The purpose of this study is to compare the characteristics of psychophysical tests between cochlear implant children with large vestibular aqueduct syndrome and normal inner ear and to analyse the characteristics of psychophysical and impedance tests for cochlear implant patients with large vestibular aqueduct syndrome. One hundred and thirty-one cochlear implant pre-lingual deafness patients participated in this study. They received cochlear implant surgery at the age of 1.5 to 12 years old from Nov, 1998 to Aug, 2003. The patients were divided into two groups. Group A had 111 patients with normal inner ear. Group B had 20 patients with radiographically proven large vestibular aqueduct syndrome. All of the patients were inserted with Nucleus 24M. The time of the first programming session was approximately 4 weeks after surgery. The psychophysical tests included T and C-Level tests. The programming techniques used in the test were suitable for the age of the patients. The R116 and R126 software were used to