PDF(Pubmed)
Abstract：
Subjective reports indicate that hearing aids can disrupt sound externalization and/or reduce the perceived distance of sounds. Here we conducted an experiment to explore this phenomenon and to quantify how frequently it occurs for different hearing-aid styles. Of particular interest were the effects of microphone position (behind the ear vs. in the ear) and dome type (closed vs. open). Participants were young adults with normal hearing or with bilateral hearing loss, who were fitted with hearing aids that allowed variations in the microphone position and the dome type. They were seated in a large sound-treated booth and presented with monosyllabic words from loudspeakers at a distance of 1.5 m. Their task was to rate the perceived externalization of each word using a rating scale that ranged from 10 (at the loudspeaker in front) to 0 (in the head) to -10 (behind the listener). On average, compared to unaided listening, hearing aids tended to reduce perceived distance and lead to more in-the-head responses. This was especially true for closed domes in combination with behind-the-ear microphones. The behavioral data along with acoustical recordings made in the ear canals of a manikin suggest that increased low-frequency ear-canal levels (with closed domes) and ambiguous spatial cues (with behind-the-ear microphones) may both contribute to breakdowns of externalization.
摘要：
主观报告表明，助听器可以破坏声音外部化和/或减少声音的感知距离。在这里，我们进行了一项实验，以探索这种现象，并量化不同助听器样式发生的频率。特别感兴趣的是麦克风位置的影响(耳后vs.在耳朵中）和圆顶型（封闭与open).参与者是听力正常或双侧听力损失的年轻人，他们配备了助听器，允许麦克风位置和圆顶类型的变化。他们坐在一个经过声音处理的大型展台中，并在1.5m的距离处向扬声器展示单音节单词。他们的任务是使用范围从10（在前面的扬声器）到0（在头部）到-10（在听众后面）的评分等级对每个单词的感知外部化进行评分。平均而言,与独立倾听相比，助听器倾向于减少感知距离并导致更多的头部反应。对于结合耳后麦克风的封闭圆顶尤其如此。行为数据以及在人体模型的耳道中进行的声学记录表明，低频耳道水平的增加（具有封闭的圆顶）和模棱两可的空间线索（具有耳后麦克风）都可能导致外部化的崩溃。
