Amplitude envelope perception, phonology and prosodic sensitivity in children with developmental dyslexia

Here we explore relations between auditory perception of amplitude envelope structure, prosodic sensitivity, and phonological awareness in a sample of 56 typically-developing children and children with developmental dyslexia. We examine whether rise time sensitivity is linked to prosodic sensitivity, and whether prosodic sensitivity is linked to phonological awareness. Prosodic sensitivity was measured by two reiterant speech tasks modelled on Kitzen (2001). The children with developmental dyslexia were significantly impaired in the reiterant speech tasks and in the phonological awareness tasks (onset and rime awareness). There were significant predictive relations between basic auditory processing of amplitude envelope structure (in particular, rise time), prosodic sensitivity, phonological awareness, reading, and spelling. The auditory processing difficulties that characterise children with developmental dyslexia appear to impair their sensitivity to phrase-level prosodic cues such as metrical structure as well as to phonology, but in this study phonological and prosodic sensitivity made largely independent contributions to reading.     

Auditory processing interventions and developmental dyslexia: a comparison of phonemic and rhythmic approaches

The purpose of this study was to compare the efficacy of two auditory processing interventions for developmental dyslexia, one based on rhythm and one based on phonetic training. Thirty-three children with dyslexia participated and were assigned to one of three groups (a) a novel rhythmic processing intervention designed to highlight auditory rhythmic information in non-speech and speech stimuli; (b) a commercially-available phoneme discrimination intervention; and (c) a no-intervention control. The intervention lasted for 6 weeks. Both interventions yielded equivalent and significant gains on measures of phonological awareness (at both rhyme and phoneme levels), with large effect sizes at the phoneme level. Both programs had medium effect sizes on literacy outcome measures, although gains were non-significant when compared to the controls. The data suggest that rhythmic training has an important role to play in developing the phonological skills that are critical for efficient literacy acquisition. It is suggested that combining both prosodic/rhythmic and phonemic cues in auditory training programs may offer advantages for children with developmental dyslexia. This may be especially true for those who appear resistant to conventional phonics training methods.     

The contribution of sensitivity to speech rhythm and non‐speech rhythm to early reading development

Both sensitivity to speech rhythm and non‐speech rhythm have been associated with successful phonological awareness and reading development in separate studies. However, the extent to which speech rhythm, non‐speech rhythm and literacy skills are interrelated has not been examined. As a result, five‐ to seven‐year‐old English‐speaking children were assessed on measures of speech rhythm sensitivity, non‐speech rhythm sensitivity (both receptive and productive), reading attainment and phonological awareness. Hierarchical regression analyses revealed that productive non‐speech rhythm was unable to predict variance in reading attainment independently of phonological awareness and speech rhythm sensitivity. Receptive sensitivity to speech rhythm and non‐speech rhythm were both able to predict a significant amount of unique variance in reading attainment after controlling for age, vocabulary, phonological awareness, short‐term memory and each other. The findings suggest that receptive sensitivity to speech rhythm and non‐speech rhythm, while related to each other, also make contributions to reading attainment that are independent of each other. These findings provide only partial consistency with the general auditory processing deficit theory of reading difficulties, but are in line with the emerging theoretical claim that sensitivity to speech prosody may be implicated in successful literacy development.     

Auditory Processing of Amplitude Envelope Rise Time in Adults Diagnosed With Developmental Dyslexia

Studies of basic (nonspeech) auditory processing in adults thought to have developmental dyslexia have yielded a variety of data. Yet there has been little consensus regarding the explanatory value of auditory processing in accounting for reading difficulties. Recently, however, a number of studies of basic auditory processing in children with developmental dyslexia have suggested that a reduced ability to discriminate the rate of change in amplitude envelope onsets (rise time) may be linked to phonological processing difficulties and thereby to reading difficulties. Here, we select a range of different rise-time tasks used with children, and give them to adults with developmental dyslexia, along with 2 other auditory tasks (intensity discrimination and temporal order judgment). Deficits in both rise-time perception and temporal order judgment were found to predict literacy attainment in adults with developmental dyslexia, but the data were suggestive of different causal pathways.     

