News

Published research findings

Wideband tympanometry absorbance can effectively detect mechanical changes in the acoustical pathway following cochlear implant surgery. 

Interpretability of the inter-phase gap offset effect — a promising method for representing neural health in cochlear implant (CI) users, based on the electrically-evoked compound action potential — seems more complex in CI recipients with preoperative acoustic hearing, which is especially relevant considering the increasing proportion of this group among CI users. 

The ZH-ECochG plot is an innovative visual framework to facilitate the interpretation of electrocochleography recordings and enable comparisons between different studies.

Under bone conduction hearing, the intracranial content, such as the brain and cerebrospinal fluid, have a limited effect on the motion of the skull bone, with a trend towards a reduction of the stimuli's natural frequencies.

 

New group members

Our bone conduction research team is growing! Antonio Garcia Bustos and Johannes Niermann both started their PhD projects at the beginning of 2024, both bringing valuable engineering knowledge and experience to their project.

Dominik Etter also joined our group at the beginning of 2024, to conduct his PhD as part of a joint project with the X-Ray Imaging and Microscopy group at the Institute for Biomedical Engineering at ETH Zurich. He holds an MSc. in Interdisciplinary Sciences, Physics & Biology track, from ETH Zurich and will work on improving ear CT with refraction using grating interferometry and projects related to the study of middle-ear mechanics.

Dr. Yu Si joined our group as an academic guest from the Department of Otorhinolaryngology at Sun Yat-sen University (SYSU), Guangzhou, China.

Dr. Samuel Söderqvist joined us as a visiting researcher from the University Hospital in Helsinki, Finland in June and July 2024.

Timona Oesch, who successfully completed her MSc. thesis on psychoacoustic measurements in cochlear implant users within our group, joined us as a research assistant from August 2024. 

Séverine Buffoni joined us in September 2024 as an expert on regulatory aspects of clinical studies, bringing many years of valuable experience as a clinical study coordinator.  

Published research findings

Attenuation of middle-ear transfer function changes with direction of preload on partial ossicular replacement prostheses

The promontory velocity, often used in experiments, might not be sufficiently representative of basilar membrane motion at mid-frequencies

A new method for tracking the 3D motion of the ossicles expands our understanding regarding behavior of the human middle ear under circumferential pressure changes and thus provides information to improve middle-ear prosthesis design

Support Vector Machine and Random Forest classifiers, trained on electrocochleography recordings, could not distinguish cases with hearing preservation and hearing loss

 

New group members

Yuan Zhan is a new PhD candidate in our group since August 2023, who will work on sound propagation in bone conduction hearing (the CHEWBACHA project). Yuan is a medical doctor who brings research experience at the TU Dresden and the otolaryngology department of the University Hospital in Dresden.

Tobias Mair joined our group as a PhD candidate shortly after, and will also work on experimental investigations of bone conduction hearing.

Dr. Wei Fanqin joined our group as an academic guest from the First Affiliated Hospital of Sun Yat-Sen University in Guangzhou, China. His research at our group focuses on future fully implantable cochlear implant systems.

 

Completed PhD theses

Nuwan Liyanage successfully defended his PhD at the end of March. His work contributed to the development of a fully implantable cochlear implant, and in addition, he studied the effect of cochlear implants on tinnitus relief. 

Shortly after, at the end of April, we had another successful PhD defense by Tahmine Farahmandi. She presented her experimental work on sound wave propagation in bone conduction hearing, which was very well received.

 

Selected grants

Merlin Schär, PhD, received a grant for the project 'Investigation of Optimal Characteristics of Micromechanical Stiffness Sensors for Reconstructive Middle-Ear Surgery' from the EMDO Stiftung Zürich.

Prof. Alex Huber and Prof. Jae Hoon Sim started the project named 'A surgical simulator for surgical training and assessment of middle-ear implants' in collaboration with Heinz Kurz GmbH Medizintechnik.

Prof. Christof Röösli obtained a grant for the project 'Bilateral stimulation of the cochlea in bone conduction' from the Swiss National Foundation.

Published research findings

Skull bone and vault contents interact during bone conduction sound transmission

Bone conduction transcranial attenuation still holds many secrets

The source of wave propagation across the parietal plates and skull base, critical for contralateral stimulation, is influenced by the potential structural differences between neighboring regions of skull rather than coupling type

Three-point and four-point impedance measurements can predict cochlear implant electrode placement

 

New group members

Marlies Geys joined our group as a PhD student working on the InnoSuisse CHECK project. Marlies received her MSc. degree in Audiology from the University of Leuven and after that, she worked as a clinical audiologist in our hospital for two years. We are happy to have her on our team!

Ahmet Kunut joined our team as a Dr. med candidate, supervised by Dr.  Adrian Dalbert. He is working on electrocochleography in mice as well as in human CI recipients.

 

Completed PhD theses

In July, Leanne Sijgers successfully defended her PhD thesis on objective measures in cochlear implants. This was well celebrated afterwards! Leanne will continue as a postdoc in our group, working on the InnoSuisse CHECK project.

Merlin Schär completed his PhD thesis on protective and adaptive functions of the human middle ear. He successfully defended his work at the beginning of February. We are happy to announce that Merlin will continue his research within our group as a postdoctoral researcher.

 

Selected grants

Our SNF grant application "Computing human head elastic waves for bone-anchored hearing aids (CHEWBACHA) - Finite element modeling based on micro-macro validation measurements", led by PD Dr. Flurin Pfiffner in collaboration with our partners from EMPA, has been approved. 

Our grant application "Improving Hearing Outcome in Cochlear Implant Patients with a CHECK (Cochlear Health Evaluation for CI-patients Kit)", led by PD Dr. Flurin Pfiffner in collaboration with Sonova, has been approved by InnoSuisse. 

Prof. Dr. Christof Roösli received a grant for the project 'Intensiv-Rehabilitation nach Cochlea-Implantation' from the USZ Innovationspool, to enable intensive rehabilitation of cochlear implant recipients within the clinic. 

Published research findings

Phase changes in electrocochleography represent an independent marker for changes of inner ear mechanics

Proven usability of an adhesive connection for bone conduction audiometry

Positive correlation between postoperative electrocochleography in cochlear implant recipients and speech perception outcomes

Overview of the current state of cochlear implantation from a clinical perspective

Cadaver models could predict bone conduction transcranial transmission in patients, but not skin attenuation

In single sided deafness, rehabilitation with cochlear implant provides superior gain, understanding in noise, localization of sounds and reduction of tinnitus compared to alternative therapies

Morphological changes in the ossicular joints of the middle ear could explain worsening of bone conduction hearing with age

A new bone conduction hearing aid, AdHear, produces comparable promotory motion and cranial surface wave pattern to traditional Baha Power.

Cochlear implantation is cost-effective to treat patients with single sided deafness

The intraoperative description of facial nerve course matches tractography finding

The Bonebridge (an active bone conduction implant) is long-term efficacious in adults with single sided deafness 

Cochlear implant outcome in regard of hearing preseravtion and word perception is not influenced by semicircular canal dehiscence

A Finite Element computer model of the human head and ear can predict the skull bone and cochlear response under bone conduction stimulation

Positive correlation between postoperative electrocochleography in cochlear implant recipients and speech perception outcomes

Simultaneous intra- and extracochlear electrocochleography during cochlear implantation enhances response interpretation

Pre-surgical intratympanic gentamicin is suitable for reducing the drop in peripheral-vestibular function after vestibular Schwannoma resection

The new SH coupler provides an alternative of the current Vibroplasty Clip coupler under insufficient space after canal-wall-down mastoidectomy.

Flexibility of the IMJ provides better sound transmission through the middle ear and thus better hearing under static pressure changes

Endolymphatic hydrops can cause symptoms similar to eustachian tube dysfunction and has to be considered as a differential diagnosis in eustachian tube dysfunction

 

New group members

Bastian Baselt and Rahel Bertschinger joined our group in October 2021 to conduct their PhD. Rahel will investigate extracochlear electrical stimulation as a hearing therapy and a tinnitus treatment; Bastian's project focuses on the function of the human tympanic membrane. Both Bastian and Rahel are enrolled in the doctoral program Clinical Science at the University of Zurich.

 

Completed PhD theses

Birthe Warnholtz successfully conducted her PhD defense in September 2021. She investigated the functionality of the normal and reconstructed human middle ear under static pressure loads. We wish her all the best on her future endeavors.

 

Selected grants

The research project «Detailed Characterization of Cochlear Health by Electrocochleography» led by Dr. Adrian Dalbert is supported by the Vontobel Foundation.

PD Dr. Jae Hoon Sim and Prof. Alexander Huber obtained an SNF grant for the project «Acousto-vibratory functions of tympanic membrane: Investigation on normal, pathological, and surgically reconstructed conditions».

The grant «Evaluation einer extracochleären Hörprothese» by Prof. Alexander Huber was granted by the Palatin foundation.