Gradient boosted decision trees reveal nuances of auditory discrimination behavior.

Animal psychophysics can generate rich behavioral datasets, often comprised of many 1000s of trials for an individual subject. Gradient-boosted models are a promising machine learning approach for analyzing such data, partly due to the tools that allow users to gain insight into how the model makes predictions. We trained ferrets to report a target word's presence, timing, and lateralization within a stream of consecutively presented non-target words. To assess the animals' ability to generalize across pitch, we manipulated the fundamental frequency (F0) of the speech stimuli across trials, and to assess the contribution of pitch to streaming, we roved the F0 from word token to token. We then implemented gradient-boosted regression and decision trees on the trial outcome and reaction time data to understand the behavioral factors behind the ferrets' decision-making. We visualized model contributions by implementing SHAPs feature importance and partial dependency plots. While ferrets could accurately perform the task across all pitch-shifted conditions, our models reveal subtle effects of shifting F0 on performance, with within-trial pitch shifting elevating false alarms and extending reaction times. Our models identified a subset of non-target words that animals commonly false alarmed to. Follow-up analysis demonstrated that the spectrotemporal similarity of target and non-target words rather than similarity in duration or amplitude waveform was the strongest predictor of the likelihood of false alarming. Finally, we compared the results with those obtained with traditional mixed effects models, revealing equivalent or better performance for the gradient-boosted models over these approaches.

The Costs (and Benefits?) of Effortful Listening for Older Adults: Insights from Simultaneous Electrophysiology, Pupillometry, and Memory.

Although the impact of acoustic challenge on speech processing and memory increases as a person ages, older adults may engage in strategies that help them compensate for these demands. In the current preregistered study, older adults (n = 48) listened to sentences-presented in quiet or in noise-that were high constraint with either expected or unexpected endings or were low constraint with unexpected endings. Pupillometry and EEG were simultaneously recorded, and subsequent sentence recognition and word recall were measured. Like young adults in prior work, we found that noise led to increases in pupil size, delayed and reduced ERP responses, and decreased recall for unexpected words. However, in contrast to prior work in young adults where a larger pupillary response predicted a recovery of the N400 at the cost of poorer memory performance in noise, older adults did not show an associated recovery of the N400 despite decreased memory performance. Instead, we found that in quiet, increases in pupil size were associated with delays in N400 onset latencies and increased recognition memory performance. In conclusion, we found that transient variation in pupil-linked arousal predicted trade-offs between real-time lexical processing and memory that emerged at lower levels of task demand in aging. Moreover, with increased acoustic challenge, older adults still exhibited costs associated with transient increases in arousal without the corresponding benefits.

Objective assessment of autism spectrum disorder based on performance in structured interpersonal acting-out tasks with prosodic stability and variability.

In this study, we sought to objectively and quantitatively characterize the prosodic features of autism spectrum disorder (ASD) via the characteristics of prosody in a newly developed structured speech experiment. Male adults with high-functioning ASD and age/intelligence-matched men with typical development (TD) were asked to read 29 brief scripts aloud in response to preceding auditory stimuli. To investigate whether (1) highly structured acting-out tasks can uncover the prosodic of difference between those with ASD and TD, and (2) the prosodic stableness and flexibleness can be used for objective automatic assessment of ASD, we compared prosodic features such as fundamental frequency, intensity, and mora duration. The results indicate that individuals with ASD exhibit stable pitch registers or volume levels in some affective vocal-expression scenarios, such as those involving anger or sadness, compared with TD and those with TD. However, unstable prosody was observed in some timing control or emphasis tasks in the participants with ASD. Automatic classification of the ASD and TD groups using a support vector machine (SVM) with speech features exhibited an accuracy of 90.4%. A machine learning-based assessment of the degree of ASD core symptoms using support vector regression (SVR) also had good performance. These results may inform the development of a new easy-to-use assessment tool for ASD core symptoms using recorded audio signals.

EEG-based Objective Quality Assessment of Interrupted Speech.

