Auditory Midbrain Implant Study
Condition: Deafness; Perception
MeSH terms: Deafness; Hearing Loss, Sensorineural
Study type: Interventional

Summary: 
      The objectives of the clinical study are to implant five deaf patients (those with
      Neurofibromatosis Type II, NF2) with a new two-shank auditory midbrain implant array (AMI;
      developed by Cochlear Limited) into the central nucleus of the inferior colliculus in order
      to assess the safety, reliability, consistency of placement, and performance of the AMI
      device. The clinical trial is being performed at Hannover Medical School in Germany in
      collaboration with University of Minnesota (USA) and Cochlear Limited (Australia). The
      clinical trial is being managed by Hannover Clinical Trial Center in Germany.
    

Detailed description: 
      Cochlear implants are used in the cochlea (part of the inner ear) where they send electrical
      signals for activation of the auditory nerve to restore hearing to deaf patients. For
      patients without a functioning auditory nerve, there is an auditory brainstem implant (ABI),
      which is placed on the surface of the brainstem in a more central location to restore
      hearing. Unfortunately, the hearing performance of the ABI is typically lower than the
      performance of the cochlear implant. There are several reasons for the lower success of the
      ABI. Due to the tumor and/or tumor removal process for the NF2 condition, there is potential
      damage caused at the brainstem level that has been linked to the poorer performance. The
      anatomical changes caused by the tumor also make it difficult to properly visualize and place
      the ABI surface array into the correct location. In addition, if there is a large tumor that
      needs to or has been removed, then there can be a large cavity in the brainstem space with
      the possibility that the ABI surface array can move from its initial location over time.

      Therefore, for the past 16 years, a new implant has been developed in an international
      collaboration that presents electrical stimuli into a midbrain region, the inferior
      colliculus. This new implant is called the auditory midbrain implant (AMI). The current
      version consists of two shanks with with 11 electrode contacts linearly spaced along each
      shank. The two shanks are inserted into the inferior colliculus to align the electrodes along
      different pitch layers to be able to stimulate them individually with varying temporal pulse
      patterns.

      In the period from 2006 to 2010, a former version of the current AMI was implanted and
      evaluated in five NF2 deaf patients for hearing restoration. This first AMI implant consisted
      of only one shank in contrast with the current two-shank array. Encouragingly, the clinical
      trial at that time showed that the AMI was safe for all five patients. All patients achieved
      improvements in their hearing capacity, especially in the form of environmental sound
      awareness and lip-reading enhancement. One patient additionally attained good speech
      perception that is within the upper range of ABI NF2 patients. However, this speech
      perception is not yet at the level that can be attained in cochlear implant patients.

      Based on these experiences and additional studies in animals, we have developed the second
      version of the AMI that consists of two shanks that will be implanted into the inferior
      colliculus and is expected to provide significant improvements in hearing performance
      compared to the previous AMI by stimulating more effectively across the three-dimensional
      inferior colliculus.

      The purpose of this clinical trial is to evaluate the safety, reliability, and performance of
      the new two-shank AMI in deaf NF2 patients. The ability to consistency place the AMI array
      into the inferior colliculus will also be evaluated.
    

Intervention name(s): auditory midbrain implant (AMI)
Intervention type(s): Device
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment