Development of auditory selective attention: event-related potential measures of channel selection and target detection

Development of auditory scene analysis: a mini-review

Most auditory environments contain multiple sound waves that are mixed before reaching the ears. In such situations, listeners must disentangle individual sounds from the mixture, performing the auditory scene analysis. Analyzing complex auditory scenes relies on listeners ability to segregate acoustic events into different streams, and to selectively attend to the stream of interest. Both segregation and selective attention are known to be challenging for adults with normal hearing, and seem to be even more difficult for children. Here, we review the recent literature on the development of auditory scene analysis, presenting behavioral and neurophysiological results. In short, cognitive and neural mechanisms supporting stream segregation are functional from birth but keep developing until adolescence. Similarly, from 6 months of age, infants can orient their attention toward a target in the presence of distractors. However, selective auditory attention in the presence of interfering streams only reaches maturity in late childhood at the earliest. Methodological limitations are discussed, and a new paradigm is proposed to clarify the relationship between auditory scene analysis and speech perception in noise throughout development.

How bilingualism modulates selective attention in children

There is substantial evidence that learning and using multiple languages modulates selective attention in children. The current study investigated the mechanisms that drive this modification. Specifically, we asked whether the need for constant management of competing languages in bilinguals increases attentional capacity, or draws on the available resources such that they need to be economised to support optimal task performance. Monolingual and bilingual children aged 7–12 attended to a narrative presented in one ear, while ignoring different types of interference in the other ear. We used EEG to capture the neural encoding of attended and unattended speech envelopes, and assess how well they can be reconstructed from the responses of the neuronal populations that encode them. Despite equivalent behavioral performance, monolingual and bilingual children encoded attended speech differently, with the pattern of encoding across conditions in bilinguals suggesting a redistribution of the available attentional capacity, rather than its enhancement.

Switching Streams Across Ears to Evaluate Informational Masking of Speech-on-Speech

OBJECTIVES

This study aimed to evaluate the informational component of speech-on-speech masking. Speech perception in the presence of a competing talker involves not only informational masking (IM) but also a number of masking processes involving interaction of masker and target energy in the auditory periphery. Such peripherally generated masking can be eliminated by presenting the target and masker in opposite ears (dichotically). However, this also reduces IM by providing listeners with lateralization cues that support spatial release from masking (SRM). In tonal sequences, IM can be isolated by rapidly switching the lateralization of dichotic target and masker streams across the ears, presumably producing ambiguous spatial percepts that interfere with SRM. However, it is not clear whether this technique works with speech materials.

DESIGN

Speech reception thresholds (SRTs) were measured in 17 young normal-hearing adults for sentences produced by a female talker in the presence of a competing male talker under three different conditions: diotic (target and masker in both ears), dichotic, and dichotic but switching the target and masker streams across the ears. Because switching rate and signal coherence were expected to influence the amount of IM observed, these two factors varied across conditions. When switches occurred, they were either at word boundaries or periodically (every 116 msec) and either with or without a brief gap (84 msec) at every switch point. In addition, SRTs were measured in a quiet condition to rule out audibility as a limiting factor.

RESULTS

SRTs were poorer for the four switching dichotic conditions than for the nonswitching dichotic condition, but better than for the diotic condition. Periodic switches without gaps resulted in the worst SRTs compared to the other switch conditions, thus maximizing IM.

CONCLUSIONS

These findings suggest that periodically switching the target and masker streams across the ears (without gaps) was the most efficient in disrupting SRM. Thus, this approach can be used in experiments that seek a relatively pure measure of IM, and could be readily extended to translational research.

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.

Auditory attention in childhood and adolescence: An event-related potential study of spatial selective attention to one of two simultaneous stories

Auditory selective attention is a critical skill for goal-directed behavior, especially where noisy distractions may impede focusing attention. To better understand the developmental trajectory of auditory spatial selective attention in an acoustically complex environment, in the current study we measured auditory event-related potentials (ERPs) across five age groups: 3-5 years; 10 years; 13 years; 16 years; and young adults. Using a naturalistic dichotic listening paradigm, we characterized the ERP morphology for nonlinguistic and linguistic auditory probes embedded in attended and unattended stories. We documented robust maturational changes in auditory evoked potentials that were specific to the types of probes. Furthermore, we found a remarkable interplay between age and attention-modulation of auditory evoked potentials in terms of morphology and latency from the early years of childhood through young adulthood. The results are consistent with the view that attention can operate across age groups by modulating the amplitude of maturing auditory early-latency evoked potentials or by invoking later endogenous attention processes. Development of these processes is not uniform for probes with different acoustic properties within our acoustically dense speech-based dichotic listening task. In light of the developmental differences we demonstrate, researchers conducting future attention studies of children and adolescents should be wary of combining analyses across diverse ages.

The prospects of brain — computer interface applications in children

The restoring of motor functions in adults through brain-computer interface applications is widely studied in the contemporary literature. But there is a lack of similar analyses and research on the application of brain-computer interfaces in the neurorehabilitation of children. There is a need for expanded knowledge in the aforementioned area. This article aims at investigating the extent to which the available opportunities in the area of neurorehabilitation and neurological physiotherapy of children with severe neurological deficits using brain-computer interfaces are being applied, including our own concepts, research and observations.

Novel sounds as a psychophysiological measure of listening effort in older listeners with and without hearing loss

OBJECTIVE

To investigate whether task-irrelevant novel sounds presented during an auditory task can provide information about the level of listening effort.

METHODS

Event-related potentials (ERPs) were recorded for novel sounds presented during two Experiments, a frequency discrimination task and a speech-perception-in-noise (SPIN) test, each with varying degrees of task difficulty (easy, medium, hard). Difficulty was adjusted to the individual frequency discrimination threshold and 50% speech recognition signal-to-noise ratio (SNR), respectively. Older listeners (age range 60-86 years) with either normal hearing for their age or a mild-to-moderate hearing loss participated.

