[[alternative]]Efficacy of electrically evoked auditory brainstem response and electrically evoked compound action potential in programming children with the Nucleus-24 Cochlear Implants

[[abstract]]許多的研究報告以顯示人工耳蝸植入對語音聽知覺有幫助，而人工耳蝸使用者的行為閾級值和行為舒適級值的設定對於聽知覺表現非常重要，電誘發複合活動電位或電誘發腦幹聽性反應的研究，認為兩者皆可以協助人工耳蝸使用者設定個人的電流調整參數，特別是電刺激下難以準確獲得行為閾級值和舒適級值的嬰幼兒。本研究是透過比較電誘發腦幹聽性反應閾值、電誘發複合活動電位閾值行為閾值級和行為舒適值級，來評估此兩種電誘發反應或電位閾值使用於人工耳蝸核式24植入兒童電流調整的效益。 十七位核式24人工耳蝸使用者參與這項研究，所有個案接受人工耳蝸植入至少一年，透過語言處理機測量行為閾級值和舒適級值，且他們的行為聽覺反應是可信賴的並且已建立穩定的電流圖。以NRT 3.0版本軟體（Nucleus，Australia）記錄電誘發複合活動電位閾值；電誘發腦幹聽性反應閾值運用誘發電位儀器（Bravo, Nicolet, USA）測量。統計乃使用SPSS 10.0軟體，以迴歸模式和配對t檢定分析電誘發複合活動電位閾值、電誘發腦幹聽性反應閾值、行為閾級值和舒適級值之關係。 針對76個可測得行為反應閾值的有效電極，電誘發複合活動電位閾值可在64 %測得，而電誘發腦幹聽性反應閾值有71 %可測得，無法測得電誘發複合活動電位和電誘發腦幹聽性反應的個案，大多數為內耳重度畸形或內耳鈣化，其中四位個案的電誘發複合活動電位和電誘發腦幹聽性反應皆無法測得，如果排除內耳重度畸形或鈣化之個案，電誘發腦幹聽性反應可測得的比例為94.2 %，電誘發複合活動電位為84.6%。電誘發腦幹聽性反應閾值比電誘發複合活動電位閾值平均高6.17個電流單位（current levels），電誘發腦幹聽性反應閾值和電誘發複合活動電位閾值間關聯性呈強度（r = 0.755）並且顯著（p < 0.01），配對t檢定顯示兩者無顯著差異性（p ＝ 0.051）。行為閾級值與電誘發複合活動電位閾值或電誘發腦幹聽性反應閾值為輕度關聯性（分別為r = 0.409, r = 0.304），行為舒適級值與電誘發複合活動電位閾值為中度關聯性（r = 0.61），而行為舒適級值與電誘發腦幹聽性反應為輕度關聯性（r = 0.283）。 行為電流圖與電誘發腦幹聽性反應閾值或電誘發複合活動電位閾值的關聯性不強，然而，電誘發複合活動電位和電誘發腦幹聽性反應，對於嬰幼兒的電流圖設定閾級值和舒適級值還是有用的輔助工具。電誘發腦幹聽性反應可記錄到的比率，比電誘發複合活動電位高，但是，電誘發複合活動電位比電誘發腦幹聽性反應容易記錄且節省時間，電誘發複合活動電位可以作為客觀閾值測量的第一選擇，電誘發腦幹聽性反應測量適合無法測得電誘發複合活動電位之個案。因為電誘發複合活動電位和電誘發腦幹聽性反應在內耳重度畸形或鈣化的個案可測得率低，無法提供對於人工耳蝸植入兒童提供電流調整的訊息。[[abstract]]Several reports have shown the benefit in speech perception of cochlear implants. Determination of behavioral threshold levels (T-levels) and comfort levels (C-levels) of the cochlear implant users is very important for their performance of auditory perception. Either electrically evoked compound action potential (ECAP) or electrically evoked auditory brainstem response (EABR) has been studied to help with optimizing individual’s map parameters of cochlear implant users, particularly young children, in whom accurate behavioral T-levels and C-levels to electrical stimulation are difficult to obtain. The purpose of this study was to evaluate the efficacy of EABR and ECAP in programming children with Nucleus-24 cochlear implants by comparing their thresholds with behavioral T-levels and C-levels. Seventeen subjects (7 males and 10 females) with Nucleus 24 cochlear implant participated in this study. All subjects have received implantation at least for one year. Behavioral T-level and C-level were measured through the speech processor. Their auditory behavioral responses were reliable and stable MAPs were established. ECAP thresholds were recorded with the NRT 3.0v software (Cochlear, Australia). EABR thresholds were measured with evoked potential technique (Bravo, Nicolet, USA). SPSS 10.0 for Windows (SPSS Inc., Chicago, USA) was used for analysis. Regression models and paired t-tests were used to analyze the correlations between ECAP threshold, EABR threshold, behavioral T-level and C-level. ECAP thresholds were measured successfully in 64% of active electrodes measured, whereas EABR thresholds were measured in 71%. Unsuccessful recording of ECAP and EABR was observed mostly in subjects either with severe malformations or calcification of inner ear. Both ECAP and EABR could not be measured in four cases. When the subjects with severe malformations or calcification of inner ear were excluded, the rate of successful measurement raised to 94.2 % for EABR and 84.6 % for ECAP, respectively. EABR thresholds were on average 6.17 programming units (current levels) higher than ECAP thresholds. The correlation between EABR and ECAP thresholds was moderate (r = 0.755) and significant (p < 0.01). Paired t-tests revealed no significant difference between EABR and ECAP statistically (p = 0.051). The correlation between behavioral T-levels and ECAP thresholds or EABR thresholds was fair (r = 0.409 and 0.304, respectively). The correlation between behavioral C-levels and ECAP thresholds was moderate (r = 0.61), whereas the correlation between behavioral C-levels and EABR thresholds were fair (r = 0.283). The correlation between behavioral maps and EABR thresholds or ECAP thresholds is not strong. However, EABR and ECAP can be used as ancillary tools in programming MAP T-levels and C-levels of young children. In general, the rate of successful recording of EABR was higher than that of ECAP. Because recording of ECAP is easier and less time consuming than EABR, ECAP may be the choice of objective measurement. EABR measurement may be preferable for individuals whose ECAP can not be recorded successfully. Because of the very low rate of successful recording in young children either with severe malformations or calcification of inner ear, measurement of EABR and ECAP may not play a role in programming them