Lombard and sidetone amplification effects in normal and misarticulating children.

Misarticulating and normal-speaking children participated in Lombard and sidetone amplification procedures, under standard instructions and under instructions designed to maximize the response to the procedures. The experimental group consisted of twelve 8-year-old children who misarticulated the /r/ sound. They were matched with normal-speaking school peers. In the Lombard procedure, the children told stories about familiar pictures under 60 dB SPL and 90 dB SPL of masking noise. In the sidetone amplification procedure, they performed the same task under 0 and +20 dB of amplified feedback. The dependent measure was vocal intensity. Both groups increased intensity under the noise and decreased under amplification. The instructions enhanced the effects for both groups, but more for the normals than for the misarticulating children in the case of the sidetone amplification procedure. In general, the procedures were effective with both groups, and there was no evidence that misarticulating children suffer from a generalized deficit in feedback processing.