As an important dimension of speech degradation, interruption destroys the acoustic waveform information of a speech signal and seriously affects the quality rating in speech perception. Existing studies assessing the quality of interrupted speech mainly focus on subjective methods. This work used event-related potentials (ERPs) to objectively investigate the effects of two interruption factors (i.e., interruption duty cycle and interruption rate) on the perceived quality of the periodically interrupted speech. An oddball-paradigm based ERP experiment was designed, and the periodically interrupted stimuli were presented to participants in the ERP experiment. Meanwhile, participants were instructed to provide their subjective quality ratings of interrupted speech under the same interruption conditions. The experimental results showed that the degree of both interruption duty cycle and interruption rate affected the peak latency of mismatch negativity (MMN) of the collected ERP response, with a smaller MMN peak latency under conditions with a smaller interruption duty cycle or a larger interruption rate. These findings are largely consistent with the subjective quality rating results, suggesting that the peak latency of MMN response can be potentially used as an objective quality indicator of the periodically interrupted speech.

A new tool for the assessment of speech understanding and spatial hearing difficulties in children: the Kid-SSQ questionnaire.

PURPOSE: To develop and validate a new questionnaire, the Kid-SSQ, for the rapid screening of hearing abilities in children with hearing impairment, aged 7-17 years. METHODS: The questionnaire was constructed from two existing, validated versions of the 'Speech, Spatial and Qualities of Hearing' - (SSQ) questionnaire (pediatric form and adult short-form). The 12 selected items included auditory aspects from three subscales: speech perception, spatial hearing, and qualities of hearing. This new short form was then validated in 154 children with cochlear implants (100 bilaterally, and 54 unilaterally implanted children). Construct validity was assessed by testing relationships between Kid-SSQ scores and objective clinical parameters (e.g., age at test, pure-tone audiometry-PTA threshold, speech reception threshold-SRT, duration of binaural experience). RESULTS: Completion time was acceptable for use with children (less than 10 min) and the non-response rate was less than 1%. Good internal consistency was obtained (Cronbach's α = 0.78), with a stable internal structure corresponding to the 3 intended subscales. External validity showed the specificity of each subscale: speech subscale scores were significantly predicted (r = 0.32, p < 0.001) by both 2 kHz PTA threshold (ß = 0.33, p < 0.001) and SRT (ß = - 0.23, p < 0.001). Children with more binaural experience showed significantly higher scores on the spatial subscale than children with less binaural experience (F(1,98) = 5.1, p < 0.03) and the qualities of hearing subscale scores significantly depended on both age and SRT (r = 0.32, p < 0.001). CONCLUSIONS: The Kid-SSQ questionnaire is a robust and clinically useful questionnaire for self-assessment of difficulties in various auditory domains.

Field assessment of acute auditory responses to environmental exposures in close quarters tactics training.

OBJECTIVE: The purpose of this study was to evaluate auditory performance of military instructors as part of a training course involving noise and blast exposure. Boothless audiometry was used to estimate the test-retest reliability of the auditory measures under realistic field conditions and to determine risk of acute auditory injury during standard training practices. DESIGN AND STUDY SAMPLE: Thirteen U.S. Marine instructors participated in study activities. An audiologic testing suite embedded in a noise-attenuating headset was used to test various tone detection tasks on subjects after exposure. Acoustic exposures were captured with sound level meters. RESULTS: Boothless audiometry provide highly repeatable results for various tests of auditory performance in the field environment. In this test population, changes in auditory performance pre- and post-noise exposure were minimal for most measures. The notable exception was binaural (NoSπ) tone detection, which showed significant degradations both as a function of pre- and post-noise exposure on the same day and as a result of cumulative noise exposure over the period of the study. CONCLUSIONS: Study outcomes are consistent with prior laboratory and epidemiological work and suggest a link between the binaural processes required for NoSπ detection and the hearing-related issues reported by blast-exposed service members.

Production and Perception Evidence of a Merger: [l] and [n] in Fuzhou Min.

