BioKim Lab for Biomechanics and Human Rehabilitation

My overarching research objective is to innovate rehabilitative interventions and assistive technologies to facilitate the recovery of sensory and motor functions in individuals with neurological disorders or traumatic injuries. I pursue this goal by delving into the fundamental principles governing motor learning and motor control, seeking to uncover insights that can drive the development of more effective interventions and systems.

Motor Learning and Retention:

Motor learning encompasses various component processes, including adaptation, plasticity based on usage, and retention. My research involves conducting psychophysical experiments centered on locomotion, both in healthy individuals and patients, to delve into these processes. Through this approach, I aim to deepen our understanding of the mechanisms involved in motor learning. Additionally, I endeavor to devise rehabilitative strategies that expedite and improve the acquisition and retention of motor skills.

Visuomotor Adaptation of Human Locomotion with Visual Feedback Distortion (VFD):

Visuomotor adaptation, a form of sensorimotor learning, describes the phenomenon where visually guided motor behavior adjusts in response to visual feedback. Visuomotor adaptation, which is thought to be an implicit process and plays an important role in motor planning and execution, has been widely studied and generally involves individuals making arm-reaching movements towards a target. This has led to many findings about how the brain integrates visual information to adjust motor commands. However, less is known about how visuomotor adaptation affects and is involved in human locomotion.

To address this gap, I have proposed a novel task design—visual feedback distortion—where participants adapt their gait patterns to external visual distortions during treadmill walking. Individuals walk on a treadmill while viewing a screen displaying vertical bars representing step length. Distortions applied to these bars prompt adaptation in gait symmetric patterns. My research investigates various aspects of this approach: 1) identifying whether adapted gait pattern occurs via implicit (prediction error-based), cognitive (explicit strategic), or combined processes, 2) examining how instruction and explicit task knowledge influence the adaptation in gait symmetry, 3) investigating how factors like walking speed and unilateral loading impact gait adaptation driven by visual feedback distortion, 4) assessing how implicit adaptation through visual feedback distortion enhances retention of motor learning, 5) exploring how different modalities of visual feedback compromise gait adaptation, 6) examining how an individual's belief in the accuracy of visual feedback influence gait adaptation, and 7) identifying whether combining visual feedback distortion with split-belt treadmill walking leads to more efficient adaptation of gait asymmetry. 

Effects of Functional Electrical Stimulation (FES)-based Perturbation on Locomotion Adaptation:

Human locomotion involves rhythmic actions, often controlled by deep brain and spinal cord regions. One notable characteristic is its capacity for entrainment, where individuals spontaneously synchronize their gait cycle with external perturbations. In my research, I explore: 1) whether plantar-flexion ankle movements induced by Functional Electrical Stimulation (FES) can induce entrainment during treadmill walking, 2) the effectiveness of a carefully designed FES-induced perturbation method in inducing gait adaptation, especially spatial and temporal asymmetrical components. Through these investigations, I aim to determine the efficacy of FES-induced perturbation methods in gait rehabilitation.