scholarly journals Hearing Impaired Participants Improve More Under Envelope-Transcranial Alternating Current Stimulation When Signal to Noise Ratio Is High

2021 ◽  
Vol 16 ◽  
pp. 263310552098885
Author(s):  
Jules Erkens ◽  
Michael Schulte ◽  
Matthias Vormann ◽  
Anna Wilsch ◽  
Christoph S Herrmann

An issue commonly expressed by hearing aid users is a difficulty to understand speech in complex hearing scenarios, that is, when speech is presented together with background noise or in situations with multiple speakers. Conventional hearing aids are already designed with these issues in mind, using beamforming to only enhance sound from a specific direction, but these are limited in solving these issues as they can only modulate incoming sound at the cochlear level. However, evidence exists that age-related hearing loss might partially be caused later in the hearing processes due to brain processes slowing down and becoming less efficient. In this study, we tested whether it would be possible to improve the hearing process at the cortical level by improving neural tracking of speech. The speech envelopes of target sentences were transformed into an electrical signal and stimulated onto elderly participants’ cortices using transcranial alternating current stimulation (tACS). We compared 2 different signal to noise ratios (SNRs) with 5 different delays between sound presentation and stimulation ranging from 50 ms to 150 ms, and the differences in effects between elderly normal hearing and elderly hearing impaired participants. When the task was performed at a high SNR, hearing impaired participants appeared to gain more from envelope-tACS compared to when the task was performed at a lower SNR. This was not the case for normal hearing participants. Furthermore, a post-hoc analysis of the different time-lags suggest that elderly were significantly better at a stimulation time-lag of 150 ms when the task was presented at a high SNR. In this paper, we outline why these effects are worth exploring further, and what they tell us about the optimal tACS time-lag.

2020 ◽  
Vol 15 ◽  
pp. 263310552093662
Author(s):  
Jules Erkens ◽  
Michael Schulte ◽  
Matthias Vormann ◽  
Christoph S Herrmann

In recent years, several studies have reported beneficial effects of transcranial alternating current stimulation (tACS) in experiments regarding sound and speech perception. A new development in this field is envelope-tACS: The goal of this method is to improve cortical entrainment to the speech signal by stimulating with a waveform based on the speech envelope. One challenge of this stimulation method is timing; the electrical stimulation needs to be phase-aligned with the naturally occurring cortical entrainment to the auditory stimuli. Due to individual differences in anatomy and processing speed, the optimal time-lag between presentation of sound and applying envelope-tACS varies between participants. To better investigate the effects of envelope-tACS, we performed a speech comprehension task with a larger amount of time-lags than previous experiments, as well as an equal amount of sham conditions. No significant difference between optimal stimulation time-lag condition and best sham condition was found. Further investigation of the data revealed a significant difference between the positive and negative half-cycles of the stimulation conditions but not for sham. However, we also found a significant learning effect over the course of the experiment which was of comparable size to the effects of envelope-tACS found in previous auditory tACS studies. In this article, we discuss possible explanations for why our findings did not match up with those of previous studies and the issues that come with researching and developing envelope-tACS.


2000 ◽  
Vol 43 (3) ◽  
pp. 661-674 ◽  
Author(s):  
Pamela E. Souza

This study compared the ability of younger and older listeners to use temporal information in speech when that information was altered by compression amplification. Recognition of vowel-consonant-vowel syllables was measured for four groups of adult listeners (younger normal hearing, older normal hearing, younger hearing impaired, older hearing impaired). There were four conditions. Syllables were processed with wide-dynamic range compression (WDRC) amplification and with linear amplification. In each of those conditions, recognition was measured for syllables containing only temporal information and for syllables containing spectral and temporal information. Recognition of WDRC-amplified speech provided an estimate of the ability to use altered amplitude envelope cues. Syllables were presented with a high-frequency masker to minimize confounding differences in high-frequency sensitivity between the younger and older groups. Scores were lower for WDRC-amplified speech than for linearly amplified speech, and older listeners performed more poorly than younger listeners. When spectral information was unrestricted, the age-related decrement was similar for both amplification types. When spectral information was restricted for listeners with normal hearing, the age-related decrement was greater for WDRC-amplified speech than for linearly amplified speech. When spectral information was restricted for listeners with hearing loss, the age-related decrement was similar for both amplification types. Clinically, these results imply that when spectral cues are available (i.e., when the listener has adequate spectral resolution) older listeners can use WDRC hearing aids to the same extent as younger listeners. For older listeners without hearing loss, poorer scores for compression-amplified speech suggest an age-related deficit in temporal resolution.


