Periodic Reporting for period 2 - IBiDT (Individualized Binaural Diagnostics and Technology)
Reporting period: 2019-07-01 to 2020-12-31
A sound arriving from a certain direction in space (e.g. off the midline) arrives at the two ears at slightly different times, generating an interaural time difference (ITD). In addition, the head attenuates the sound at the ear opposite to the sound source to produce an interaural level difference (ILD). Brainstem circuits are specialized in detecting ITDs and ILDs with a temporal precision unique within the nervous system. As soon as one or two hearing aids or cochlear implants are applied to the ears, any difference in their sound processing corrupts the interaural differences, reducing the binaural advantage. Further, a fair number of people that are said to be “normal hearing” in clinical terms does not get the “normal” advantage of listening with two ears – binaural hearing. This includes particularly people with a neurologic history, such as a stroke but can also happen in completely healthy individuals. To date hearing researchers can list many factors that may limit the binaural benefit. However, due to the complexity of the auditory system (a complex inner ear followed by an even more complex brain), they have only a limited understanding in which way and in which situation a certain pathology corrupts binaural hearing. Hearing devices are far from employing such causalities for optimizing algorithms to the specific pathology.
The objective of the project is therefore to better relate neurophysiology and pathophysiology to normal and impaired perception. This is done by developing a detailed computer simulation of the auditory system validated through a broad range of listening experiments. Once we are confident that we know the pathology of an individual we can then simulate this impairment and see when and how it causes the most extreme and maybe a unique problem. More though, we can develop algorithms, similar to those in hearing aids, but specific to the pathology, optimize them with the simulation and test them with the patient. If the patient shows the same improvement we have predicted in our simulation, we have not only helped the patient but demonstrated that our novel approach can potentially help hundreds of thousand people to improve their binaural hearing and hence their quality of life. Our team is thrilled to pioneer this approach and hope to trigger many follow-up studies.
A study investigating spatial hearing with stroke patients has been designed and experiments will start as soon as Covid-19 regulation allow.
At an early stage of the project we showed that subjects with two cochlear implants can have improved sound localization when we artificially increase the differences between the two ears.
A new model-steered measurement design is currently being developed. After each response from the test subject our newly developed system predicts on-line with which next test condition we learn most about the pathologies. This approach has the potential to revolutionize auditory experimentation as well as audiologic diagnostics. We expect that the new method will result in improving time efficiency by a factor of two, if not more. It is not expected to be applicable in all situations and with too complex models.