Results of electric acoustic stimulation for partial deafness in japan: three case reports

Abstract

We evaluated the benefits of Electric Acoustic Stimulation (EAS) for patients with normal or moderate hearing loss in the lower frequencies or steeply sloping severe high-frequency hearing loss, and determined the effects of EAS in individuals with residual lower frequency hearing. All patients underwent cochlear implantation by the round window approach as an atraumatic surgery, using the MED-EL FLEXeas electrode array. They received treatment with the DUET2 processor, which combines electric and acoustic stimulation in one device. Assessment using an audiological test battery was performed as follows: postoperative residual hearing in lower frequencies; Japanese monosyllable words and speech discrimination abilities were evaluated at the time-points of 1, 3, 6 and 12 months after the EAS. Low-frequency residual hearing was preserved in all three patients during the long-term observation after cochlear implantation. The audiological test results revealed significant efficacy and benefits of EAS as compared to electrical stimulation alone, especially under noisy conditions. Thus, lower-frequency hearing preservation is possible after cochlear implantation by the round window approach and use of the FLEXeas electrode. We suggest that EAS is an effective treatment strategy for partial deafness, and yields improvements in monosyllable word discrimination and speech perception, even in Japanese speakers.