- 期刊
中耳炎患者之助聽器選配
Hearing Aid Fitting in Patients with Otitis Media
摘要
慢性中耳炎所引起的傳導性或混合性聽障，多可以手術的方式處理。對少數不願意、不適合接受手術或是接受手術後聽力仍不理想的患者，則可選擇配戴助聽器來幫助溝通。這些患者配戴助聽器時，可以有下列的選擇：1. 骨導式助聽器，此種助聽器耳內不必戴東西，但高頻之增益十分有限，有時振動器與乳突間不易密合，影響傳聲效果。另外振動器之壓力常造成患者之乳突疼痛甚至頭痛。2. 植入型骨導助聽器，對於不適合配戴骨導或氣導式的助聽器者，提供另一種選擇。3.一般氣導式助聽器。在選配時需注意的事項如下：(1)原則上中耳炎的患者一般以配戴耳掛型為佳。(2)配前評估方面，中耳炎患者之不舒適導度值較感音性患者高，因較可忍受較大的放大音。助聽器之最大輸出功率，因此可以調高。(3)選配方面，一般對中耳炎患者的增益，可根據針對感音性患者之公式所得之值，再加上氣骨導差值的20%~25%，但以不增日超過8dB為限。(4)驗証方面，中耳炎之真耳測試不同於一般耳，且各別差異大，必須每個患者都做，不可用平均之數據。(5)效果評估方面，在鼓膜穿孔之患者，塞入性增益會比功能性增益為大，尤其是氣骨導差值大的患者，因此只單獨使用塞入性增益可能會高估了對患者的幫助。總結而言，中耳炎患者配戴傳統氣導式助理器有許多要特別注意的地方，必須格外留意，才能將助聽器功能做最大發揮。
並列摘要
Surgical correction of conductive hearing loss is the principal and preferred treatment by most patients with chronic otitis media. But not all patients are good candidates for surgery for medical or personal reasons. These patients can use hearing aids and obtain additional benefit from amplification. Options for selecting hearing aids for conductive or mixed hearing loss include: bone conductive hearing aids and traditional air conduction hearing aids. Bone conduction hearing aids deliver amplified sound to the inner ear via a vibrator placed over the mastoid process. The use of bone conduction hearing aid is limited because of minimal gain at high frequency and difficulties in achieving precise placement and tension of the vibrator on the mastoid. The implantable bone anchored hearing aids do not have these limitations. However it required an operation and lifelong care of a percutaneous wound. For conventional air conduction aids, the fitting and verification strategies are different in several ways: 1) In general, BTE (Behind the ear) type is preferable for patients with chronic otitis media. 2) In pre-fitting evaluation, the loudness discomfort levels are usually high in conductive or mixed hearing loss. Therefore the maximal output of the hearing aid can be set up higher to increase headroom. 3) The prescribed hearing aid gain can be based on the air conduction threshold with additional gain to compensate for the magnitude of air-bone gap. 4) In verifying hearing aid performance using real ear measurements, the real –ear to coupler difference and real-ear unaided responses are different from the averaged data. Therefore each real ear measures have to be performed individually for each subject. Finally, in validation, functional gain substantially overestimates the functional gain in subjects with chronic otitis media, the differences is especially noticeable in patients with larger air-bone gaps.