Increased reliance on top-down information to compensate for reduced bottom-up use of acoustic cues in dyslexia

Internal Cognitive Load Differentially Influences Acoustic and Lexical Context Effects in Speech Perception: Evidence From a Population With Attention-Deficit/Hyperactivity Disorder

BACKGROUND

To overcome variability in spoken language, listeners utilize various types of context information for disambiguating speech sounds. Context effects have been shown to be affected by cognitive load. However, previous results are mixed regarding the influence of cognitive load on the use of context information in speech perception.

PURPOSE

We tested a population characterized by an attention-deficit/hyperactivity disorder (ADHD) to better understand the relationship between attention (or internal cognitive load) and context effects.

METHOD

The use of acoustic versus lexical properties of the surrounding signal to disambiguate speech sounds was examined in listeners with ADHD and neurotypical listeners.

RESULTS

Compared to neurotypicals, individuals with ADHD relied more strongly on lexical context for speech perception; however, reliance on acoustic context information from speech rate did not differ.

CONCLUSION

These findings confirm that cognitive load impacts the use of high-level but not low-level context information in speech and imply that speech recognition deficits in ADHD likely arise due to impaired higher order cognitive processes.

Intact Utilization of Contextual Information in Speech Categorization in Autism

Current theories of Autism Spectrum Disorder (ASD) suggest atypical use of context in ASD, but little is known about how these atypicalities influence speech perception. We examined the influence of contextual information (lexical, spectral, and temporal) on phoneme categorization of people with ASD and in typically developed (TD) people. Across three experiments, we found that people with ASD used all types of contextual information for disambiguating speech sounds to the same extent as TD; yet they exhibited a shallower identification curve when phoneme categorization required temporal processing. Overall, the results suggest that the observed atypicalities in speech perception in ASD, including the reduced sensitivity observed here, cannot be attributed merely to the limited ability to utilize context during speech perception.

Do individual differences in lexical reliance reflect states or traits?

Research suggests that individuals differ in the degree to which they rely on lexical information to support speech perception. However, the locus of these differences is not yet known; nor is it known whether these individual differences reflect a context-dependent "state" or a stable listener "trait." Here we test the hypothesis that individual differences in lexical reliance are a stable trait that is linked to individuals' relative weighting of lexical and acoustic-phonetic information for speech perception. At each of two sessions, listeners (n = 73) completed a Ganong task, a phonemic restoration task, and a locally time-reversed speech task - three tasks that have been used to demonstrate a lexical influence on speech perception. Robust lexical effects on speech perception were observed for each task in the aggregate. Individual differences in lexical reliance were stable across sessions; however, relationships among the three tasks in each session were weak. For the Ganong and locally time-reversed speech tasks, increased reliance on lexical information was associated with weaker reliance on acoustic-phonetic information. Collectively, these results (1) provide some evidence to suggest that individual differences in lexical reliance for a given task are a stable reflection of the relative weighting of acoustic-phonetic and lexical cues for speech perception in that task, and (2) highlight the need for a better understanding of the psychometric characteristics of tasks used in the psycholinguistic domain to build theories that can accommodate individual differences in mapping speech to meaning.

Impaired and Spared Auditory Category Learning in Developmental Dyslexia

Categorization has a deep impact on behavior, but whether category learning is served by a single system or multiple systems remains debated. Here, we designed two well-equated nonspeech auditory category learning challenges to draw on putative procedural (information-integration) versus declarative (rule-based) learning systems among adult Hebrew-speaking control participants and individuals with dyslexia, a language disorder that has been linked to a selective disruption in the procedural memory system and in which phonological deficits are ubiquitous. We observed impaired information-integration category learning and spared rule-based category learning in the dyslexia group compared with the neurotypical group. Quantitative model-based analyses revealed reduced use of, and slower shifting to, optimal procedural-based strategies in dyslexia with hypothesis-testing strategy use on par with control participants. The dissociation is consistent with multiple category learning systems and points to the possibility that procedural learning inefficiencies across categories defined by complex, multidimensional exemplars may result in difficulty in phonetic category acquisition in dyslexia.

Encoding speech rate in challenging listening conditions: White noise and reverberation

Temporal contrasts in speech are perceived relative to the speech rate of the surrounding context. That is, following a fast context sentence, listeners interpret a given target sound as longer than following a slow context, and vice versa. This rate effect, often referred to as "rate-dependent speech perception," has been suggested to be the result of a robust, low-level perceptual process, typically examined in quiet laboratory settings. However, speech perception often occurs in more challenging listening conditions. Therefore, we asked whether rate-dependent perception would be (partially) compromised by signal degradation relative to a clear listening condition. Specifically, we tested effects of white noise and reverberation, with the latter specifically distorting temporal information. We hypothesized that signal degradation would reduce the precision of encoding the speech rate in the context and thereby reduce the rate effect relative to a clear context. This prediction was borne out for both types of degradation in Experiment 1, where the context sentences but not the subsequent target words were degraded. However, in Experiment 2, which compared rate effects when contexts and targets were coherent in terms of signal quality, no reduction of the rate effect was found. This suggests that, when confronted with coherently degraded signals, listeners adapt to challenging listening situations, eliminating the difference between rate-dependent perception in clear and degraded conditions. Overall, the present study contributes towards understanding the consequences of different types of listening environments on the functioning of low-level perceptual processes that listeners use during speech perception.

Two sides of the same coin: accessibility practices and neurodivergent users' experience of extended reality

Purpose

This paper explores the accessibility barriers faced by neurodivergent individuals regarding the use of Extended Reality (XR) technologies and the difficulties faced by developers in creating neurodivergent inclusive XR experiences.

Design/methodology/approach

The authors carried out a survey with neurodivergent participants, and a series of semi-structured interviews with neurodivergent adults and XR developers.

Findings

Neurodivergent individuals experience sensory overload when using XR technologies; these negative experiences are exacerbated by excessive multisensory stimulation. Allowing for the customization of sensory settings was seen as the only way to potentially limit negative experiences. The authors found that XR developers lacked awareness of accessibility requirements and struggled to integrate them in current software development practices.

Social implications

Accessibility understanding regarding neurodivergence is increasingly available and the time has come to bring computing and information services within the reach of all neurodivergent individuals. The power in the design of XR, which is crucial, is decentralized from neurotypical XR developing practices to avoid artificial barriers that decrease the quality of life.

Originality/value

There is a lack of studies exploring how neurodivergent individuals experience XR considering their different sensory processing patterns. There is also no research exploring XR developers' awareness of accessibility needs of neurodivergent individuals. This paper presents an account of the challenges faced by neurodivergent XR users, the difficulties faced by XR developers to integrate neurodivergent accessibility requirements, and proposes specific strategies to overcome challenges.

Cognitive load does not increase reliance on speaker information in phonetic categorization

Past research on speech perception has shown that speaker information, such as gender, affects phoneme categorization. Additionally, studies on listening under divided attention have argued that cognitive load decreases attention to phonetic detail and increases reliance on higher-level cues such as lexical information. This study examines the processing of speaker information under divided attention. The results of two perception experiments indicate that additional cognitive load does not increase listeners' reliance on the gender of the speaker during phoneme categorization tasks. This suggests that the processing of speaker information may pattern with lower-level acoustic rather than higher-level lexical information.