A Multi-Sample Comparison and Rasch Analysis of the Evaluation of Children's Listening and Processing Skills Questionnaire.

OBJECTIVES: Assessing listening difficulties and associated complaints can be challenging. Often, measures of peripheral auditory functions are within normal ranges, making clinicians feel unsure about proper management strategies. The range and nature of observed or experienced difficulties might be better captured using a qualitative measure. The Evaluation of Children's Listening and Processing Skills (ECLiPS) questionnaire was designed to broadly profile the auditory and cognitive problems often present in children with listening difficulties. This 38-item questionnaire was initially standardized in British children aged 6 to 11 years, was subsequently modified for use with North-American children, and was recently translated into Flemish-Dutch. This study aimed to compare typical scores of the Flemish version with the UK and US versions, and to evaluate and compare its psychometric quality based on Rasch analysis. DESIGN: We selected 112 Flemish children aged 6 to 11 years with verified normal hearing and typical development, and asked two caregivers of every child to fill out the ECLiPS. Data from two comparator samples were analyzed, including responses for 71 North-American children and 650 British children. Typical values for ECLiPS factors and aggregates were determined as a function of age and gender, and meaningful differences across samples were analyzed. Rasch analyses were performed to evaluate whether ECLiPS response categories work as intended, and whether item scores fit a linear equal interval measurement scale that works the same way for everyone. Item and person metrics were derived, including separation and reliability indices. We investigated whether items function similarly across linguistically and culturally different samples. RESULTS: ECLiPS scores were relatively invariant to age. Girls obtained higher scores compared with boys, mainly for items related to memory and attention, and pragmatic and social skills. Across ECLiPS versions, the most pronounced differences were found for items probing social skills. With respect to its psychometric quality, ECLiPS response categories work as intended, and ECLiPS items were found to fit the Rasch measurement scale. Cultural differences in responses were noted for some items, belonging to different factors. Item separation and reliability indices generally pointed toward sufficient variation in item difficulty. In general, person separation (and reliability) metrics, quantifying the instrument's ability to distinguish between poor and strong performers (in a reproducible manner), were low. This is expected from samples of typically developing children with homogeneous and high levels of listening ability. CONCLUSIONS: Across the languages assessed here, the ECLiPS caregiver questionnaire was verified to be a psychometrically valid qualitative measure to assess listening and processing skills, which can be used to support the assessment and management of elementary school children referred with LiD.

Toward a Listening Training Paradigm: Evaluation in Normal-Hearing Young and Middle-Aged Adults.

OBJECTIVES: Adults' most common complaint relates to understanding speech in noisy environments. Hearing aids can compensate for sensory loss but do not restore hearing to normal. Listening training has the potential to partially remediate these problems. In this study, we propose and evaluate a Flemish version of a listening training paradigm, which involves the use of cognitive control as well as auditory perception. The paradigm entails a discrimination task where participants are cued to attend to one of two concurrent talkers with target speakers randomly varying between a female and a male voice. We evaluate learning effects, different scenarios, and masking types. DESIGN: In total, 70 young and 54 middle-aged adults participated in this study. Each adult performed one or more conditions. Participants' hearing was screened before participation, all middle-aged adults passed a cognitive screening task. RESULTS: Analyses indicated learning effects across scenarios that were similar in terms of speech intelligibility. Our results indicated better speech intelligibility when the female speaker was the target, but speech intelligibility did not differ when the target was the male speaker. An unintelligible masker noise results in worse speech intelligibility than a competing talker masker. Our results suggest that listeners could use an intensity cue to identify and/or select the target speaker when presented at a lower signal to noise ratio (SNR). Error analysis suggested higher cognitive control demands when the target and masker were presented at similar levels (i.e., around 0 dB SNR). The addition of independent trials with the intensity of target and masker reversed improved speech intelligibility. Inhibitory control, but not task switching, was reliably correlated with listening performance. CONCLUSIONS: The proposed paradigm turned out to be feasible and practicable, demonstrating its potential for training speech intelligibility in noise. We believe that this training paradigm can generate real-life benefits including for persons with hearing loss. This latter application awaits future evaluation.

Comparing the Outcomes of a Personalized Versus Nonpersonalized Home-Based Auditory Training Program for Cochlear Implant Users.

OBJECTIVES: Audiological rehabilitation includes sensory management, auditory training (AT), and counseling and can alleviate the negative consequences associated with (untreated) hearing impairment. AT aims at improving auditory skills through structured analytical (bottom-up) or synthetic (top-down) listening exercises. The evidence for AT to improve auditory outcomes of postlingually deafened adults with a cochlear implant (CI) remains a point of debate due to the relatively limited number of studies and methodological shortcomings. There is a general agreement that more rigorous scientific study designs are needed to determine the effectiveness, generalization, and consolidation of AT for CI users. The present study aimed to investigate the effectiveness of a personalized AT program compared to a nonpersonalized Active Control program with adult CI users in a stratified randomized controlled clinical trial. DESIGN: Off-task outcomes were sentence understanding in noise, executive functioning, and health-related quality of life. Participants were tested before and after 16 weeks of training and after a further 8 months without training. Participant expectations of the training program were assessed before the start of training. RESULTS: The personalized and nonpersonalized AT programs yielded similar results. Significant on-task improvements were observed. Moreover, AT generalized to improved speech understanding in noise for both programs. Half of the CI users reached a clinically relevant improvement in speech understanding in noise of at least 2 dB SNR post-training. These improvements were maintained 8 months after completion of the training. In addition, a significant improvement in quality of life was observed for participants in both treatment groups. Adherence to the training programs was high, and both programs were considered user-friendly. CONCLUSIONS: Training in both treatments yielded similar results. For half of the CI users, AT transferred to better performance with generalization of learning for speech understanding in noise and quality of life. Our study supports the previous findings that AT can be beneficial for some CI users.

Lilliput: speech perception in speech-weighted noise and in quiet in young children.

OBJECTIVE: The aim of this study was to develop an open-set word recognition task in speech-weighted noise and in quiet for young children and examine age effects for open versus closed response formats. DESIGN: Dutch monosyllabic words were presented in quiet and in stationary speech-weighted noise to 4- and 5-year-old children as well as to young adults in an open-set response format. Additionally, performance in open and closed context was assessed, as well as in a picture-pointing paradigm. STUDY SAMPLE: More than 200 children and 50 adults with normal hearing participated in the various validation phases. RESULTS: Average fitted speech reception thresholds (50%) yielded an age effect between 4-year and 5-year olds (and adults), both in speech-weighted noise and in quiet. The closed-set format yielded lower (better) SNRs than the open-set format, and children benefitted to the same extent as adults from phonetically similar words in speech-weighted noise. Additionally, the 4 AFC picture-pointing paradigm can be used to assess word recognition in quiet from 3 years of age. CONCLUSIONS: The same materials reveal performance differences between 4 and 5 years of age (and adults), both in quiet and speech-weighted noise using an open-set response format. This relatively small yet significant difference in SRT for a gap of only 1 year shows a developmental change for word recognition in speech-weighted noise and in quiet in the first decade of life.The study is part of the protocol registered on ClinicalTrials.gov (ID = NCT04063748).

Instant improvement in monaural spatial hearing abilities through cognitive feedback.

Several studies report that sound localization performance of acute and chronic monauralized normal-hearing listeners can improve through training. Typically, training sessions are administered daily for several days or weeks. While this intensive training is effective, it may also be that monaural localization abilities improve instantly after providing explicit top-down information about the direction dependent change in timbre and level. The aim of the present study was to investigate whether cognitive feedback (i.e., top-down information) could instantly improve sound localization in naive acutely monauralized listeners. Forty-three normal-hearing listeners (experimental group), divided over five different centers, were tested. Two control groups, consisting of, respectively, nine and eleven normal-hearing listeners, were tested in one center. Broadband sounds (0.5-20 kHz) were presented from visible loudspeakers, positioned in azimuth (- 90° to 90°). Participants in the experimental group received explicit information about the noticeable difference in timbre and the poor localization in the monauralized listening condition, resulting in an instant improvement in sound localization abilities. With subsequent roving of stimulus level (20 dB), sound localization performance deteriorated immediately. The reported improvement is related to the context of the localization test. The results provide important implications for studies investigating sound localization in a clinical setting, especially during closed-set testing, and indicate the importance of top-down information.

The digit triplet test as a self-test for hearing screening at the age of school-entry.

