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

Abstract

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.

Statistical Learning of Speech Sounds in Dyslexic and Typical Reading Children

“…Auditory processing has frequently been investigated in dyslexia, and empirical evidence, often-though not always-has confirmed the presence of an auditory deficit, especially when stimuli contain acoustic changes over time (Hämäläinen, Salminen, & Leppänen, 2012). The observed auditory impairments can hinder phoneme perception (Talcott et al, 2002;Vandermosten et al, 2010Vandermosten et al, , 2011 but can also affect other aspects of speech processing such as syllable identification and the processing of prosody (Goswami, 2015;Halliday, Tuomainen, & Rosen, 2017;Law et al, 2017;Poelmans et al, 2011). Moreover, auditory deficits can only partially explain the variability seen in dyslexics' phonological and reading performance (Law et al, 2017); hence, deficient statistical learning might also contribute.…”

Investigating Auditory Spectral and Temporal Resolution Deficits in Children with Reading Difficulties

“…A recent meta-analysis of phonological skills and their role in learning to read found that phonemic awareness had the strongest correlation with word reading ability (Melby-Lervåg et al, 2012). However, there is much debate over what timescale these phonological deficits are related to (Hämäläinen et al, 2012;Halliday et al, 2017). Currently, the two most popular theories for phonological deficits in dyslexia are the rate-processing constraint hypothesis, which relates to short timescale processing (Tallal, 1980;1984;2004; see also Farmer and Klein, 1995, for a review), and the temporal sampling framework hypothesis (Goswami, 2011), which relates to longer timescale processing.…”

“…Gamma neural oscillations predominantly in the left auditory cortex are believed to correspond to phonemic-level processing (Poeppel, 2003;Giraud and Poeppel, 2012). A rate-processing deficit is thought to lead to inaccurate phoneme perception and, therefore, result in the development of less precise phonological representations of these phonemes (see Halliday et al, 2017;Hämäläinen et al, 2012, for a review).…”

“…Children's awareness of syllables is usually present when they are three to four years old, whereas phoneme awareness only develops once a child is taught to read and write (see Ziegler and Goswami, 2005, for a review). A temporal sampling deficit is thought to cause problems with the segmentation of speech into smaller elements, such as syllables (see Halliday et al, 2017;Hämäläinen et al, 2012 for a review). Theta neural oscillations predominantly in the right auditory cortex are believed to moderate syllable-level processing (Poeppel, 2003;Giraud and Poeppel, 2012).…”

“…In light of these mixed findings and the highly heterogeneous nature of reading difficulties, we believe that dyslexia may not be able to be explained by one theory, and hence that there may not be a single cause for all reading difficulties. Both the rate-processing constraint hypothesis and the temporal sampling framework hypothesis are examples of single distal cause models as they propose that their respective auditoryprocessing deficit is the sole cause of dyslexia (Halliday et al, 2017). As a result, they are seen to be competing theories, so evidence for one is interpreted as evidence against the other (Protopapas, 2013).…”