耳模和声管长短的声学效果评估

Assessment to the Acoustic Effect of the Length of the Earmould and Tubing

目的 了解耳模和声管长短对声学效果的影响。方法 任选外耳道结构正常的受试者３０人（６０耳），并按耳印在第二峡部的平均直径≥４.０ｍｍ者为甲组，＜４．０ mｍ者为乙组。采用丹麦产Ａｕｒｉｃａｌ真耳分析仪，运用台湾产恒昇４８６笔记本电脑在Ｎｏａｈ平台下操作，应用同一固定的助听器，按常规真耳测试方法分析耳模及声管在长短不同的Ａ、Ｂ、Ｃ三种类型下的声学效果，即 Ａ型为耳模与声管等长且距离鼓膜约 １.０ ｃｍ，型耳模及声管均比 Ａ型短０．５ ｃｍ，Ｂ型的声管与 Ａ型等长而耳模与 Ｃ型等长，实验中分别测量 Ａ、Ｂ、Ｃ型耳模在２５０、５００、７５０、１ ０００、１ ５００、２ ０００、３ ０００、４ ０００、６ ０００ Ｈz时的介入增益值，即 Ａ、Ｂ及 Ｃ值，并将测量结果进行 ＳＡＳ软件分析。结果 甲组在２５０、５００Ｈｚ处的Ａ、Ｂ值较Ｃ值有显著性差异（Ｐ＜０.０５），在３ ０００、４ ０００、６ ０００Ｈz处Ａ值与Ｃ值均有高度显著性差异（Ｐ＜０.０１），Ｂ值与Ｃ值均有显著性差异（Ｐ＜０．０５），在７５０、１ ０００、１ ５００和２ ０００ Ｈz 处Ａ、Ｂ和Ｃ值无明显变化（Ｐ＞０．０５）；乙组中Ａ、Ｂ值较Ｃ值仅在２５０、５００ Ｈz有显著性差异（Ｐ＜０．０５）?

Objective To know the acoustic effect of the length of the earmould and tubing. Methods Thirty persons (sixty ears) with normal structure of the external acoustic meatus were divided into two groups according to the average diameter of ear impression in the second narrow, which less than 4.0 mm is group Ⅱ, the others belonged to group Ⅰ. In additional, three types ear-mould were made. Type A which earmould is the same length as tubing is about 1.0cm to tympani membrane, type C which all is 0.5 cm shorter than A, type B which the earmould is the same as C and the tubing as A. Then the insertion gains were tested with Aurical real ear analyzer in different frequencies: 250, 500, 750, 1 000, 1 500, 2000, 3 000, 4 000 and 6 000 Hz. In the end analyzing the results with SAS soft. Results Group I showed A, B than C had differed significantly in 250, 500 Hz( P <0.05), very differed significantly in 3 000, 4 000, 6 000 Hz(P<0.01), and no differed in the others(P>0.05). Group II showed A, B than C had differed significantly in 250, 500 Hz( P <0.05) and no in others( P> 0.05). Conclusion Increasing the length may enhance the gain of low and high frequencies when external acoustic meatus is wider, but only low frequencies when narrow,