On the importance of considering individual profiles when investigating the role of auditory sequential deficits in developmental dyslexia (original) (raw)
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Auditory Temporal Processing and Lexical/Nonlexical Reading in Developmental Dyslexics
Journal of The American Academy of Audiology, 2000
Relationships between lexical/nonlexical reading and auditory temporal processing were examined. Poor nonlexical readers (poor nonword readers, phonologic dyslexics) had difficulty across tone tasks irrespective of speed of presentation or mode of recall. Poor lexical readers (poor irregular word readers, surface dyslexics) had difficulty recalling tones in a sequence only when they were presented rapidly. Covariate analysis supported these findings, revealing that nonlexical (nonword) reading performance is associated with general auditory performance, but lexical (irregular word) reading is particularly associated with auditory sequencing. These findings suggest that phonologic and surface dyslexics perform differently on nonspeech auditory tasks. Because the two different types of poor readers did not differ significantly on tests of memory and learning but did differ on auditory tasks, we suggest that their performance on the auditory tasks may reflect auditory processing abnormalities as opposed to more general learning or memory difficulties. In addition to these observed qualitative differences between groups on the tone tasks, collapsing groups (all readers) revealed significant correlations between nonword reading and the Same-Different tone tasks in particular, whereas irregular word reading was not associated with any tone tasks ; there also appears to be a quantitative relationship between nonlexical reading and Same-Different tone task performance as better or worse nonword reading predicts better or worse performance on the Same-Different tone tasks. In particular, it is conceivable that an auditory temporal processing deficit might contribute to poor nonword reading .
Age, dyslexia subtype and comorbidity modulate rapid auditory processing in developmental dyslexia
Frontiers in Human Neuroscience, 2014
The nature of Rapid Auditory Processing (RAP) deficits in dyslexia remains debated, together with the specificity of the problem to certain types of stimuli and/or restricted subgroups of individuals. Following the hypothesis that the heterogeneity of the dyslexic population may have led to contrasting results, the aim of the study was to define the effect of age, dyslexia subtype and comorbidity on the discrimination and reproduction of non-verbal tone sequences. Participants were 46 children aged 8-14 (26 with dyslexia, subdivided according to age, presence of a previous language delay, and type of dyslexia). Experimental tasks were a Temporal Order Judgment (TOJ) (manipulating tone length, ISI and sequence length), and a Pattern Discrimination Task. Dyslexic children showed general RAP deficits. Tone length and ISI influenced dyslexic and control children's performance in a similar way, but dyslexic children were more affected by an increase from 2 to 5 sounds. As to age, older dyslexic children's difficulty in reproducing sequences of 4 and 5 tones was similar to that of normally reading younger (but not older) children.
Auditory stream segregation in dyslexic adults
Brain, 1999
Developmental dyslexia is often associated with problems in phonological processing based on, or accompanied by, deficits in the perception of rapid auditory changes. Thirteen dyslexic adults and 18 control subjects were tested on sequences of alternating tones of high (1000 Hz) and low (400 Hz) pitch, which at short stimulus onset asynchronies (SOAs) led to perceptual separation of the sound sequence into high-and low-pitched streams. The control subjects perceived the tone sequence as connected Abbreviations: SLI ϭ specific language impairment; SOA ϭ stimulus onset asynchrony by guest on July 22, 2016 http://brain.oxfordjournals.org/
Neuropsychologia, 2007
This study investigates whether the core bottleneck of literacy-impairment should be situated at the phonological level or at a more basic sensory level, as postulated by supporters of the auditory temporal processing theory. Phonological ability, speech perception and low-level auditory processing were assessed in a group of 5-year-old pre-school children at high-family risk for dyslexia, compared to a group of wellmatched low-risk control children. Based on family risk status and first grade literacy achievement children were categorized in groups and pre-school data were retrospectively reanalyzed. On average, children showing both increased family risk and literacy-impairment at the end of first grade, presented significant pre-school deficits in phonological awareness, rapid automatized naming, speech-in-noise perception and frequency modulation detection. The concurrent presence of these deficits before receiving any formal reading instruction, might suggest a causal relation with problematic literacy development. However, a closer inspection of the individual data indicates that the core of the literacy problem is situated at the level of higher-order phonological processing. Although auditory and speech perception problems are relatively over-represented in literacy-impaired subjects and might possibly aggravate the phonological and literacy problem, it is unlikely that they would be at the basis of these problems. At a neurobiological level, results are interpreted as evidence for dysfunctional processing along the auditory-to-articulation stream that is implied in phonological processing, in combination with a relatively intact or inconsistently impaired functioning of the auditory-to-meaning stream that subserves auditory processing and speech perception.