OBJECTIVE: The current study aimed to investigate the feasibility of the digit triplet test (DTT) as a self-test in normal-hearing children at school-entry age (5-6 years) compared to an administrator-controlled test. DESIGN AND STUDY SAMPLE: Thirty-seven first grade elementary school children took part in this study. Next to a pure-tone screening, the test battery consisted of a DTT speech-in-noise screening (self-test and administrator-controlled assessment), and cognitive tests related to auditory/working memory and attention skills. RESULTS: The reference-SRT ± 2SD, obtained with the administrator-controlled DTT, was -9.8 ± 1.6 dB SNR, and could be estimated with a precision of 0.7 dB. The test duration for one ear was about 4.5 min. Self-tests resulted in higher (poorer) SRTs. Only a small proportion of children performed stably across repeated self-test administrations. With about 6 min for one ear, the test duration was rather long. The influence of auditory/working memory and attentional abilities appeared to be limited. CONCLUSION: Our data suggest that a self-administered DTT is not suitable for a large proportion of children at school-entry.

Brain mapping of auditory steady-state responses: A broad view of cortical and subcortical sources.

Auditory steady-state responses (ASSRs) are evoked brain responses to modulated or repetitive acoustic stimuli. Investigating the underlying neural generators of ASSRs is important to gain in-depth insight into the mechanisms of auditory temporal processing. The aim of this study is to reconstruct an extensive range of neural generators, that is, cortical and subcortical, as well as primary and non-primary ones. This extensive overview of neural generators provides an appropriate basis for studying functional connectivity. To this end, a minimum-norm imaging (MNI) technique is employed. We also present a novel extension to MNI which facilitates source analysis by quantifying the ASSR for each dipole. Results demonstrate that the proposed MNI approach is successful in reconstructing sources located both within (primary) and outside (non-primary) of the auditory cortex (AC). Primary sources are detected in different stimulation conditions (four modulation frequencies and two sides of stimulation), thereby demonstrating the robustness of the approach. This study is one of the first investigations to identify non-primary sources. Moreover, we show that the MNI approach is also capable of reconstructing the subcortical activities of ASSRs. Finally, the results obtained using the MNI approach outperform the group-independent component analysis method on the same data, in terms of detection of sources in the AC, reconstructing the subcortical activities and reducing computational load.

The Cost of Intrinsic and Extrinsic Cognitive Demands on Auditory Functioning in Older Adults With Normal Hearing or Using Hearing Aids.

OBJECTIVES: We investigated the impact of both intrinsic and extrinsic cognitive demands on auditory and secondary task performance in older adults with normal hearing (NH) and adults using hearing aids (HAs) in an ecologically relevant listening environment. DESIGN: Fifteen adults with NH and 15 adults using HAs (60 to 72 years of age) were recruited to perform the "Audiovisual True-to-Life Assessment of Auditory Rehabilitation"-paradigm (AVATAR), which combines an auditory-visual speech-in-noise task with three secondary tasks on either auditory localization or visual short-term memory in a preload multitask paradigm. Intrinsic demands were altered by presenting speech either at equivalent speech accuracy levels of 50% correct (SPIN50%) or equivalent speech-to-noise ratios of +5dB SNR (SPIN+5dB). We manipulated the amount of extrinsic cognitive demands by including one (dual condition) or three secondary tasks (quadruple condition). Performance decrements on the secondary tasks were considered to reflect an increase in resource allocation to speech understanding and thus an increase in listening effort. In addition, we administered a cognitive test battery as well as a questionnaire on self-reported hearing difficulties and subjective measures of effort and motivation. RESULTS: Speech understanding and secondary task performance on the visual short-term memory task were lower in the SPIN50% condition compared to SPIN+5dB. Whereas speech understanding at SPIN50% was equally high in the dual and quadruple conditions, the quadruple condition resulted in lower secondary task performance on the visual short-term memory task, higher levels of self-reported effort, and lower motivation compared to the dual-task condition. The same was true for experimental conditions at SPIN+5dB. Additionally, adults with NH outperformed adults using HAs on speech understanding, auditory localization, and self-reported hearing abilities, but no group differences were observed on secondary task costs or cognitive measures. CONCLUSIONS: This study showed that, irrespective of the hearing status of the listener, speech performance was not affected by the amount of extrinsic cognitive demands, but was worse and required more effort under conditions with a more negative SNR. Also, increasing the extrinsic cognitive demands resulted in lower performance on one of the secondary tasks, suggesting that more complex listening environments require more effort. Although adults with NH outperformed HA users on speech understanding and auditory localization, the two groups did not differ with respect to secondary task costs.

