Mei-Hua Lee, Ph.D. - US grants

Children with severe movement impairments often depend on assistive devices such as wheelchairs, robotic arms, or communication aids for activities of their daily lives. However, learning to control these complex devices can be challenging for children. In this project, the investigators explore the development of a general purpose body-machine interface that allows children to control several devices using movements of the body. A key advantage of this type of interface is that it is non-invasive, easy to wear, and can "grow" with the child. The project will enhance basic understanding of how body movements can be exploited to control external devices, especially in children. The project will have an impact on the independence and quality of life for children with severe movement impairments. A key challenge of this research is to translate the body movements of the user into commands that can control the robotic arm for performing an intended task. The traditional approach to this translation problem has been based on principal components analysis (PCA); however, this is not well suited for complex tasks requiring the control of many degrees of freedom. In this project, the investigators will develop alternative, novel methods that can take full advantage of the movement repertoire of the user and can also yield intuitive control. In addition to the significant impact of this research on the quality of life of individuals with disabilities, the project includes outreach to K12 students and teachers to interest them in STEM and improve their understanding of disabilities and motor development.

The current work will be carried out through three aims. These are: 1) utilize a principal component analysis-based approach for control of high degree of freedom movements within the robot; 2) develop a virtual body model approach; and 3) determine learning characteristics of high-degree of freedom body machine interfaces in children. Each aspect of the research will be assessed through rigorous performance metrics. Specifically, the objectives of this project are to: capture a wide range of motion patterns using sensors on the head and upper body; and to map anatomically distinct motion patterns to commands for controlling the robot arm using a virtual model of the user's body. Based on the sensor data from the user, algorithms will be used to calculate how the virtual model bends, twists, and turns; and these deformations will then be translated into commands that control the robotic arm. In addition to developing these methods, the investigators will also evaluate the intuitiveness of these new methods by testing how quickly children can learn to control a robotic arm using these methods.

This project will examine how children's ability to explore different movement patterns affects their ability to learn new motor skills. This project will enhance basic understanding of the differences between how children and adults learn to acquire such motor skills, which will provide theoretical insight into how the brain organizes movement and learning. The knowledge gained from this project has important implications for how learning and rehabilitation paradigms should be customized for children, especially in cases of movement disorders such as cerebral palsy. The project will also include an outreach component to involve middle and high-school students in STEM research. Because children are not simply smaller versions of adults, rehabilitation programs must be tailored in age-specific manners; by adopting a developmental focus, this research will facilitate the creation of such child-appropriate programs.

Although there is evidence that children and adults differ in terms of motor learning, the mechanisms underlying these differences are poorly understood. The investigators hypothesize that motor exploration--the ability to generate different movement patterns--may play a critical role in this difference. This project examines the role of motor exploration in motor learning with a specific focus on how this relation changes with development during childhood. Specifically, the investigators attempt to answer three research questions: (1) how does motor exploration during learning change with development, (2) how does age mediate the relation between motor exploration and learning, and (3) can practice schedules that modify motor exploration be used to facilitate learning? The investigators use a novel paradigm called a body-machine interface to minimize typical confounds (such as body size and strength) to compare motor learning across different age groups. This research will contribute to a more elaborated understanding of how children acquire complex motor skills during development.