RESULTS

Amplitudes of Novelty P3 and late positive potential (LPP) increased with increasing task difficulty, whereas amplitudes of N1 and N2 decreased. Participants with hearing loss had significantly larger LPP amplitudes in the easy condition of the SPIN test than did normal-hearing listeners. Most correlations between ERP amplitudes and behavioral data were not significant suggesting that listening effort is not a simple equivalent of behavioral performance.

CONCLUSIONS

LPP amplitude appeared to be the most sensitive component for capturing listening effort reflecting the arousal level of the listener.

SIGNIFICANCE

ERPs to novel sounds could be easily recorded during hearing tests and provide an objective physiological measure of listening effort, thus supplementing behavioral performance data.

Beyond DSM: the role of auditory processing in attention and its disorders

This article reviews and synthesizes recent research regarding auditory processing, attention, and their roles in generating both adaptive and maladaptive behavioral responses. Research in these areas is beginning to converge on the role of polymorphisms associated with catecholamine metabolism and transport, particularly the neurotransmitter dopamine. The synthesis offered in this article appears to be the first to argue that genetic differences in dopamine metabolism may be the common factor in four disparate disorders that are often observed to be comorbid, i.e., attention-deficit hyperactivity disorder, auditory processing disorders, developmental language disorders, and reading disorders.

Nonverbal spatially selective attention in 4- and 5-year-old children

Under some conditions 4- and 5-year-old children can differentially process sounds from attended and unattended locations. In fact, the latency of spatially selective attention effects on auditory processing as measured with event-related potentials (ERPs) is quite similar in young children and adults. However, it is not clear if developmental differences in the polarity, distribution, and duration of attention effects are best attributed to acoustic characteristics, availability of non-spatial attention cues, task demands, or domain. In the current study adults and children were instructed to attend to one of two simultaneously presented soundscapes (e.g., city sounds or night sounds) to detect targets (e.g., car horn or owl hoot) in the attended channel only. Probes presented from the same location as the attended soundscape elicited a larger negativity by 80 ms after onset in both adults and children. This initial negative difference (Nd) was followed by a larger positivity for attended probes in adults and another negativity for attended probes in children. The results indicate that the neural systems by which attention modulates early auditory processing are available for young children even when presented with nonverbal sounds. They also suggest important interactions between attention, acoustic characteristics, and maturity on auditory evoked potentials.

Auditory selective attention and processing in children with attention-deficit/hyperactivity disorder

OBJECTIVE

This study sought to better characterize the contributions of deficits in attention allocation and distracter inhibition to the poor performance on attention tasks often seen in children with ADHD.

METHODS

Electrophysiological (Nd, P3b) and behavioral measures (speed and accuracy) were examined during an auditory selective attention task in children with ADHD, children with typical development (TD), and adults. Thirty children (15 ADHD; 13 females) between the ages of 7 and 13 and 16 adults (8 females) participated.

RESULTS

Nd waveforms were elicited from adults and children with TD, but not from children with ADHD. Further, those with ADHD exhibited significantly smaller auditory responses at 100 ms (Ta). P3bs were elicited in all three groups by targets but not by unattended deviants. Performance was significantly poorer in children with ADHD than TD and RTs were more variable.

CONCLUSIONS

Children with ADHD evidenced poorer attention allocation, as measured by Nd and hits, but were not more distracted by unattended deviants, as measured by P3b and false alarms, than children with TD.

SIGNIFICANCE

Findings for Nd, P3b, and Ta considered together suggest that deficits in auditory selective attention in children with ADHD may be attributable to reduced information early in the processing stream.

Electrophysiological correlates of selective attention: a lifespan comparison

Background

To study how event-related brain potentials (ERPs) and underlying cortical mechanisms of selective attention change from childhood to old age, we investigated lifespan age differences in ERPs during an auditory oddball task in four age groups including 24 younger children (9–10 years), 28 older children (11–12 years), 31 younger adults (18–25), and 28 older adults (63–74 years). In the Unattend condition, participants were asked to simply listen to the tones. In the Attend condition, participants were asked to count the deviant stimuli. Five primary ERP components (N1, P2, N2, P3 and N3) were extracted for deviant stimuli under Attend conditions for lifespan comparison. Furthermore, Mismatch Negativity (MMN) and Late Discriminative Negativity (LDN) were computed as difference waves between deviant and standard tones, whereas Early and Late Processing Negativity (EPN and LPN) were calculated as difference waves between tones processed under Attend and Unattend conditions. These four secondary ERP-derived measures were taken as indicators for change detection (MMN and LDN) and selective attention (EPN and LPN), respectively. To examine lifespan age differences, the derived difference-wave components for attended (MMN and LDN) and deviant (EPN and LPN) stimuli were specifically compared across the four age groups.

Results

Both primary and secondary ERP components showed age-related differences in peak amplitude, peak latency, and topological distribution. The P2 amplitude was higher in adults compared to children, whereas N2 showed the opposite effect. P3 peak amplitude was higher in older children and younger adults than in older adults. The amplitudes of N3, LDN, and LPN were higher in older children compared with both of the adult groups. In addition, both P3 and N3 peak latencies were significantly longer in older than in younger adults. Interestingly, in the young adult sample P3 peak amplitude correlated positively and P3 peak latency correlated negatively with performance in the Identical Picture test, a marker measure of fluid intelligence.

Conclusion

The present findings suggest that patterns of event-related brain potentials are highly malleable within individuals and undergo profound reorganization from childhood to adulthood and old age.