Efforts to Quantify Adaptation in Modeling of Postural Control
The ability to maintain stability and to withstand the effects of gravity on stance and motion is important to a large variety of human activities. It is assumed that adaptation is a necessary quality in human postural control. Studies of adaptation generally include evaluation of gain or amplitude of various parameters of the responses to repeated identical perturbations (Nashner 1976, Nashner and McCollum, 1985, Roos et al., 1988). Such a procedure will inevitably include some possibility of anticipatory action of the subject and one may have some doubts on the generality of the results. Moreover, the evaluation will concentrate on the reduction of responses more than on the time span required to achieve such a reduction. There is a multitude of studies on adaptation of the vestibular ocular reflex where one observes diminishing responses to repeated stimuli, but also over time to repeated sessions of exposure to a stimulus (c.f. Bock et al., 1979; Wilson and Melville-Jones, 1979). Furthermore, the observation of the compensatory process after acute vestibular lesions as well as of reduced symptoms of motion sickness with the adaptation to a moving surrounding or microgravity also exemplifies the conditioning of vestibular responses over time (Wilson and Melville-Jones, 1979).
KeywordsTorque Attenuation Coherence Cross Correlation
Unable to display preview. Download preview PDF.
- Fransson, P.-A., Magnusson M., and Johansson, R., 1995, Analysis of adaptation in anteroposterior dynamics of human postural control (Submitted).Google Scholar
- Johansson, R., System Modeling and Identification, Prentice-Hall, Englewood Cliffs, N.J., 1993.Google Scholar
- Johansson, R, Magnusson, M., and Fransson, P.-A. Galvanic vestibular stimulation for analysis of postural adaptation and stability. Determination of a Postural Adaptation Time Constant. IEEE Trans Biomed Eng 1995, 282–292.Google Scholar
- Ljung, L., System identification - Theory for the user, Prentice-Hall, Englewood Cliffs, NJ, 1987.Google Scholar
- Nashner, L.M., Adapting reflexes controlling the human posture. Exp Brain Res 26(1):58–72.Google Scholar
- Roos, H., Bles, W., and Bos, J.E., Postural control after repeated exposure to a tilting room. In: Posture and gait: Development, adaptation and modulation. B. Amblard, A. Berthoz, and F. Clarac (Eds.), Elsevier, Amsterdam, pp. I 37–144, 1988.Google Scholar
- Wilson, J., and Melville-Jones, G., Mammalian Vestibular Physiology, Plenum New York, 1979.Google Scholar