Masking release in cortical auditory evoked potentials with speech stimulus

Abstract

Purpose To analyze the effect of masking on the Cortical Auditory Evoked Potential with speech stimulus in young adults. Methods Fourteen individuals aged between 19 and 28 years of both sexes with no hearing loss participated in the study. The Cortical Auditory Evoked Potential examination was performed with synthetic speech stimulus /ba/ simultaneous to Speech Shaped Noise presented under three conditions: steady noise with a 30 dB SPLep intensity (weak steady noise), steady noise with a 65 dB SPLep intensity o (strong steady noise) and modulated noise with 30 dB SPLep and 65 dB SPLep intensities at 25Hz and modulation period of 40 ms. Results Higher latencies were observed in the cortical components, except P2, in the condition of strong steady noise and more meaningful measures of amplitude of the cortical components P1, N1 and P2 in the condition of modulated noise with statistically significant difference in comparison to the strong steady noise condition. There was worse wave morphology in the condition of strong steady noise, when compared to the other records. The average electrophysiological thresholds for the conditions of strong steady noise and modulated noise were 60 dB SPLep and 49 dB SPLep, respectively, showing a 11.7 dB mean difference. Conclusion We could infer that there was a lower masking effect of modulated noise when compared to the strong steady noise condition, in the amplitude measurements of the cortical components and an average difference of 11.7 dB between the electrophysiological thresholds (interpreted as the measure of the Masking Release).

Effect of Modulated Masking on Cortical Auditory Evoked Potential in Normal Hearing Individuals: A Systematic Review and Meta-analysis

“…The studies included were conducted between 2006 and 2023, in Germany, 14 the United Kingdom, 19 China, 15 the United States, 16,17 and Brazil. 18 Regarding the number of study participants, a minimum of 10 and a maximum of 30 individuals of both sexes were found, except for one study, 14 which did not specify the sex of the participants. The studies were conducted with young and adult participants, aged 19 to 55 years, and only one study 16 included elderly subjects.…”

“…In the quality assessment through the adapted NOS, the scores of the studies ranged from 5 to 7 points, and we identified that out of the six studies analyzed, five [14][15][16][17][18] had high methodological quality and one study 19 was identified as having moderate quality. All evaluated studies had low scores in the sample selection component, for they did not describe the sampling strategy neither did they jusstify the sample size.…”

“…As for the auditory profile of the participants, five [14][15][16][17][18] out of the six studies reported on the audiological assessment, with the use of pure tone audiometric thresholds. A variation in the evaluation parameters used could be observed: two studies 15,17 included the thresholds of frequencies from 250 Hz to 8.000 Hz, while two other studies 14,16 considered frequencies up to 4,000 Hz.…”

“…Such methodologies are not only complementary, but have the potential to assess temporal processing skills in participants who are unable to provide reliable behavioral responses. 8,9 Investigations on CAEPs make it possible to evaluate the entire auditory system, from the brainstem to the auditory cortex, and CAEPs can be obtained through different types of stimuli. 10 Moreover, studies on the auditory cortical wave complex (P1-N1-P2) provide important information on the neural processes responsible for speech perception, maturation of the auditory system, as well as the quality of auditory information processing.…”

“…In addition, such investigation aims to provide understanding of speech perception disorders in noise. 9 Considering the importance of studying cortical auditory measures with modulated maskers for a better understanding of the processes involved in speech recognition in noisy environments, in addition to the temporal processing skills involved in this aspect, the present review is considered relevant. The goal of the current study was to investigate the behavior of CAEPS with masking with and without modulation in the normal-hearing population, through a systematic review of the literature.…”