[The changes of fundamental frequency and formants of vowel in cochlear implant pre-lingual children of different age].

OBJECTIVE: To observe the changes of fundamental frequency and formants of vowel in cochlear implant pre-lingual children of different age and to provide the basis and direction for post-operative rehabilitation. To find the key period of language development from the aspect of phonetics and to illustrate the necessity of early implantation.

METHOD: Nineteen pre-lingual cochlear implant children age from 3-13 who use 24 M or 24 Contour implant and Esprint speech processor participate the experiment. Voice analysis software was Vs99 which was explored by Beijing yangchen electronic technology corporation. Fundamental frequency and formants were abstracted from the sustained segment of vowel[a:].

RESULT: No significant difference of fundamental frequency was found between the age 4 group and normative group. Significant difference of fundamental frequency was found between the age 10 group and normative group (P < 0.05). No significant difference of formant 1 was found between the age 4 group and normative group. Significant difference of formant 1 was found between the age 10 group and normative group (P < 0.01). Formant 2 of the age 4 group was higher than the normative group, significantly. No significant difference of formant 2 was found between the age 10 group and normative group. No significant difference of the ratio of formant 1 to 2 was found between the age 4 group and normative group. Significant difference of the ratio of formant 1 to 2 was found between the age 10 group and normative group (P < 0.01).

CONCLUSION: The phonation of the children from the age 4 to age 10 was obviously affected by age. This stage was the key stage for language development.