Age-Related Changes in Listening Effort for Children and Teenagers With Normal Hearing and Cochlear Implants.

OBJECTIVES: A clinically viable measure of listening effort is crucial in safeguarding the educational success of hard-of-hearing students enrolled in mainstream schools. To this end, a novel behavioral paradigm of listening effort targeting school-age children has been designed and reported in Hsu et al. (2017). The current article consists of two follow-up experiments investigating the effects of noise, processing depth, and age in a similar paradigm, first in a group of participants with normal hearing (NH) followed by a sample of school-age cochlear implant (CI) users. Research objectives include the construction of normative values of listening effort and comparing outcomes between age-matched NH and CI participants. DESIGN: In Experiment 1, the listening effort dual-task paradigm was evaluated in a group of 90 NH participants with roughly even age distribution between 6 and 26 years. The primary task asked a participant to verbally repeat each of the target words presented in either quiet or noise, while the secondary task consisted of categorization true-or-false questions "animal" and "dangerous," representing two levels of semantic processing depth. Two outcome measures were obtained for each condition: a classic word recognition score (WRS) and an average response time (RT) measured during the secondary task. The RT was defined as the main listening effort metric throughout the study. Each NH participant's long-term memory retrieval speed and working memory capacity were also assessed through standardized tests. It was hypothesized that adding noise would negatively affect both WRS and RT, whereas an increase in age would see significant improvement in both measures. A subsequent Experiment 2 administered a shortened version of the paradigm to 14 school-age CI users between 5 and 14 years old at a university clinic. The patterns of results from the CI group were expected to approximate those of the NH group, except with larger between-subject variability. RESULTS: For NH participants, while WRS was significantly affected by age and noise levels, RT was significantly affected by age, noise levels, and depth of processing. RT was significantly correlated with long-term memory retrieval speed but not with working memory capacity. There was also a significant interaction effect between age and noise levels for both WRS and RT. The RT data set from the NH group served as a basis to establish age-dependent 95% prediction intervals for expected future observations. For CI participants, the effect of age on the two outcome measures was more visible when target words were presented in quiet. Depending on the condition, between 35.7% and 72.7% of the children with CI exhibited higher-than-norms listening effort as measured by categorization processing times. CONCLUSION: Listening effort appears to decrease with age from early school-age years to late teenage years. The effects of background noise and processing depth are comparable with those reported in Hsu et al. (2017). Future studies interested in expanding the paradigm's clinical viability should focus on the reduction of testing time while maintaining or increasing the sensitivity and external validity of its outcome measures.

The digit triplet test: a scoping review.

OBJECTIVE: This review article presents an overview of all Digit Triplet Tests (DTT) and digits-in-noise tests (DIN) and their variations in language, speech material, masking noise, test procedures, and targeted population. The effects on aspects of validity, reliability, and feasibility are investigated. DESIGN: Scoping review. STUDY SAMPLE: All studies referring to the DTT and DIN were collected from Pubmed and Embase. Search terms "digit triplet test" and "digits in noise" were used. Citations of selected articles were scanned backwards in time (the bibliography of the already selected research article) and forward in time (articles that cited the already selected research article). The search terms yielded 95 results in total. Eventually, 39 papers were selected. RESULTS: Analyses showed psychometric reference-curves with steep slopes and speech reception thresholds with high measurement precision which are strongly associated with pure tone audiometry. High sensitivity and specificity to detect elevated pure tone thresholds were noted for test variants. Certain procedural modifications of the DTT and DIN can further improve the test. Additionally, large-scale application of the DTT and DIN is feasible. CONCLUSION: The DTT and DIN are a very valuable tool for screening and diagnostics for a wide variety of populations.

AVATAR Assesses Speech Understanding and Multitask Costs in Ecologically Relevant Listening Situations.

