Maturation of cortical auditory evoked potentials (CAEPs) to speech recorded from frontocentral and temporal sites: Three months to eight years of age

Abstract

The goal of the current analysis was to examine the maturation of cortical auditory evoked potentials (CAEPs) from three months of age to eight years of age. The superior frontal positive-negative-positive sequence (P1, N2, P2) and the temporal site, negative-positive-negative sequence (possibly, Na, Ta, Tb of the T-complex) were examined. Event-related potentials were recorded from 63 scalp sites to a 250- ms vowel. Amplitude and latency of peaks were measured at left and right frontal sites (near Fz) and at left and right temporal sites (T7 and T8). In addition the largest peak (typically corresponding to P1) was selected from global field power (GFP). The results revealed a large positive peak (P1) easily identified at frontal sites across all ages. The N2 emerged after 6 months of age and the following P2 between 8 and 30 months of age. The latencies of these peaks decreased exponentially with the most rapid decrease observed for P1. For amplitude, only P1 showed a clear relationship with age, becoming more positive in a somewhat linear fashion. At the temporal sites only a negative peak, which might be Na, was clearly observed at both left and right sites in children older than 14 months and peaking between 100 and 200 ms. P1 measures at frontal sites and Na peak latencies were moderately correlated. The temporal negative peak latency showed a different maturational timecourse (linear in nature) than the P1 peak, suggesting at least partial independence. Distinct Ta (positive) and Tb (negative) peaks, following Na and peaking between 120 and 220 ms were not consistently found in most age groups of children, except Ta which was present in 7 year olds. Future research, which includes manipulation of stimulus factors, and use of modeling techniques will be needed to explain the apparent, protracted maturation of the temporal site measures in the current study.

Audição e linguagem em crianças nascidas a termo e pré-termo

“…The subjects of this study already presented the exogenous components P1 and N1 of the cortical potentials, when evaluated with 1 month of life, results that are in agreement with other studies (9,16,17) . Regarding the evaluation carried out after two years and six months, which verified the presence of components P2 and N2 of CAEP, observing, in the descriptive analysis, the mean latencies in milliseconds, it is known that other authors, when researching CAEP in the age group from 1 year and 9 months to 2 years and 6 months old, observed P2 latencies in 332 milliseconds (21) . In the same study, children who were 2 years and 6 months presented significantly lower latencies when compared to the ones from younger age groups of 12 and 18 months.…”

“…It is believed that from cortical maturation, these components originate the cortical endogenous complex in adults (20) . In order to clarify the effects of maturation of CAEP components, some studies (6,21) indicate the relationship between the variable age and the reduction of latencies of P1 and N1. The reduction in latency values is related to the gradual process of myelination of the central structures and maturation of central auditory pathways, which are processes of cortical organization that are necessary for the proper development of hearing and language (1,6) .…”

Potenciais corticais auditivos: uso de diferentes estímulos de fala em populações infantis

“…The mean latency intervals for P1, N1, P2 and N2 components ranged from 87 ms to 221 ms for children in the studied age range, according to the reference of other studies that used complex stimuli (11,12,24) . The morphology analysis of LLAEP P1-N1-P2 complex, regarding speech stimuli, expresses exogenous responses related to the acoustic characteristics of sound processing (1) .…”

“…LLAEP are recorded and analyzed by a sequence of peaks with positive-negative polarity, i.e., P1, N1, P2, N2 and P3. In the literature, authors reported that the components P1, N1, P2 and N2, when generated by speech stimuli, vary from 100 ms to 300 ms (11,12) . The P1-N1-P2 complex signals the neural processing of the acoustic signal at the level of the auditory cortex and can be elicited in response to tonal and speech stimuli, presenting the syllable /da/.…”

Maturação dos potenciais evocados auditivos de longa latência em crianças ouvintes: análise do complexo P1-N1-P2-N2

“…Despite these findings, other studies only infrequently observe the components P1 and N1 in infants and children, with the component P2 being the most encountered (17) . On the other hand, in another study, it was observed that only the P1 peak was clearly present in children of 3 to 7 months of age (18) and that, additionally, the components N1 and P2 are observed with greater frequency from 12 years of age (12) . Given the divergence between these results, the need for further research that would evaluate LLAEP in small children becomes evident.…”