The Effect of Ankle Foot Orthosis Influences the Prefrontal Load in Stroke Patients During Dual Task Walking
Phase: NA
Conditions: Ankle Foot Orthosis (AFO), Dual Task Walking
Sponsor: National Cheng-Kung University Hospital

 
document date：March 29, 2024 
Cover letter for Clinical Trail Registration  
 
Official Title: The effect of ankle foot orthosis influences the prefrontal load in stroke 
patients during dual task walking. 
NCT NO.: not available yet  
Documentation date : March 29, 2024  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
document date：March 29, 2024 
Study Protocol 
Background: Foot drop is a common gait impairment in individuals with stroke. 
Clinically, ankle–foot orthoses (AFOs) are frequently prescribed to provide ankle 
stability and support during the swing phase of gait. Previous studies have shown that 
AFO use can improve gait symmetry, increase walking speed, and reduce oxygen 
consumption during walking. The ability to walk while performing concurrent tasks is 
essential for individuals with stroke to function safely in community environments. 
Functional near-infrared spectroscopy (fNIRS) can be used to measure changes in 
oxygenated hemoglobin (HbO) concentration in the prefrontal cortex, reflecting 
cognitive workload during walking tasks. Carbon-fiber AFOs can store and release 
elastic energy during the gait cycle, assisting push-off and improving walking 
efficiency. Previous studies have shown that walking with carbon-fiber AFOs can 
increase walking speed and reduce oxygen consumption. However, whether carbon-
fiber AFOs reduce prefrontal cortical workload during dual-task walking in 
individuals with stroke remains unclear. Therefore, this study aims to investigate the 
effects of carbon-fiber AFOs on dual-task performance and prefrontal cortical 
activation during dual-task walking in individuals with stroke. 
Design: A repeated-measures design will be adopted with two AFO conditions (with 
AFO and without AFO) and three walking task conditions (single-task walking, 
cognitive dual-task walking, and motor dual-task walking). 
Methodology protocols: Participants with stroke will complete the Mini-Mental State 
Examination (MMSE) to confirm cognitive eligibility, provide demographic 
information, and will sign the informed consent form. Functional near-infrared 
spectroscopy (fNIRS) sensors will be placed on the participant’s forehead and secured 
using an elastic headband. Inertial sensors will be attached to the dorsum of both feet 
to record gait performance. An additional inertial sensor will be attached to the center 
of the tray to assess tray stability. Participants will be instructed to walk at a self-
selected comfortable speed along a 13-m walkway under all conditions. Two 
experimental factors will be examined: AFO condition and dual-task condition: 
Participants will wear their own athletic shoes during all walking trials. 
 

 
document date：March 29, 2024 
AFO Conditions: 
1. Walking without an carbon-fiber ankle-foot orthosis (AFO) 
2. Walking with a carbon-fiber AFO 
Dual-task conditions 
1. Single-task walking 
2. Cognitive dual-task walking (auditory Stroop task) 
3. Motor dual-task walking (carrying a tray with the non-paretic hand) 
During the cognitive dual-task condition, participants will wear a wireless Bluetooth 
headset and will perform an auditory Stroop task while walking. Participants will be 
instructed to respond based on the pitch of the auditory stimulus rather than its 
semantic meaning. For example, when hearing the word “low” presented in a high 
pitch, participants will respond “high.” All verbal responses will be recorded. 
Accuracy (correct response rate) and reaction time will be measured. During the 
motor dual-task condition, participants will be asked to walk while carrying a tray 
with three wooden blocks stacked on top of each other using their non-paretic hand. 
The number of blocks that fall from the tray will be recorded. The number of blocks 
that fall from the tray will be recorded. Each experimental condition will be repeated 
for five trials, and rest periods will be provided between trials to minimize fatigue. 
Statistical Analysis Plan: 
Since it is difficult to directly compare the motor and cognitive dual-task walking 
conditions, the analysis will be conducted separately for each dual-task condition. 
To analyze gait parameters, a repeated-measures ANOVA will be used to examine the 
effects of task condition and AFO use. In addition, dual-task cost (DTC) will also be 
calculated for each gait parameter to quantify the relative change in performance 
during dual-task walking. Hotelling’s T² test may be used to compare the dual-task 
cost of multiple gait variables between walking with and without an AFO. To evaluate 
secondary task performance, Hotelling’s T² test will be used to examine the dual-task 
cost of correct response rate and reaction time between the AFO and no-AFO 
conditions. To examine changes in oxyhemoglobin(HbO) concentration in the 
prefrontal cortex, a repeated-measures ANOVA will be conducted at the subject level 
to test the effects of task and AFO use. If variability in participants’ mobility function 
is observed, a linear mixed model will be applied to control for accounting for inter 
individual difference and to evaluate the effects of task and AFO use at the trial level. 
All statistical analyses will be performed using IBM SPSS Statistics (version 19.0), 
and the level of statistical significance will be set at p < 0.05.