Award Date

5-18-2020

Degree Type

Dissertation

Degree Name

Doctor of Physical Therapy (DPT)

Department

Physical Therapy

Advisor 1

Jing Nong Liang

Advisor 2

Kai-Yu Ho

First Committee Member

Merrill Landers

Second Committee Member

Daniel Young

Number of Pages

58

Abstract

Background and Purpose: Stroke is a leading cause of disability that results in various neurological deficits, one of which is hemiplegia. This deficit alters the gait cycle, resulting in decreased propulsion force by plantar flexor muscles, decreased activation of dorsiflexor (DF) muscles, and increased coactivation of antagonistic ankle muscles. Stroke also leads to altered somatosensory input which results in decreased balance and gait speed, ultimately increasing fall risk. Therapies targeting increased somatosensory input have been shown to be beneficial in stroke as well as other neurological populations. However, no known studies have investigated the acute effects of local vibration to the plantar side of the foot. Our study aims to investigate the effect of vibratory insoles, referred to as tactor insoles, on propulsion forces, ankle joint kinematics and muscle activation in individuals with chronic post-stroke hemiparesis. Subjects: Fifteen participants with chronic stroke and fifteen age-similar, non-neurologically impaired participants were recruited. Inclusion criteria included >6 months post-stroke with hemiparesis and ability to walk without an assistive device for 2 minutes. Exclusion criteria included cerebellar stroke and/or inability to walk without an assistive device for more than 2 minutes. Methods: All participants underwent assessment of anthropometrics, Lower Extremity Fugl-Meyer, and a 2-minute walk test. A 3-D motion capture system and instrumented treadmill were used to obtain lower extremity kinematics and propulsive/braking force profiles. Co-contraction index of lower leg musculature (tibialis anterior and medial gastrocnemius) electromyography was also obtained. Participants were asked to walk with No Tactor (NT) at a self-selected speed and then were randomly assigned to 4 different tactor vibration conditions (Bilateral Off [BOFF], Bilateral On {BON], Ipsilateral On [ION], and Contralateral On [CON]) at the same walking speed. A 3x5 mixed factorial ANOVA was used to compare each outcome variable between 3 legs and between the 5 tactor conditions. The 3 legs examined were paretic limb of participant post-stroke, non-paretic limb of participant post-stroke, and non-impaired limb of non-neurologically impaired individuals. Results: There was a significant interaction of limb and condition on ankle angle at heel strike. In the paretic limb, ankle dorsiflexion at heel strike was greater for ION and CON conditions when compared to NT condition. There was a significant main effect of limb for peak propulsive force, propulsive impulse, peak braking force, braking impulse, and ankle angle at toe-off. When five tactor conditions were combined, we observed that the paretic limb exhibited significantly less peak propulsive force, propulsive impulse, peak braking force, and braking impulse. A significant main effect of condition was found for peak braking force, ankle angle at toe-off, and peak plantarflexion during swing. When compared to NT condition, 3 limbs being combined showed that peak braking force was greater at BON condition, ankle plantarflexion at toe-off was smaller at BOFF condition, and peak plantarflexion during swing was smaller at BON condition. Discussion: We observed that gait in post-stroke individuals can be acutely modified by adding additional somatosensory input, particularly for ankle dorsiflexion at heel strike.

Keywords

Somatosensory input; Stroke; Post-stroke Hemiparesis; Walking; Ambulation; Gait; Biomechanics; Kinematics; Co-contraction index

Disciplines

Medicine and Health Sciences | Physical Therapy | Rehabilitation and Therapy

File Format

pdf

File Size

1.084 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/


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