OBJECTIVES: There is a high need among clinicians and researchers for an ecologically valid measure of auditory functioning and listening effort. Therefore, we developed AVATAR: an "Audiovisual True-to-life Assessment of Auditory Rehabilitation" which takes important characteristics of real-life listening situations into account, such as multimodal speech presentation, spatial separation of sound sources and multitasking. As such, AVATAR aims to assess both auditory functioning and the amount of allocated processing resources during listening in a realistic yet controllable way. In the present study, we evaluated AVATAR and investigated whether speech understanding in noise and multitask costs during realistic listening environments changed with increasing task complexity. DESIGN: Thirty-five young normal-hearing participants performed different task combinations of an auditory-visual speech-in-noise task and three secondary tasks on both auditory localization and visual short-term memory in a simulated restaurant environment. Tasks were combined in increasing complexity and multitask costs on the secondary tasks were investigated as an estimate of the amount of cognitive resources allocated during listening and multitasking. In addition to behavioral measures of auditory functioning and effort, working memory capacity and self-reported hearing difficulties were established using a reading span test and a questionnaire on daily hearing abilities. RESULTS: Whereas performance on the speech-in-noise task was not affected by task complexity, multitask costs on one of the secondary tasks became significantly larger with increasing task complexity. Working memory capacity correlated significantly with multitask costs, but no association was observed between behavioral outcome measures and self-reported hearing abilities or effort. CONCLUSIONS: AVATAR proved to be a promising model to assess speech intelligibility and auditory localization abilities and to gauge the amount of processing resources during effortful listening in ecologically relevant multitasking situations by means of multitask costs. In contrast with current clinical measures of auditory functioning, results showed that listening and multitasking in challenging listening environments can require a considerable amount of processing resources, even for young normal-hearing adults. Furthermore, the allocation of resources increased in more demanding listening situations. These findings open avenues for a more realistic assessment of auditory functioning and individually tuned auditory rehabilitation for individuals of different age and hearing profiles.

Age Affects Speech Understanding and Multitask Costs.

OBJECTIVES: We examined the effect of age on speech understanding and multitask costs in the ecologically relevant "Audiovisual True-to-Life Assessment of Auditory Rehabilitation"-paradigm (AVATAR). DESIGN: Twenty-nine normal-hearing middle-aged adults completed AVATAR, which combines an auditory-visual speech-in-noise task with three secondary tasks on auditory localization or visual short-term memory in different dual-, triple-, and quadruple-task combinations. Performance decrements on the secondary tasks were considered to reflect the cognitive resources allocated during listening. Self-reported hearing difficulties were administered via a questionnaire. Results were compared with scores of 35 young normal-hearing adults. RESULTS: Middle-aged adults performed consistently worse than young adults on speech understanding and, in the triple- and quadruple-task combinations only, on secondary task performance. Furthermore, middle-agers reported higher levels of daily listening concentration and more difficulties with speech understanding. CONCLUSIONS: This study demonstrated the adverse effect of age on speech-in-noise understanding and the amount of allocated cognitive resources during challenging listening situations realized in AVATAR.

Sonority-Related Novel Word Learning Ability of Children With Cochlear Implants With Optimal Oral Language Exposure.

OBJECTIVES: The present study investigated how children with cochlear implants (CIs), with optimal exposure to oral language, perform on sonority-related novel word learning tasks. By optimal oral language exposure, we refer to bilateral cochlear implantation below the age of 2 years. Sonority is the relative perceptual prominence/loudness of speech sounds of the same length, stress, and pitch. The present study is guided by a previous study that investigated the sonority-related novel word learning ability of a group of children with CIs, in the Greek language, of which the majority were implanted beyond the age of 2 unilaterally. DESIGN: A case-control study with 15 Dutch-speaking participants in each of the three groups, i.e., children with CIs, normal-hearing children (NHC), and normal-hearing adults, was conducted using a sonority-related novel "CVC" word learning task. All children with CIs are implanted before the age of 2 years with preimplant hearing aids. Thirteen out of the 15 children had bilateral CIs. The CVC words were constructed according to four sonority conditions, where N is nonsonorous and S is a sonorous phoneme: NSN, NSS, SSN, and SSS. Outcome measures were accuracy and reaction times (RTs). In addition, the Peabody picture vocabulary test and the digit span forward test were administered to the children. RESULTS: There were no statistical differences in accuracy or RTs between the children groups on the overall score and across the different conditions. However, children with CIs, unlike NHC, scored statistically less accurately and with longer RTs relative to normal-hearing adults, on the overall task. Within-group comparisons showed that none of the groups performed statistically differently on any of the conditions. The NHC showed higher receptive vocabulary scores relative to children with CIs. In addition, the group of children with CIs entailed a statistically significantly higher number of children with "weak" short-term memory. CONCLUSIONS: Children with CIs who have optimal oral language exposure showed age-appropriate sonority-related novel word learning abilities and strategies relative to their NH peers. However, children with CIs continue to show lower receptive vocabulary scores than NHC, despite the equivalent novel word learning ability. This suggests that children with CIs may have difficulties in retaining newly learned words. Future work should look into possible causes of the gap in performance. This would eventually aid in rehabilitation tailored to the needs of the individual.

