Correction Factor Evaluation and Between-System Comparison of Behavioral Threshold Predictions From Auditory Brainstem Response Measures in Infants.

Purpose: Auditory brainstem response (ABR) thresholds are corrected to estimate behavioral thresholds in infants. Corrections were validated, and a comparison of behavioral threshold estimates between systems was conducted to inform equipment transition and protocols in Ontario, Canada.

Method: In Study 1, a retrospective file review was conducted.

Parent-Reported Ease of Listening in Preschool-Aged Children With Bilateral and Unilateral Hearing Loss.

Objectives: Evidence from school-aged children suggests that the ease with which children listen varies with the presence of hearing loss and the acoustic environment despite the use of devices like hearing aids. However, little is known about the ease of listening in preschool-aged children with hearing loss-an age at which rapid learning occurs and increased listening difficulty or effort may diminish the required capacity to learn new skills. To this end, the objectives of the present study were to (i) assess parent-reported aided ease of listening as a function of hearing loss configuration (hearing loss in one versus both ears) and device configuration among children with hearing loss in one ear (unilateral hearing loss), and (ii) investigate factors that influence children's ease of listening.

Neural Envelope Processing at Low Frequencies Predicts Speech Understanding of Children With Hearing Loss in Noise and Reverberation.

Objective: Children with hearing loss experience greater difficulty understanding speech in the presence of noise and reverberation relative to their normal hearing peers despite provision of appropriate amplification. The fidelity of fundamental frequency of voice (f0) encoding-a salient temporal cue for understanding speech in noise-could play a significant role in explaining the variance in abilities among children. However, the nature of deficits in f0 encoding and its relationship with speech understanding are poorly understood.

Factors that influence stress in caregivers of 5-year-old children with hearing loss wearing hearing aids or cochlear implants.

Objective: Stress levels among caregivers of children with hearing loss could influence caregiver-child interactions and ultimately, children's developmental outcomes. Given the limited understanding of stress levels among caregivers of Australian children with hearing loss, the present study aimed to examine stress in caregivers of 5-year-old children with hearing loss wearing hearing aids or cochlear implants and to identify factors associated with greater stress levels.

Methods: A total of 99 caregivers of 70 hearing aid users and 29 cochlear implant users participated in the study.

Assessing Speech Audibility via Syllabic-Rate Neural Responses in Adults and Children With and Without Hearing Loss.

An objective method for assessing speech audibility is essential to evaluate hearing aid benefit in children who are unable to participate in hearing tests. With consonant-vowel syllables, brainstem-dominant responses elicited at the voice fundamental frequency have proven successful for assessing audibility. This study aimed to harness the neural activity elicited by the slow envelope of the same repetitive consonant-vowel syllables to assess audibility.

Development of amplitude modulation, voice onset time, and consonant identification in noise and reverberation.

Children's speech understanding is vulnerable to indoor noise and reverberation: e.g., from classrooms.

The Use of Telepractice to Administer Norm-Referenced Communication and Cognition Assessments in Children With Hearing Loss: A Rapid Review.

Purpose: Telepractice administration of norm-referenced assessments of communication and cognition is relatively new, and evidence to support this practice for children with hearing loss is limited. This rapid review examines the validity, reliability, feasibility, and common features of telepractice-administered norm-referenced assessments of communication and cognition for children with hearing loss to determine whether results via telepractice-administration are usable.

Method: This rapid review was conducted in accordance with the Cochrane Collaboration Rapid Reviews Methods Group recommendations.

Auditory brainstem mechanisms likely compensate for self-imposed peripheral inhibition.

Feedback networks in the brain regulate downstream auditory function as peripheral as the cochlea. However, the upstream neural consequences of this peripheral regulation are less understood. For instance, the medial olivocochlear reflex (MOCR) in the brainstem causes putative attenuation of responses generated in the cochlea and cortex, but those generated in the brainstem are perplexingly unaffected.

Differences between children and adults in the neural encoding of voice fundamental frequency in the presence of noise and reverberation.