Auditory frequency discrimination in children with dyslexia

A popular hypothesis holds that developmental dyslexia is caused by phonological processing problems and is therefore linked to difficulties in the analysis of spoken as well as written language. It has been suggested that these phonological deficits might be attributable to low‐level problems in processing the temporal fine structure of auditory cues. Evidence for this has come from studies showing poor performance of dyslexic individuals on measures of auditory frequency discrimination (FD). We compared the FD thresholds of 28 children with dyslexia to 28 age‐matched controls aged 6–13, on a task that minimised demands on short‐term memory. To investigate the mechanisms involved in potential FD deficits, FD thresholds were measured at 1 kHz, where temporal cues were available, and at 6 kHz, where they were not. The dyslexic group had significantly higher FD thresholds than controls in both the 1‐ and 6‐kHz conditions. These findings confirm that children with dyslexia often have poor FD, even when, as in this sample, they have normal language comprehension and expressive vocabulary, and when they are tested using a paradigm that minimises memory demands. However, their perceptual deficit was evident for both the 1‐ and 6‐kHz tones, and so cannot readily be explained in terms of problems in processing temporal fine structure.     

Auditory Sensitivity,Speech Perception,and Reading Development and Impairment

While the importance of phonological sensitivity for understanding reading acquisition and impairment across orthographies is well documented, what underlies deficits in phonological sensitivity is not well understood. Some researchers have argued that speech perception underlies variability in phonological representations. Others have investigated the role of more general auditory sensitivity for reading development and reading difficulties, arguing that poor phonological representations may actually be due to broad underlying auditory deficits, which are not restricted to speech stimuli. We argue that these hypotheses are not necessarily mutually exclusive. In this review, we demonstrate that auditory sensitivity and speech perception can be integrated into a single developmental model, in which auditory sensitivity may have an indirect impact on reading; this impact is mediated by speech perception. In the model, we distinguish general auditory sensitivity as falling into at least two general categories: rhythmic and temporal. Correspondingly, speech perception itself can be distinguished as suprasegmental and segmental. Theoretically, the proposed model integrates a broad range of studies on general auditory and speech perception to suggest a developmental trajectory for reading acquisition that can be explored from before birth. Practically, the proposed model points to different ways of understanding and diagnosing reading difficulties and distinguishing reading difficulties across languages and orthographies.     

Whole‐word shape effect in dyslexia

The research question here was whether whole‐word shape cues might facilitate reading in dyslexia following reports of how normal‐reading children benefit from using this cue when learning to read. We predicted that adults with dyslexia would tend to rely more on orthographic rather than other cues when reading, and therefore would be more affected by word shape manipulations. This prediction was tested in a lexical decision task on words with a flat or a non‐flat outline (i.e. without or with letters with ascending/descending features). We found that readers with dyslexia were significantly faster when reading non‐flat compared with flat words, while typical readers did not benefit from whole‐word shape cues. The interaction of participants' group and word shape was not modulated by word frequency; that is word outline shape facilitated reading for both rare and frequent words. Our results suggest that enhanced sensitivity to orthographic cues is developed in some cases of dyslexia when normal, phonology‐based word recognition processing is not exploited.     

Timing precision and rhythm in developmental dyslexia

Current research on the etiology ofdevelopmental dyslexia is generally informed byeither of two major hypotheses. One of theseassumes that the phonological processing ofconsonants and vowels at a segmental levelidentifies the core deficit in developmentaldyslexia and that it cannot be reduced todomain-general deficits of temporal informationprocessing. The other hypothesis holds thatphonological processing deficits aresymptomatic of an underlying, domain-generaldysfunction; and that at least some dyslexiasubtypes are causally related to domain generaldeficits of temporal information processing forauditory and visual stimuli. This report startsfrom the assumption that the terms temporal information processing andphonological processing as applied in currentdyslexia research, are frequently conflated. Further, it assumes that the conflated termsmust be decomposed into their concretebehavioral referents before the causalsignificance of either can be investigatedsystematically.The studies to be summarized in thisreport represents one step toward suchdecomposition. The findings indicated thatduring a motor sequencing task, dyslexicstudents anticipated the signal of anisochronic pacing metronome by intervals thatwere two or three times as long as those ofage matched normal readers or normal adults.These group differences were significant whenparticipants tapped with the preferred indexfinger alone or with both fingers in unison.Dyslexic students also took significantlylonger than normal readers did to recalibratetheir tapping responses when the metronome ratewas experimentally changed in the middle of atrial.In addition, dyslexic students, bycontrast to normal readers, had inordinatedifficulty reproducing simple motor rhythms byfinger tapping, and similar difficultyreproducing the appropriate speech rhythm oflinguistically neutral nonsense syllables.These difficulties were exaggerated whenparticipants had to synchronize theirperformance to an external pacing metronome.The implications of the findings for temporalinformation processing deficits on one hand,and impaired phonological processing on theother, are discussed.     