2019 ◽  
Vol 23 ◽  
pp. 233121651988761 ◽  
Author(s):  
Gilles Courtois ◽  
Vincent Grimaldi ◽  
Hervé Lissek ◽  
Philippe Estoppey ◽  
Eleftheria Georganti

The auditory system allows the estimation of the distance to sound-emitting objects using multiple spatial cues. In virtual acoustics over headphones, a prerequisite to render auditory distance impression is sound externalization, which denotes the perception of synthesized stimuli outside of the head. Prior studies have found that listeners with mild-to-moderate hearing loss are able to perceive auditory distance and are sensitive to externalization. However, this ability may be degraded by certain factors, such as non-linear amplification in hearing aids or the use of a remote wireless microphone. In this study, 10 normal-hearing and 20 moderate-to-profound hearing-impaired listeners were instructed to estimate the distance of stimuli processed with different methods yielding various perceived auditory distances in the vicinity of the listeners. Two different configurations of non-linear amplification were implemented, and a novel feature aiming to restore a sense of distance in wireless microphone systems was tested. The results showed that the hearing-impaired listeners, even those with a profound hearing loss, were able to discriminate nearby and far sounds that were equalized in level. Their perception of auditory distance was however more contracted than in normal-hearing listeners. Non-linear amplification was found to distort the original spatial cues, but no adverse effect on the ratings of auditory distance was evident. Finally, it was shown that the novel feature was successful in allowing the hearing-impaired participants to perceive externalized sounds with wireless microphone systems.


Author(s):  
Л. Е. Голованова ◽  
Е. А. Огородникова ◽  
Е. С. Лаптева ◽  
М. Ю. Бобошко

Целью исследования было изучение качества жизни лиц с нарушениями слуха в разных возрастных группах. Обследованы 100 пациентов, обратившихся в городской сурдологический центр для взрослых в связи с нарушением слуха: 50 человек - 34-59 лет, 50 - 60 лет и старше, из которых 32 человека были пожилого возраста (60-74 года)и 18 - старческого (75-86 лет). Степень тугоухости оценивали на основании результатов тональной пороговой аудиометрии. Для исследования качества жизни все пациенты заполняли общий опросник MOS SF-36, отражающий физический и психологический компоненты здоровья, а также специальный опросник HHIА(E)-S для лиц с нарушениями слуха. Установлено, что шкала HHIА(E)-S демонстрирует высокую корреляцию со степенью тугоухости у пациентов моложе 60 лет ( R =0,98; достоверность различий на уровне p <0,05), которая снижается у пациентов 60 лет и старше ( R =0,94; различия в оценках при разной степени тугоухости недостоверны). Значительные трудности в старшей возрастной группе могут быть связаны с тем, что людям пожилого и, особенно, старческого возраста сложно пользоваться слуховыми аппаратами (или они для них неэффективны) и оценивать свои затруднения по шкалам опросника. Целесообразно использовать шкалу HHIА(Е)-S в качестве скринингового инструмента для раннего выявления тугоухости, направления пациентов к сурдологу и своевременного слухопротезирования. The aim of the research was to study the quality of life in hearing impaired patients of different age. 100 patients referred to the city audiology centre because of their hearing disorders were examined: 50 patients from 34 to 59 years old and 50 patients from 60 years and older, from which 32 patients were of older age (60 to 74 years old) and 18 of oldest age (75 to 86 years old). A degree of hearing loss was assessed according to results of pure tone audiometry. To study the quality of life all patients filled in the questionnaire MOS SF-36, which evaluates physical and psychological components of health, and the questionnaire HHIA(E)-S, designed specifically for patients with hearing disorders. The HHIA(E)-S scale was found to show high correlation with hearing loss degree in patients younger than 60 years old ( R =0,98 with statistically significant difference, p <0,05), with decreasing correlation in patients from 60 years and older ( R =0,98; no significant difference while assessing various hearing loss degrees). Considerable difficulties in this age group may be explained by the fact, that older and especially oldest patients have a challenge with hearing aids usage (or they are of low efficiency for them) and with assessing theirs difficulties on the questionnaire scales. The HHIA(E)-S scale is useful as a screening tool for early detection of hearing loss, referral of patients to an audiologist and prompt hearing aid fitting.


