Kirk K I, Pisoni D B, Miyamoto R C
Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis 46202, USA.
J Speech Lang Hear Res. 1997 Dec;40(6):1395-405. doi: 10.1044/jslhr.4006.1395.
Traditional word-recognition tests typically use phonetically balanced (PB) word lists produced by one talker at one speaking rate. Intelligibility measures based on these tests may not adequately evaluate the perceptual processes used to perceive speech under more natural listening conditions involving many sources of stimulus variability. The purpose of this study was to examine the influence of stimulus variability and lexical difficulty on the speech-perception abilities of 17 adults with mild-to-moderate hearing loss. The effects of stimulus variability were studied by comparing word-identification performance in single-talker versus multiple-talker conditions and at different speaking rates. Lexical difficulty was assessed by comparing recognition of "easy" words (i.e., words that occur frequently and have few phonemically similar neighbors) with "hard" words (i.e., words that occur infrequently and have many similar neighbors). Subjects also completed a 20-item questionnaire to rate their speech understanding abilities in daily listening situations. Both sources of stimulus variability produced significant effects on speech intelligibility. Identification scores were poorer in the multiple-talker condition than in the single-talker condition, and word-recognition performance decreased as speaking rate increased. Lexical effects on speech intelligibility were also observed. Word-recognition performance was significantly higher for lexically easy words than lexically hard words. Finally, word-recognition performance was correlated with scores on the self-report questionnaire rating speech understanding under natural listening conditions. The pattern of results suggest that perceptually robust speech-discrimination tests are able to assess several underlying aspects of speech perception in the laboratory and clinic that appear to generalize to conditions encountered in natural listening situations where the listener is faced with many different sources of stimulus variability. That is, word-recognition performance measured under conditions where the talker varied from trial to trial was better correlated with self-reports of listening ability than was performance in a single-talker condition where variability was constrained.
传统的单词识别测试通常使用由一名说话者以一种语速生成的语音平衡（PB）单词列表。基于这些测试的可懂度测量可能无法充分评估在涉及多种刺激变异性来源的更自然聆听条件下用于感知语音的感知过程。本研究的目的是检查刺激变异性和词汇难度对17名轻度至中度听力损失成年人的语音感知能力的影响。通过比较单说话者与多说话者条件下以及不同语速下的单词识别表现来研究刺激变异性的影响。通过比较“简单”单词（即出现频率高且语音相似的邻词少的单词）与“难”单词（即出现频率低且相似邻词多的单词）的识别来评估词汇难度。受试者还完成了一份20项问卷，以对他们在日常聆听情况下的语音理解能力进行评分。两种刺激变异性来源均对语音可懂度产生了显著影响。多说话者条件下的识别分数比单说话者条件下的差，并且单词识别表现随着语速的增加而下降。还观察到了词汇对语音可懂度的影响。词汇简单的单词的单词识别表现明显高于词汇难的单词。最后，单词识别表现与自然聆听条件下自我报告问卷中语音理解评分的分数相关。结果模式表明，感知稳健的语音辨别测试能够在实验室和临床中评估语音感知的几个潜在方面，这些方面似乎可以推广到自然聆听情况下遇到的条件，即听众面临许多不同的刺激变异性来源。也就是说，在说话者每次试验都不同的条件下测量的单词识别表现与听力能力的自我报告之间的相关性比在变异性受到限制的单说话者条件下的表现更好。
