Flow Changes of Vestibular System due to Changes in Volume and Ellipticity

Motion sickness is a very common condition shared among human beings. The generally accepted explanation for motion sickness is a disconnect between the motion the brain is expecting and the experienced motion. Many studies have been performed to investigate the external inputs and internal factors related to an individual's susceptibility of motion. There is no general agreement on the definitive cause of motion sickness. It is our great interest to explore why some individuals are more sensitive to motion. The vestibular system located in the human inner ear is important in sensing motion and maintaining balance of the body. The focus of the current study is to investigate the effects of the canal volume and ellipticity on the response of motion. It is difficult to research pressure differences experimentally in the ear because of how small the vestibules are and the inadequacies of current measuring tools. Computational fluid dynamics was therefore used to model the vestibules to observe fluid movement and pressure distributions in the middle ear. Flow differences around varied structures could explain what causes some humans to be sensitive to mechanical stresses and help explain the experience of motion sickness. The superior vestibule was modeled and analyzed as the head is rapidly turned. It was found that the responses change with the volume and ellipticity.