Howard N. Zelaznik, Ph.D. - US grants

In the study of skilled performance, it is fairly well accepted that the cerebellum provides a timing process that is involved in the production of motor skills. This project looks at whether different types of timing tasks use the same cerebellar-timing system. It is expected that discrete tasks with a clear beginning and end (such as tapping) use a cerebellar timing system, because such tasks involve an explicit timing process. Other tasks, however, are not expected to use an explicit timing process. One example is continuous circle drawing. In these cases, continuous timing processes may not depend upon a normal functioning cerebellum. Individuals who have brain damage to one side of the cerebellum will be tested. These patients exhibit a normal, unimpaired hand which is controlled by the normal side cerebellum, and a movement-damaged hand controlled by the damaged side of the cerebellum. By comparing performance of the impaired and unimpaired hand for continuous and discrete tapping and circle drawing, it can be ascertained whether the cerebellum is important for such performance. For smooth continuous tasks such as circle drawing, it is expected that the cerebellum is not crucial for timing performance. However, discrete tasks should require an intact cerebellum.

This project will provide important new insight into cerebellar functioning and motor skills.

The goal of this research is to study the dynamics of human posture on a balance board with tunable stiffness and time delay and exploit this understanding to improve the early detection of neuromuscular disease and the rehabilitation of balance compromised populations. The research will develop new mathematical models of human posture coupled to an external system and study the emergent dynamics therein; and develop a novel balance board with tunable board rotational stiffness and time delay. This tunable device will be used to assess the potential advantages of bifurcation-based approaches for the early detection of neuromuscular disorder and improved rehabilitation of younger subjects, older subjects and individuals with multiple sclerosis (MS), in collaboration with the Indiana University School of Medicine. In addition an inter-generational service-learning program focused on improving balance will be developed at a local retirement home, a campus wide forum/seminar series on dynamical systems in perception, cognition, and motor control will be created, senior undergraduate students will be mentored in research projects, and the team will reach out to local MS support groups.

The development of the tunable balance board could be a major improvement in rehabilitative devices as it can manipulate and thus, explore the contribution of muscle stiffness and time delay to balance. If successful the idea of using bifurcation thresholds on the tunable balance boards as a means of indicating early stage neuromuscular disease could lead to early diagnosis of fall-propensity in frail older adults and adults with MS, Parkinson?s disease or persons suffering from traumatic brain injury. New detection and training concepts using these tunable balance boards delay could eventually be commercialized and improve quality of life of balance-compromised individuals. In addition, the substantial economic cost associated with falls, valued at over $19 billion in direct medical costs in 2000, may be reduced.