Is There a Relationship Between Speech and Nonspeech Auditory Processing in Children With Dyslexia?
Journal of Speech Language and Hearing Research, 2001
Although there is good evidence that some dyslexic children show at least small deficits in speech perceptual tasks, it is not yet clear the extent to which this results from a general auditory, as opposed to a specifically linguistic/phonological problem. Here we have investigated the extent to which performance in backward and forward masking can explain identification and discrimination ability for speech sounds in which the crucial acoustic contrast (the second formant transition) is followed ("ba" vs. "da") or preceded ("ab" vs. "ad") by a vowel. More specifically, we expect children with elevated thresholds in backward masking to be relatively more impaired for tasks involving "ba" and "da" than for tasks involving "ab" and "ad". In order to determine whether poor performance with speech sounds reflects a general deficit for perceiving formant transitions, we also constructed nonspeech analogues of the speech syllables-the contrastive second formant presented in isolation. Two groups of 8 children matched for age (mean of 13 years) and nonverbal intelligence were selected to be well separated in terms of their performance in reading and spelling. All underwent the same set of auditory tasks: 1) forward, backward and simultaneous masking with a short (20 ms) 1-kHz probe tone in a broadband and notched noise; 2) identification as "b" or "d" of synthetic "ba"-"da" and "ab"-"ad" continua; 3) same/different discrimination of pairs of stimuli drawn from the endpoints of the two speech continua (e.g., "ba-da", "da-ba", "da-da", "baba"), as well as their nonspeech analogues. There were no differences between dyslexic and control children in forward and simultaneous masking, but thresholds for backward masking in a broadband noise were elevated for the dyslexics as a group. Overall speech identification and discrimination performance was superior for the controls (barely so for identification), but did not differ otherwise for the two speech contrasts (one of which should be influenced by backward masking, and one by forward). Thus, although dyslexics show a clear group deficit in backward masking, this has no simple relationship to the perception of crucial acoustic features in speech. Furthermore, the deficit for the nonspeech analogues was much less marked than for the speech sounds, with ¾ of the dyslexic listeners performing equivalently to controls. Either there is a linguistic/phonological component to the speech perception deficit, or there is an important effect of acoustic complexity.
Phonological but not auditory discrimination is impaired in dyslexia
European Journal of Neuroscience, 2006
Deficient phonological skills are considered to be a core problem in developmental dyslexia. Children with dyslexia often demonstrate poorer performance than non-impaired readers when categorizing speech-sounds. Using the automatic mismatch response, we show that in contrast to this deficit at the behavioural level, neurophysiological responding in dyslexic children indicates their ability to automatically discriminate syllables. Therefore, the phonological deficit is unlikely to be caused by a temporal deficit or by a noisy functional organization in the respective representational cortex. We obtained measures of reading, spelling and categorical speechperception from 58 dyslexic children and 21 control children. The children also participated in magnetoencephalographic measurements while being stimulated acoustically with the syllables ⁄ ba ⁄ and ⁄ da ⁄ in an oddball paradigm. Mismatch field (MMF) amplitudes between standard and deviant stimuli were obtained. Dyslexic children performed more poorly than control children on all test measures. However, the groups did not differ in MMF amplitude or latency. No correlations were found between MMF amplitudes and behavioural performance.These results were obtained with a large sample size and thus speak robustly against a general deficit in auditory discrimination in dyslexia. These results are compatible with the idea that decoding difficulties occur later in the processing stream where access to the phonological lexicon is attempted.
Annals of Dyslexia, 2012
The simultaneous auditory processing skills of 17 dyslexic children and 17 skilled readers were measured using a dichotic listening task. Results showed that the dyslexic children exhibited difficulties reporting syllabic material when presented simultaneously. As a measure of simultaneous visual processing, visual attention span skills were assessed in the dyslexic children. We presented the dyslexic children with a phonological short-term memory task and a phonemic awareness task to quantify their phonological skills. Visual attention spans correlated positively with individual scores obtained on the dichotic listening task while phonological skills did not correlate with either dichotic scores or visual attention span measures. Moreover, all the dyslexic children with a dichotic listening deficit showed a simultaneous visual processing deficit, and a substantial number of dyslexic children exhibited phonological processing deficits whether or not they exhibited low dichotic listening scores. These findings suggest that processing simultaneous auditory stimuli may be impaired in dyslexic children regardless of phonological processing difficulties and be linked to similar problems in the visual modality.