Lebacq Jean, Schoentgen Jean, Cantarella Giovanna, Bruss Franz Thomas, Manfredi Claudia, DeJonckere Philippe
Neurosciences Institute, University of Louvain, Brussels, Belgium.
B.E.A.M.S. Department, Faculty of Applied Sciences, Université Libre de Bruxelles, Brussels, Belgium.
J Voice. 2017 Sep;31(5):550-556. doi: 10.1016/j.jvoice.2017.02.017. Epub 2017 Mar 18.
Smartphone technology provides new opportunities for recording standardized voice samples of patients and transmitting the audio files to the voice laboratory. This drastically improves the achievement of baseline designs, used in research on efficiency of voice treatments. However, the basic requirement is the suitability of smartphones for recording and digitizing pathologic voices (mainly characterized by period perturbations and noise) without significant distortion. In a previous article, this was tested using realistic synthesized deviant voice samples (/a:/) with three precisely known levels of jitter and of noise in all combinations. High correlations were found between jitter and noise to harmonics ratio measured in (1) recordings via smartphones, (2) direct microphone recordings, and (3) sound files generated by the synthesizer. In the present work, similar experiments were performed (1) in the presence of increasing levels of ambient noise and (2) using synthetic deviant voice samples (/a:/) as well as synthetic voice material simulating a deviant short voiced utterance (/aiuaiuaiu/).
Ambient noise levels up to 50 dB are acceptable. However, signal processing occurs in some smartphones, and this significantly affects estimates of jitter and noise to harmonics ratio when formant changes are introduced in analogy with running speech. The conclusion is that voice material must provisionally be limited to a sustained /a/.
智能手机技术为记录患者标准化语音样本并将音频文件传输至语音实验室提供了新机遇。这极大地提升了基线设计的达成度，该设计用于语音治疗效率的研究。然而，基本要求是智能手机要适合记录并数字化病理性语音（主要特征为周期扰动和噪声）且无明显失真。在之前的一篇文章中，通过使用具有三种精确已知的抖动和噪声水平所有组合的逼真合成异常语音样本（/a:/）对此进行了测试。发现在（1）通过智能手机录制、（2）直接用麦克风录制以及（3）合成器生成的声音文件中测量的抖动与噪声谐波比之间存在高度相关性。在本研究中，进行了类似实验：（1）在环境噪声水平不断增加的情况下，以及（2）使用合成异常语音样本（/a:/）以及模拟异常短语音发声（/aiuaiuaiu/）的合成语音材料。
高达50分贝的环境噪声水平是可接受的。然而，一些智能手机会进行信号处理，当引入类似于连续语音的共振峰变化时，这会显著影响抖动和噪声谐波比的估计。结论是语音材料目前必须限于持续的/a/音。
