Gantz Bruce J, Turner Christopher
Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, IA 52242-1078, USA.
Acta Otolaryngol. 2004 May;124(4):344-7. doi: 10.1080/00016480410016423.
In this paper we test the concept of combining electrical stimulation for high-frequency sound with acoustic hearing for low-frequency information in the same ear. In addition, we test whether residual hearing can be preserved when an electrode is placed up to 10 mm into the inner ear, and whether the site of electrical stimulation influences speech perception.
Nine post-lingual adults with severe high-frequency hearing impairment were recruited to participate in the study. A single-subject clinical trial design was employed. A unique six-channel cochlear implant was designed for this clinical trial. The intracochlear electrodes were either 6 or 10 mm in length based on a Nucleus CI-24 multichannel implant. Monosyllabic word understanding and consonant identification in a recorded sound-only condition were used to assess changes in speech perception. Follow-up was > 12 months.
Acoustic hearing was preserved in all nine subjects. Preoperative monosyllabic word and sentence scores were unchanged in all subjects following implantation. A 30-40% improvement in consonant recognition occurred with the 10-mm electrode. The 10-mm electrode subjects were able to understand 83-90% of the monosyllabic words using the implant plus binaural hearing aids. Scores were more than doubled when compared to preoperative scores achieved with hearing aids only.
The human ear has the capability to integrate both acoustic and high-frequency electrically processed speech information. Placement of a short 10-mm electrode does not appear to damage residual low-frequency inner ear hair cell function, interfere with the micro-mechanics of normal cochlear vibration or decrease residual speech perception. The improvement in speech recognition was due primarily to the increased perception of higher-frequency consonantal speech cues. Such a device can provide a substantial benefit in terms of speech understanding to those with severe high-frequency hearing loss, while still maintaining the benefits of the residual lower-frequency acoustic hearing. The position of the electrode and the site of frequency information within the cochlea are shown to be important factors in the success of such a device.
在本文中，我们测试了在同一只耳朵中将高频声音的电刺激与低频信息的声学听力相结合的概念。此外，我们测试了将电极插入内耳达10毫米时残余听力是否能够得以保留，以及电刺激的部位是否会影响言语感知。
招募了9名患有严重高频听力障碍的语后聋成年人参与该研究。采用单受试者临床试验设计。为此项临床试验设计了一种独特的六通道人工耳蜗。基于Nucleus CI-24多通道植入体，耳蜗内电极长度为6毫米或10毫米。在仅声音记录条件下的单音节词理解和辅音识别用于评估言语感知的变化。随访时间超过12个月。
所有9名受试者的声学听力均得以保留。植入后，所有受试者术前的单音节词和句子得分均未改变。使用10毫米电极时，辅音识别提高了30%-40%。使用植入体加双耳助听器，10毫米电极组受试者能够理解83%-90%的单音节词。与仅使用助听器的术前得分相比，得分增加了一倍多。
人耳有能力整合声学和高频电处理语音信息。放置10毫米的短电极似乎不会损害残余的低频内耳毛细胞功能，不会干扰正常耳蜗振动的微力学，也不会降低残余言语感知。言语识别的改善主要归因于对高频辅音语音线索感知的增加。这样一种装置对于严重高频听力损失者而言，在言语理解方面可带来实质性益处，同时仍保留残余低频声学听力的益处。结果表明，电极的位置以及耳蜗内频率信息的部位是这种装置成功的重要因素。
