title: Brain atrophy and trunk stability during dual-task walking among older adults.
abstract: BACKGROUND
  Dual-task walking is believed to be more cognitively demanding than normal walking and alters trunk movement among older adults. However, the possible association between brain atrophy and spatiotemporal gait parameters, particularly during dual-task walking, is poorly understood. In this study, we examined the relationship between dual-task walking and brain atrophy.
  
  
  METHODS
  One hundred ten elderly adults (aged 65-94 years, women n = 55) underwent magnetic resonance imaging scanning and gait experiments under normal and dual-task walking conditions. Linear accelerations of the trunk were measured in vertical, anteroposterior, and mediolateral directions using a triaxial accelerometer attached to the lower trunk. Gait speed, stride length, and cadence were recorded. The harmonic ratio, a measure of trunk stability, was computed separately in each direction to evaluate the smoothness of trunk movement during walking. Brain atrophy was quantitatively assessed using magnetic resonance image data.
  
  
  RESULTS
  Gait speed, stride length, cadence, and harmonic ratio in all directions were lower in dual-task walking than in normal walking (p < .05). The dual-task-related changes in harmonic ratio were independently correlated with brain atrophy adjusted for subject characteristics only in the vertical direction (p < .05).
  
  
  CONCLUSIONS
  Our findings support the hypothesis that dual-task walking is more cognitively demanding than normal walking. Decreased trunk stability during dual-task walking is associated with brain atrophy. Additional studies are necessary to elucidate the effects of regional brain atrophy on the control of walking.
authors.affiliation: Section for Health Promotion, Department of Health and Medical Care, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, 35 Gengo, Morioka, Obu, Aichi 474-8511, Japan. take-d@ncgg.go.jp
authors.forename: Takehiko
authors.initials: T
authors.lastname: Doi
authors.forename: Hyuma
authors.initials: H
authors.lastname: Makizako
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shimada
authors.forename: Daisuke
authors.initials: D
authors.lastname: Yoshida
authors.forename: Kengo
authors.initials: K
authors.lastname: Ito
authors.forename: Takashi
authors.initials: T
authors.lastname: Kato
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ando
authors.forename: Takao
authors.initials: T
authors.lastname: Suzuki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001284:Atrophy; D001921:Brain / Q000473:pathology*; D003071:Cognition; D005260:Female; D005684:Gait; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D060726:Torso / Q000502:physiology*; D016138:Walking