The current study investigated the merger-in-progress between word-initial nasal and lateral consonants in Fuzhou Min, examining the linguistic and social factors that modulate the merger. First, the acoustic cues to the l-n distinction were examined in Fuzhou Min. Acoustic analyses suggested a collapse of phonemic contrast between prescriptive L and N (phonemes in the unmerged system), with none of the six acoustic cues showing any difference across L and N. Linear discriminant analysis did identify acoustically distinct [l] and [n] tokens, although the mapping onto the phonetic space of prescriptive L and N substantially overlapped. Speakers of all ages and both genders tended to produce [l], and low vowels correlated with more [n]-like classification. In perception, AX discrimination data showed Fuzhou Min listeners confused both prescriptive L and N and acoustic [l] and [n]. Greater sensitivity to the acoustic differences occurred in the context of low vowels and a nasal coda, supported by the acoustics of the stimuli, and younger listeners were more sensitive to the difference between [l] and [n] than older listeners. In two-alternative forced choice (2AFC) identification, Fuzhou Min listeners also identified the merged form as L more frequently than N, with more L responses elicited in the context of low vowels and in the absence of nasal codas. Overall, although Fuzhou Min speakers produced some acoustically distinct [l] and [n] tokens in the context of a sound merger, these productions did not map onto prescriptive L and N. In addition, younger listeners were more sensitive to the acoustic distinction than older listeners, suggesting an emerging acoustic contrast possibly arising due to contact with Mandarin.

Effortful Listening Despite Correct Responses: The Cost of Mental Repair in Sentence Recognition by Listeners With Cochlear Implants.

PURPOSE: Speech recognition percent correct scores fail to capture the effort of mentally repairing the perception of speech that was initially misheard. This study measured the effort of listening to stimuli specifically designed to elicit mental repair in adults who use cochlear implants (CIs). METHOD: CI listeners heard and repeated sentences in which specific words were distorted or masked by noise but recovered based on later context: a signature of mental repair. Changes in pupil dilation were tracked as an index of effort and time-locked with specific landmarks during perception. RESULTS: Effort significantly increases when a listener needs to repair a misperceived word, even if the verbal response is ultimately correct. Mental repair of words in a sentence was accompanied by greater prevalence of errors elsewhere in the same sentence, suggesting that effort spreads to consume resources across time. The cost of mental repair in CI listeners was essentially the same as that observed in listeners with normal hearing in previous work. CONCLUSIONS: Listening effort as tracked by pupil dilation is better explained by the mental repair and reconstruction of words rather than the appearance of correct or incorrect perception. Linguistic coherence drives effort more heavily than the mere presence of mistakes, highlighting the importance of testing materials that do not constrain coherence by design.

Assessment of outcome measures after audiological computer-based auditory training in cochlear implant children.

OBJECTIVE: To validate the clinical use of acoustic change complex (ACC) as an objective outcome measure of auditory training in Egyptian cochlear implant (CI) children and explore how far electrophysiological measures could be correlated to behavioral measures in assessing training outcome. Also to explore the efficacy of computer-based auditory training programs (CBATP) in the rehabilitation process of CI children. METHODS: Sixty Arabic speaking children participated in the present study. Forty children using monaural CI device served as study group (20 children in subgroup A and 20 children in subgroup B). Both subgroups received traditional speech therapy sessions, additionally subgroup (A) children received computer-based auditory training program (CBATP) at home for three months. Their age ranged from 8 to 17 years. 20 age and sex-matched normal hearing children served as control group as a standardization for the stimuli used to elicit ACC. The study group children were subjected to detailed history taking, parent reported questionnaire (MAIS, Arabic version), aided sound field evaluation, psychophysical evaluation using auditory fusion test (AFT), speech perception testing according to language age, ACC in response to gaps in 1000 Hz tones and language evaluation. This work-up was repeated after 3&6 months for both study subgroups. RESULTS: Children of study subgroup (A) showed improvement of auditory fusion test (AFT) thresholds at 3 & 6 months post-training follow up. As regards acoustic change complex (ACC), it can be detected in 85% of subgroup (A) children, 85% of subgroup (B) children and 100% of control group children. Lower ACC gap detection thresholds were obtained only after 3 months in subgroup (A), while after 6 months in subgroup (B). There were statistically significant differences between initial assessment and 3 & 6 months follow up as regards ACC P1 and N2 latencies and amplitudes in both study subgroups, however in subgroup (A), ACC P1 amplitude at 6 months post-training was significantly larger than values of 3 months follow up. There was highly significant correlation between thresholds of AFT and ACC gap detection threshold. CONCLUSIONS: ACC can be used as a reliable tool for evaluating auditory training outcome in CI children. ACC gap detection threshold can predict psychophysical temporal resolution after auditory training in difficult to test population. CBATP is an easy and accessible method which may be effective in improving CI outcome.

