Projects
Our Research Goal
Our research adopts a neuromechanics approach to study human gait and balance with the goal to improve mobility for people with neurological deficits and to reduce fall risk in the community.
Project 1: Cortical contribution to gait dysfunction for post-stroke population
Restoring gait function is a high priority for populations with neurological deficits. However, cortical contribution to gait deficits is not fully understood. Our research aims to address the critical gap to improve gait function in post-stroke population.
Project 2: Sensory-motor mechanism to maintain locomotion stability
Understanding cortical mechanism for balance control during gait has great potential to improve current design of perturbation training or rehabilitation assistive device to reduce risk of falls for aging and population with neurological disorders. Although sensory and motor deficits both contribute to increased risk of falls in these vulnerable populations, most research efforts have been focused on impairments in motor execution (e.g. Buurke, Liu et al. 2021; Liu et al. 2022). Thus, we aim to use both experimental and computational methods to fully comprehend how our brain leverages sensory information to generate balance correction strategies. (Aim 1) We will establish individual disturbance threshold for different perturbation paradigms during gait: slip-/trip- perturbations (occur at the foot) and pelvis perturbations (occur at the center of mass) for neurotypical, people with peripheral sensorimotor deficits, and people with cortical deficits. (Aim 2) We will quantify the timing of cortical signatures of loss of balance following perturbations below and above thresholds. (Aim 3) We will assess the cortical mechanism, including brain activity at the sensorimotor area, posterior parietal, and cingulate area following different mechanical perturbation paradigms at the loss of balance. If cortical mechanism following foot-based perturbations is different from pelvis-based perturbations, this would help explain the limited generalizability of task-specific perturbation-based training.
Project 2.1 Develop computation tools to quantify the sensory contribution to locomotion stability
This project builds upon my doctoral work, which used system identification techniques to infer locomotor control strategies for neurotypical individuals during perturbed walking. I will extend the same technical framework to people with sensorimotor deficits and develop computation tools to infer changes in control strategies during multidirectional perturbations. In addition, I will incorporate multi-sensory information during the perturbation response such as vestibular information. With the current development of in-ear EEG and miniature accelerometer, we can obtain a proxy of vestibular afferent information and how the brain perceives the vestibular information in the temporal area. These results will provide a more comprehensive view of how neurotypical and people post-stroke restore balance and inform the generalizability of bio-inspired assistive devices to improve human-machine interaction.
Project 3: Transition from lab to real-world gait behavior for rehabilitation
One main obstacle to improving gait rehabilitation is a lack of understanding of the cortical processes responsible for gait deficits during early rehabilitation post-brain injury. However, frequent visits to the lab can be hindered by the availability of transportation and caregivers. My goal is to advance the current brain-body imaging technique to facilitate the assessment of neural correlates of biomechanical gait impairments for people with sensorimotor deficits in a portable and convenient-to-use manner. This novel technique can establish a new platform to monitor the progress of post-stroke neural recovery and expand research participation for stroke survivors to inpatient rehabilitation clinics and home-based settings. We will first acquire mobile EEG and biomechanics data while people perform locomotor tasks in the laboratory setting. We will 1) determine neural correlates of biomechanical gait impairments derived from wearable sensors, 2) minimize EEG and wearable sensor configuration needed for neural correlates during gait using machine learning algorithm, and 3) transition to a large study aiming to study longitudinal gait behavior post brain injury.
Tools
Our research uses tools such as motion capture tools and force plates to capture the kinetics and kinematics of human movement in the lab and inertial measurement units to capture gait parameters in real-world settings. We also use mobile brain imaging tools via high-density non-invasive electroencephalogram (EEG) to quantify brain dynamics during highly mobile locomotor tasks.
Prior Research Projects
Supraspinal control of human locomotion using mobile electroencephalography (EEG) during terrain negotiation
- Led a large study on investigating brain activity during negotiation over uneven terrain using mobile imaging with EEG in young and older adults.
- Compared to flat walking, walking over uneven terrain increased theta band power (synchronization), and decreased alpha and beta-band power (desynchronization) near sensorimotor and parietal posterior areas, indicating increased level of visuospatial attention to the environment and greater alertness to balance threat with terrain unevenness.
- These results will serve as a benchmark for evaluating cortical contribution to mobility deficits in older adults.