Agnew, J. A., Dorn, C., & Eden, G. F. (2004). Effect of intensive training on auditory processing and reading skills. Brain and Language, 88(1), 21-25. (click here)

This study assessed the ability of seven children to accurately judge relative durations of auditory and visual stimuli before and after participation in a language remediation program. The goal of the intervention program is to improve the children's ability to detect and identify rapidly changing auditory stimuli, and thereby improve their language- related skills. Children showed improved accuracy on a test of auditory duration judgement following the intervention without analogous improvements in the visual domain, supporting the assertion that intensive training with modi.ed speech improves auditory temporal discrimination. However, these improvements did not generalize to reading skills, as assessed by standard measures of phonological awareness and non-word reading.

 

 

AlonsoBua, B., Diaz, F., & Ferraces, M. J. (2006). The contribution of AER-Ps (MMN and LDN) to studying temporal vs. linguistic processing deficits in children with reading difficulties. International Journal of Psychophysiology, 59(2), 159-167.

 

 

Au, A., & Lovegrove, B. (2001). The role of visual and auditory temporal processing in reading irregular and nonsense words. Perception and Psychophysics, 30(9), 1127-1142. (click here)

In the present study, we compared the rapid visual and auditory temporal processing ability of above average and average readers. One hundred five undergraduates participated in various visual and auditory temporal tasks. The above average readers exhibited lower auditory and visual temporal resolution thresholds than did the average readers, but only the differences in the auditory tasks were statistically significant, especially when nonverbal IQ was controlled for. Furthermore, both the correlation and stepwise multiple regression analyses revealed a relationship between the auditory measures and the wide range achievement test (WRAT) reading measure and a relationship between the auditory measures and a low spatial frequency visual measure and the WRAT spelling measure. Discriminant analysis showed that together both the visual and auditory measures correctly classified 75% of the subjects into above average and average reading groups, respectively. The results suggest that differences in temporal processing ability in relation to differences in reading proficiency are not confined to the comparison between poor and normal readers.

 

 

Au, A., & Lovegrove, B. (2001). Temporal processing ability in above average and average readers. Perception &Psychophysics, 63(1), 148- 155.(click here)

In the present study, we compared the rapid visual and auditory temporal processing ability of above average and average readers. One hundred five undergraduates participated in various visual and auditory temporal tasks. The above average readers exhibited lower auditory and visual temporal resolution thresholds than did the average readers, but only the differences in the auditory tasks were statistically significant, especially when nonverbal IQ was controlled for. Furthermore, both the correlation and stepwise multiple regression analyses revealed a relationship between the auditory measures and the wide range achievement test (WRAT) reading measure and a relationship between the auditory measures and a low spatial frequency visual measure and the WRAT spelling measure. Discriminant analysis showed that together both the visual and auditory measures correctly classified 75% of the subjects into above average and average reading groups, respectively. The results suggest that differences in temporal processing ability in relation to differences in reading proficiency are not confined to the comparison between poor and normal readers.

 

 

Boets, B., Wouters, J., vanWieringen, A., & Ghesquiere, P. (2006). Auditory temporal information processing in preschool children at family risk for dyslexia: Relations with phonological abilities and developing literacy skills. Brain and Language, 97(1), 64-79. (click here)

In this project, the hypothesis of an auditory temporal processing deficit in dyslexia was tested by examining auditory processing in relation to phonological skills in two contrasting groups of Wve-year-old preschool children, a familial high risk and a familial low risk group. Participants were individually matched for gender, age, non- verbal IQ, school environment, and parental educational level. Psychophysical thresholds were estimated for gap-detection, frequency modulation detection, and tone-in-                noise detection using a three- interval forced-choice adaptive staircase paradigm embedded within a computer game. Phonological skills were measured by tasks assessing phonological awareness, rapid serial naming, and verbal short-term memory. Significant group differences were found for phonological awareness and letter knowledge. In contrast, none of the auditory tasks differentiated significantly between both groups. However, both frequency modulation and tone-in-noise detection were significantly related to phonological awareness. This relation with phonological skills was not present for gap-detection.