Phonology,reading development,and dyslexia: A cross-linguistic perspective

In this paper, I present a theoretical overview at the cognitive level of the role of phonological awareness in reading development and developmental dyslexia across languages. My assumption is that the primary deficit in developmental dyslexia in all languages lies in representing speech sounds: a deficit in “phonological representation.” I will argue that this deficit manifests in somewhat different ways, depending on orthography. I will also argue that the phonological deficit in dyslexia is initially at the syllable and onset-rime levels of phonological awareness, with the development of “phonemic” awareness being a consequence rather than a precursor of reading. Finally, I will suggest that some of the processes underpinning language acquisition are disrupted in dyslexia, in particular, the detection of rhythm in speech.     

Visual and Auditory Morphological Priming in Adults With Developmental Dyslexia

The quality of implicit morphological knowledge in adult Hebrew readers with developmental dyslexia was investigated. The priming paradigm was used to examine whether these adults extract and represent morphemic units similarly to normal readers during online word recognition. The group with dyslexia as a whole did not exhibit priming with visual presentation as opposed to both age- and reading-level controls. Priming was absent when the prime and target words shared a morpheme and even when the prime and the target were identical. Only the students with phonological dyslexia, who exhibited relatively good performance in the orthographic judgment task, exhibited repetition priming but not morphological priming. Strong repetition and morphological priming effects were found for participants with dyslexia when the stimuli were auditory. The implications of the dissociation between visual and auditory priming for the locus of the deficit in morphological processing during word recognition are discussed.     

Pushing the Speed of Assistive Technologies for Reading

People who are practiced in using text‐to‐speech can drive listening speeds to surprisingly high limits. Here, we investigate the extent to which people who are otherwise untrained, with and without dyslexia, can increase their reading speed when forcibly accelerated visual or auditory presentations are used in isolation or in tandem. The experiment examined the reading speed and comprehension of 43 college students using three methods enabled by software on a handheld device: forcibly accelerated visual augmentation, auditory text‐to‐speech, and a combination of the two. We found that both typical and impaired readers attained the highest reading speed using the combined method, controlling for comprehension. Importantly, those with dyslexia using the combined methods reached the equivalent reading speed of typical readers using paper, visual, or auditory methods, with no loss in comprehension. Findings here suggest that in future evolutions—using technologies available today—parallel neurological pathways for language processing can be exploited to optimize reading for those impaired.     

The immediate and longer‐term effectiveness of a speech‐rhythm‐based reading intervention for beginning readers

Despite empirical evidence of a relationship between sensitivity to speech rhythm and reading, there have been few studies that have examined the impact of rhythmic training on reading attainment, and no intervention study has focused on speech rhythm sensitivity specifically to enhance reading skills. Seventy‐three typically developing 4‐ to 5‐year‐old children were randomly allocated to one of three treatment groups and received a speech‐rhythm‐based intervention, a phonological‐awareness‐based intervention, or a control intervention over 10 weeks. All children completed pre‐test, post‐test and delayed post‐test measures of speech rhythm sensitivity, single‐word reading, phonological awareness and vocabulary. The results show that it is possible to train speech rhythm sensitivity in this age group and that children who undertook the speech rhythm intervention showed a significant improvement in their word reading performance compared to children in the control group. Group differences were maintained 3 months later.     

