Consonant articulation acoustics and intelligibility in Swedish speakers with Parkinson’s disease: a pilot study

Imprecise consonant articulation is common in speakers with Parkinson’s disease and can affect intelligibility. The research on the relationship between acoustic speech measures and intelligibility in Parkinson’s disease is limited, and most of the research has been conducted on English. This pilot study investigated aspects of consonant articulation acoustics in eleven Swedish speakers with Parkinson’s disease and six neurologically healthy persons. The focus of the study was on consonant cluster production, articulatory motion rate and variation, and voice onset time, and how these acoustic features correlate with speech intelligibility. Among the measures in the present study, typicality ratings of heterorganic consonant clusters /spr/ and /skr/ had the strongest correlations with intelligibility. Measures based on syllable repetition, such as repetition rate and voice onset time, showed varying results with weak to moderate correlations with intelligibility. One conclusion is that some acoustic measures may be more sensitive than others to the impact of the underlying sensory-motor impairment and dysarthria on speech production and intelligibility in speakers with Parkinson’s disease. Some aspects of articulation appear to be equally demanding in terms of acoustic realisation for elderly healthy speakers and for speakers with Parkinson’s disease, such as sequential motion rate measures. Clinically, this would imply that for the purpose of detecting signs of disordered speech motor control, choosing measures with less variation among older speakers without articulation impairment would lead to more robust results.

帕金森病患者常出现辅音发音不准确的情况，且该症状会影响言语可懂度（intelligibility）。目前针对帕金森病患者的声学言语指标与言语可懂度之间关联的研究较为有限，且多数相关研究均以英语群体为对象。本预实验对11名瑞典籍帕金森病患者与6名神经系统健康对照者的辅音发音声学特征展开了研究，考察重点包括辅音丛发音、发音运动速率与变异度、嗓音起始时间（Voice Onset Time, VOT），以及上述声学特征与言语可懂度的关联模式。在本研究采用的各项指标中，异部位辅音丛/spr/与/skr/的典型性评分与言语可懂度的相关性最强。基于音节重复的指标（如重复速率与嗓音起始时间）则呈现出不一的结果，其与言语可懂度的相关性处于弱至中等水平。本研究得出的一项结论为：相较于其他指标，部分声学指标对帕金森病患者潜在的感觉运动损伤与构音障碍（dysarthria）带来的言语产生与可懂度变化更为敏感。部分发音特征的声学实现难度对老年健康者与帕金森病患者而言并无显著差异，例如连续运动速率指标。从临床角度而言，若旨在检测言语运动控制异常的早期征象，选取在无构音障碍的老年人群中变异度更低的指标，将能获得更为可靠的研究结果。