Lorna F. Halliday

Frequency discrimination in children: perception, learning and attention.

It is generally believed that both sensory immaturity and inattention contribute to the poor listening of some children. However, the relative contribution of each factor, within and between individuals, and the nature of the inattention are poorly understood. In three experiments we examined the threshold and response variability of 6-11 y.o. children on pure tone frequency discrimination (FD) tasks. We first confirmed that younger children had both higher thresholds and greater within- and between-listener variability than older children and adults. Higher thresholds were mostly attributed to high response variability due to poor sustained attention. We next compared performance on the auditory FD task with that on visual spatial FD. No correlation was found between the thresholds or variability of individuals on the two tasks, suggesting involvement of modality-specific attention. Finally, we found lower thresholds for 8-9 y.o. children performing auditory FD training in a classroom than in the laboratory, possibly due to training session length or to a more familiar, motivating and focussed training environment. The adult-like performance of many younger children at times during their testing or training, together with the high response variability of immature performers, suggested that most elevated FD thresholds in children are due to inattention.

Frequency discrimination learning in children.

Psychoacoustic thresholds of pure tone frequency discrimination (FD) in children are elevated relative to those of adults. It has been shown that it is possible to improve FD thresholds in adults, following a single (subhour) training session. To determine whether FD thresholds in children may be improved by training and, consequently, reduced to adult levels, 100 normally hearing 6- to 11-year-old children and adults received approximately 1 h of training on a FD task at 1 kHz. At the start of training, a quarter of all child participants had FD thresholds that resembled those of naive adults (adult-like subgroup). Another quarter achieved thresholds that were adult-like at some point during training (trainable subgroup). For the remainder (nonadult-like subgroup), thresholds did not reach those of naive adult listeners at any point in the training session. Subgroup membership was linked to the influence of three factors-age, nonverbal IQ, and attention. However, across subgroups, learning was found not to generalize to either a different standard frequency (4 kHz) or a variable (roving) presentation paradigm. The results indicate that it is possible for some children to achieve FD thresholds comparable to those of naive adults, either natively or after limited training.

Use of auditory learning to manage listening problems in children

This paper reviews recent studies that have used adaptive auditory training to address communication problems experienced by some children in their everyday life. It considers the auditory contribution to developmental listening and language problems and the underlying principles of auditory learning that may drive further refinement of auditory learning applications. Following strong claims that language and listening skills in children could be improved by auditory learning, researchers have debated what aspect of training contributed to the improvement and even whether the claimed improvements reflect primarily a retest effect on the skill measures. Key to understanding this research have been more circumscribed studies of the transfer of learning and the use of multiple control groups to examine auditory and non-auditory contributions to the learning. Significant auditory learning can occur during relatively brief periods of training. As children mature, their ability to train improves, but the relation between the duration of training, amount of learning and benefit remains unclear. Individual differences in initial performance and amount of subsequent learning advocate tailoring training to individual learners. The mechanisms of learning remain obscure, especially in children, but it appears that the development of cognitive skills is of at least equal importance to the refinement of sensory processing. Promotion of retention and transfer of learning are major goals for further research.

Dimension-specific attention directs learning and listening on auditory training tasks

The relative contributions of bottom-up versus top-down sensory inputs to auditory learning are not well established. In our experiment, listeners were instructed to perform either a frequency discrimination (FD) task (“FD-train group”) or an intensity discrimination (ID) task (“ID-train group”) during training on a set of physically identical tones that were impossible to discriminate consistently above chance, allowing us to vary top-down attention whilst keeping bottom-up inputs fixed. A third, control group did not receive any training. Only the FD-train group improved on a FD probe following training, whereas all groups improved on ID following training. However, only the ID-train group also showed changes in performance accuracy as a function of interval with training on the ID task. These findings suggest that top-down, dimension-specific attention can direct auditory learning, even when this learning is not reflected in conventional performance measures of threshold change.

Language Development and Impairment in Children With Mild to Moderate Sensorineural Hearing Loss

Purpose The goal of this study was to examine language development and factors related to language impairments in children with mild to moderate sensorineural hearing loss (MMHL). Method Ninety children, aged 8-16 years (46 children with MMHL; 44 aged-matched controls), were administered a battery of standardized language assessments, including measures of phonological processing, receptive and expressive vocabulary and grammar, word and nonword reading, and parental report of communication skills. Group differences were examined after controlling for nonverbal ability. Results Children with MMHL performed as well as controls on receptive vocabulary and word and nonword reading. They also performed within normal limits, albeit significantly worse than controls, on expressive vocabulary, and on receptive and expressive grammar, and worse than both controls and standardized norms on phonological processing and parental report of communication skills. However, there was considerable variation in performance, with 26% showing evidence of clinically significant oral or written language impairments. Poor performance was not linked to severity of hearing loss nor age of diagnosis. Rather, outcomes were related to nonverbal ability, maternal education, and presence/absence of family history of language problems. Conclusions Clinically significant language impairments are not an inevitable consequence of MMHL. Risk factors appear to include lower maternal education and family history of language problems, whereas nonverbal ability may constitute a protective factor.

