[Audiological target parameters in clinical studies with implantable hearing systems].

A multitude of new implantable hearing systems and applications creates new options for pathologies which have been difficult to treat in the past. For many of these hearing systems preclinical technical methods to characterize devices and applications are limited. Therefore, clearly structured clinical investigations and trials are necessary to render results of devices and applications comparable for meta-analysis. Beside optimizing results in current applications, this is also essential for comparisons with established treatment options and differential indication criteria. Even during planning and design of studies, the timing of reference measurements and the choice of-on-off vs. pre-post comparisons in audiological testing decides the focus of the study. This applies equally to the choice for a monaural vs. a binaural test design, which decides whether the study will have the device or the overall result of the treatment in focus. Additional measures such as effective gain, coupling efficiency, and maximal possible intelligibility (WRSmax) can be performed with standard methods and equipment and enable better insight into functional principles of devices and applications. However, testing methods have inherent limitations that have to be taken into account for correct and meaningful interpretations. The use of standardized audiological instruments is essential and permits comparison of devices and treatment results. This is equally important for the creation of evidence-based differential indication criteria between different types of devices as well as for choosing the optimal treatment.