title: Carotid flow pulsatility is higher in women with greater decrement in gait speed during multi-tasking.
abstract: Central arterial hemodynamics is associated with cognitive impairment. Reductions in gait speed during walking while performing concurrent tasks known as dual-tasking (DT) or multi-tasking (MT) is thought to reflect the cognitive cost that exceeds neural capacity to share resources. We hypothesized that central vascular function would associate with decrements in gait speed during DT or MT.
  
  
  
  Gait speed was measured using a motion capture system in 56 women (30-80y) without mild-cognitive impairment. Dual-tasking was considered walking at a fast-pace while balancing a tray. Multi-tasking was the DT condition plus subtracting by serial 7's. Applanation tonometry was used for measurement of aortic stiffness and central pulse pressure. Doppler-ultrasound was used to measure blood flow velocity and β-stiffness index in the common carotid artery.
  
  
  
  The percent change in gait speed was larger for MT than DT (14.1±11.2 vs. 8.7±9.6%, p <0.01). Tertiles were formed based on the percent change in gait speed for each condition. No vascular parameters differed across tertiles for DT. In contrast, carotid flow pulsatility (1.85±0.43 vs. 1.47±0.42, p=0.02) and resistance (0.75±0.07 vs. 0.68±0.07, p=0.01) indices were higher in women with more decrement (third tertile) as compared to women with less decrement (first tertile) in gait speed during MT after adjusting for age, gait speed, and task error. Carotid pulse pressure and β-stiffness did not contribute to these tertile differences.
  
  
  
  Elevated carotid flow pulsatility and resistance are characteristics found in healthy women that show lower cognitive capacity to walk and perform multiple concurrent tasks.
authors.affiliation: Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, TX, USA. Electronic address: joaquin.gonzales@ttu.edu.
authors.forename: Joaquin U
authors.initials: JU
authors.lastname: Gonzales
authors.affiliation: Department of Rehabilitation Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
authors.forename: C Roger
authors.initials: CR
authors.lastname: James
authors.affiliation: Department of Rehabilitation Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
authors.forename: Hyung Suk
authors.initials: HS
authors.lastname: Yang
authors.affiliation: Department of Rehabilitation Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Jensen
authors.affiliation: Department of Rehabilitation Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
authors.forename: Lee
authors.initials: L
authors.lastname: Atkins
authors.affiliation: Department of Human Development and Family Studies, Texas Tech University, Lubbock, TX, USA.
authors.forename: Kareem
authors.initials: K
authors.lastname: Al-Khalil
authors.affiliation: Department of Human Development and Family Studies, Texas Tech University, Lubbock, TX, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: O'Boyle
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000502:physiology; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000503:physiopathology*; D060825:Cognitive Dysfunction / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D000073456:Multitasking Behavior / Q000502:physiology*; D011673:Pulsatile Flow / Q000502:physiology*; D018608:Ultrasonography, Doppler / Q000379:methods; D059289:Vascular Stiffness / Q000502:physiology*; D016138:Walking / Q000502:physiology; D000072797:Walking Speed / Q000502:physiology*
keywords: Carotid artery; Dual-task; Gait speed; Pulsatility index; Vascular function; Walking