The influence of speech stimuli contrast in cortical auditory evoked potentials

Abstract

The speech stimulus contrast, vocalic or consonantal, must be taken into account in the analysis of the cortical auditory evoked potential, N2 component, and auditory cognitive P3 potential.

Potenciais evocados auditivos corticais em neonatos nascidos a termo e pré-termo

“…Moreover, the wave N2 presents greater negativity in children under five years old, becoming stable only after this age. Exogenous potentials are known as cortical auditory evoked potentials, whereas the endogenous potential is known as the cognitive potential (6) . From birth, responses in the CAEP, whether by stimulation of pure tones and/or by complex stimuli (syllables), show the organization of cortical generators and the development of the central auditory system (7) .…”

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

“…Therefore, recognition becomes more complex and the speed and quality of auditory processing can be affected. Thus, the response latency of the late component of LLAEP observed in this research can be justified by the complexity of the speech stimulus discrimination in Test 1 (6) . The increased amplitude for the P3 component, in this study, suggests changes in the synaptic magnitude (27) , compatible with the greater demand for electrical activation, necessary for the distinction between /ba/ x /da/.…”

“…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/. The presence of the P1-N1-P2 complex suggests that the speech was coded at the level of the auditory cortex and the absence of response is consistent with some imprecision in this process (6,13,14,15) . Some authors have carried out studies on the influence of vowel and consonant speech stimuli on long-latency auditory evoked potentials in children and adults with normal hearing, and could observe that there was influence on the measurements of the components P1, N1, N2 and P3, due to the level of complexity of the speech stimulus (16,17) .…”

“…The morphology analysis of LLAEP P1-N1-P2 complex, regarding speech stimuli, expresses exogenous responses related to the acoustic characteristics of sound processing (1) . The use of different speech stimuli with phonemic contrasts expresses the complexity of acoustic information at the level of the cortex and throughout the maturation of the auditory system (6,12) . In children older than 6 years, the response of the exogenous components of LLAEP is similar to that of adults, which justifies the choice of the population of this study (12) .…”

“…LLAEP recording and analysis can be elicited through different types of stimulus. The most used are pure tone and tone burst, but the literature (5,6) has demonstrated the use of speech stimuli to elicit the response of these potentials, emphasizing the possibility of analyzing complex signals in the auditory cortex through these measures (7,8) . Auditory potentials, when generated by speech stimuli, seek to understand the underlying processes of speech coding and decoding in the central auditory system.…”