| Autor: |
Dietrich H; German Center for Vertigo and Balance Disorders, University Hospital, LMU, Munich, Germany., Heidger F; Department of Neurology, University Hospital, LMU, Munich, Germany., Schniepp R; German Center for Vertigo and Balance Disorders, University Hospital, LMU, Munich, Germany.; Department of Neurology, University Hospital, LMU, Munich, Germany., MacNeilage PR; German Center for Vertigo and Balance Disorders, University Hospital, LMU, Munich, Germany.; Department of Psychology, Cognitive and Brain Sciences, University of Nevada, Nevada, USA., Glasauer S; German Center for Vertigo and Balance Disorders, University Hospital, LMU, Munich, Germany.; Institute of Medical Technology, Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany., Wuehr M; German Center for Vertigo and Balance Disorders, University Hospital, LMU, Munich, Germany. Max.Wuehr@med.uni-muenchen.de. |
| Abstrakt: |
Vestibular balance control is dynamically weighted during locomotion. This might result from a selective suppression of vestibular inputs in favor of a feed-forward balance regulation based on locomotor efference copies. The feasibility of such a feed-forward mechanism should however critically depend on the predictability of head movements (HMP) during locomotion. To test this, we studied in 10 healthy subjects the differential impact of a stochastic vestibular stimulation (SVS) on body sway (center-of-pressure, COP) during standing and walking at different speeds and compared it to activity-dependent changes in HMP. SVS-COP coupling was determined by correlation analysis in frequency and time domains. HMP was quantified as the proportion of head motion variance that can be explained by the average head trajectory across the locomotor cycle. SVS-COP coupling decreased from standing to walking and further dropped with faster locomotion. Correspondingly, HMP increased with faster locomotion. Furthermore, SVS-COP coupling depended on the gait-cycle-phase with peaks corresponding to periods of least HMP. These findings support the assumption that during stereotyped human self-motion, locomotor efference copies selectively replace vestibular cues, similar to what was previously observed in animal models. |