Parametric Cognitive Load Reveals Hidden Costs in the Neural Processing of Perfectly Intelligible Degraded Speech.

Speech is often degraded by environmental noise or hearing impairment. People can compensate for degradation, but this requires cognitive effort. Previous research has identified frontotemporal networks involved in effortful perception, but materials in these works were also less intelligible, and so it is not clear whether activity reflected effort or intelligibility differences. We used functional magnetic resonance imaging to assess the degree to which spoken sentences were processed under distraction and whether this depended on speech quality even when intelligibility of degraded speech was matched to that of clear speech (close to 100%). On each trial, male and female human participants either attended to a sentence or to a concurrent multiple object tracking (MOT) task that imposed parametric cognitive load. Activity in bilateral anterior insula reflected task demands; during the MOT task, activity increased as cognitive load increased, and during speech listening, activity increased as speech became more degraded. In marked contrast, activity in bilateral anterior temporal cortex was speech selective and gated by attention when speech was degraded. In this region, performance of the MOT task with a trivial load blocked processing of degraded speech, whereas processing of clear speech was unaffected. As load increased, responses to clear speech in these areas declined, consistent with reduced capacity to process it. This result dissociates cognitive control from speech processing; substantially less cognitive control is required to process clear speech than is required to understand even very mildly degraded, 100% intelligible speech. Perceptual and control systems clearly interact dynamically during real-world speech comprehension.SIGNIFICANCE STATEMENT Speech is often perfectly intelligible even when degraded, for example, by background sound, phone transmission, or hearing loss. How does degradation alter cognitive demands? Here, we use fMRI to demonstrate a novel and critical role for cognitive control in the processing of mildly degraded but perfectly intelligible speech. We compare speech that is matched for intelligibility but differs in putative control demands, dissociating cognitive control from speech processing. We also impose a parametric cognitive load during perception, dissociating processes that depend on tasks from those that depend on available capacity. Our findings distinguish between frontal and temporal contributions to speech perception and reveal a hidden cost to processing mildly degraded speech, underscoring the importance of cognitive control for everyday speech comprehension.

Automatic Speech Discrimination Assessment Methods Based on Event-Related Potentials (ERP).

Speech discrimination is used by audiologists in diagnosing and determining treatment for hearing loss patients. Usually, assessing speech discrimination requires subjective responses. Using electroencephalography (EEG), a method that is based on event-related potentials (ERPs), could provide objective speech discrimination. In this work we proposed a visual-ERP-based method to assess speech discrimination using pictures that represent word meaning. The proposed method was implemented with three strategies, each with different number of pictures and test sequences. Machine learning was adopted to classify between the task conditions based on features that were extracted from EEG signals. The results from the proposed method were compared to that of a similar visual-ERP-based method using letters and a method that is based on the auditory mismatch negativity (MMN) component. The P3 component and the late positive potential (LPP) component were observed in the two visual-ERP-based methods while MMN was observed during the MMN-based method. A total of two out of three strategies of the proposed method, along with the MMN-based method, achieved approximately 80% average classification accuracy by a combination of support vector machine (SVM) and common spatial pattern (CSP). Potentially, these methods could serve as a pre-screening tool to make speech discrimination assessment more accessible, particularly in areas with a shortage of audiologists.

On prediction of aided behavioural measures using speech auditory brainstem responses and decision trees.

