Supplementary Material for: Perceptual outcome measures for supplementing transcription intelligibility in speakers with Parkinson’s disease and mild dysarthria

Introduction: Intelligibility is the gold-standard metric of speech function in dysarthria; however, intelligibility alone may not capture subtle speech impairments. This study evaluated the extent to which related, but distinct, perceptual metrics of listener effort, speech severity, and speech naturalness were sensitive to mild speech impairment in speakers with Parkinson’s disease (PD), providing supplemental information to transcription intelligibility.
Methods: Speech samples were collected from 30 speakers with PD and 14 healthy controls. Listeners judged intelligibility using orthographic transcription and provided visual analog scale (VAS) judgments of listener effort, speech severity, and speech naturalness. A correlation analysis assessed the convergent validity between metrics. Linear mixed-effects analysis assessed differences between perceptual metrics.
Results: VAS ratings of listener effort were most strongly correlated with intelligibility, while speech naturalness had the weakest relationship to other perceptual measures and the poorest listener reliability. Transcription intelligibility scores were equivalently high for PD and control groups. VAS ratings of listener effort, speech severity, and speech naturalness were significantly lower than intelligibility scores across both groups.
Conclusion: For speakers with mild PD, transcription intelligibility did not capture subtle speech deficits detected by VAS metrics. Supplemental perceptual metrics provided a fuller picture of the speech impairment in these individuals.

引言：可懂度（Intelligibility）是构音障碍（dysarthria）患者言语功能的金标准评估指标，但仅依靠可懂度难以捕捉到细微的言语损伤。本研究评估了相关但彼此独立的听者努力程度、言语严重程度及言语自然度等感知指标对帕金森病（PD）患者轻度言语损伤的敏感度，旨在为转录可懂度提供补充信息。
方法：本研究共招募30名帕金森病患者与14名健康对照者，采集其言语样本。听者通过正字法转写评估言语可懂度，并采用视觉模拟量表（Visual Analog Scale, VAS）对听者努力程度、言语严重程度及言语自然度进行评分。通过相关分析评估各指标间的会聚效度，采用线性混合效应分析比较各感知指标间的差异。
结果：听者努力程度的VAS评分与可懂度的相关性最强，而言语自然度与其他感知指标的关联最弱，且听者评分的信度最差。帕金森病患者组与健康对照组的转录可懂度评分均处于较高水平且无显著差异。两组中，听者努力程度、言语严重程度及言语自然度的VAS评分均显著低于可懂度评分。
结论：对于轻度帕金森病患者而言，转录可懂度无法捕捉到VAS指标所识别出的细微言语缺陷；补充的感知指标能够更全面地展现该类人群的言语损伤状况。