Does the degree of linguistic experience (native versus nonnative) modulate the degree to which listeners can benefit from a delay between the onset of the maskers and the onset of the target speech?

Adaptation in auditory processing

Adaptation is an essential feature of auditory neurons, which reduces their responses to unchanging and recurring sounds and allows their response properties to be matched to the constantly changing statistics of sounds that reach the ears. As a consequence, processing in the auditory system highlights novel or unpredictable sounds and produces an efficient representation of the vast range of sounds that animals can perceive by continually adjusting the sensitivity and, to a lesser extent, the tuning properties of neurons to the most commonly encountered stimulus values. Together with attentional modulation, adaptation to sound statistics also helps to generate neural representations of sound that are tolerant to background noise and therefore plays a vital role in auditory scene analysis. In this review, we consider the diverse forms of adaptation that are found in the auditory system in terms of the processing levels at which they arise, the underlying neural mechanisms, and their impact on neural coding and perception. We also ask what the dynamics of adaptation, which can occur over multiple timescales, reveal about the statistical properties of the environment. Finally, we examine how adaptation to sound statistics is influenced by learning and experience and changes as a result of aging and hearing loss.

Speech Processing as a Far-Transfer Gauge of Serious Games for Cognitive Training in Aging: Randomized Controlled Trial of Web-Based Effectivate Training

BACKGROUND

The number of serious games for cognitive training in aging (SGCTAs) is proliferating in the market and attempting to combat one of the most feared aspects of aging-cognitive decline. However, the efficacy of many SGCTAs is still questionable. Even the measures used to validate SGCTAs are up for debate, with most studies using cognitive measures that gauge improvement in trained tasks, also known as near transfer. This study takes a different approach, testing the efficacy of the SGCTA-Effectivate-in generating tangible far-transfer improvements in a nontrained task-the Eye tracking of Word Identification in Noise Under Memory Increased Load (E-WINDMIL)-which tests speech processing in adverse conditions.

OBJECTIVE

This study aimed to validate the use of a real-time measure of speech processing as a gauge of the far-transfer efficacy of an SGCTA designed to train executive functions.

METHODS

In a randomized controlled trial that included 40 participants, we tested 20 (50%) older adults before and after self-administering the SGCTA Effectivate training and compared their performance with that of the control group of 20 (50%) older adults. The E-WINDMIL eye-tracking task was administered to all participants by blinded experimenters in 2 sessions separated by 2 to 8 weeks.

RESULTS

Specifically, we tested the change between sessions in the efficiency of segregating the spoken target word from its sound-sharing alternative, as the word unfolds in time. We found that training with the SGCTA Effectivate improved both early and late speech processing in adverse conditions, with higher discrimination scores in the training group than in the control group (early processing: F_1,38=7.371; P=.01; η_p²=0.162 and late processing: F_1,38=9.003; P=.005; η_p²=0.192).

CONCLUSIONS

This study found the E-WINDMIL measure of speech processing to be a valid gauge for the far-transfer effects of executive function training. As the SGCTA Effectivate does not train any auditory task or language processing, our results provide preliminary support for the ability of Effectivate to create a generalized cognitive improvement. Given the crucial role of speech processing in healthy and successful aging, we encourage researchers and developers to use speech processing measures, the E-WINDMIL in particular, to gauge the efficacy of SGCTAs. We advocate for increased industry-wide adoption of far-transfer metrics to gauge SGCTAs.

Adaptation to noise in normal and impaired hearing

Many aspects of hearing function are negatively affected by background noise. Listeners, however, have some ability to adapt to background noise. For instance, the detection of pure tones and the recognition of isolated words embedded in noise can improve gradually as tones and words are delayed a few hundred milliseconds in the noise. While some evidence suggests that adaptation to noise could be mediated by the medial olivocochlear reflex, adaptation can occur for people who do not have a functional reflex. Since adaptation can facilitate hearing in noise, and hearing in noise is often harder for hearing-impaired than for normal-hearing listeners, it is conceivable that adaptation is impaired with hearing loss. It remains unclear, however, if and to what extent this is the case, or whether impaired adaptation contributes to the greater difficulties experienced by hearing-impaired listeners understanding speech in noise. Here, we review adaptation to noise, the mechanisms potentially contributing to this adaptation, and factors that might reduce the ability to adapt to background noise, including cochlear hearing loss, cochlear synaptopathy, aging, and noise exposure. The review highlights few knowns and many unknowns about adaptation to noise, and thus paves the way for further research on this topic.