Current clinical strategies to assess benefits from hearing aids (HAs) are based on self-reported questionnaires and speech-in-noise (SIN) tests; which require behavioural cooperation. Instead, objective measures based on Auditory Brainstem Responses (ABRs) to speech stimuli would not require the individuals' cooperation. Here, we re-analysed an existing dataset to predict behavioural measures with speech-ABRs using regression trees. Ninety-two HA users completed a self-reported questionnaire (SSQ-Speech) and performed two aided SIN tests: sentences in noise (BKB-SIN) and vowel-consonant-vowels (VCV) in noise. Speech-ABRs were evoked by a 40 ms [da] and recorded in 2x2 conditions: aided vs. unaided and quiet vs. background noise. For each recording condition, two sets of features were extracted: 1) amplitudes and latencies of speech-ABR peaks, 2) amplitudes and latencies of speech-ABR F0 encoding. Two regression trees were fitted for each of the three behavioural measures with either feature set and age, digit-span forward and backward, and pure tone average (PTA) as possible predictors. The PTA was the only predictor in the SSQ-Speech trees. In the BKB-SIN trees, performance was predicted by the aided latency of peak F in quiet for participants with PTAs between 43 and 61 dB HL. In the VCV trees, performance was predicted by the aided F0 encoding latency and the aided amplitude of peak VA in quiet for participants with PTAs ≤ 47 dB HL. These findings indicate that PTA was more informative than any speech-ABR measure, as these were relevant only for a subset of the participants. Therefore, speech-ABRs evoked by a 40 ms [da] are not a clinical predictor of behavioural measures in HA users.

Ecological Momentary Assessment: A Field Evaluation of Subjective Ratings of Speech in Noise.

PURPOSE: As hearing rehabilitation research evolves to include both retrospective and momentary assessment outcome measures, it is important to understand how in-the-moment contextual factors influence subjective ratings. We aimed to determine, over a 4-week period of participants responding to ecological momentary assessments (EMAs) in their own environments, whether: (1) participants will complete surveys in speech-in-noise listening situations; (2) ratings of speech in noise change in a predictable manner as the acoustic conditions change; and (3) EMAs provide patient insights beyond those provided from retrospective ratings. DESIGN: Fourteen adults aged 26 to 86 years with at least 6 months of hearing aid experience were recruited for an 8-week crossover field trial (4 weeks wearing hearing aids with no EMA; 4 weeks wearing hearing aids with EMA). Participants were fitted with hearing aids and provided with a streamer and a smartphone with an app that analyzed the acoustic signal from the hearing aids and alerted the participant to respond to a survey when predetermined acoustic conditions were detected. Participants were prompted to complete brief surveys up to 9 times/day that contained establishing questions, quality ratings, and items assessing perceived benefit, residual activity limitation, and satisfaction. Participants also completed retrospective questionnaires at intake and after each 4-week field trial. RESULTS: Participants completed an average of 4.4 surveys per day. The quality ratings changed as the acoustics changed: Ratings of intelligibility were lower for 10 dB signal-to-noise ratio (SNR) than 20 dB SNR (p = 0.006); ratings of noisiness were higher for 10 dB SNR than 20 dB SNR (p = 0.001) and higher for 65 dB SPL than 50 dB SPL (p < 0.001); ratings of effort were higher for 65 dB SPL than 50 dB SPL (p = 0.004); ratings of loudness were higher for 65 dB SPL than 50 dB SPL (p = 0.001). Descriptive analysis of satisfaction, benefit, and residual activity limitation responses showed that the momentary surveys provided more detail about individual variability across acoustic conditions than the retrospective questions. CONCLUSIONS: Participants completed more than 99% of the triggered surveys, demonstrating high compliance. Because the quality ratings generally changed in the hypothesized direction, it is concluded that the participants provided valid responses. The greater variability in responses with EMA than retrospective questionnaires demonstrates its potential utility as a clinical tool for exploring hearing aid outcomes in real-world environments.

Markov chain Monte Carlo methods for hierarchical clustering of dynamic causal models.

