Studying brain activity of cochlear implant users

Objective spatio-temporal study of auditory cortical activity from cochlear implants with NIRS-EEG

The medical device company Cochlear specializes in implantable hearing solutions for adults and children who are affected by deafness or hearing loss. Despite tremendous advances in implantable hearing solutions, the prediction of substantial communication benefits after cochlear implantation in patients with pre-lingual deafness is still a clinical dilemma. This wide range in performance might be related to widely-varying brain activity patterns in these patients.

Cochlear implantation is an important treatment for severe to profound hearing loss, which can prevent potential social isolation of patients. Approximately 219,000 adults and children worldwide (~2800 in the Netherlands) are users of cochlear implant (CI). All of these CI-users benefit greatly from the ability to hear anything. Still, the actual individual auditory performance in everyday life and in crowded environments can differ significantly, by yet unknown causes. Because of the aging population and the associated increase in old-age hearing impairment, and because of the expansion of implant criteria that lead to implantation in children as early as possible, it is important both to predict whether an implant will actually be effective and to optimize the settings of an implant for the individual patient.

Functional neuroimaging techniques offer, in principle, the possibility to determine the efficacy of a cochlear implant in driving brain activity of a CI user. Unfortunately, the conventional methods are limited when measuring CI users. Some techniques are influenced by, and/or have influence on the metallic, magnetic components of the implant, while other techniques are burdensome for the patient (due to the requirement of an injection of a radioactive). Near-infrared spectroscopy (NIRS) is an optical technique that does not suffer from these drawbacks.

In this project Radboudumc and the company Cochlear have demonstrated that the use of the fNIRS technique for cochlear implant patients is a promising technology to assess object information about brain activation by the implant. In future experiments we will further explore how we can use this technique to optimise the cochlear implant device settings on the basis of objectively measured brain signals.

More information on this website.

Summary
The prediction of substantial communication benefits after cochlear implantation in the deaf is still a clinical dilemma. By applying the only neuroimaging method that is insensitive to electromagnetic artefacts caused by the implant (near-infrared spectroscopy), the activity of the deaf brain can be viewed during listening after cochlear implantation.
Technology Readiness Level (TRL)
2 - 4
Time period
24 months
Partners