 

 

Breier, J. I., Fletcher, J. M., Foorman, B. R., Klaas, P., &Gray, L. C. (2003). Auditory temporal processing in children with specific reading disability with and without attention deficit/hyperactivity disorder. Journal of Speech Language and Hearing Research, 46(1), 31- 42. (click here)

The auditory temporal deficit hypothesis predicts that children with specific reading disability (RD) will exhibit a deficit in the perception of auditory temporal cues in nonspeech stimuli. Tasks assessing perception of auditory temporal and nontemporal cues were administered to children with (a) RD without attentiondeficit/ hyperactivity disorder (RD/no- ADHD, n = 40), (b) ADHD alone (ADHD/no-RD, n = 33), (c) RD and ADHD (RD/ADHD, n = 36), and (d) no impairment(Ni, n = 41). The presence of RD was associated with a specific deficit in detection of a tone onset time asynchrony, but no reduction in performance on other tasks assessing perception of temporal or nontemporal acoustic cues. The presence of ADHD was associated with a general reduction in performance across tasks. The pattern of results did not indicate a pervasive deficit in auditory temporal function in children With RD, but did suggest a possible sensitivity to backward masking in this group. Results also indicated that the comorbid presence of ADHD is a significant factor in the performance of children with RD on psychoacoustic tasks.

 

 

Cacace, A., McFarland, D., Ouimet, J., Schriber, E., &Marro, P. (2000). Temporal processing deficits in remediation-resistant reading-impaired children. Audiology and Neurotology, 5(2), 83-97.

             There is considerable interest in whether a deficit in temporal processing underlies specific learning and language disabilities in school- aged children. This view is particularly controversial in the area of developmental reading problems. The temporal-processing hypothesis was tested in a sample of normal children, 9-11 years of age, and in a sample of age-matched children with reading impairments, by assessing temporal-order discrimination. Five different binary temporal- order tasks were evaluated in the auditory and visual sensory modalities. Other basic discrimination abilities for single auditory stimuli were also assessed, including just noticeable differences (JNDs) for frequency and intensity and a simple threshold detection task. In these tasks, the temporal dimension was the duration of the individual stimuli (20 and 200 ms). All data were obtained using forced- choice psychophysical methods, either in a single-track adaptive format or using psychometric functions. The results from these experiments showed that children with reading impairments had deficits in temporal-order discrimination, but these effects were not modality specific. These same children also had significantly elevated frequency and intensity JNDs and their performance on these tasks were not dependent on stimulus duration. No group differences were observed on the threshold detection task, and the derived measurements of temporal integration (i.e. the threshold difference between the 20- and 200-ms stimuli) were considered normal, averaging 11.7 dB. As a whole, discrimination deficits observed in the reading- impaired group only occurred with suprathreshold stimuli. The deficits were neither modality specific nor temporal (duration) specific.

 

Cestnick, L., & Jerger, J. (2000). Auditory temporal processing and lexical/nonlexical reading in developmental dyslexics. Journal of the American Academy of Audiology, 11(9), 501-513.

             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.

 

 

CohenMimran, R. (2006). Temporal processing deficits in Hebrew speaking children with reading disabilities. Journal of Speech Language and Hearing Research, 49(1), 127- 137.(click here)

             The purpose of this study was to assess to what extent specific reading disabilities and poor phonologic processing in children who read Hebrew, a primarily consonant orthography, are related to central auditory temporal processing deficits (TPDs). Twenty- four Hebrew-speaking children (ages 10- 13) with and without reading disabilities were asked to discriminate auditorily pairs of syllables (/ba/ vs. /pa/) that differ by voice onset time (VOT) only. Two paradigms were used, 1 with a short interstimulus interval (ISI) (50 ms) and 1 with a long ISI (500 ms). Event-related potentials (ERPs) were measured in response to the two syllables in an auditory oddball task. Results showed significantly lowered accuracy, longer reaction times, and prolonged P3 latency among the group with reading disabilities compared with the control group. No significant differences were found between the short ISI task and the long ISI task. However, significant correlations were found between the phonologic processing tasks and the short ISI task. These findings in the Hebrew language are consistent with findings from other languages and add support to the central TPD hypothesis of reading disabilities. The discussion highlights how investigating different orthographic systems can deepen our understanding of the role TPD plays in reading

 

Conlon, E., Sanders, M., & Zapart, S. (2004). Temporal processing in poor adult readers. Neuropsychologia, 42(2), 142-157. (click here)

