Radboudumc

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Hearing & Implants

Hearing & Implants is a subdivision of the department of otorhinolaryngology responsible for the clinical care of patients with various types of hearing loss which cannot be resolved through surgical reconstruction nor rehabilitation with conventional hearing aid fitting, and therefore are indicated for an otologic active implant. Our department has a longstanding history of care for these patients and has accumulated substantial experience and knowledge in active implants in otology. Clinical care is backed with scientific research. (Indeed, our scientific work in this field is well known, nationally and internationally.) We continue to endeavor research of fundamental and translational nature partly embedded in the Donders Center for Neuroscience (DCN). A short summary of some of the current research lines is presented.

Implantable Bone Conduction Devices

  • Osseointegration of percutaneous implants in the temporal bone
    Myrthe Hol and Emmanuel Mylanus

    This research covers various types of percutaneous titanium implants, evaluating clinical stability in the temporal bone with resonance frequency measurements after implantation and following loading with the active bone conduction transducer. Adverse soft tissue reactions are observed relative to the abutments’ design. Various variables and predisposing factors like Diabetes Mellitus are assessed.
      
  • Directionality in hearing with Implantable Bone Conduction Devices (IBCD)
    Martijn Agterberg (DCN), John van Opstal (DCN) and Ad Snik
      
    In conductive hearing loss, an IBCD might provide the necessary cues for directionality in azimuth. In our special sound localization set-up, patients with conductive hearing loss appear to profit from IBCD application but to various degrees depending on pre intervention coping strategies. Research embedded in the DCN, dr. Martijn Agterberg, prof. dr. John van Opstal, prof. dr. Ad Snik

Active Middle Ear Implants (MEI)

  • The Vibrant Soundbridge for unilateral conductive hearing loss
    Martijn Agterberg (DCN), John van Opstal (DCN) and Ad Snik
     
    The Vibrant Soundbridge is currently the most frequently implemented active middle ear implant, with the transducer coupled to the intact incus. A new indication is the implementation of this implant in patients with unilateral conductive or mixed hearing loss. In such patients, a normal contralateral hearing might lead to cross hearing with IBCD. Using a MEI might avoid this problem and provide sufficient gain for bilateral summation and squelch.
     
  • Mechanical intracochlear stimulation in patients with mixed hearing loss (CODACS)
     Emmanuel Mylanus and Ad Snik
      
    A new development in the treatment of advanced otosclerosis is the implementation of a direct stimulator of the inner ear. The conventional stapes piston is attached with an active transducer which is implanted in the mastoid cavity. Ongoing research focuses on clinical outcome, and evaluation of new designs. 

Cochlear Implants

  • Bilateral Cochlear implantation
    Margreet Langereis, Anneke Vermeulen, Ad Snik, Andy Beynon, Emmanuel Mylanus
      
    Both in children and in adults, the clinical results of bilateral CI are evaluated. Main outcome measures are speech recognition in noise, and directionality. In children research is focused on language acquisition and verbal intelligence. Objective measures include brainstem evoked responses and cortical responses.
     
  • Surgical approaches for the cochlear scale and the cochlear nerve for electrical stimulation
    Berit Verbist (Radiology) and Emmanuel Mylanus (Project leaders)

    A project in collaboration with the department of Nuclear Medicine, the Biomechanical Laboratory and the department of Radiology
      
    The feasibility of the approach of the cochlear scalae, and the cochlear nerve is evaluated using micro-CT imaging, temporal bone dissection and histologic sections. In situ evaluation of the electrode array is performed with high resolution CT and cone-beam CT scanning. Qualitative differences are evaluated.
     
  • BCI for recipients with developmental delays
    Margreet Langereis, Ad Snik, Saskia Ariens, Emmanuel Mylanus
      
    For counseling purposes, it is of importance to be aware of the possible outcome of CI in children with developmental delays. Extensive research covers the pre-operative radiological and psychologic evaluation of children with deafness as a result of a CMV infection and CHARGE syndrome, and the post-implantation performance. In general, a pre-implantation evaluation tool, measuring pre-verbal communication abilities, is used to predict the performance outcome in this special group of children.
  • The evaluation of the developing brain after CI
    Marc van Wanrooy (DCN), John van Opstal (DCN), Jef Mulder, Ad Snik
      
    Various techniques are used to evaluate the effect of electrical stimulation of the auditory system after cochlear implantation. EEG, PET and NIRS (Near Infra Red spectrometry) are tools that are evaluated for its versatility. Patient groups include prelingually deafened adults. In this latter group of recipients, it is of interest to assess whether the auditory cortex has been used for visual perception, and whether this cortex is plastic enough to allow audiologic cues to be processed. 
  • CI and hearing aids combined
    Lucas Mens, Marc van Wanrooy (DCN), Martijn Agterberg (DCN), Ad Snik, John van Opstal (DCN)
      
    CI users with severe hearing loss might benefit from the fitting of a hearing aid contra laterally (bimodal stimulation). However, stimulation modes are very different. Interactions are being studied as well as optimizing device fittings.