In this article, we address technical difficulties that arise when applying Markov chain Monte Carlo (MCMC) to hierarchical models designed to perform clustering in the space of latent parameters of subject-wise generative models. Specifically, we focus on the case where the subject-wise generative model is a dynamic causal model (DCM) for functional magnetic resonance imaging (fMRI) and clusters are defined in terms of effective brain connectivity. While an attractive approach for detecting mechanistically interpretable subgroups in heterogeneous populations, inverting such a hierarchical model represents a particularly challenging case, since DCM is often characterized by high posterior correlations between its parameters. In this context, standard MCMC schemes exhibit poor performance and extremely slow convergence. In this article, we investigate the properties of hierarchical clustering which lead to the observed failure of standard MCMC schemes and propose a solution designed to improve convergence but preserve computational complexity. Specifically, we introduce a class of proposal distributions which aims to capture the interdependencies between the parameters of the clustering and subject-wise generative models and helps to reduce random walk behaviour of the MCMC scheme. Critically, these proposal distributions only introduce a single hyperparameter that needs to be tuned to achieve good performance. For validation, we apply our proposed solution to synthetic and real-world datasets and also compare it, in terms of computational complexity and performance, to Hamiltonian Monte Carlo (HMC), a state-of-the-art Monte Carlo technique. Our results indicate that, for the specific application domain considered here, our proposed solution shows good convergence performance and superior runtime compared to HMC.

Both activation and deactivation of functional networks support increased sentence processing costs.

The research on the neural correlates underlying the language system has gradually moved away from the traditional Broca-Wernicke framework to a network perspective in the past 15 years. Language processing is found to be supported by the co-activation of both core and peripheral brain regions. However, the dynamic co-activation patterns of these brain regions serving different language functions remain to be fully revealed. The present functional magnetic resonance imaging (fMRI) study focused on sentence processing at different syntactic complexity levels to examine how the co-activation of different brain networks will be modulated by increased processing costs. Chinese relative clauses were used to probe the two dimensions of syntactic complexity: embeddedness (left-branching vs. center-embedded) and gap-filler dependency (subject-gap vs. object-gap) using the general linear model (GLM) approach, independent component analysis (ICA) and graph theoretical analysis. In contrast to localized activation revealed by the GLM approach, ICA identified more extensive networks both positively and negatively correlated with the task. We found that the posterior default mode network was anti-correlated to the gap-filler integration costs with increased deactivation for the left-branching object relative clauses compared to subject relative clauses, suggesting the involvement of this network in leveraging the cognitive resources based on the complexity level of the language task. Concurrent activation and deactivation of networks were found to be associated with the higher costs induced by center-embedding and its interaction with gap-filler integration. The graph theoretical analysis further unveiled that center-embeddedness imposed more attentional demand on the subject relative clause, as characterized by its higher degree and strength in the ventral attention network, and higher processing costs of syntactic reanalysis on the object relative clause, as characterized by increased intermodular connections of the language network with other networks. The results suggest that network activation and deactivation profiles are modulated by different dimensions of syntactic complexity to serve the higher demand of creating a coherent semantic representation.

Assessment of Cochlear Implants for Adult Medicare Beneficiaries Aged 65 Years or Older Who Meet Expanded Indications of Open-Set Sentence Recognition: A Multicenter Nonrandomized Clinical Trial.