More Than Words: the Relative Roles of Prosody and Semantics in the Perception of Emotions in Spoken Language by Postlingual Cochlear Implant Users

OBJECTIVES

The processing of emotional speech calls for the perception and integration of semantic and prosodic cues. Although cochlear implants allow for significant auditory improvements, they are limited in the transmission of spectro-temporal fine-structure information that may not support the processing of voice pitch cues. The goal of the current study is to compare the performance of postlingual cochlear implant (CI) users and a matched control group on perception, selective attention, and integration of emotional semantics and prosody.

DESIGN

Fifteen CI users and 15 normal hearing (NH) peers (age range, 18-65 years) 1istened to spoken sentences composed of different combinations of four discrete emotions (anger, happiness, sadness, and neutrality) presented in prosodic and semantic channels-T-RES: Test for Rating Emotions in Speech. In three separate tasks, listeners were asked to attend to the sentence as a whole, thus integrating both speech channels (integration), or to focus on one channel only (rating of target emotion) and ignore the other (selective attention). Their task was to rate how much they agreed that the sentence conveyed each of the predefined emotions. In addition, all participants performed standard tests of speech perception.

RESULTS

When asked to focus on one channel, semantics or prosody, both groups rated emotions similarly with comparable levels of selective attention. When the task was called for channel integration, group differences were found. CI users appeared to use semantic emotional information more than did their NH peers. CI users assigned higher ratings than did their NH peers to sentences that did not present the target emotion, indicating some degree of confusion. In addition, for CI users, individual differences in speech comprehension over the phone and identification of intonation were significantly related to emotional semantic and prosodic ratings, respectively.

CONCLUSIONS

CI users and NH controls did not differ in perception of prosodic and semantic emotions and in auditory selective attention. However, when the task called for integration of prosody and semantics, CI users overused the semantic information (as compared with NH). We suggest that as CI users adopt diverse cue weighting strategies with device experience, their weighting of prosody and semantics differs from those used by NH. Finally, CI users may benefit from rehabilitation strategies that strengthen perception of prosodic information to better understand emotional speech.

Focusing on Emotional and Social Intelligence Stimulation of People With Dementia by Playing a Serious Game—Proof of Concept Study

Context: Dementia is one of the top five chronic diseases, which has an overwhelming impact on patients' life quality, family, and caregivers. Currently, research relating to people with dementia (PwD) focuses on the deterioration of cognitive abilities. A more innovative approach, and the one taken by this paper, is focusing on methods to maintain and improve functionality, communication and quality of life of PwD by building on remaining capacities in the yet unexplored domain of emotional and social intelligence (ESI). The use of serious games for PwD (SG4D) aimed at building social and emotional capacity is a budding field of research.

Objectives: Proof of concept that the, low cost, easy to deploy SG4D, called “My Brain Works” (MBW), co-designed with PwD, enhances ESI, based on the Bar-On ESI model.

Methods: 27 PwD, clients at MELABEV dementia day center, participated in a mixed methods 12 weeks pilot, proof of concept study using a tablet SG4D co-designed with PwD. Quantitative performance data was collected automatically by the tablet during game sessions. In this paper we focus on the analysis of the qualitative and quantitative data related to ESI, observed by 10 different researchers, during each game session.

Results: Quantitative data revealed: both the PwD with high and low MoCA scores had similar average ESI scores. Qualitative analysis revealed that the PwD demonstrated 9 sub-components of the Bar-On ESI Model.

Conclusion: While there is no drug to stop cognitive decline associated with dementia, interventions related to ESI, on the other hand, may improve functioning and quality of life. Despite declines in cognitive abilities, our study shows that a tablet based SG4D can stimulate their ESI and evoke responses in self-awareness, empathy, social and communication capacities. Using SG4D to exercise and maintain social skills is an area that may be promising in the future and may help counter the negative effects of social isolation and loneliness. Such games, while not focusing on cognitive improvement, may also impact on cognitive functioning and help bridge the gap between caregiver and PwD. More research is needed with larger sample sizes.

