Did you know that cooling during surgery can help improve hearing outcomes for individuals with cochlear implants?

Cochlear implants (CI) provide life changing benefits to thousands of people who have hearing loss. CI technology has advanced tremendously over the past few decades, combining electrical and acoustic stimulation of the ear in tandem with the ear’s natural low frequency residual hearing. This combined approach leads to better hearing of speech, melodies, and even instruments. Unfortunately, CI surgeries cause inflammation and trauma during implantation, which can result in the loss of sensory hair cells and spiral ganglion neurons– structures that are essential for hearing. Because of this, 30-50% of individuals with CIs experienced loss of residual hearing after surgery. 

How can you reduce inflammation in the body? With ice, of course! When we sprain our ankle, hit our head, or get a tooth pulled, we are told to ice the area. With this in mind, RestorEar’s research partners wanted to see if the application of mild therapeutic hypothermia (MTH) before and after CI implantation would help preserve residual hearing after surgery.

After performing baseline hearing tests, researchers provided localized MTH directly to the inner ears of CI recipients for 20 minutes before and after implantation using specialized cooling technology from their lab. They performed the same hearing tests after surgery and up to 3 months post-op. These results were compared to CI recipients that didn’t receive cooling alongside surgery, as well as a control group. 

They found that those who received cooling had better residual hearing for up to 3 months after implantation compared to those that didn’t receive cooling. Through RNA sequencing analyses, they also found that cooling helped moderate damaging inflammatory responses to surgical trauma in the ear. Taken together, cooling was safe and effective for preserving residual hearing for cochlear implant recipients.