Importance: Current indications for Medicare beneficiaries to receive a cochlear implant are outdated. Multichannel cochlear implant systems may be effective when provided to Medicare beneficiaries using expanded indications. Objective: To examine the effectiveness of cochlear implants, as measured by improvement on the AzBio Sentence Test, for newly implanted Medicare beneficiaries who meet the expanded indications of an AzBio Sentence Test score of 41% to 60% in their best-aided condition. Design, Setting, and Participants: A multicenter nonrandomized trial examined preoperative and postoperative speech recognition, telephone communication, hearing device benefit, health utility, and quality of life for 34 participants enrolled at 8 different centers who received a cochlear implant between September 17, 2014, and July 10, 2018. All participants were 65 years or older, had bilateral moderate to profound hearing loss, and had a best-aided preoperative AzBio Sentence Test score in quiet of 41% to 60%. Analysis was performed on an intention-to-treat basis. Statistical analysis of final results took place from July 29 to October 1, 2019. Intervention: Multichannel cochlear implants. Main Outcomes and Measures: The study examined the a priori hypothesis that the cochlear implant would improve the AzBio Sentence Test score in the best-aided condition by 25% or more and in the implanted ear-alone condition by 30% or more. The study additionally examined word and telephone recognition and examined device benefit, health utility, and quality of life. Results: A total of 34 participants received a cochlear implant; 31 (23 men [74%]; median age, 73.6 years [range, 65.7-85.1 years]) completed testing through the 6-month evaluation, and 29 completed testing through the 12-month evaluation. Median preoperative AzBio Sentence Test scores were 53% (range, 26%-60%) for the best-aided condition and 24% (range, 0%-53%) for the cochlear implant-alone condition; median scores 12 months after implantation improved to 89% (range, 36%-100%) for the best-aided condition and 77% (range, 13%-100%) for the cochlear implant-alone condition. This outcome represents a median change of 36% (range, -22% to 75%) for the best-aided condition (lower bound of 1-sided 95% CI, 31%) and a median change of 53% (range, -15% to 93%) for the cochlear implant-alone condition (lower bound of 1-sided 95% CI, 45%). Conclusions and Relevance: Intervention with a cochlear implant was associated with improved sentence, word, and telephone recognition in adult Medicare beneficiaries whose preoperative AzBio Sentence Test scores were between 41% and 60%. These findings support expansion of the Center for Medicare & Medicaid current indications for cochlear implants. Trial Registration: ClinicalTrials.gov Identifier: NCT02075229.

Assessment of Speech Understanding After Cochlear Implantation in Adult Hearing Aid Users: A Nonrandomized Controlled Trial.

Importance: Cochlear implants were approved for use in adults in the 1980s, but use remains low owing to a lack of awareness regarding cochlear implantation candidacy criteria and expected outcomes. There have been limited, small series examining the safety and effectiveness of cochlear implantation in adult hearing aid (HA) users with and without mild cognitive impairment (MCI). Objective: To investigate the safety and effectiveness of a single-ear cochlear implant in a group of optimized adult HA users with and without MCI across a variety of domains. Design, Setting, and Participants: In this nonrandomized controlled trial, a multicenter, prospective, repeated-measures investigation was conducted at 13 US institutions. The setting was academic and community-based cochlear implant programs. Eligible participants were 100 adults (aged >18 years) with postlinguistic onset of bilateral moderate sloping to profound or worse sensorineural hearing loss (≤20 years' duration). Fluent English speakers underwent an optimized bilateral HA trial for at least 30 days. Individuals with aided Consonant-Vowel Nucleus-Consonant (CNC) word score in quiet of 40% or less correct in the ear to be implanted and 50% or less correct in the contralateral ear were offered cochlear implants. The first participant was enrolled on February 20, 2017, and the last participant was enrolled on May 3, 2018. The final follow-up was on December 21, 2018. Interventions: Participants received the same cochlear implant system and contralateral HA. Main Outcomes and Measures: The primary outcome measure was speech understanding in quiet (CNC word score) using both the cochlear implant and opposite ear HA. Secondary outcome measures included the following: adverse events; speech understanding in noise (AzBio signal-to-noise ratio of +10 db [+10 SNR]) Health Utilities Index Mark 3 (HUI3); Speech, Spatial, and Qualities of Hearing Questionnaire 49 (SSQ49); and Montreal Cognitive Assessment (MoCA). Results: The median age at cochlear implantation of the 96 patients included in the trial was 71 years (range, 23-91 years), and 62 patients (65%) were male. Three serious adverse events requiring revision surgery occurred, and all resolved without sequelae. By 6 months after activation, the absolute marginal mean change in CNC word score and AzBio +10 SNR was 40.5% (95% CI, 35.9%-45.0%) and 24.1% (95% CI, 18.9%-29.4%), respectively. Ninety-one percent (87 of 96) of participants had a clinically important improvement (>15%) in the CNC word score in the implant ear. Mild cognitive impairment (MoCA total score ≤25) was observed in 48 of 81 study participants (59%) at baseline. Speech perception marginal mean improvements were similar between individuals with and without baseline MCI, with values of 40.9% (95% CI, 35.2%-46.6%) and 39.6% (95% CI, 31.8%-47.4%), respectively, for CNC word score and 27.5% (95% CI, 21.0%-33.9%) and 17.8% (95% CI, 9.0%-26.6%), respectively, for AzBio +10 SNR. Statistically significant and clinically important improvements in the HUI3 and SSQ49 were evident at 6 months. Conclusions and Relevance: The findings of this nonrandomized controlled trial seem to indicate that cochlear implants are safe and effective in restoring speech understanding in both quiet and noise and improve quality of life in individuals with and without MCI. Trial Registration: ClinicalTrials.gov Identifier: NCT03007472.