The aim of this study was to investigate the relationships between two different temporal processing tasks and word identification performance in skilled, dyslexic and poor adult readers. In Experiment 1 spatial and temporal sequencing tasks were conducted. It was found that adult dyslexics were significantly less accurate than skilled readers across all conditions in the temporal sequencing task, and when higher numbers of stimuli were presented in the spatial task. Experiment 2 replicated Experiment 1 in the temporal sequencing task and also found that poor readers had significantly higher motion coherence thresholds than those found in the skilled reader group. Ten percent of the variance in coherence thresholds was accounted for by performance on the temporal sequencing task. Multiple regression analyses determined that performance on the two temporal tasks could explain seventy percent of the variance in word identification scores, with the temporal sequencing task making the larger independent contribution. Experiment 3 replicated the findings of Experiment 2, while taking into account IQ, verbal memory and processing speed. Three things were concluded. First, the temporal tasks measure different aspects of temporal processing. The contribution to performance of higher-level perceptual and attentional components of the temporal sequencing task accounts for the relatively weak correlation found between the two measures. While sensory sensitivity to motion is measured at MT, the involvement of this area and PPC in higher-level perceptual and attentional processes is suggested by the findings of this study. Second, the association between temporal sequencing and reading skills may provide a stronger link between neural processing and poor reading skills than basic sensory processing measures alone, suggesting that a sensory magnocellular (M) system deficit cannot fully explain the relationship found between reading and visual neural processing. Third, problems with rapid sequential processing are predicted to be a generalised problem in poor adult readers, whether they are formally classified as dyslexic, or are poor performers on measures of word identification. Temporal processing may follow a distribution similar to that found for word identification skills.

 

 

DeMartino, S., Espesser, R., Rey, V., & Habib, M. (2001). The ''temporal processing deficit'' hypothesis in dyslexia: New experimental evidence. Brain and Cognition, 46(1-2), 104-108. (click here)

 

Eden, G., Stein, J., Wood, H., & Wood, F. (1995). Temporal and spatial processing in reading disabled and normal children. Cortex, 31(3), 451- 468.

             The ability to process temporal and spatial visual stimuli was studied to investigate the role these functions play in the reading process. Previous studies of this type have often been confounded by memory involvement, or did not take into account the evidence which suggests a visual transient deficient in some dyslexics. Normal (n = 39), reading disabled (n = 26), and backward reading children (n=12) were compared on a visual computer game, which consisted of a temporal and a analogous spatial dot counting task. Reading disabled children performed significantly worse than normal children on the Temporal Dot Task, but were only mildly impaired on the Spatial Dot Task, Backward readers were not significantly better than the reading disabled group on either task, suggesting that poor poor visual temporal processing is not specific to dyslexia. In a group of 93 children, a regression model including age, verbal IQ, phonological awareness, and visual temporal processing ability, predicted 73% of the variance of reading ability. The results suggest that dyslexics perform worse in tasks that require fast, sequential processing and that this impairment may be partially responsible for their reading difficulties.

 

 

Edwards, V., Giaschi, D., Dougherty, R., Edgell, D., Bjornson, B., Lyons, C., & Douglas, R. (2004). Psychophysical indexes of temporal processing abnormalities in children with developmental dyslexia. Developmental Neuropsychology, 25(3) (click here)

             Children with dyslexia and children progressing normally in reading performed several perceptual tasks to determine (a) the psychophysical measures that best differentiate children with dyslexia from children with average reading abilities; (b) the extent of temporal processing deficits in a single, well-defined group of children with dyslexia; and (c) the co-occurrence of visual and auditory temporal processing deficits in children with dyslexia. 4 of our 12 psychophysical tasks indicated differences in temporal processing ability between children with dyslexia and children with good reading skills. These included 2 auditory tasks (dichotic pitch perception and FM tone discrimination) and 2 visual tasks (global motion perception and contrast sensitivity). The battery of 12 tasks successfully classified 80% of the children into their respective reading-level groups. Within the group of children with dyslexia who had temporal processing deficits, most were affected in either audition or vision; few children were affected in both modalities. The observed deficits suggest that impaired temporal processing in dyslexia is most evident on tasks that require the ability to synthesize local, temporally modulated inputs into a global percept and the ability to extract the resultant global percept from a noisy environment.

 

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Farmer, M. E., & Klein, R. M. (1995). The evidence for a temporal processing deficit linked to dyslexia:  A review. Psychonomic Bulletin and Review, 2(4), 460-493.(click here)

The existence of a phonemic deficit that is predictive of, and probably causal to, many cases of reading difficulty is well established. Tallal (1984) has suggested that this phonemic deficit is in fact a symptom of an underlying auditory temporal processing deficit. Our purpose in this paper is to evaluate the plausibility of this hypothesis. The various components that might constitute sequential (or temporal) processing are described. Our review of the literature reveals considerable evidence for a deficit in dyslexics in stimulus individuation tasks (e.g., gap detection) and temporal order judgments in both the auditory and visual modalities. The possibility that a general temporal processing deficit is associated with dyslexia, as suggested by Tallal (1984), is explored, and possible etiologies for such a deficit are discussed. The possibility of a causal link between temporal processing deficits and some reading disabilities is demonstrated, and converging evidence from morphological studies is reviewed. It is concluded that a temporal processing deficit does appear to be present in many developmental dyslexics, and strategies are suggested for further research aimed at evaluating the hypothesis that this deficit may be the root cause of a number of cases of dyslexia itself.

