Lee Alice S Y, Whitehill Tara L, Ciocca Valter, Samman Nabil
Department of Speech and Hearing Sciences, University of Hong Kong, Hong Kong.
J Oral Maxillofac Surg. 2002 Apr;60(4):364-72; discussion 372-3. doi: 10.1053/joms.2002.31221.
Orthognathic surgery may have a positive or negative effect on speech. Perceptual evaluation of presurgical and postsurgical articulation is difficult because speech errors, when they occur, are usually fricative distortions, which may be difficult to document reliably. In this study, acoustic analysis was used to supplement perceptual judgment of presurgical and postsurgical productions of /s/.
The study population consisted of 9 Cantonese speakers undergoing osteotomy for Class III skeletal deformity and 9 age- and gender-matched adults with normal occlusion and speech. The speech sample consisted of 6 words with the initial sibilant sound /s/. Perceptual analysis included narrow phonetic transcription and classification of error types. Acoustic analysis included measurement of first and second spectral peaks, fricative duration, noise bandwidth, and noise-to-vowel decibel ratio.
The results of the perceptual analysis showed a decrease in articulatory errors for the group after surgery, although 5 patients had no perceptual errors before surgery. Acoustic analysis showed significant differences between the experimental and control groups before surgery for 2 variables (spectral peak I and bandwidth). Three months after surgery there were no significant differences between the control group and the experimental group, except for bandwidth. Twelve months after surgery, there were significant differences between the 2 groups in noise bandwidth and spectral peak II.
The results suggest a possible relapse at 1 year after surgery, based on spectral peak values. Osteotomy appears to result in a positive change in articulation for most patients, but speech outcome after osteotomy must be evaluated both 1 year and shortly after surgery.
正颌手术可能对语音产生正面或负面影响。术前和术后发音的感知评估较为困难，因为语音错误一旦出现，通常是擦音失真，可能难以可靠记录。在本研究中，使用声学分析来辅助对术前和术后/s/音发音的感知判断。
研究对象包括9名接受Ⅲ类骨骼畸形截骨术的粤语使用者，以及9名年龄和性别匹配、咬合与语音正常的成年人。语音样本由6个以清擦音/s/开头的单词组成。感知分析包括精细语音转录和错误类型分类。声学分析包括测量第一和第二频谱峰值、擦音时长、噪声带宽以及噪声与元音的分贝比。
感知分析结果显示，术后该组发音错误减少，尽管有5名患者术前无感知错误。声学分析表明，术前实验组和对照组在2个变量（频谱峰值I和带宽）上存在显著差异。术后3个月，除带宽外，对照组和实验组之间无显著差异。术后12个月，两组在噪声带宽和频谱峰值II上存在显著差异。
基于频谱峰值，结果提示术后1年可能出现复发。截骨术似乎使大多数患者的发音产生了积极变化，但截骨术后的语音结果必须在术后1年及术后不久进行评估。
