有低频残余听力感音神经聋的人工耳蜗植入术

Cochlear implantation in patients with residual low frequency hearing

目的介绍一种有低频残余听力感音神经聋的人工耳蜗植入技术,探讨人工耳蜗植入手术对有残余听力患者的治疗效果和价值。方法15例有残余听力的患者接受了保护残余听力的人工耳蜗植入手术。术中电极植入深度在19mm～24mm左右。术后分别检测单纯使用助听器、单纯使用人工耳蜗、人工耳蜗结合助听器三种不同状态下的听力。结果15例患者中,有13例术后残余听力保存良好,仅分别丢失5～20dB听力,但另2例术后残余听力全部丧失。术后在安静、信噪比15dB和10dB三种不同状态下的言语测试结果显示,人工耳蜗结合助听器使用者测试得分始终保持在很高水平;单纯使用人工耳蜗者也有较好的成绩,但在信噪比达10dB的条件下,测试成绩下降;而单纯使用助听器者,不仅在安静状态下听力成绩不甚理想,一旦加入竞争性噪声,听力测试成绩急剧下降。结论保护和利用残余听力的人工耳蜗植入技术,使人工耳蜗植入手术对象从重度或极重度聋扩大到高频为重度或极重度聋,低频(≤500Hz)为中、轻度聋的患者。接受这项技术患者的听力和言语识别能力均明显优于其单纯配戴助听器和单纯使用人工耳蜗时的听力和言语识别能力。

Objective To investigate the possibility of preserving and utilizing residual hearing in cochlear implantation. Methods Fifteen patients with residual hearing received cochlear implantation with the goal of preserving and utilizoffing their residual hearing. All patients were subject to following inclusion hearing loss criteria：≥65 dB HL at 1 kHz,60 dB HL at 500 and 250 Hz,≥70 dB HL at 2-8 kHz; and monosyllabic discrimination score with high-power hearing aid 45%. An electrode was placed into the inner ear up to 24 mm. Hearing examinations including pure tone and speech tests were done at various time intervals after operation. Patients were tested with ipsilateral hearing aid alone （HA）,cochlear implant alone （CI） or with both hearing aid and cochlear implant. Results Postoperative hearing thresholds were within 0-10 dB of the preoperative levels in 8 patients and 11-20 dB in 5 patients,Two patients lost all hearing following surgery for unknown reasons. The best results in speech understanding were obtained under the condition of combined HA and CI,in quiet environment,and at a signal to noise ratio of 15 dB. Use of CI alone resulted in relatively good speech understanding,although performance decreased at a signal to noise ratio of 10 dB. Performance with hearing aid alone dropped sharply from quiet to noisy conditions. Conclusion The technique appears to provide the possibility of preserving and utilizing residual hearing in cochlear implantation,which provide a substantial benefit in hearing and speech understanding to individuals with severe high-frequency hearing loss,while retaining the benefits of residual low-frequency hearing. HA and CI combination resulted in more natural and pleasant sound perception than either HA or CI alone. A careful shallow insertion of the electrode array into the basal part of the cochlea is the most important factor in the success of this technique.