Environmental noise and reverberation challenge speech understanding more significantly in children than in adults. However, the neural/sensory basis for the difference is poorly understood. We evaluated the impact of noise and reverberation on the neural processing of the fundamental frequency of voice (f )-an important cue to tag or recognize a speaker.

Predicting Hearing aid Benefit Using Speech-Evoked Envelope Following Responses in Children With Hearing Loss.

Electroencephalography could serve as an objective tool to evaluate hearing aid benefit in infants who are developmentally unable to participate in hearing tests. We investigated whether speech-evoked envelope following responses (EFRs), a type of electroencephalography-based measure, could predict improved audibility with the use of a hearing aid in children with mild-to-severe permanent, mainly sensorineural, hearing loss. In 18 children, EFRs were elicited by six male-spoken band-limited phonemic stimuli--the first formants of /u/ and /i/, the second and higher formants of /u/ and /i/, and the fricatives /s/ and /∫/--presented together as /su∫i/.

External and middle ear influence on envelope following responses.

Considerable between-subject variability in envelope following response (EFR) amplitude limits its clinical translation. Based on a pattern of lower amplitude and larger variability in the low (<1.2 kHz) and high (>8 kHz), relative to mid (1-3 kHz) frequency carriers, we hypothesized that the between-subject variability in external and middle ear (EM) contribute to between-subject variability in EFR amplitude.

The Influence of Male- and Female-Spoken Vowel Acoustics on Envelope-Following Responses.

The influence of male and female vowel characteristics on the envelope-following responses (EFRs) is not well understood. This study explored the role of vowel characteristics on the EFR at the fundamental frequency (f0) in response to the vowel /ε/ (as in "head"). Vowel tokens were spoken by five males and five females and EFRs were measured in 25 young adults (21 females).

Speech-Evoked Envelope Following Responses in Children and Adults.

Purpose: Envelope following responses (EFRs) could be useful for objectively evaluating audibility of speech in children who are unable to participate in routine clinical tests. However, relative to adults, the characteristics of EFRs elicited by frequency-specific speech and their utility in predicting audibility in children are unknown.

Method: EFRs were elicited by the first (F1) and second and higher formants (F2+) of male-spoken vowels /u/ and /i/ and by fricatives /ʃ/ and /s/ in the token /suʃi/ presented at 15, 35, 55, 65, and 75 dB SPL.

Variability in the Estimated Amplitude of Vowel-Evoked Envelope Following Responses Caused by Assumed Neurophysiologic Processing Delays.

Vowel-evoked envelope following responses (EFRs) reflect neural encoding of the fundamental frequency of voice (f). Accurate analysis of EFRs elicited by natural vowels requires the use of methods like the Fourier analyzer (FA) to consider the production-related f changes. The FA's accuracy in estimating EFRs is, however, dependent on the assumed neurophysiological processing delay needed to time-align the f time course and the recorded electroencephalogram (EEG).

The influence of phoneme contexts on adaptation in vowel-evoked envelope following responses.

Repeated stimulus presentation leads to neural adaptation and consequent amplitude reduction in vowel-evoked envelope following responses (EFRs)-a response that reflects neural activity phase-locked to envelope periodicity. EFRs are elicited by vowels presented in isolation or in the context of other phonemes such as consonants in syllables. While context phonemes could exert some forward influence on vowel-evoked EFRs, they may reduce the degree of adaptation.

Performance of Statistical Indicators in the Objective Detection of Speech-Evoked Envelope Following Responses.

Objectives: To assess the sensitivity of statistical indicators used for the objective detection of speech-evoked envelope following responses (EFRs) in infants and adults.

Design: Twenty-three adults and 21 infants with normal hearing participated in this study. A modified/susa∫i/speech token was presented at 65 dB SPL monoaurally.

Sensitivity of Vowel-Evoked Envelope Following Responses to Spectra and Level of Preceding Phoneme Context.

Objective: Vowel-evoked envelope following responses (EFRs) could be a useful noninvasive tool for evaluating neural activity phase-locked to the fundamental frequency of voice (f0). Vowel-evoked EFRs are often elicited by vowels in consonant-vowel syllables or words. Considering neural activity is susceptible to temporal masking, EFR characteristics elicited by the same vowel may vary with the features of the preceding phoneme.