An optimal dichotic-listening paradigm for the assessment of hemispheric dominance for speech processing.

Dichotic-listening paradigms are widely accepted as non-invasive tests of hemispheric dominance for language processing and represent a standard diagnostic tool for the assessment of developmental auditory and language disorders. Despite its popularity in research and clinical settings, dichotic paradigms show comparatively low reliability, significantly threatening the validity of conclusions drawn from the results. Thus, the aim of the present work was to design and evaluate a novel, highly reliable dichotic-listening paradigm for the assessment of hemispheric differences. Based on an extensive literature review, the paradigm was optimized to account for the main experimental variables which are known to systematically bias task performance or affect random error variance. The main design principle was to minimize the relevance of higher cognitive functions on task performance in order to obtain stimulus-driven laterality estimates. To this end, the key design features of the paradigm were the use of stop-consonant vowel (CV) syllables as stimulus material, a single stimulus pair per trial presentation mode, and a free recall (single) response instruction. Evaluating a verbal and manual response-format version of the paradigm in a sample of N = 50 healthy participants, we yielded test-retest intra-class correlations of rICC = .91 and .93 for the two response format versions. These excellent reliability estimates suggest that the optimal paradigm may offer an effective and efficient alternative to currently used paradigms both in research and diagnostic.

Assessment of Hidden Hearing Loss in Normal Hearing Individuals with and Without Tinnitus.

OBJECTIVES: To evaluate the functions of cochlear structures and the distal part of auditory nerve as well as dead regions within the cochlea in individuals with normal hearing with or without tinnitus by using electrophysiological tests. MATERIALS AND METHODS: Nine individuals (ages: 21-59 years) with normal hearing with tinnitus were included in the study group. Thirteen individuals (ages: 25-60 years) with normal hearing without tinnitus were included in the control group. Immitancemetric examination, pure-tone audiometry (125Hz-16kHz), speech audiometry in quiet and noise environments, transient evoked otoacoustic emissions (TEOAEs), distortion product otoacoustic emissions (DPOAEs), threshold equalizing noise (TEN test (500Hz-4kHz), and ECochG tests, Beck Depression Questionnaire, Tinnitus Handicap Questionnaire, and Visual Analog Scale were performed. RESULTS: In the study group, three patients were found to have a minimal depression and six were found to have a mild depression. In pure-tone audiometry, the threshold (6-16 kHz) in the study group was significantly higher than that of the control group at all frequencies. In the study group, lower performance scores were obtained in speech discrimination in noise in both ears. In the control group, no dead region was detected in the TEN test whereas 75% of subjects in the study group had dead regions. DPOAE and TEOAE responses between study and control group subjects were not different. In the ECochG test, subjects in the study group showed an increase in the summating potential/action potential (SP/AP) ratio in both ears. CONCLUSION: Determination of the SP/AP ratio in patients with tinnitus may be useful in diagnosing hidden hearing loss. Detection of dead regions in 75% of patients in the TEN test may indicate that inner hair cells may be responsible for tinnitus.