title: Test-retest reliability of stride time variability while dual tasking in healthy and demented adults with frontotemporal degeneration.
abstract: BACKGROUND
  Although test-retest reliability of mean values of spatio-temporal gait parameters has been assessed for reliability while walking alone (i.e., single tasking), little is known about the test-retest reliability of stride time variability (STV) while performing an attention demanding-task (i.e., dual tasking). The objective of this study was to examine immediate test-retest reliability of STV while single and dual tasking in cognitively healthy older individuals (CHI) and in demented patients with frontotemporal degeneration (FTD).
  
  
  METHODS
  Based on a cross-sectional design, 69 community-dwelling CHI (mean age 75.5 ± 4.3; 43.5% women) and 14 demented patients with FTD (mean age 65.7 ± 9.8 years; 6.7% women) walked alone (without performing an additional task; i.e., single tasking) and while counting backward (CB) aloud starting from 50 (i.e., dual tasking). Each subject completed two trials for all the testing conditions. The mean value and the coefficient of variation (CoV) of stride time while walking alone and while CB at self-selected walking speed were measured using GAITRite® and SMTEC® footswitch systems.
  
  
  RESULTS
  ICC of mean value in CHI under both walking conditions were higher than ICC of demented patients with FTD and indicated perfect reliability (ICC > 0.80). Reliability of mean value was better while single tasking than dual tasking in CHI (ICC = 0.96 under single-task and ICC = 0.86 under dual-task), whereas it was the opposite in demented patients (ICC = 0.65 under single-task and ICC = 0.81 under dual-task). ICC of CoV was slight to poor whatever the group of participants and the walking condition (ICC < 0.20), except while dual tasking in demented patients where it was fair (ICC = 0.34).
  
  
  CONCLUSIONS
  The immediate test-retest reliability of the mean value of stride time in single and dual tasking was good in older CHI as well as in demented patients with FTD. In contrast, the variability of stride time was low in both groups of participants.
authors: Department of Internal Medicine and Geriatrics, Angers University Hospital (4 rue larrey), Angers (F-49933), France. olbeauchet@chu-angers.fr
authors: Olivier
authors: O
authors: Beauchet
authors: Ellen
authors: E
authors: Freiberger
authors: Cedric
authors: C
authors: Annweiler
authors: Reto W
authors: RW
authors: Kressig
authors: Francois R
authors: FR
authors: Herrmann
authors: Gilles
authors: G
authors: Allali
mesh_terms: D000368:Aged; D001259:Ataxia / Q000175:diagnosis* / Q000209:etiology; D003430:Cross-Sectional Studies; D005260:Female; D057174:Frontotemporal Lobar Degeneration / Q000150:complications / Q000175:diagnosis*; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D009460:Neurologic Examination / Q000379:methods*; D015203:Reproducibility of Results; D013647:Task Performance and Analysis