Effects of noise precursors on the detection of amplitude and frequency modulation for tones in noise

Recent studies on amplitude modulation (AM) detection for tones in noise reported that AM-detection thresholds improve when the AM stimulus is preceded by a noise precursor. The physiological mechanisms underlying this AM unmasking are unknown. One possibility is that adaptation to the level of the noise precursor facilitates AM encoding by causing a shift in neural rate-level functions to optimize level encoding around the precursor level. The aims of this study were to investigate whether such a dynamic-range adaptation is a plausible mechanism for the AM unmasking and whether frequency modulation (FM), thought to be encoded via AM, also exhibits the unmasking effect. Detection thresholds for AM and FM of tones in noise were measured with and without a fixed-level precursor. Listeners showing the unmasking effect were then tested with the precursor level roved over a wide range to modulate the effect of adaptation to the precursor level on the detection of the subsequent AM. It was found that FM detection benefits from a precursor and the magnitude of FM unmasking correlates with that of AM unmasking. Moreover, consistent with dynamic-range adaptation, the unmasking magnitude weakens as the level difference between the precursor and simultaneous masker of the tone increases.

Listening in complex acoustic scenes

Being able to pick out particular sounds, such as speech, against a background of other sounds represents one of the key tasks performed by the auditory system. Understanding how this happens is important because speech recognition in noise is particularly challenging for older listeners and for people with hearing impairments. Central to this ability is the capacity of neurons to adapt to the statistics of sounds reaching the ears, which helps to generate noise-tolerant representations of sounds in the brain. In more complex auditory scenes, such as a cocktail party — where the background noise comprises other voices, sound features associated with each source have to be grouped together and segregated from those belonging to other sources. This depends on precise temporal coding and modulation of cortical response properties when attending to a particular speaker in a multi-talker environment. Furthermore, the neural processing underlying auditory scene analysis is shaped by experience over multiple timescales.

Differences in Working Memory Capacity Affect Online Spoken Word Recognition: Evidence From Eye Movements

Individual differences in working memory capacity have been gaining recognition as playing an important role in speech comprehension, especially in noisy environments. Using the visual world eye-tracking paradigm, a recent study by Hadar and coworkers found that online spoken word recognition was slowed when listeners were required to retain in memory a list of four spoken digits (high load) compared with only one (low load). In the current study, we recognized that the influence of a digit preload might be greater for individuals who have a more limited memory span. We compared participants with higher and lower memory spans on the time course for spoken word recognition by testing eye-fixations on a named object, relative to fixations on an object whose name shared phonology with the named object. Results show that when a low load was imposed, differences in memory span had no effect on the time course of preferential fixations. However, with a high load, listeners with lower span were delayed by ∼550 ms in discriminating target from sound-sharing competitors, relative to higher span listeners. This follows an assumption that the interference effect of a memory preload is not a fixed value, but rather, its effect is greater for individuals with a smaller memory span. Interestingly, span differences affected the timeline for spoken word recognition in noise, but not offline accuracy. This highlights the significance of using eye-tracking as a measure for online speech processing. Results further emphasize the importance of considering differences in cognitive capacity, even when testing normal hearing young adults.

Speech predictability can hinder communication in difficult listening conditions

In difficult listening situations, such as in noisy environments, one would expect speech intelligibility to improve over time thanks to noise adaptation and/or to speech predictability facilitating the recognition of upcoming words. We tested this possibility by presenting normal-hearing human listeners (N = 100; 70 women) with sentences and measuring word recognition as a function of word position in a sentence. Sentences were presented in quiet and in competition with various masker sounds at individualized levels where listeners had 50% probability of recognizing a full sentence. Contrary to expectations, recognition was best for the first word and gradually deteriorated with increasing word position along the sentence. The worsening in recognition was unlikely due to differences in word audibility or word type and was uncorrelated with age or working memory capacity. Using a probabilistic model of word recognition, we show that the worsening effect probably occurs because misunderstandings generate inaccurate predictions that outweigh the benefits from accurate predictions. Analyses also revealed that predictions overruled the potential benefits from noise adaptation. We conclude that although speech predictability can facilitate sentence recognition, it can also result in declines in word recognition as the sentence unfolds because of inaccuracies in prediction.

