Electrical stimulation through cochlear implants for tinnitus: Scientific outcomes, related factors and patient needs

Tinnitus is the perception of sound without an external stimulus, often experienced as a ringing, buzzing sound. It has a prevalence ranging from 10 to 30% of the general population with up to 3% of people with tinnitus experiencing severe and bothersome tinnitus resulting in a substantial reduction of the quality of life. To date, there is no cure for tinnitus. Cochlear implantation may be an effective treatment for patients with moderate to severe tinnitus and hearing loss who do not respond to conventional treatments. This thesis contributed to higher-level evidence on the effect of electrical stimulation of the auditory nerve through cochlear implants for people suffering from moderate to severe tinnitus. We have shown that electrical stimulation through cochlear implants showed overall a positive effect on tinnitus in patients with tinnitus as a primary complaint. However, there are several considerations before drawing conclusions on the potential of electrical stimulation through cochlear implants as a viable treatment for tinnitus for patients with accompanying hearing loss. This thesis underlines the importance of patient selection and appropriate tinnitus evaluation after cochlear implantation in research studies and clinical practices. In addition, the thesis contributed to a better understanding of the impact of tinnitus on cochlear implant recipients, which findings can be used to further promote a patient-centred approach. A mixed-methods study provided insight in the potential benefits of the sound processor use and thus intracochlear electrical stimulation on tinnitus impact. Further research is needed to predict tinnitus outcomes after implantation and ideally to better understand the mechanisms of actions of electrical stimulation. Through collaboration between clinicians, scientists and industrial partners, a curative treatment for tinnitus could be developed through electrical stimulation of the auditory nerve.