Department of Communication Sciences and Disorders, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel.
J Speech Lang Hear Res. 2010 Feb;53(1):114-25. doi: 10.1044/1092-4388(2009/08-0184). Epub 2009 Nov 30.
The vowel space area (VSA) has been used as an acoustic metric of dysarthric speech, but with varying degrees of success. In this study, the authors aimed to test an alternative metric to the VSA-the formant centralization ratio (FCR), which is hypothesized to more effectively differentiate dysarthric from healthy speech and register treatment effects.
Speech recordings of 38 individuals with idiopathic Parkinson's disease and dysarthria (19 of whom received 1 month of intensive speech therapy [Lee Silverman Voice Treatment; LSVT LOUD]) and 14 healthy control participants were acoustically analyzed. Vowels were extracted from short phrases. The same vowel-formant elements were used to construct the FCR, expressed as (F2u + F2a + F1i + F1u) / (F2i + F1a), the VSA, expressed as ABS([F1i x (F2a - F2u) + F1a x (F2u - F2i) + F1u x (F2i - F2a)] / 2), a logarithmically scaled version of the VSA (LnVSA), and the F2i /F2u ratio.
Unlike the VSA and the LnVSA, the FCR and F2i/F2u ratio robustly differentiated dysarthric from healthy speech and were not gender sensitive. All metrics effectively registered treatment effects and were strongly correlated with each other.
Albeit preliminary, the present findings indicate that the FCR is a sensitive, valid, and reliable acoustic metric for distinguishing dysarthric from unimpaired speech and for monitoring treatment effects, probably because of reduced sensitivity to interspeaker variability and enhanced sensitivity to vowel centralization.
元音声区（VSA）已被用作构音障碍语音的声学度量，但成功率不一。在这项研究中，作者旨在测试 VSA 的替代度量——共振峰集中比（FCR），其被假设能更有效地区分构音障碍和健康语音，并能记录治疗效果。
对 38 名特发性帕金森病伴构音障碍患者（其中 19 名接受了 1 个月的强化言语治疗[Lee Silverman 嗓音治疗；LSVT LOUD]）和 14 名健康对照参与者的语音记录进行了声学分析。从短语中提取元音。使用相同的元音-共振峰元素构建 FCR，表达式为（F2u + F2a + F1i + F1u）/（F2i + F1a），VSA，表达式为 ABS([F1i x (F2a - F2u) + F1a x (F2u - F2i) + F1u x (F2i - F2a)] / 2)，VSA 的对数比例（LnVSA），以及 F2i/F2u 比值。
与 VSA 和 LnVSA 不同，FCR 和 F2i/F2u 比值能稳健地区分构音障碍和健康语音，且不受性别影响。所有度量指标都有效地记录了治疗效果，并且彼此之间高度相关。
尽管初步研究，但目前的研究结果表明，FCR 是一种敏感、有效且可靠的声学度量方法，可用于区分构音障碍和未受损语音，并监测治疗效果，这可能是因为它对说话人差异的敏感性降低，对元音集中的敏感性增强。