Card playing enhances speech perception among aging adults: comparison with aging musicians

Speech perception and auditory processing have been shown to be enhanced among aging musicians as compared to non-musicians. In the present study, the aim was to test whether these functions are also enhanced among those who are engaged in a non-musical mentally challenging leisure activity (card playing). Three groups of 23 aging adults, aged 60-80 years, were recruited for the study: Musicians, Card players, and Controls. Participants were matched for age, gender, Wechsler Adult Intelligence Scale-III Matrix Reasoning, and Digit Span scores. Their performance was measured using auditory spectral and spatial temporal order judgment tests, and four tasks of speech perception in conditions of: no background noise, background noise of speech frequencies, background noise of white noise, and 60% compressed speech. Musicians were better in auditory and speech perception than the other two groups. Card players were similar to Controls in auditory perception tasks, but were better in the speech perception tasks. Non-musician aging adults may be able to improve their speech perception ability by engaging in leisure activity requiring cognitive effort.

Adaptation to Noise in Human Speech Recognition Unrelated to the Medial Olivocochlear Reflex

Sensory systems constantly adapt their responses to the current environment. In hearing, adaptation may facilitate communication in noisy settings, a benefit frequently (but controversially) attributed to the medial olivocochlear reflex (MOCR) enhancing the neural representation of speech. Here, we show that human listeners (N = 14; five male) recognize more words presented monaurally in ipsilateral, contralateral, and bilateral noise when they are given some time to adapt to the noise. This finding challenges models and theories that claim that speech intelligibility in noise is invariant over time. In addition, we show that this adaptation to the noise occurs also for words processed to maintain the slow-amplitude modulations in speech (the envelope) disregarding the faster fluctuations (the temporal fine structure). This demonstrates that noise adaptation reflects an enhancement of amplitude modulation speech cues and is unaffected by temporal fine structure cues. Last, we show that cochlear implant users (N = 7; four male) show normal monaural adaptation to ipsilateral noise. Because the electrical stimulation delivered by cochlear implants is independent from the MOCR, this demonstrates that noise adaptation does not require the MOCR. We argue that noise adaptation probably reflects adaptation of the dynamic range of auditory neurons to the noise level statistics.SIGNIFICANCE STATEMENT People find it easier to understand speech in noisy environments when they are given some time to adapt to the noise. This benefit is frequently but controversially attributed to the medial olivocochlear efferent reflex enhancing the representation of speech cues in the auditory nerve. Here, we show that the adaptation to noise reflects an enhancement of the slow fluctuations in amplitude over time that are present in speech. In addition, we show that adaptation to noise for cochlear implant users is not statistically different from that for listeners with normal hearing. Because the electrical stimulation delivered by cochlear implants is independent from the medial olivocochlear efferent reflex, this demonstrates that adaptation to noise does not require this reflex.

Sibilant production in Hebrew-speaking adults: Apical versus laminal

The Hebrew IPA charts describe the sibilants /s, z/ as 'alveolar fricatives', where the place of articulation on the palate is the alveolar ridge. The point of constriction on the tongue is not defined - apical (tip) or laminal (blade). Usually, speech and language pathologists (SLPs) use the apical placement in Hebrew articulation therapy. Some researchers and SLPs suggested that acceptable /s, z/ could be also produced with the laminal placement (i.e. the tip of the tongue approximating the lower incisors). The present study focused at the clinical level, attempting to determine the prevalence of these alternative points of constriction on the tongue for /s/ and /z/ in three different samples of Hebrew-speaking young adults (total n = 242), with typical articulation. Around 60% of the participants reported using the laminal position, regardless of several speaker-related variables (e.g. tongue-thrust swallowing, gender). Laminal production was more common in /s/ (than /z/), coda (than onset) position of the sibilant, mono- (than di-) syllabic words, and with non-alveolar (than alveolar) adjacent consonants. Experiment 3 revealed no acoustical differences between apical and laminal productions of /s/ and of /z/. From a clinical perspective, we wish to raise the awareness of SLPs to the prevalence of the two placements when treating Hebrew speakers, noting that tongue placements were highly correlated across sibilants. Finally, we recommend adopting a client-centred practice, where tongue placement is matched to the client. We further recommend selecting targets for intervention based on our findings, and separating between different prosodic positions in treatment.