Children's understanding of emotion in speech

Children's understanding of emotion in speech was explored in three experiments. In Experiment 1, 4- to 10-year-old children and adults (N = 165) judged the happiness or sadness of the speaker from cues conveyed by propositional content and affective paralanguage. When the cues conflicted (i.e., a happy situation was described with sad paralanguage), children relied primarily on content, in contrast to adults, who relied on paralanguage. There were gradual developmental changes from 4-year-olds' almost exclusive focus on content to adults' exclusive focus on paralanguage. Children of all ages exhibited greater response latencies to utterances with conflicting cues than to those with nonconflicting cues, indicating that they processed both sources of emotional information. Children accurately labeled the affective paralanguage when the propositional cues to emotion were obscured by a foreign language (Experiment 2, N = 20) or by low-pass filtering (Experiment 3, N = 60). The findings are consistent with children's limited understanding of the communicative functions of affective paralanguage.     

Sensitivity to rhythmic parameters in dyslexic children: a comparison of Hungarian and English

It has been proposed that sensitivity to the parameters underlying speech rhythm may be important in setting up well-specified phonological representations in the mental lexicon. However, different acoustic parameters may contribute differentially to rhythm and stress in different languages. Here we contrast sensitivity to one such cue, amplitude envelope onset (rise time), in dyslexic and normally-developing children in two languages, Hungarian and English, ages from 7 to 11. Dyslexic and control children received phonological tasks, reading and spelling tasks and auditory processing tasks. While sensitivity to rise time was related to phonological representation in both languages, clear differences were found between languages. It is suggested that these differences may reflect differential language-specific weighting of different acoustic cues to rhythm and stress.

Visual stress in adults with and without dyslexia

The relationship between dyslexia and visual stress (sometimes known as Meares‐Irlen syndrome) is uncertain. While some theorists have hypothesised an aetiological link between the two conditions, mediated by the magnocellular visual system, at the present time the predominant theories of dyslexia and visual stress see them as distinct, unrelated conditions, a view that has received some support from studies with children. Studies of visual stress in adults are rare, yet recent reports of a high incidence of this phenomenon amongst university students with diagnosed dyslexia call for further investigation of the issue. This study sought to clarify the relationship between visual stress and dyslexia by comparing the reading performance of dyslexic and non‐dyslexic adults with, and without, colour. Degree of susceptibility to visual stress was determined by means of a symptom rating scale. Optimal colour was determined using an Intuitive Colorimeter, which was also employed to assess reading speed under the two experimental conditions. Only the dyslexic students with high visual stress showed significant gains in reading speed when using optimal colour. The use of response to treatment (rather than symptomatology) as a diagnostic criterion for visual stress is questioned, especially when applied to adults, as this may give misleading findings. On the basis of reported symptomatology, students who experience high levels of visual stress are more likely to show improvements in reading rate with optimal colour if they also have dyslexia than if they do not have dyslexia. Although not establishing an aetiological link, these findings imply an interaction between the two conditions with major implications for theory, diagnosis and treatment.     

Basic auditory processing and developmental dyslexia in Chinese

The present study explores the relationship between basic auditory processing of sound rise time, frequency, duration and intensity, phonological skills (onset-rime and tone awareness, sound blending, RAN, and phonological memory) and reading disability in Chinese. A series of psychometric, literacy, phonological, auditory, and character processing tasks were given to 73 native speakers of Mandarin with an average age of 9.7 years. Twenty-six children had developmental dyslexia, 29 were chronological age-matched controls (CA controls) and 18 were reading-matched controls (RL controls). Chinese children with dyslexia were significantly poorer than CA controls in almost all phonological tasks, in semantic radical search, and in phonological recoding proficiency. Chinese children with dyslexia also showed significant impairments in most of the basic auditory processing tasks. Regression analyses demonstrated that different auditory measures of rise time discrimination were the strongest predictors of individual differences in Chinese character reading (1 Rise task) and phonological recoding (2 Rise task) respectively, with frequency discrimination also important for nonsense syllable decoding. Our results support the hypothesis that accurate perception of the amplitude envelope of speech is critical for phonological development and consequently reading acquisition across languages.     