The Influence of Sensation Level on Speech-Evoked Envelope Following Responses.

Objectives: To evaluate sensation level (SL)-dependent characteristics of envelope following responses (EFRs) elicited by band-limited speech dominant in low, mid, and high frequencies.

Design: In 21 young normal hearing adults, EFRs were elicited by 8 male-spoken speech stimuli-the first formant, and second and higher formants of /u/, /a/ and /i/, and modulated fricatives, /∫/ and /s/. Stimulus SL was computed from behaviorally measured thresholds.

Characteristics of Speech-Evoked Envelope Following Responses in Infancy.

Envelope following responses (EFRs) may be a useful tool for evaluating the audibility of speech sounds in infants. The present study aimed to evaluate the characteristics of speech-evoked EFRs in infants with normal hearing, relative to adults, and identify age-dependent changes in EFR characteristics during infancy. In 42 infants and 21 young adults, EFRs were elicited by the first (F1) and the second and higher formants (F2+) of the vowels /u/, /a/, and /i/, dominant in low and mid frequencies, respectively, and by amplitude-modulated fricatives /s/ and /∫/, dominant in high frequencies.

Fundamental frequency-dependent changes in vowel-evoked envelope following responses.

Scalp-recorded envelope following responses (EFRs) provide a non-invasive method to assess the encoding of the fundamental frequency (f) of voice that is important for speech understanding. It is well-known that EFRs are influenced by voice f. However, this effect of f has not been examined independent of concomitant changes in spectra or neural generators.

Montage-related Variability in the Characteristics of Envelope Following Responses.

Objectives: The study aimed to compare two electrode montages commonly used for recording speech-evoked envelope following responses.

Design: Twenty-three normal-hearing adults participated in this study. EFRs were elicited by a naturally spoken, modified /susa∫i/ stimulus presented at 65 dB SPL monaurally.

The Influence of Vowel Identity, Vowel Production Variability, and Consonant Environment on Envelope Following Responses.

Objectives: The vowel-evoked envelope following response (EFR) is a useful tool for studying brainstem processing of speech in natural consonant-vowel productions. Previous work, however, demonstrates that the amplitude of EFRs is highly variable across vowels. To clarify factors contributing to the variability observed, the objectives of the present study were to evaluate: (1) the influence of vowel identity and the consonant context surrounding each vowel on EFR amplitude and (2) the effect of variations in repeated productions of a vowel on EFR amplitude while controlling for the consonant context.

The Accuracy of Envelope Following Responses in Predicting Speech Audibility.

Objectives: The present study aimed to (1) evaluate the accuracy of envelope following responses (EFRs) in predicting speech audibility as a function of the statistical indicator used for objective response detection, stimulus phoneme, frequency, and level, and (2) quantify the minimum sensation level (SL; stimulus level above behavioral threshold) needed for detecting EFRs.

Design: In 21 participants with normal hearing, EFRs were elicited by 8 band-limited phonemes in the male-spoken token /susa∫i/ (2.05 sec) presented between 20 and 65 dB SPL in 15 dB increments.

Interhemispheric auditory connectivity requires normal access to sound in both ears during development.

Despite early bilateral cochlear implantation, children with congenital deafness do not develop accurate spatial hearing; we thus asked whether auditory brain networks are disrupted in these children. EEG responses were evoked unilaterally and bilaterally in 13 children with normal hearing and 16 children receiving bilateral cochlear implants simultaneously. Active cortical areas were estimated by the Time Restricted Artifact and Coherent source Suppression (TRACS) beamformer and connected cortical areas were identified by measuring coherence between source responses.

Investigating potential interactions between envelope following responses elicited simultaneously by different vowel formants.

Envelope following responses (EFRs) evoked by the periodicity of voicing in vowels are elicited at the fundamental frequency of voice (f), irrespective of the harmonics that initiate it. One approach of improving the frequency specificity of vowel stimuli without increasing test-time is by altering the f selectively in one or more formants. The harmonics contributing to an EFR can then be differentiated by the unique f at which the EFRs are elicited.