Department of Physical Therapy Student Theses, Dissertations and Capstones

Document Type


Degree Name

Doctor of Philosophy (PhD) in Physical Therapy

Copyright Statement

All rights reserved. This publication is intended for use solely by faculty, students, and staff of Nova Southeastern University. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, now known or later developed, including but not limited to photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author or the publisher.


College of Health Care Sciences - Physical Therapy Department

First Advisor

Mary T Blackinton

Second Advisor

Joann Gallichio

Third Advisor

Mirtha Whaley

Publication Date / Copyright Date



Nova Southeastern University


Background and Purpose: The purpose of this study was to determine how different cognitive dual-tasks impact gaitvariability in community-dwelling adults using the Quantitative Timed Up and Go (QTUG).

Methods: Participants aged 65 and older were recruited from two communities in Iowa and Wisconsin. Inclusion criteria: theability to stand and ambulate without an assistive device, having no orthopedic surgical procedures in the previous six weeks, living independently in the community, demonstrating corrected vision and ability to read, sufficient auditory function to carry on a conversation and ability to follow directions. Participants needed to follow three step commands and have no history of falls inthe past 30 days. Participant’s demographic data included height, weight, BMI, gender, fall history for 12 months, number ofmedications, education, and age. The Activities-specific Balance Confidence Scale (ABC) and Screening Assessment for Falls Evaluation (SAFE) tests were administered.

The QTUG body-worn sensors were applied on participant’s shins to record data for temporal and spatial gait parameters. Each participant performed the TUG test 10 times. The first two TUG tests were used as a control; then, participants performed two trials in random order for each of the four distinct dual cognitive tasks. Serial subtraction tasks (Subtract), reading tasks(Read), auditory response naming questions (Audible), and visual confrontation naming pictures (Visual) conditions were used as a dual-cognitive task.

Results: Forty-four participants (30 female, 14 male) with mean age 73.11 years were included in the study. The dual-taskcosts of Subtract was significantly different (p <.0001) from standard TUG. Read condition was also significantly different from standard TUG (p <.006) for TUG recording time. Post hoc pairwise comparisons showed that Subtract was also significantly different from the other three conditions. Subtract conditions consistently demonstrated greater dual-task cost than the other conditions in stride time, step time, stride length, stride velocity, and cadence. Significant differences were also found between fallers and non-fallers in all conditions for mean pre-turn time: Subtraction condition for fallers (M = 5.58, SD = 1.00) and non-fallers (M = 4.56, SD = 1.19), t(42) = -2.43, p = .019; Reading conditions for fallers (M = 5.32, SD = 1.22), for non-fallers (M = 4.46, SD =.97) t(42) = -2.32, p = .025; Audible conditions for fallers (M = 5.13, SD = 1.28), for non-fallers (M = 4.29, SD = .89) t(42) = -2.37, p = .022; Visual condition for fallers (M = 5.20, SD = 1.37), for non-fallers (M = 4.40, SD = .97) t(42) = -2.10, p = .042.

There was a significant p < .01 moderate negative correlation between SAFE and TUG pre-turn times. SAFE scores were moderately positively correlated to stride length at p < 0.01 level. ABC had a significant p < .01 moderate negative correlation to TUG and pre-turn times. There were no significant variability differences in the conditions or in participants with a history offalls.

Conclusion: Of the four dual-task conditions, the cognitive task of Subtract significantly impacts dual task costs for TUG recording times, stride time, step time, stance time, stride length, stride velocity, and cadence. The four cognitive conditions (reading, answering a question, identifying pictures by name, and serial subtraction) impact gait differently as measured by theQTUG. The QTUG was able to distinguish fallers from non-fallers under all cognitive conditions for TUG pre-turn time.

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Physical Therapy


Dual-task, Gait Variability, Quantitative Timed Up and Go, Timed Up and Go