My research focuses on improving mobility during daily life in people with neurological dysfunction, particularly those with brain injuries. Using core concepts from biomechanics and motor control, my lab concentrates on functionally relevant balance that is typical during daily life. These common, yet complex tasks, such as maintaining balance while changing directions or walking and talking at the same time, require robust, flexible control. Our goal is to improve rehabilitation approaches.
Research Areas
Humans are inherently unstable - we resemble an inverted pendulum that is constantly falling over. Humans use a variety of strategies to stay upright, including using torque about the ankles or hips when standing, controlling the placement of their foot when walking, and even using their arms to provide a stabilizing counter-rotation. Our work probes how individuals maintain stability and -in the event of perturbations- regain stability.
Example: We actively control where we place our foot when walking over uneven ground. For example, we may modify where we place our foot if we see an uneven patch of ground or an upcoming rock. Using a custom mechanized shoe, we study how individuals use different information to control their foot placement and regulate stability during walking and turning. We've found that while it is important to know when a perturbation will occur and to have enough time to prepare, knowing what you will encounter is most important to improving your balance recovery.
Stability during walking and standing
Common, yet complex, locomotion
While most gait research has considered straight gait, we do not walk in a straight line with no added tasks. Simultaneous cognitive tasks and turns are commonplace in everyday locomotion and may pose a greater risk of adverse events. Our work examines the kinematics and kinetics of gait to probe how people walk in everyday life, and how neurological injury or disease affects tasks representative of daily living.
Example: People with chronic mild traumatic brain injury (mTBI) turn their bodies slower when walking along a winding path. While people with mTBI also tend to walk slower than healthy individuals, only turning outcomes related to self-reported complaints of headache, nausea, and other somatic symptoms, suggesting a sought-after link between self-reported symptoms and mobility may reside in turning and non-straight gait.
Inertial sensors for clinical gait and balance assessments
Inertial sensors are becoming increasingly popular for gait and mobility analysis. Our work uses inertial sensors to probe clinical questions in a more objective way using both commercial and in-house algorithms.
Example: Inertial sensors can capture objective measures of reactive responses - an important component of balance that enables us to regain balance after a loss of stability. We are using inertial sensors to quantify reactive balance in NCAA collegiate athletes to better understand musculoskeletal injury risk and concussion recovery. Our results indicate that the longer someone takes to recover their balance, quantified using inertial sensors, the higher the risk for future musculoskeletal injury.
Neuroanatomical origins of motor dysfunction post-concussion
Our research team collaborates with autonomic neurologists and neuropsychologists who focus on neuroimaging to understand how motor behavior interacts with physiology after mild traumatic brain injuries (e.g., concussions).
Example: The brainstem contains several key nuclei for motor function and serving as a pathway for all ascending sensory information and descending motor commands to and from subcortical and cortical structures. Yet, the brainstem is relatively understudied in people with mild traumatic brain injury. We use high-definition magnetic resonance imaging (MRI) acquisition and then deterministic tractography techniques to create profiles of various white matter tracts in the brainstem. We are now examining the relationship between these important markers of brain health to other measures of motor function.
Nonlinear dynamic analysis of human movement
Human movement is complex and resembles nonlinear dynamical systems. Utilizing analyses stemming from nonlinear dynamics to assess the structure of locomotor and postural control, our research examines how neurophysiological changes impact locomotor and postural stability.
Example: Using data from a tri-axial accelerometer, we can separate walking and turning bouts to construct state-space attractors. Features of the state-space (e.g., the rate of divergence of nearby trajectories) can be useful tools for examining locomotor and postural control by identifying phase-dependent dual-task costs in people with Parkinson's disease or persistent locomotor abnormalities in people with a previous concussion.