2004 ◽  
Vol 116 (4) ◽  
pp. 2395-2405 ◽  
Author(s):  
Mead C. Killion ◽  
Patricia A. Niquette ◽  
Gail I. Gudmundsen ◽  
Lawrence J. Revit ◽  
Shilpi Banerjee

2005 ◽  
Vol 48 (5) ◽  
pp. 1165-1186 ◽  
Author(s):  
Tracy S. Fitzgerald ◽  
Beth A. Prieve

Although many distortion-product otoacoustic emissions (DPOAEs) may be measured in the ear canal in response to 2 pure tone stimuli, the majority of clinical studies have focused exclusively on the DPOAE at the frequency 2f1-f2. This study investigated another DPOAE, 2f2-f1, in an attempt to determine the following: (a) the optimal stimulus parameters for its clinical measurement and (b) its utility in differentiating between normal-hearing and hearing-impaired ears at low-to-mid frequencies (≤2000 Hz) when measured either alone or in conjunction with the 2f1-f2 DPOAE. Two experiments were conducted. In Experiment 1, the effects of primary level, level separation, and frequency separation (f2/f1) on 2f2-f1 DPOAE level were evaluated in normal-hearing ears for low-to-mid f2 frequencies (700–2000 Hz). Moderately high-level primaries (60–70 dB SPL) presented at equal levels or with f2 slightly higher than f1 produced the highest 2f2-f1 DPOAE levels. When the f2/f1 ratio that produced the highest 2f2-f1 DPOAE levels was examined across participants, the mean optimal f2/f1 ratio across f2 frequencies and primary level separations was 1.08. In Experiment 2, the accuracy with which DPOAE level or signal-to-noise ratio identified hearing status at the f2 frequency as normal or impaired was evaluated using clinical decision analysis. The 2f2-f1 and 2f1-f2 DPOAEs were measured from both normal-hearing and hearing-impaired ears using 2 sets of stimulus parameters: (a) the traditional parameters for measuring the 2f1-f2 DPOAE (f2/f1 = 1.22; L1, L2 = 65, 55 dB SPL) and (b) the new parameters that were deemed optimal for the 2f2-f1 DPOAE in Experiment 1 (f2/f1 = 1.073, L1 and L2 = 65 dB SPL). Identification of hearing status using 2f2-f1 DPOAE level and signal-to-noise ratio was more accurate when the new stimulus parameters were used compared with the results achieved when the 2f2-f1 DPOAE was recorded using the traditional parameters. However, identification of hearing status was less accurate for the 2f2-f1 DPOAE measured using the new parameters than for the 2f1-f2 DPOAE measured using the traditional parameters. No statistically significant improvements in test performance were achieved when the information from the 2 DPOAEs was combined, either by summing the DPOAE levels or by using logistic regression analysis.


1992 ◽  
Vol 35 (4) ◽  
pp. 942-949 ◽  
Author(s):  
Christopher W. Turner ◽  
David A. Fabry ◽  
Stephanie Barrett ◽  
Amy R. Horwitz

This study examined the possibility that hearing-impaired listeners, in addition to displaying poorer-than-normal recognition of speech presented in background noise, require a larger signal-to-noise ratio for the detection of the speech sounds. Psychometric functions for the detection and recognition of stop consonants were obtained from both normal-hearing and hearing-impaired listeners. Expressing the speech levels in terms of their short-term spectra, the detection of consonants for both subject groups occurred at the same signal-to-noise ratio. In contrast, the hearing-impaired listeners displayed poorer recognition performance than the normal-hearing listeners. These results imply that the higher signal-to-noise ratios required for a given level of recognition by some subjects with hearing loss are not due in part to a deficit in detection of the signals in the masking noise, but rather are due exclusively to a deficit in recognition.


2018 ◽  
Vol 22 ◽  
pp. 233121651775354 ◽  
Author(s):  
Gilles Courtois ◽  
Hervé Lissek ◽  
Philippe Estoppey ◽  
Yves Oesch ◽  
Xavier Gigandet

2000 ◽  
Vol 43 (4) ◽  
pp. 902-914 ◽  
Author(s):  
Patricia G. Stelmachowicz ◽  
Brenda M. Hoover ◽  
Dawna E. Lewis ◽  
Reinier W. L. Kortekaas ◽  
Andrea L. Pittman

In this study, the influence of stimulus context and audibility on sentence recognition was assessed in 60 normal-hearing children, 23 hearing-impaired children, and 20 normal-hearing adults. Performance-intensity (PI) functions were obtained for 60 semantically correct and 60 semantically anomalous sentences. For each participant, an audibility index (AI) was calculated at each presentation level, and a logistic function was fitted to rau-transformed percent-correct values to estimate the SPL and AI required to achieve 70% performance. For both types of sentences, there was a systematic age-related shift in the PI functions, suggesting that young children require a higher AI to achieve performance equivalent to that of adults. Improvement in performance with the addition of semantic context was statistically significant only for the normal-hearing 5-year-olds and adults. Data from the hearing-impaired children showed age-related trends that were similar to those of the normal-hearing children, with the majority of individual data falling within the 5th and 95th percentile of normal. The implications of these findings in terms of hearing-aid fitting strategies for young children are discussed.


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