title: Quantitative gait analysis under dual-task in older people with mild cognitive impairment: a reliability study.
abstract: BACKGROUND
  Reliability of quantitative gait assessment while dual-tasking (walking while doing a secondary task such as talking) in people with cognitive impairment is unknown. Dual-tasking gait assessment is becoming highly important for mobility research with older adults since better reflects their performance in the basic activities of daily living. Our purpose was to establish the test-retest reliability of assessing quantitative gait variables using an electronic walkway in older adults with mild cognitive impairment (MCI) under single and dual-task conditions.
  
  
  METHODS
  The gait performance of 11 elderly individuals with MCI was evaluated using an electronic walkway (GAITRite System) in two sessions, one week apart. Six gait parameters (gait velocity, step length, stride length, step time, stride time, and double support time) were assessed under two conditions: single-task (sG: usual walking) and dual-task (dG: counting backwards from 100 while walking). Test-retest reliability was determined using intra-class correlation coefficient (ICC). Gait variability was measured using coefficient of variation (CoV).
  
  
  RESULTS
  Eleven participants (average age = 76.6 years, SD = 7.3) were assessed. They were high functioning (Clinical Dementia Rating Score = 0.5) with a mean Mini-Mental Status Exam (MMSE) score of 28 (SD = 1.56), and a mean Montreal Cognitive Assessment (MoCA) score of 22.8 (SD = 1.23). Under dual-task conditions, mean gait velocity (GV) decreased significantly (sGV = 119.11 +/- 20.20 cm/s; dGV = 110.88 +/- 19.76 cm/s; p = 0.005). Additionally, under dual-task conditions, higher gait variability was found on stride time, step time, and double support time. Test-retest reliability was high (ICC>0.85) for the six parameters evaluated under both conditions.
  
  
  CONCLUSIONS
  In older people with MCI, variability of time-related gait parameters increased with dual-tasking suggesting cognitive control of gait performance. Assessment of quantitative gait variables using an electronic walkway is highly reliable under single and dual-task conditions. The presence of cognitive impairment did not preclude performance of dual-tasking in our sample supporting that this methodology can be reliably used in cognitive impaired older individuals.
authors.affiliation: Department of Medicine, Division of Geriatric Medicine, Parkwood Hospital, University of Western Ontario, London, ON, Canada. Manuel.MonteroOdasso@sjhc.london.on.ca
authors.forename: Manuel
authors.initials: M
authors.lastname: Montero-Odasso
authors.forename: Alvaro
authors.initials: A
authors.lastname: Casas
authors.forename: Kevin T
authors.initials: KT
authors.lastname: Hansen
authors.forename: Patricia
authors.initials: P
authors.lastname: Bilski
authors.forename: Iris
authors.initials: I
authors.lastname: Gutmanis
authors.forename: Jennie L
authors.initials: JL
authors.lastname: Wells
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Borrie
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001288:Attention / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D004185:Disability Evaluation; D005080:Exercise Test / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D015203:Reproducibility of Results