Cochlear Implant Performance in Adult Patients with Absent Intraoperative Electrically Evoked Compound Action...

Area of Science:

• Audiology
• Neurosurgery
• Otolaryngology

Background:

• Intraoperative electrically evoked compound action potential (ECAP) measurements are often used to confirm neural integrity during cochlear implantation.
• Absent ECAP responses during surgery may raise concerns about potential hearing outcomes.
• Limited data exists on the long-term performance of cochlear implants in adult patients with absent intraoperative ECAP responses.

Purpose of the Study:

• To describe cochlear implant performance outcomes in adult patients who had no intraoperative ECAP responses despite successful intracochlear electrode placement.
• To evaluate the functional hearing gains achieved by these patients post-implantation.

Main Methods:

• Retrospective case review of adult cochlear implant patients (≥18 years) between May 2010 and September 2018.
• Identification of cases with absent intraoperative ECAP measurements despite intracochlear electrode placement.
• Comparison of pre- and post-operative sentence recognition scores (Hearing in Noise Test [HINT] and AzBio) at 6-12 months.

Main Results:

• Absent intraoperative ECAP responses occurred in 15 of 383 cochlear implant cases (3.9%).
• Patients with absent ECAP showed significant improvement in mean HINT scores from 0% preoperatively to 57.8% at 6-12 months postoperatively (42.6% improvement).
• Preoperative hearing loss was severe to profound, with many patients having 0% word recognition and HINT scores.

Conclusions:

• Cochlear implantation can yield substantial hearing benefits even in the absence of intraoperative ECAP responses.
• Performance outcomes vary widely, from basic sound awareness to excellent sentence recognition.
• Intraoperative ECAP absence should not preclude cochlear implantation if other criteria are met.