Dynamics of alpha suppression index both modality specific and general attention processes

EEG alpha power varies under many circumstances requiring visual attention. However, mounting evidence indicates that alpha may not only serve visual processing, but also the processing of stimuli presented in other sensory modalities, including hearing. We previously showed that alpha dynamics during an auditory task vary as a function of competition from the visual modality (Clements et al., 2022) suggesting that alpha may be engaged in multimodal processing. Here we assessed the impact of allocating attention to the visual or auditory modality on alpha dynamics at parietal and occipital electrodes, during the preparatory period of a cued-conflict task. In this task, bimodal precues indicated the modality (vision, hearing) relevant to a subsequent reaction stimulus, allowing us to assess alpha during modality-specific preparation and while switching between modalities. Alpha suppression following the precue occurred in all conditions, indicating that it may reflect general preparatory mechanisms. However, we observed a switch effect when preparing to attend to the auditory modality, in which greater alpha suppression was elicited when switching to the auditory modality compared to repeating. No switch effect was evident when preparing to attend to visual information (although robust suppression did occur in both conditions). In addition, waning alpha suppression preceded error trials, irrespective of sensory modality. These findings indicate that alpha can be used to monitor the level of preparatory attention to process both visual and auditory information, and support the emerging view that alpha band activity may index a general attention control mechanism used across modalities.

Target voice probability influences enhancement in auditory selective attention

Auditory selective attention is thought to consist of two mechanisms: an enhancement mechanism that boosts the target signal, and a suppression mechanism that attenuates concurrent distracting signals. The current study explored the conditions necessary to observe enhancement of predictable auditory objects. Participants heard scenes consisting of three voices and a distracting noise. They were asked to find the gender singleton (target) and report whether it was saying even or odd numbers. One of the voices appeared as the high-probability target (70%) across trials. We expected responses to be faster when the high-probability target was in the scene, and results from Experiment 1 supported that prediction. However, this target enhancement effect was substantially weakened when a distracting noise was also in the scene, suggesting that the distractor captured attention and interfered with enhancement. Experiment 2 tested the hypothesis that distractor predictability modulates target enhancement by varying the probability of the distractor. Although this hypothesis was not supported, the results of Experiment 1 were replicated. Findings support the existence of an easily disruptable enhancement mechanism that boosts the representation of highly probable target objects.

The influence of auditory selective attention on linguistic outcomes in deaf and hard of hearing children with cochlear implants

PURPOSE

Auditory selective attention (ASA) is crucial to focus on significant auditory stimuli without being distracted by irrelevant auditory signals and plays an important role in language development. The present study aimed to investigate the unique contribution of ASA to the linguistic levels achieved by a group of cochlear implanted (CI) children.

METHODS

Thirty-four CI children with a median age of 10.05 years were tested using both the "Batteria per la Valutazione dell'Attenzione Uditiva e della Memoria di Lavoro Fonologica nell'età evolutiva-VAUM-ELF" to assess their ASA skills, and two Italian standardized tests to measure lexical and morphosyntactic skills. A regression analysis, including demographic and audiological variables, was conducted to assess the unique contribution of ASA to language skills.

RESULTS

The percentages of CI children with adequate ASA performances ranged from 50 to 29.4%. Bilateral CI children performed better than their monolateral peers. ASA skills contributed significantly to linguistic skills, accounting alone for the 25% of the observed variance.

CONCLUSIONS

The present findings are clinically relevant as they highlight the importance to assess ASA skills as early as possible, reflecting their important role in language development. Using simple clinical tools, ASA skills could be studied at early developmental stages. This may provide additional information to outcomes from traditional auditory tests and may allow us to implement specific training programs that could positively contribute to the development of neural mechanisms of ASA and, consequently, induce improvements in language skills.

Distractor probability influences suppression in auditory selective attention

Auditory selective attention is thought to facilitate listening to the sound of interest (e.g., voice or music) in a noisy environment. One mechanism thought to underlie this ability is suppression of distracting stimuli. However, little is known about its operation or characteristics. We tested whether suppression in auditory selective attention capitalizes on statistical regularities in the environment to facilitate attention. Participants listened to seven-second scenes consisting of several voices speaking sequences of numbers and a distractor, which occurred more (70%) or less (30%) frequently across trials. Participants had to find the voice that was a gender singleton and report whether it was saying even or odd numbers. If suppression is an active component of auditory selective attention, task performance was expected to be better when the more frequent distractor was present. Results across the experiment and three replications revealed significantly shorter RTs when the high-probability distractor was in the scene relative to the low-probability distractor. Results are suggestive of a suppression mechanism that mitigates the detrimental influence of a frequently occurring distracting sound.

