LOW-FREQUENCY COCHLEAR IMPLANT (CI) STIMULATION AND PRESERVED HIGH FREQUENCY HEARING IN A CASE OF PARTIAL DEAFNESS: POSSIBLE EXPANSION OF CI CANDIDACY

Introduction Thanks to ongoing advancements in cochlear implant (CI) technology and surgical techniques, the eligibility criteria for CIs have expanded to include patients with various levels of low-frequency hearing. However, there is another group of patients with non-functional (or borderline functional) hearing at low frequencies but preserved residual hearing in the high-frequency range, thus making them off-label for a CI even though they get limited benefit from a hearing aid. Case report This study presents a 47-year-old patient with residual hearing at the functional border (75 dB HL or better) for low and mid frequencies (125–1500 Hz) and functional residual hearing (70 dB HL or better) for high frequencies (2000–8000 Hz). CI surgery was performed using the Med-El Flex26 electrode via round window insertion. Hearing preservation (HP) was complete up to at least 24 months and partial up to 36 months. For the high-frequencies only (2000–8000 Hz) there was complete HP for the entire 36 months. At 12 months post-surgery, the patient’s word recognition scores (WRS) had improved by 75 percentage points in quiet and 70 points in noise. Conclusions The patient’s results demonstrate that preserving functional residual hearing in the basal cochlea is possible after CI surgery, even though this region is very susceptible to insertion trauma. The presence of functional high-frequency hearing should not be the only reason for withholding CI surgery, especially if a hearing aid is ineffective.