Speaking clearly for children with learning disabilities: sentence perception in noise

This study compared the speech-in-noise perception abilities of children with and without diagnosed learning disabilities (LDs) and investigated whether naturally produced clear speech yields perception benefits for these children. A group of children with LDs (n = 63) and a control group of children without LDs (n = 36) were presented with simple English sentences embedded in noise. Factors that varied within participants were speaking style (conversational vs. clear) and signal-to-noise ratio (-4 dB vs. -8 dB); talker (male vs. female) varied between participants. Results indicated that the group of children with LDs had poorer overall sentence-in-noise perception than the control group. Furthermore, both groups had poorer speech perception with decreasing signal-to-noise ratio; however the children with LDs were more adversely affected by a decreasing signal-to-noise ratio than the control group. Both groups benefited substantially from naturally produced clear speech, and for both groups, the female talker evoked a larger clear speech benefit than the male talker. The clear speech benefit was consistent across groups; required no listener training; and, for a large proportion of the children with LDs, was sufficient to bring their performance within the range of the control group with conversational speech. Moreover, an acoustic comparison of conversational-to-clear speech modifications across the two talkers provided insight into the acoustic-phonetic features of naturally produced clear speech that are most important for promoting intelligibility for this population.