Changing Vertical Self-motion Perception After Trampoline Jumping; Assessing Otolith Function in an Elevator

The detection of displacement is important information to maintaining balance, postural control, and gait during daily living activities. This detection of displacement or self-motion perception is accomplished by the human vestibular system, particularly the otolith organs, the sacculus and utriculus. Both primarily respond to whole-body acceleration or tilt in gravity. The saccule and utricle detect linear motion as well as the static orientation of the head relative to gravity, which is itself a linear acceleration. The saccule is more sensitive to vertical acceleration (sensing elevator acceleration) and the utricle is more sensitive to horizontal acceleration (sensing a car accelerate). The signals from the vestibular system are transmitted o the central nervous system for further processing.

Testing the otolith function is difficult since it always a combination of the tested inertial acceleration (t) and gravity (g). Therefore the Vector of acceleration is skew. An isolated vertical direction testing of the saccule is to our knowledge not done. Testing the function of the saccule in an elevator would eliminate the any horizontal accelerations other than gravity. Using the decelerations phase of an elevator ride during both up and down ride could give important inside of the self-motion perception (sensation of acceleration of a subject). The reaction force F which accts on the otolith would be maximal when the elevator ride downwards would stop. The force acting on the otolith when the elevator got upwards is breaking is smaller than g.

A better understanding the adaption of the self-motion perception could be beneficial for patients with hypersensitive vestibular functioning, e.g. patients with vestibular migraine. We hypothesized that (a) healthy subjects change the self-motion perception after hyper-stimulation with repeated vertical acceleration.

The objective of this study is to explore the "vertical self-motion perception" on in healthy young individuals using an elevator as accelerator. Secondary aim is to explore the effects of repeated vertical acceleration on vertical vestibular sensibility.