Speech-evoked neurophysiologic responses in children with learning problems: Development and behavioral correlates of perception

Objectives: To evaluate the maturational progression of speech-evoked P1/N1 /N2 cortical responses over the life span, determine whether responses are distinctive in clinical populations experiencing learning problems and eluc idate the functional significance of these responses. Design: The P1/N1/N2 complex was measured in 150 normal subjects (5 to 78 y r) and 86 subjects with learning problems (LP) (8 to 15 yr) to a synthetic CV syllable. Analyses included description and comparison of the developmen tal time course in both groups and evaluation of the relationship between P 1/N1/N2 and children's performance on speech discrimination tasks and stand ardized learning measures. Results: Findings revealed significant changes in waveform morphology, late ncy and amplitude as a function of age. Maturational patterns in the group of children with learning problems did not differ from the normal group. P1 /N1/N2 parameters were significantly correlated with standardized tests of Spelling, Auditory Processing and Listening Comprehension in the LP group. Moreover, there was a predictive relationship between Auditory Processing a nd N2 latency. Conclusions: The P1/N1/N2 complex changes throughout life from school-age t o old age. The developmental sequence throughout the school-age years is si milar in normal and LP children. Thus, differences in the rate of P1/N1/N2 latency and amplitude development do not appear to be distinctive in these two populations. The relationship between P1/N1/N2 parameters and standardi zed measures of learning (particularly between Auditory Processing and N2 l atency) provides new information about the role of these responses in heari ng and highlights the potential value in characterizing auditory processing deficits.