<p>In community mobility, walking is commonly completed with
other concurrent tasks, described as locomotor multitasks. Many locomotor
multitasks rely on vision for both gait and concurrent tasks. When each
of the individual tasks uses the same perceptual modality (e.g. vision),
structural interference occurs.
Structural interference is different from capacity interference, which refers
to tasks competing for limited cognitive resources. While locomotor multitask
studies have demonstrated that completing the locomotor multitask typically leads
to performance impairment in gait and/or the concurrent task, the wide range of
tasks has confounded the ability to fully understand how structural and
capacity interference affect multitask performance. Thus,
the purpose of this dissertation was to delineate how structural interference
(Study 1) and capacity interference (Study 2) affect gait multitask
performance. To facilitate comparison across studies, the two studies (Study 1
and Study 2) in this dissertation used the same gait task – obstacle crossing –
and the same cognitive task – a visual discrete reaction time (RT) task. A
discrete RT task was completed while approaching to an obstacle, where visual
information regarding obstacle is being gathered to plan for the successful
obstacle crossing. In Study 1, to determine if structural interference affects
performance impairment in young and older adults, gaze diversion was manipulated
by the RT task location (gaze diverted to the obstacle, and gaze diverted away
from the obstacle). The RT task was also completed while standing to strengthen
the interpretation that any performance impairments were due to structural
interference. Study 1 results indicated that structural interference affects
both gait and cognitive task performance. Structural interference demonstrated
performance impairments in both young and older adults, but the strategies were
different. Young adults were more likely adopt gait behavior that increased the
risk of tripping when gaze was diverted away from the obstacle (high structural
interference), but older adults demonstrated a strategy that decreased the risk
of trip when gaze was diverted to the obstacle (low structural interference).
This finding highlights the critical role of vision in adaptive gait. In study
2, to determine if capacity interference affects performance impairment in
young adults, both gait and cognitive task were manipulated while structural
interference was held constant; gait task was manipulated by obstacle height
(level walking, 15% leg length height, and 30% leg length height obstacle), and
cognitive tasks were three RT tasks (Simple RT, Choice RT, Simon RT). The
baseline for each gait task (without RT task) and cognitive task (while
seating) was also measured. Capacity interference demonstrated that task
prioritization strategy was different for gait challenge versus cognitive
challenge in young adults. As gait task difficulty increased, gait task was
prioritized. Conversely, as cognitive task difficulty increased, cognitive task
was prioritized. This finding highlights that young adults have the ability to
flexibly allocate the resources to accomplish the multitask. Lastly, an
interesting finding from two studies (Study 1 and Study 2) was when
interference is applied during the planning phase – during the approach to the
obstacle – structural interference has a greater effect on obstacle crossing
performance than capacity interference.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/13333358 |
| Date | 04 December 2020 |
| Creators | HyeYoung Cho (9731969) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Multitask_performance_in_adaptive_gait_structural_and_capacity_interference/13333358 |
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