Neural Representation of Amplified Speech Sounds

Tremblay, Kelly L.; Billings, Curtis J.; Friesen, Lendra; Souza, Pamela E.

doi:10.1097/01.aud.0000202288.21315.bd

Cited by 98 publications

(126 citation statements)

References 49 publications

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“…Some authors have studied the effect of intensity by means of interfacing with a hearing aid. A study showed that speech evoked a cortical response in normal-hearing individuals with and without amplification and found no significant effect of amplification (gain) in latency or amplitude [20] . In a previous study [17] , intensity function in hearing impaired elderly in aided conditionswas investigated by varying the intensity of the pure tones through a hearing aid, and it was reported that a larger amplitude at P2 only in the aided condition.…”

Section: Introductionmentioning

confidence: 99%

“…CAEP differences between speech stimuli are an indication of different underlying neural representations of speech sounds and suggest that the information needed to differentiate the stimuli is available to the listener. There has been increasing interest in the use of cortical potentials to investigate the neural encoding of speech [20] . However, the influence of various parameters of speech stimulus on ALLR is less studied, especially stimulus intensity.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Intensity on the Speech Evoked Auditory Late Latency Response in Normal Hearing Individuals

Prakash

Abraham²,

Rajashekar³

et al. 2016

Int Adv Otol

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OBJECTIVE:Among the stimulus factors, the influence of presentation level is less studied in normal-hearing individuals when using speech stimuli withvarious presentation levels for the auditory late latency response (ALLR). Hence, the present study aimed to explore the Latency-Intensity (L-I) function, i.e., how the latency and amplitude change as a function of intensity using speech stimuli. MATERIALS and METHODS:Speech-evoked ALLR was obtained from 15 normal-hearing individuals. The syllable/ta/ was used to record ALLR with an intensity of 30, 50, 70, and 90 dBSPL. Electroencephalography (EEG) from five channels was recorded and analyzed offline. RESULTS:The overall results revealed that there is an influence of intensity on P1 and N1 latencies in a nonlinear fashion. The latency change is consistent at lower intensities than at moderate and high intensities. The amplitude changes did not reach significance, though a decrease with a reduction in intensity was obvious. CONCLUSION:There is a significant effect of intensity on the latency and amplitude of ALLR in speech stimulus. However, this effect may vary for different speech stimuli.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Effect of Intensity on the Speech Evoked Auditory Late Latency Response in Normal Hearing Individuals

Prakash

Abraham²,

Rajashekar³

et al. 2016

Int Adv Otol

View full text Add to dashboard Cite

show abstract

“…Natural speech was used as the stimulus because LLRs for natural speech show remarkable stability between recordings from the same individual. Given this stability, any significant alteration in morphology would likely reflect changes in neural activation to speech and not simply random variability [23] . Most auditory-evoked responses are onset responses triggered by the leading edge as well as the first few tens of milliseconds of the stimulus envelope, for which there is some integration of sound energy.…”

Section: Stimuli For Recording Llrsmentioning

confidence: 99%

Cortical Evoked Potentials and Hearing Aids in Individuals with Auditory Dys-Synchrony

Yuvaraj

Mohan²

2016

Int Adv Otol

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OBJECTIVE:The purpose of the present study was to investigate the relationship between cortical processing of speech and benefit from hearing aids in individuals with auditory dys-synchrony. MATERIALS and METHODS:Data were collected from 38 individuals with auditory dys-synchrony. Participants were selected based on hearing thresholds, middle ear reflexes, otoacoustic emissions, and auditory brain stem responses. Cortical-evoked potentials were recorded for click and speech. Participants with auditory dys-synchrony were fitted with bilateral multichannel wide dynamic range compression hearing aids. Aided and unaided speech identification scores for 40 words were obtained for each participant. RESULTS:Hierarchical cluster analysis using Ward's method clearly showed four subgroups of participants with auditory dys-synchrony based on the hearing aid benefit score (aided minus unaided speech identification score). The difference in the mean aided and unaided speech identification scores was significantly different in participants with auditory dys-synchrony. However, the mean unaided speech identification scores were not significantly different between the four subgroups. The N2 amplitude and P1 latency of the speech-evoked cortical potentials were significantly different between the four subgroups formed based on hearing aid benefit scores. CONCLUSION:The results indicated that subgroups of individuals with auditory dys-synchrony who benefit from hearing aids exist. Individuals who benefitted from hearing aids showed decreased N2 amplitudes compared with those who did not. N2 amplitude is associated with greater suppression of background noise while processing speech.

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“…Cortical auditory evoked potentials (CAEPs) are noninvasive electrophysiological measures of central auditory system function that may help to determine how hearing aid signal processing is affecting neural encoding and resulting perception (Tremblay, Billings, Friesen, & Souza, 2006). To be specific, P1-N1-P2 CAEPs are sometimes used clinically to estimate hearing thresholds and is therefore a potential tool for measuring the neural representation and threshold of amplified sound (for a review see Martin, Tremblay, & Korczak, 2008).…”

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confidence: 99%

Aided Electrophysiology Using Direct Audio Input: Effects of Amplification and Absolute Signal Level

et al. 2016

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Purpose This study investigated (a) the effect of amplification on cortical auditory evoked potentials (CAEPs) at different signal levels when signal-to-noise ratios (SNRs) were equated between unaided and aided conditions, and (b) the effect of absolute signal level on aided CAEPs when SNR was held constant. Method CAEPs were recorded from 13 young adults with normal hearing. A 1000-Hz pure tone was presented in unaided and aided conditions with a linear analog hearing aid. Direct audio input was used, allowing recorded hearing aid noise floor to be added to unaided conditions to equate SNRs between conditions. An additional stimulus was created through scaling the noise floor to study the effect of signal level. Results Amplification resulted in delayed N1 and P2 peak latencies relative to the unaided condition. An effect of absolute signal level (when SNR was constant) was present for aided CAEP area measures, such that larger area measures were found at higher levels. Conclusion Results of this study further demonstrate that factors in addition to SNR must also be considered before CAEPs can be used to clinically to measure aided thresholds.

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Neural Representation of Amplified Speech Sounds

Abstract: Speech-evoked cortical potentials can be recorded reliably in individuals during hearing aid use. A better understanding of how amplification (and device settings) affects neural response patterns is still needed.

Cited by 98 publications

References 49 publications

The Effect of Intensity on the Speech Evoked Auditory Late Latency Response in Normal Hearing Individuals

The Effect of Intensity on the Speech Evoked Auditory Late Latency Response in Normal Hearing Individuals

Cortical Evoked Potentials and Hearing Aids in Individuals with Auditory Dys-Synchrony

Aided Electrophysiology Using Direct Audio Input: Effects of Amplification and Absolute Signal Level

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