Cochlear Implant Data Logs Predict Children's Receptive Vocabulary.

OBJECTIVES: The data logs of Cochlear Nucleus cochlear implant (CI) sound processors show large interindividual variation in children's daily CI use and auditory environments. This study explored whether these differences are associated with differences in the receptive vocabulary of young implanted children. DESIGN: Data of 52 prelingually deaf children, who had received a CI before 3 years of age, were obtained from their clinical records. In total, 73 Peabody Picture Vocabulary tests and CI data logs for 1 year preceding each test were collected. The data logs were used to determine the children's average daily amount of CI use and exposure to speech, speech in noise, noise, music, and quiet. In addition, information was collected about other potential predictors of language abilities, namely gender, age, age at implantation, etiology of deafness, educational placement, and implantation mode (unilateral, bilateral). Model selection with Akaike's information criterion was used to determine which data-logging metrics, other variables, and combinations of both best predict receptive vocabulary scores. RESULTS: The data showed a strong positive association between receptive vocabulary and daily CI use, and a negative association between receptive vocabulary and daily exposure to music. Associations with the data logs' speech and noise metrics were less clear. The most important other variable was educational placement. The best model performance was achieved when data logs and other information were combined. CONCLUSIONS: The results emphasize the importance of consistent CI use and a rich auditory environment for the early language development of young CI users. The study also shows that CI data logs capture information about children's environment and CI use that are related to language performance and can help to detect and address problems and improve the auditory rehabilitation after cochlear implantation.

Neural Modulation Transmission Is a Marker for Speech Perception in Noise in Cochlear Implant Users.

OBJECTIVES: Cochlear implants (CIs) restore functional hearing in persons with a severe hearing impairment. Despite being one of the most successful bionic prosthesis, performance with CI (in particular speech understanding in noise) varies considerably across its users. The ability of the auditory pathway to encode temporal envelope modulations (TEMs) and the effect of degenerative processes associated with hearing loss on TEM encoding is assumed to be one of the reasons underlying the large intersubject differences in CI performance. The objective of the present study was to investigate how TEM encoding of the stimulated neural ensembles of human CI recipients is related to speech perception in noise (SPIN). DESIGN: We used electroencephalography as a noninvasive electrophysiological measure to assess TEM encoding in the auditory pathway of CI users by means of the 40-Hz electrically evoked auditory steady state response (EASSR). Nine CI users with a wide range of SPIN outcome were included in the present study. TEM encoding was assessed for each stimulation electrode of each subject and new metrics; the CI neural modulation transmission difference (CIMTD) and the CI neural modulation transmission index (CIMTI) were developed to quantify the amount of variability in TEM encoding across the stimulated neural ensembles of the CI electrode array. RESULTS: EASSR patterns varied across the CI electrode array and subjects. We found a strong correlation (r = 0.89, p = 0.001) between the SPIN outcomes and the variability in EASSR amplitudes across the array as assessed with CIMTD/CIMTI. CONCLUSIONS: The results of the present study show that the 40-Hz EASSR can be used to objectively assess the neural encoding of TEMs in human CI recipients. Overall reduced or largely variable TEM encoding of the neural ensembles across the electrode array, as quantified with the CIMTD/CIMTI, is highly correlated with speech perception in noise outcome with a CI.

Contributions of non-primary cortical sources to auditory temporal processing.

