Variability in vowel formant frequencies of children with cerebral palsy

Variability in vowel formant frequencies of children with cerebral palsy

腦性麻痺為發展性運動神經障礙，而研究腦性麻痺語言特徵及其發展模式對於幼童早期語言發展的了解相當重要。母音在初期語言發展就已出現並且是了解語音聲學特性的關鍵。本研究旨在檢視五位腦性麻痺嚴重程度不同以及年齡層介於三到七歲的腦性麻痺幼童之母音共振峰頻率的差異。測量F1和F2的變化、母音空間分佈、母音空間面積。本研究結果顯示：1）三歲到七歲之間沒有發現F2 明顯的下降；2）母音橢圓形軌跡都有明顯的重疊；3）母音分佈沒有顯著的擴張，研究結果顯示這五位腦性麻痺小朋友有語言運動神經不協調和發音發展遲緩的情形。

Cerebral palsy (CP) is a developmental motor disorder and the study of the speech characteristics and developmental speech patterns may provide valuable information on early speech development. Vowels appear early in speech development and they are central to the understanding of the acoustic properties of speech. Therefore, the current study aimed to examine the differences of vowel formant frequencies among five children with cerebral palsy in different severity ranging from ages 3 to 7. First and second vowel formants (F1 and F2) were measured to investigate: 1) the changes of the F1 and F2 values, 2) vowel space, and 3) the vowel space area in CP children of different ages and severity. The major findings are: 1) There was no obvious decline in F2 values from 3 to 7 years old, which indicated delayed speech development; 2) The overlapping ellipses of all vowel spaces illustrated unstable motor control in all the five children; and 3) The five CP children had centralized corner vowels and there was no expansion of vowel spaces at different ages. This indicated their limited motor control.