young adults. Functional imaging data revealed little change of prefrontal activation from single- to dual-task walking in young individuals. In the elderly, however, prefrontal activation substantially decreased during dual-task walking with a complex visual task.
  
  
  CONCLUSIONS
  We interpret these findings as evidence for a shift of processing resources from the prefrontal cortex to other brain regions when seniors face the challenge of walking and concurrently executing a visually demanding task.
authors.affiliation: Institute of Physiology and Anatomy, German Sport University, Cologne, Germany. Electronic address: rbeurskens@posteo.de.
authors.forename: Rainer
authors.initials: R
authors.lastname: Beurskens
authors.affiliation: Institute of Health Promotion and Clinical Movement Science, German Sport University, Cologne, Germany.
authors.forename: Ingo
authors.initials: I
authors.lastname: Helmich
authors.affiliation: Institute of Health Promotion and Clinical Movement Science, German Sport University, Cologne, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Rein
authors.affiliation: Institute of Physiology and Anatomy, German Sport University, Cologne, Germany.
authors.forename: Otmar
authors.initials: O
authors.lastname: Bock
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D017397:Prefrontal Cortex / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared; D014145:Trail Making Test; D016138:Walking / Q000502:physiology*; D055815:Young Adult
keywords: Aging; Dual-task walking; Executive function; Locomotion; Neural activation; fNIRS