Temporal processing is essential for speech perception and directional hearing. However, the number and locations of cortical sources involved in auditory temporal processing are still a matter of debate. Using source reconstruction of human EEG responses, we show that, in addition to primary sources in the auditory cortices, sources outside the auditory cortex, designated as non-primary sources, are involved in auditory temporal processing. Non-primary sources within the left and right motor areas, the superior parietal lobe and the right occipital lobe were activated by amplitude-modulated stimuli, and were involved in the functional network. The robustness of these findings was checked for different stimulation conditions. The non-primary sources showed weaker phase-locking and lower activity than primary sources. These findings suggest that the non-primary sources belong to the non-primary auditory pathway. This pathway and non-primary sources detected in motor area explain how, in temporal prediction of upcoming stimuli and motor theory of speech perception, the motor area receives auditory inputs.

Improving the efficiency of the digit triplet test using digit scoring with variable adaptive step sizes.

Objective: To investigate modifications of the Flemish Digit Triplet Test (DTT) to improve its efficiency, i.e. the use of a low-pass filtered noise and variable adaptive step sizes according to a digit scoring procedure, targeting different recognition probabilities. Design and study sample: Speech reception thresholds (SRT) were evaluated in terms of their test-retest reliability and correlation with pure tone averages (PTA) in a group of 68 adult participants with different degrees of hearing impairment. Results: The use of a low-pass filtered noise did not result in better test-retest reliability or an improved SRT-PTA correlation. Using digit scoring with adaptive step sizes parametrised to target a recognition probability of 79% (D79), corresponding to the recognition probability of the currently used DTT with triplet scoring and fixed adaptive step sizes of 2 dB, increased test-retest reliability. Lower recognition probabilities of 57 and 35% demonstrated worse reliability and worse SRT-PTA correlations. Conclusions: Given the increased test-retest reliability of D79, a similar reliability as for the currently used DTT could be obtained after considerably fewer trials, leading to a profit in test duration.

Sonority's Effect as a Surface Cue on Lexical Speech Perception of Children With Cochlear Implants.

OBJECTIVES: Sonority is the relative perceptual prominence/loudness of speech sounds of the same length, stress, and pitch. Children with cochlear implants (CIs), with restored audibility and relatively intact temporal processing, are expected to benefit from the perceptual prominence cues of highly sonorous sounds. Sonority also influences lexical access through the sonority-sequencing principle (SSP), a grammatical phonotactic rule, which facilitates the recognition and segmentation of syllables within speech. The more nonsonorous the onset of a syllable is, the larger is the degree of sonority rise to the nucleus, and the more optimal the SSP. Children with CIs may experience hindered or delayed development of the language-learning rule SSP, as a result of their deprived/degraded auditory experience. The purpose of the study was to explore sonority's role in speech perception and lexical access of prelingually deafened children with CIs. DESIGN: A case-control study with 15 children with CIs, 25 normal-hearing children (NHC), and 50 normal-hearing adults was conducted, using a lexical identification task of novel, nonreal CV-CV words taught via fast mapping. The CV-CV words were constructed according to four sonority conditions, entailing syllables with sonorous onsets/less optimal SSP (SS) and nonsonorous onsets/optimal SSP (NS) in all combinations, that is, SS-SS, SS-NS, NS-SS, and NS-NS. Outcome measures were accuracy and reaction times (RTs). A subgroup analysis of 12 children with CIs pair matched to 12 NHC on hearing age aimed to study the effect of oral-language exposure period on the sonority-related performance. RESULTS: The children groups showed similar accuracy performance, overall and across all the sonority conditions. However, within-group comparisons showed that the children with CIs scored more accurately on the SS-SS condition relative to the NS-NS and NS-SS conditions, while the NHC performed equally well across all conditions. Additionally, adult-comparable accuracy performance was achieved by the children with CIs only on the SS-SS condition, as opposed to NS-SS, SS-NS, and SS-SS conditions for NHC. Accuracy analysis of the subgroups of children matched in hearing age showed similar results. Overall longer RTs were recorded by the children with CIs on the sonority-treated lexical task, specifically on the SS-SS condition compared with age-matched controls. However, the subgroup analysis showed that both groups of children did not differ on RTs. CONCLUSIONS: Children with CIs performed better in lexical tasks relying on the sonority perceptual prominence cues, as in SS-SS condition, than on SSP initial relying conditions as NS-NS and NS-SS. Template-driven word learning, an early word-learning strategy, appears to play a role in the lexical access of children with CIs whether matched in hearing age or not. The SS-SS condition acts as a preferred word template. The longer RTs brought about by the highly accurate SS-SS condition in children with CIs is possibly because listening becomes more effortful. The lack of RTs difference between the children groups when matched on hearing age points out the importance of oral-language exposure period as a key factor in developing the auditory processing skills.