Rural and urban disparities in selective attention in Chinese young adults: An event-related potential study

Previous studies showed that attention system and its underlying neural mechanisms were profound affected by social inequalities. However, previous studies on social inequalities were mainly focused on family-based factors, such as parental education, parental occupation, and household income. In the present study, we investigated the neural mechanisms underlying more broader social context (e.g., rural verse urban) disparities in selective attention among young adults in China. Event-related potentials (ERPs) were recorded from 22 college students who had born and grown up in rural areas and 22 students who had born and grown up in urban areas during an auditory selective attention task. Although behavioral performance was not significantly different between groups, attentional differences in the negativity difference (Nd) were significantly larger in the urban group than the rural group. Whole sample analysis with hierarchical regression showed that rural/urban status still made a significant contribution to the prediction of Nd amplitudes even after the effects of age, sex, and various family SES measures (include parents' educational levels and annual household income) were controlled for. These findings represent a first step toward understanding the ways in which broad social environmental factors shape the neural basis of selective attention.

A randomized controlled trial to examine the effect of two teaching methods on preschool children's language and communication, executive functions, socioemotional comprehension, and early math skills

BACKGROUND

During the preschool years, children's development of skills like language and communication, executive functions, and socioemotional comprehension undergo dramatic development. Still, our knowledge of how these skills are enhanced is limited. The preschool contexts constitute a well-suited arena for investigating these skills and hold the potential for giving children an equal opportunity preparing for the school years to come. The present study compared two pedagogical methods in the Swedish preschool context as to their effect on language and communication, executive functions, socioemotional comprehension, and early math. The study targeted children in the age span four-to-six-year-old, with an additional focus on these children's backgrounds in terms of socioeconomic status, age, gender, number of languages, time spent at preschool, and preschool start. An additional goal of the study was to add to prior research by aiming at disentangling the relationship between the investigated variables.

METHOD

The study constitutes a randomized controlled trial including 18 preschools and 29 preschool units, with a total of 431 children, and 98 teachers. The interventions lasted for 6 weeks, preceded by pre-testing and followed by post-testing of the children. Randomization was conducted on the level of preschool unit, to either of the two interventions or to control. The interventions consisted of a socioemotional and material learning paradigm (SEMLA) and a digitally implemented attention and math training paradigm (DIL). The preschools were further evaluated with ECERS-3. The main analysis was a series of univariate mixed regression models, where the nested structure of individuals, preschool units and preschools were modeled using random variables.

RESULTS

The result of the intervention shows that neither of the two intervention paradigms had measurable effects on the targeted skills. However, there were results as to the follow-up questions, such as executive functions predicting all other variables (language and communication, socioemotional comprehension, and math). Background variables were related to each other in patterns congruent with earlier findings, such as socioeconomic status predicting outcome measures across the board. The results are discussed in relation to intervention fidelity, length of intervention, preschool quality, and the impact of background variables on children's developmental trajectories and life prospects.

Dimension-selective attention as a possible driver of dynamic, context-dependent re-weighting in speech processing

The contribution of acoustic dimensions to an auditory percept is dynamically adjusted and reweighted based on prior experience about how informative these dimensions are across the long-term and short-term environment. This is especially evident in speech perception, where listeners differentially weight information across multiple acoustic dimensions, and use this information selectively to update expectations about future sounds. The dynamic and selective adjustment of how acoustic input dimensions contribute to perception has made it tempting to conceive of this as a form of non-spatial auditory selective attention. Here, we review several human speech perception phenomena that might be consistent with auditory selective attention although, as of yet, the literature does not definitively support a mechanistic tie. We relate these human perceptual phenomena to illustrative nonhuman animal neurobiological findings that offer informative guideposts in how to test mechanistic connections. We next present a novel empirical approach that can serve as a methodological bridge from human research to animal neurobiological studies. Finally, we describe four preliminary results that demonstrate its utility in advancing understanding of human non-spatial dimension-based auditory selective attention.

Intentional switching in auditory selective attention: Exploring attention shifts with different reverberation times

Using a well-established binaural-listening paradigm the ability to intentionally switch auditory selective attention was examined under anechoic, low reverberation (0.8 s) and high reverberation (1.75 s) conditions. Twenty-three young, normal-hearing subjects were tested in a within-subject design to analyze influences of the reverberation times. Spoken word pairs by two speakers were presented simultaneously to subjects from two of eight azimuth positions. The stimuli consisted of a single number word, (i.e., 1 to 9), followed by either the direction "UP" or "DOWN" in German. Guided by a visual cue prior to auditory stimulus onset indicating the position of the target speaker, subjects were asked to identify whether the target number was numerically smaller or greater than five and to categorize the direction of the second word. Switch costs, (i.e. reaction time differences between a position switch of the target relative to a position repetition), were larger under the high reverberation condition. Furthermore, the error rates were highly dependent on reverberant energy and reverberation interacted with the congruence effect, (i.e. stimuli spoken by target and distractor may evoke the same answer (congruent) or different answers (incongruent)), indicating larger congruence effects under higher reverberation times.