Het Vestibulaire Implantaat: optimalisatie van uitkomsten

Bilateral loss of vestibular function is a very debilitating disorder, which can lead to a broad spectrum of symptoms like for example postural instability, impairment of spatial orientation and a distorted vision (oscillopsia). Patients with bilateral vestibular impairment often need to alter their activities. They need to perform them slower, with greater attention, or some will even be avoided. This can strongly impact quality of life, as it can lead to a decrease of physical activity and social functioning and can increase the risk of falling 31 times. Up until now no effective treatment is available for chronic bilateral vestibulopathy. Physical therapy can be helpful, but it is not always sufficient. Progress is being made with devices specifically targeting certain deficits caused by BV, but no treatment option to reestablish the full functionality of the vestibular organs exists today. In response to this therapeutic absence, the concept of a vestibular prosthesis, in analogy with a cochlear prosthesis for treating deafness, is an ongoing and important field of research. One of the vestibular implants (VI) in development is the Cochleovestibular implant (CVI). This is cochlear implant (CI) adjusted to form an additional vestibular implant. In the normal CI implant all electrodes are arranged along one array designed for a full insertion inside the cochlea. In the CVI implant, the three most basal electrodes are separated from the main electrode branch into three individual branches. These three individual branches are designed to be inserted into the semicircular canals (SCCs) to allow for stimulation of the vestibular nerves. The remaining 9 electrodes make up the cochlear array, designed to be inserted in the cochlea, analogous to a regular CI. Reallocating the electrodes within the vestibulocochlear organ offers the opportunity to stimulate the vestibular nerves, while maintaining CI functionality in order to restore hearing. The implant aims to provide the central nervous system with information about spatial orientation and movement. A sensor containing accelerometers and gyroscopes is applied to the patients' head, where it measures head angular velocity and linear acceleration in all axes of movement. The measured signals are then transduced into electric signals, which are delivered to the vestibular nerves by the implanted electrodes. Implantation of the vestibular system is a very delicate procedure as semicircular canals are very small and opening up these canals can cause hearing loss. Furthermore, the best electrode position for optimal functional results and best operative technique still need to be determined. Overall, in this project we aim to develop a safer and more efficient VI by studying possible improvements in the surgical technique and investigating the electrode positioning based on objective intra- and postoperative parameters. With this research we aim to develop a functional prosthesis which can provide a good treatment option for this highly incapacitating disease.