[The characteristics and development of auditory skill for infants with different age after cochlear implantation]

To analyze the characteristics and development of auditory skill for infants with different age before and after cochlear implantation by using infant-toddler meaningful auditory integration scale (IT-MAIS) questionnaire, and provide the useful information for the criteria of candidacy for cochlear implantation in infants and habilitation after cochlear implantation.

One hundred and thirty-nine prelingually infants with profound hearing loss were included in this study. According to the age at implantation, the infants were divided into 5 groups. They were group A ( < or =12 months), B (13-18 months), C (19-24 months), D (25-30 months) and E (31-36 months). Audiologists who were trained before this study used the IT-MAIS questionnaire to evaluate the auditory skill for all the infants and asked for the parents' or guardians' answers face to face. All the information about the infants spontaneous auditory behavioural responses was recorded in detail. The evaluation was performed before operation and 1 month, 3 months, 6 months, 12 months after switch-on.

There were no significant differences in mean scores over time between different gender who received cochlear implants by Independent-Samples T Test (P > 0.05). There were no significant differences in mean scores over time among the 5 groups by Multiple Comparison in ANOVA (P > 0.05). The scores were increased with time and there were significant differences in mean scores among the different time before and after switch-on by Multiple Comparison in ANOVA (P < 0.05) for each group.

The development of the auditory skill for infants followed the same rate in different gender. The auditory skill for infants after cochlear implantation developed rapidly regardless of age at implantation. Most of infants indicated rapid improvement in auditory skill within the first 6 months after switch-on, and then showed relative slow increase in the following 6 months.