A normative study of early prelingual auditory development.

The normal trajectory of early prelingual auditory development from birth to 24 months of age was characterized in a sample of 120 normal-hearing infants and toddlers of Mandarin-Chinese-speaking parents. The Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS) was administered to parents as a structured interview during routine pediatric health examinations. Developmental trajectories for the overall IT-MAIS score, as well as for scores on the subscales that assess behavioral evidence of spontaneous detection of and responsiveness to sound and of spontaneous recognition and discrimination of sound, were represented by logarithmic regression functions. On average, these regression functions characterized over 80% of the age-related variance in each scale. The developmental trajectories revealed that by 16 months the average infant exhibited spontaneous detection of and responsiveness to sound at all times, while spontaneous recognition and discrimination of sound was seen at all times after 26 months. The trajectory for the overall IT-MAIS scale, which combines the two subscales, reached ceiling at 22 months. The overall trajectory for Chinese infants closely matches the trajectory for normal-hearing infants of Arabic- and Hebrew-speaking parents in Israel. The Chinese IT-MAIS also exhibits similar internal consistency and item reliability to the German, Polish, and British English IT-MAIS scales. These similarities seen across culturally and linguistically diverse populations suggest the early prelingual auditory development follows the same, or a very similar course, in all infants.