| Program : Biomedical Research and Countermeasures | Ground Research | ||||
| Element : Physiology | |||||
Advanced Techniques for Assessment of Postural and Locomotor Ataxia, Spatial Orientation and Gaze Stability |
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| Principal Investigator: | |||||
Conrad C. Wall, III, Ph.D. Director, Jenks Vestibular Laboratory Massachusetts Eye and Ear Infirmary Harvard Medical School 243 Charles Street Boston, MA 02114 |
Phone: (617) 573-4153 Email: cwall@space.mit.edu Fax: (617) 573-4154 Congressional District: MA-9 | ||||
| Co-Investigator(s): | |||||
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| Monitoring Center: NSBRI | Solicitation: NSBRI | ||||
| Initial Funding Date: 1997 | Expiration: 2000 | ||||
| Students Funded Under Research: 1 | Post-Doctoral Associates: 0 | ||||
| Task Description: | |||||
| Major problems of spaceflight, in addition to adapting to microgravity, include postflight difficulties with standing, walking, turning corners, and other activities that require stable upright posture and gaze stability. These difficulties inhibit astronauts' ability to stand up, bail out, or otherwise escape from their vehicle during emergencies. The overall goal of this project is to develop quantitative, parametric approaches for assessing gaze stability and spatial orientation during normal gait and when gait is perturbed. Compared to assessments of the vestibuo-ocular reflex, analysis of vestibular effects on locomotor function is relatively less well developed and quantified. We plan to improve this situation by applying the methodology of nonlinear orbital stability to quantify responses in a single variable and by using multivariate statistical approaches to link together the responses across separate tests. In this way we will exploit the information available and increase the "resolving power" to discriminate between normal and pathological responses. Responses will be studied with and without interactive visual environments. Measures of stability and orientation will be compared and assessed with measures of dynamic visual acuity and with other vestibular function tests. The responses of normal human subjects and of subjects having well-documented pathophysiologies will be characterized. When these studies are completed, we should have a clearer idea about what constitute normal and abnormal patterns of eye, head, and body movements during locomotion and their stability in a wide range of environments. We will then use this information to characterize and validate neurovestibular rehabilitative approaches being developed in other projects. | |||||
| We have gained considerable insight into the compensatory and orienting functions of the vestibulo-collic and vestibulo-ocular reflexes during locomotion. Through this has come the development of countermeasure assessment criteria which can now be applied in studying behaviors that have proven to be difficult following exposure to microgravity. The perturbation studies have produced a simple, easy-to- implement technique of quantitative gait assessment during repeated stepping, and a novel paradigm for studying the responses to precisely applied gait disturbances which simulate a slip during locomotion. | |||||
| The development of an objective stability index in response to perturbations during gait and its application to persons having balance disorders has the potential of being developed as a diagnostic tool to determine stability during realistic everyday situations. The finding that, at low walking velocities the head is predominantly controlled by the angular vestibulo-collic reflex while at higher walking velocities it is mainly controlled by the linear vestibulo-collic reflex, will be of significant value in the development of clinical tests to differentiate pathophysiology of the linear versus the angular motion-sensing organs. | |||||
| FY00 Publications, Presentations, and Other Accomplishments: | |||||
| Imai, T., Moore, S.T., Raphan, T., and Cohen, B. ''Posture and gaze during circular locomotion.'' (abstract) Soc. Neurosc. Abstr., 2000. Raphan, T., Imai, T., Moore, S.T., Hirasaki, E., and Cohen B. ''Quantitative representations for analyzing and modeling 3-D body and head movements during locomotion.'' (abstract) The IVth International Symposium on the Head/Neck System, Japan, 1999. Moore, S.T., Hirasaki, E., Raphan, T., and Cohen, B. ''Effects of viewing distance on head-eye coordination during locomotion.'' (abstract) The IVth International Symposium on the Head/Neck System, Japan, 1999. McPartland, M.D., Krebs, D.E., and Wall III, C. ''Quantifying instability during stepping via ideal trajectory analysis.'' (abstract) 1999 Annual Fall meeting of the Biomedical Engineering Society and the 21st Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Atlanta, GA, October 13-16, 1999. Cohen, H., Bloomberg, J.,Elizalde, E., and Fregia, M. ''Sensitivity of the dynamic visual acuity test to sensorimotor change.'' (abstract) Proc. Houston Society for Engineering in Medicine and Biology, 1999. Cohen, H., and Blomberg, J.J. ''Dynamic visual acuity tests in acoustic neuroma patients.'' (abstract) Midwinter meeting of the Association for Research in Otolaryngology, St. Petersburg Beach, FL, February 20-24, 2000. Wall, C., McPartland, M.D., and Raphan, T. ''Human gait stability in response to perturbations during treadmill walking.'' (abstract) Midwinter meeting of the Association for Research in Otolaryngology, St. Petersburg Beach, FL, February 20-24, 2000. Dimitri, P.S. ''Application of multivariate statistical methods to vestibular test interpretation.'' Ph.D. Thesis. Joint Harvard Medical School- Massachusetts Institute of Technology Division of Health Sciences Technology (2000). Thurtell, M.J., Kunin, M., Raphan, T. ''Role of muscle pulleys in producing eye position-dependence in the angular vestibulo-ocular reflex: A model based approach.'' J. Neurophysiol., in press, (2000). Hirasaki, E., Moore, S.T., Raphan, T., and Cohen, B. ''Effects of walking velocity on vertical head and body movements during locomotion.'' Exp. Brain Res. 127: 117-130, (1999). Zhu, D., Moore, S.T., and Raphan, T. ''Robust pupil center detection using a curvature algorithm.'' Computer Methods and Programs in Biomedicine, 59 (3): 145-157, (1999). McPartland, M.D., Krebs, D.E. and Wall III, C. ''Quantifying ataxia: Ideal trajectory analysis.'' J Rehabil Res Develop, (accepted). Newman, D.J., Wu, R., Krebs, D., and Jackson, D.K. ''Electromyographic analysis of human false platform jumping.'' J. Appl. Physiol., (in revision). Dimitri, P.S., Wall, C., Oas, J.G., and Rauch, S.D. ''Application of multivariate statistics to vestibular testing: Discriminating between Meniere's disease and migraine associated dizziness.'' J. Vestibular Research, (accepted with revisions). Wall, C. ''Recovery trajectories during locomotor disturbances - The next Step in balance: Assessment of astronauts returning from space.'' Presented at graduate Bioengineering seminar, Boston University (October, 2000). | |||||
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