Digit Triplet Test Hearing Screening With Broadband and Low-Pass Filtered Noise in a Middle-Aged Population.

OBJECTIVES: This study investigated whether age affects Flemish Digit Triplet Test (DTT) scores, as well as sensitivity and specificity of the test to detect high-frequency hearing impairment in middle age. DESIGN: DTT performance in broadband and low-pass filtered noise was assessed for 21 young and 61 middle-aged persons with normal-hearing sensitivity. Cutoff values based on their performance were used to evaluate sensitivity and specificity of the DTT as a screening tool in 145 middle-aged persons, with varying audiometric profiles. RESULTS: DTT performance for normal-hearing persons depended on age in both noise conditions. For low-pass filtered noise, the trade-off between sensitivity and specificity also increased when age-adjusted cutoff values were applied for screening in middle age. CONCLUSIONS: The Flemish DTT with broadband noise had high sensitivity and specificity to detect high-frequency hearing impairment in middle age. Similar results were obtained for low-pass filtered noise when cutoff values for referral were age adjusted.

School-Age Hearing Screening Based on Speech-in-Noise Perception Using the Digit Triplet Test.

OBJECTIVES: This study aims to investigate the large-scale applicability of the Digit Triplet test (DTT) for school-age hearing screening in fifth grade elementary (5E) (9 to 12 years old) and third grade secondary (3S) (13 to 16 years old) school children. The reliability of the test is investigated as well as whether pass/fail criteria need to be corrected for training and/or age, and whether these criteria have to be refined with respect to referral rates and pure-tone audiometry results. DESIGN: Eleven school health service centers participated in the region of Flanders (the Northern part of Belgium). Pure-tone screening tests, which are commonly used for hearing screening in school children, were replaced by the DTT. Initial pass/fail criteria were determined. Children with speech reception thresholds (SRT) of -7.2 dB signal to noise ratio (SNR) (5E) and -8.3 dB SNR (3S) or worse were referred for an audiogram and follow-up. In total, n = 3412 (5E) and n = 3617 (3S) children participated. RESULTS: Population SRTs (±2 SD) were -9.8 (±1.8) dB SNR (5E) and -10.5 (±1.6) dB SNR (3S), and do not need correction for training and/or age. Whereas grade-specific pass/fail criteria are more appropriate, a linear regression analysis showed an improvement of 0.2 dB per year of the SRT until late adolescence. SRTs could be estimated with a within-measurement reliability of 0.6 dB. Test duration was also grade-dependent, and was 6 min 50 sec (SD = 61 sec) (5E) and 5 min 45 sec (SD = 49 sec) (3S) on average for both ears. The SRT, test reliability, and test duration were comparable across centers. With initial cut-off values, 2.9% (5E) and 3.5% (3S) of children were referred. Based on audiograms of n = 39 (5E) and n = 59 (3S) children, the diagnostic accuracy of the DTT was assessed. A peripheral hearing loss was detected in 31% (5E) and 53% (3S) of the referred children. Hearing losses found were mild. Less strict pass/fail criteria increased the diagnostic accuracy. Optimal pass/fail criteria were determined at -6.5 dB SNR (5E) and -8.1 dB SNR (3S). With these criteria, referral rates dropped to 1.3% (5E) and 2.4% (3S). CONCLUSIONS: The DTT has been implemented as the new hearing screening methodology in the Flemish school-age hearing screening program. Based on the results of this study, pass/fail criteria were determined and optimized to be used for systematic hearing screening of 5E and 3S school children. Furthermore, this study provides reference values for the DTT in children 9 to 16 years of age. Reliable SRTs can be obtained with the test, allowing accurate monitoring of hearing over time. This is important in the context of a screening guideline, which aims to identify children with noise-induced hearing loss. Validation of the screening result should go beyond taking an audiogram, as a peripheral hearing impairment cannot always be found in children with a failed test.