Increased Intelligibility in Speakers With Parkinson's Disease (Tjaden et al., 2014)

<b>Purpose </b>A speech analysis-resynthesis paradigm was used to investigate segmental and suprasegmental acoustic variables explaining intelligibility variation for 2 speakers with Parkinson's disease (PD). <br><b>Method </b>Sentences were read in conversational and clear styles. Acoustic characteristics from clear sentences were extracted and applied to conversational sentences, yielding 6 hybridized versions of sentences in which segment durations, short-term spectrum, energy characteristics, or fundamental frequency characteristics for clear productions were applied individually or in combination to conversational productions. Listeners (<i>N</i> = 20) judged intelligibility in transcription and scaling tasks. Results Intelligibility increases above conversation were more robust for transcription, but the pattern of intelligibility improvement was similar across tasks. For 1 speaker, hybridization involving only clear energy characteristics yielded an 8.7% improvement in transcription intelligibility above conversation. For the other speaker, hybridization involving clear spectrum yielded an 18% intelligibility improvement, whereas hybridization involving both clear spectrum and duration yielded a 13.4% improvement. <br><b>Conclusions </b>Not all production changes accompanying clear speech explain its improved intelligibility. Suprasegmental adjustments contributed to intelligibility improvements when segmental adjustments, as inferred from vowel space area, were not robust. Hybridization can be used to identify acoustic variables explaining intelligibility variation in mild dysarthria secondary to PD.

**研究目的** 本研究采用语音分析-再合成范式，探究可解释2名帕金森病（PD）患者语音可懂度差异的音段（segmental）与超音段（suprasegmental）声学特征变量。<br><b>研究方法</b> 受试者以会话式与清晰式两种发音风格朗读语句。提取清晰式语句的声学特征，并将其应用于会话式语句，由此生成6种混合语句版本：将清晰发音的音段时长、短时频谱、能量特征或基频特征，以单独或组合的方式应用于会话式发音。招募20名听众（N=20）开展转录判读与量表评分任务，评估语句可懂度。<br><b>研究结果</b> 转录任务中，可懂度相较于会话式语音的提升幅度更为显著，但两类任务中可懂度改善的整体趋势保持一致。对于其中1名患者，仅应用清晰语音能量特征的混合方案，可使转录任务下的可懂度较会话式语音提升8.7%；对于另1名患者，应用清晰语音频谱特征的混合方案可实现18%的可懂度提升，而同时应用清晰语音频谱与时长特征的混合方案则可实现13.4%的提升。<br><b>研究结论</b> 并非清晰语音伴随的所有发音调整都能解释其可懂度提升效果。当通过元音空间面积推断得到的音段调整效果不显著时，超音段调整可有效改善语音可懂度。混合语音合成方法可用于识别继发性帕金森病轻症构音障碍患者中可解释语音可懂度差异的声学特征变量。