Spatial selective attention and asynchrony of cognitive systems in adult dyslexic readers: an ERPs and behavioral study

The aim of this study was to gain additional knowledge about the asynchrony phenomenon in developmental dyslexia, especially when spatial selective attention is manipulated. Adults with developmental dyslexia and non-impaired readers underwent two experimental tasks, one including alphabetic stimuli (pre-lexical consonant–vowel syllables) and the other containing non-alphabetic stimuli (pictures and sounds of animals). Participants were instructed to attend to the right or left hemifields and to respond to all stimuli on that hemifield. Behavioral parameters and event-related potentials were recorded. The main finding was that the dyslexic readers demonstrated asynchrony between the auditory and visual modalities when alphabetic stimuli were presented on the right hemifield. These results suggest that intact reading is linked to a synchronized auditory and visual speed of processing even when spatial selective attention is manipulated. The findings of the current study are discussed in terms of asynchrony between modalities as a neurocognitive marker in developmental dyslexia.     

Enhancing English among second language learners: the pre‐school years

Informed by knowledge of linguistics, research findings in the areas of monolingual and bilingual acquisition, dyslexia and speech therapy clinical practice, five factors are proposed to argue that the acquisition of English by young non‐native learners can be enhanced by learning activities which take into account factors of developmental sequence in language acquisition, language‐specific properties, the relationship between oral and written language, the what‐to‐learn‐first issue and the quality of the language input. Proper language goals can be set and appropriate activities designed, only if the language input provider interacts with a learner in a concrete activity while being sensitive to the developmental trajectory of monolingual speaking children, the development of the less dominant language in a bilingual child, the prosodic and phonological differences between the learner's mother tongue and the target language, the importance of phonological awareness which defines dyslexia, the use of non‐abstract language structures grounded in concrete lexical items in the early stage of language acquisition and the strategy of expanding learners' utterance by one element as used in speech therapy.     

Computerised screening for dyslexia in adults

Identifying dyslexia in adulthood presents particular challenges because of complicating factors such as acquisition of compensatory strategies, differing degrees of intervention and the problem of distinguishing dyslexic adults from those whose literacy difficulties have non‐cognitive causes. One of the implications is that conventional literacy measures, per se, do not provide a satisfactory basis for screening for dyslexia in adulthood as some dyslexic adults have above‐average literacy skills and some non‐dyslexic adults have very poor literacy skills. This study examined an alternative approach to dyslexia screening, using three tests that depend heavily on phonological processing, lexical access and working memory, but which are not conventional measures of literacy. Using these tests, which are computer delivered, 70 dyslexic adults from three different types of educational institution were compared with 69 non‐dyslexic adults from the same institutions. The results showed that the dyslexic and non‐dyslexic groups were significantly different on all three computer‐based tests, with an average effect size of 1.55. Adaptive versions of these tests were then created to reduce overall administration time for the suite to about 15 minutes. Analysis showed that the combined scaled scores from the adaptive versions of the three tests significantly discriminated the dyslexic from the non‐dyslexic group with an increased effect size of 2.07 and with a sensitivity rate of 90.6% and a specificity rate of 90.0%. It was concluded that this approach is a valid and useful method of identifying dyslexia in adulthood, which, given the ease of administration to large numbers of adults, has noted advantages for education and employment.     

Assessing dyslexia in higher education: the York adult assessment battery‐revised

Although there are a number of standardised measures to assess dyslexia in children, there are comparatively fewer instruments suitable for the assessment of dyslexia in adults. Given the growing number of students entering UK higher education institutions, there is a need to develop reliable tools for assessing the additional needs of those with dyslexia and related difficulties. This study reports data from a revised version of the York Adult Assessment: An Assessment Battery for Dyslexia Screening in Higher Education. The current York Adult Assessment‐Revised (YAA‐R) is an assessment battery consisting of tests of reading, spelling, writing and phonological skills. Data from a normative sample of 106 adults without dyslexia and a validation sample of 20 adults with dyslexia illustrate significant group differences on the tests comprising the YAA‐R. Additionally, the YAA‐R has good discriminatory power yielding 80% sensitivity and 97% specificity. Taken together, the YAA‐R is a suitable test battery for the assessment and identification of dyslexia in university students.