老龄化对F0轮廓线索在汉语言语识别去掩蔽作用的影响

The influence of aging on the unmasking effect of F0 contour cue in Chinese speech recognition

动态基频(F0)轮廓有助于嘈杂环境下的言语识别,可以作为将目标语音从背景声中分离的知觉线索。本研究通过评估老年人与年轻人在言语掩蔽下聆听具有自然动态F0轮廓与对F0轮廓操作调节后的汉语语句的言语识别能力,探讨老龄化对F0轮廓线索在汉语言语识别去掩蔽作用中的影响。结果显示,在言语掩蔽下自然动态的F0轮廓比压扁或拉伸的F0轮廓更能帮助年轻人抵抗信息掩蔽识别目标言语;而老年人在言语掩蔽下却难以从动态F0轮廓线索中受益。研究结果揭示了老年人利用F0轮廓线索促进掩蔽下言语感知能力的老化特点。

Older adults encounter difficulty in recognizing speech in environments where multiple people are talking.Fundamental frequency(F0) contour is very important for speech recognition in daily communication and can serve as a perceptual cue to segregate speech from background noise. The effect of dynamic F0 contour cues on the speech recognition of younger adults in noisy environments has been widely studied, but the influence on older adults’ speech recognition, especially in tonal languages like Chinese, is still unclear.The present study explores whether older adults can benefit from dynamic F0 contour cues for Chinese speech recognition under the masking of speech with 12 elderly participants(6 female and 6 male, mean age 68.6 years) and 12 young participants(7 male and 5 female, aged 18~25 years old) possessing normal peripheral hearing. The speech recognition threshold for natural F0 contour sentences and the corresponding sentences with F0 contour manipulations(flattened vs. exaggerated) under two-speaker anomalous speech masking for younger adults and older adults were measured, as well as their ability to follow the target speech under speech masking.The results showed that natural dynamic F0 contour cues are important to Chinese speech recognition when multiple people are speaking. Speech recognition in all age groups improved with higher signal-to-noise ratios,but while natural F0 patterns facilitated performance of younger adults under speech masking, it had no significant effect on older adults. Under masking with two speakers, the natural dynamic F0 contour cues assist young adults to resist information masking more than a flattened or exaggerated F0 contour, but for the older adults, the speech intelligibility of the target sentences with a natural F0 contour was as poor as that of target sentences with flattened or exaggerated F0 contour.The availability of F0 contour cues seriously affects the benefits of dynamic F0 contour cues for older adults’ speech recognition against speech masking. There also appears to be an age-related reduction of the benefit from dynamic F0 contour cues in masked speech recognition, so the F0 contour of Chinese sentences may contribute more to speech recognition under speech masking for younger adults than for older adults.