Feedback Valence Affects Auditory Perceptual Learning Independently of Feedback Probability

Previous studies have suggested that negative feedback is more effective in driving learning than positive feedback. We investigated the effect on learning of providing varying amounts of negative and positive feedback while listeners attempted to discriminate between three identical tones; an impossible task that nevertheless produces robust learning. Four feedback conditions were compared during training: 90% positive feedback or 10% negative feedback informed the participants that they were doing equally well, while 10% positive or 90% negative feedback informed them they were doing equally badly. In all conditions the feedback was random in relation to the listeners’ responses (because the task was to discriminate three identical tones), yet both the valence (negative vs. positive) and the probability of feedback (10% vs. 90%) affected learning. Feedback that informed listeners they were doing badly resulted in better post-training performance than feedback that informed them they were doing well, independent of valence. In addition, positive feedback during training resulted in better post-training performance than negative feedback, but only positive feedback indicating listeners were doing badly on the task resulted in learning. As we have previously speculated, feedback that better reflected the difficulty of the task was more effective in driving learning than feedback that suggested performance was better than it should have been given perceived task difficulty. But contrary to expectations, positive feedback was more effective than negative feedback in driving learning. Feedback thus had two separable effects on learning: feedback valence affected motivation on a subjectively difficult task, and learning occurred only when feedback probability reflected the subjective difficulty. To optimize learning, training programs need to take into consideration both feedback valence and probability.

Auditory processing deficits are sometimes necessary and sometimes sufficient for language difficulties in children: Evidence from mild to moderate sensorineural hearing loss

There is a general consensus that many children and adults with dyslexia and/or specific language impairment display deficits in auditory processing. However, how these deficits are related to developmental disorders of language is uncertain, and at least four categories of model have been proposed: single distal cause models, risk factor models, association models, and consequence models. This study used children with mild to moderate sensorineural hearing loss (MMHL) to investigate the link between auditory processing deficits and language disorders. We examined the auditory processing and language skills of 46, 8-16year-old children with MMHL and 44 age-matched typically developing controls. Auditory processing abilities were assessed using child-friendly psychophysical techniques in order to obtain discrimination thresholds. Stimuli incorporated three different timescales (µs, ms, s) and three different levels of complexity (simple nonspeech tones, complex nonspeech sounds, speech sounds), and tasks required discrimination of frequency or amplitude cues. Language abilities were assessed using a battery of standardised assessments of phonological processing, reading, vocabulary, and grammar. We found evidence that three different auditory processing abilities showed different relationships with language: Deficits in a general auditory processing component were necessary but not sufficient for language difficulties, and were consistent with a risk factor model; Deficits in slow-rate amplitude modulation (envelope) detection were sufficient but not necessary for language difficulties, and were consistent with either a single distal cause or a consequence model; And deficits in the discrimination of a single speech contrast (/bɑ/ vs /dɑ/) were neither necessary nor sufficient for language difficulties, and were consistent with an association model. Our findings suggest that different auditory processing deficits may constitute distinct and independent routes to the development of language difficulties in children.

A tale of two studies on auditory training in children: A response to the claim that 'discrimination training of phonemic contrasts enhances phonological processing in mainstream school children' by Moore, Rosenberg and Coleman (2005).

In a previous article, Moore, Rosenberg and Coleman (Brain and Language, 2005, 94, 72-85) reported evidence for significant improvements in phonological awareness in mainstream children following 6 h of exposure to a commercially available phoneme discrimination training programme, but not in a control group. In a follow-up study, we failed to replicate this finding, despite using an almost identical training programme (Halliday, Taylor, Millward, & Moore, Journal of Speech, Language, and Hearing Research, 2012, 55, 168-181). This paper directly compares the methods and the results of the two studies, in an effort to explain the discrepant findings. It reports that the trained group in Moore et al. (2005) showed significantly greater improvements in phonological awareness following training than the trained group in Halliday et al. (2012). However, the control group in Halliday et al. (2012) showed significantly greater improvements in phonological awareness than the control group in Moore et al. (2005). The paper concludes that differences in the randomization, blinding, experimenter familiarity and treatment of trained and control groups contributed to the different outcomes of the two studies. The results indicate that a plethora of factors can contribute to training effects and highlight the importance of well-designed randomized controlled trials in assessing the efficacy of a given intervention.