Effect Of Disturbing Vestibular Function On Vertical Postural Stability In Healthy Human

Purposes: This study investigated the effects on vertical postural stability in healthy human when vestibular function disturbed by computational analysising time and frequency domain index of centre of pressure(COP). By the way, quantitative analysising the effectiveness of modes(head position and rotation of sitting position) of disturbing vestibular function and the compensatory mechanism between vision、vestibular sensation and proprioception. Providing a reference for vestibular rehabitation of patients and selection of aerospace pilot.Methods: According to the experiment requirement, selecting twenty healthy young people for this experiment. All the subjects are voluntary participant and not familiar with the purpose of this experiment. We collected data of COP on head anter-flexion、head rear-extension、head left-leaning、head right-leaning and after different speed(0、60、90、180°/s) of rotation. All the experiments are implemented under visionless condition. All data are saved on text documents in the form of matrix and ASCII, and then calculated by MATLAB program to getting biomechanical index. We used singal factor analysis of variance to comparing index under different conditions.Results:(1)time domain index of different head position:(1) assessing COP index on sagittal axis: there is no significant difference between head rear-extension and up-right; the vertical stability was worse on the station of head anter-flexion than head up-right, and there is significant difference between them; there is no significant difference between head left-leaning and right-leaning;(2) assessing COP index on fronral axis: there is no significant difference between head rear-extension(or anter-flexion) and up-right; the vertical stability was worse on the station of head left-leaning(or right-leaning) than head up-right, and there is significant difference between them;(2) frequency domain index related to sensory information of different head position: visual information is not effected by head position under visionless condition,(1)assessing sensory information index on sagittal axis: rear-extension could result in opposite index properties between vestibule and proprioception through statistical analysis;(2) assessing sensory information index on frontal axis: head left-leaning could result in opposite index properties between vestibule and proprioception through statistical analysis, as well as head right-leaning;(3) time domain index of different rotational speed: with the increase of speed, the vertical stability decreased significantly, but there is no significant difference between 60°/s and 0 °/s;(4) frequency domain index related to sensory information of different rotational speed: visual information is not effected by head position under visionless condition,(1)assessing sensory information index on sagittal axis: only after 180°/s, the index properties of vestibule and proprioception show the same trend through statistical analysis;(2) assessing sensory information index on frontal axis: the index properties of vestibule and proprioception show the same trend through statistical analysis after any rotational speed.Conclusion:(1) head anter-flexion is not challenging enough to disrupt vertical postural control in young people; head flexion or extension is only challenging for human to control vertical posture on sagittal axis, head leaning is only challenging for human control vertical posture on frontal axis;(2) when vestibular sensory of semicircular canal crista ampullaris disturbed, vertical postural control on frontal axis is more challenging for human compared on sagital axis; 60°/s rotation speed for 20 seconds is not challenging enough for young people to control vertical posture;(3) disturbing vestibular function of semicircular canal crista ampullaris has larger degree of interference to gaining vestibular sensory for human compared to disturbing vestibular function of macula; on the condition of vestibular dysfunction, proprioception will compensate for the short of vestibular sensory.