 

 

Fink, M., Churan, J., & Wittmann, M. (2006). Temporal processing and context dependency of phoneme discrimination in patients with aphasia. Brain and Language, 98(1), 1- 11.(click here)

Standard diagnostic procedures for assessing temporal-processing abilities of adult patients with aphasia have so far not been developed. In our study, temporal-order measurements were conducted using two diVerent experimental procedures to identify a suitable measure for clinical studies. Additionally, phoneme-discrimination abilities were tested on the word, as well as on the sentence level, as a relationship between temporal processing and phoneme-discrimination abilities is assumed. Patients with aphasia displayed significantly higher temporal-order thresholds than control subjects. The detection of an association between temporal processing and speech processing,however, depended on the stimuli and the phoneme-discrimination tasks used. Our results also suggest top–down feedback on phonemic processing.

 

 

Flax, J. F., RealpeBonilla, T., Hirsch, L. S., Brzustowicz, L. M., Bartlett, C. W., & Tallal, P. (2003). Specific language impairment in families: Evidence for co- occurrence with reading impairments. Journal of Speech Language and Hearing Research, 46(3), 530-543. (click here)

Two family aggregation studies report the occurrence and co-occurrence of oral language impairments (Lis) and reading impairments (Rls). Study 1 examined the occurrence (rate) of Li and RI in children with specific language impairment (SLI probands), a matched control group, and all nuclear family members. Study 2 included a larger sample of SLI probands, as well as their nuclear and extended family members. Probands and their family members who met specific criteria were classified as language and/or reading impaired based on current testing. In Study 1, the rates of LI and RI for nuclear family members (excluding probands) were significantly higher than those for control family members. In the SLI families, affected family members were more likely to have both Li and RI than either impairment alone. In Study 2, 68% of the SLI probands also met the diagnostic classification for RI. The language and RI rates for the other family members, excluding probands, were 25% and 23% respectively, with a high degree of co- occurrence of LI and RI (46%) in affected individuals. Significant sex ratio differences were found across generations in the families of SLI probands. There were more male than female offspring in these families, and more males than females were found to have both Lls and Rls. Results demonstrate that when Lis occur within families of SLI probands, these impairments generally co-occur with RIs. Our data are also consistent with prior findings that males show impairments more often than females.

 

Gang, M., & Siegel, L. S. (2002). Sound-symbol learning in children with dyslexia. Journal of Learning Disabilities, 35(2), 137-157. (click here)

This studv evaluated the effect of sound-symbol association training on visual and phonological memory in children with a history of dyslexia. Pretests of phonological and visual memory, a sound-symbol training procedure, and phonological and visual memory posttests were administered to children with dyslexia, to children whose dyslexia had been compensated through remedial training, and to age- and reading level- matched comparison groups. Deficits in visual and phonological memory and memory for sound-symbol associations were demonstrated in the dyslexia group. For children with dyslexia and children whose dyslexia had been remediated, the sound- symbol training scores were significantly associated with word and pseudoword reading scores and were significantly lower than those of the comparison groups. Children with dyslexia and children whose dyslexia had been compensated showed significantly less facilitation of phonological memory following the training than did typical readers. Skilled readers showed some reduction in accuracy of visual memory following the training, which may be the result of interference of verbalization with a predominantly visual task. A parallel decrease was not observed in the children with dyslexia, possibly because these children did not use the verbal cues. Children with dvslexia and children whose dvslexia had been compensated seemed to have difficulty encoding the novel sounds in memory. As a result, thev derived less phonological memory advantage and less visual memory interference from the training than did typical readers. Children in the compensated dyslexia group scored lower on sound- symbol training than their age peers. In other respects, the scores of these children were equivalent to those of the typically reading comparison groups. Children in the compensated dyslexia group exhibited higher phonological rehearsal, iconic memorv, and associative memory scores than children in the dyslexia group. Implications for the remediation of dyslexia are discussed.

 

 

Goswami, U. (2003). How to Beat Dyslexia:  The Broadbent Lecture 2003. The Psychologist, 16(9), 462-465.

 

Griffiths, Y. M., Hill, N. I., Bailey, P. J., & Snowling, M. J. (2003). Auditory temporal order discrimination and backward recognition masking in adults with dyslexia. Journal of Speech Language and Hearing Research, 46(6), 1352-1366.(click here)

The ability of 20 adult dyslexic readers to extract frequency information from successive tone pairs was compared with that of IQ- matched controls using temporal order discrimination and auditory backward recognition masking (ABRM) tasks. In both paradigms, the interstimulus interval (ISI) between tones in a pair was either short (20 ms) or long (200 ms). Temporal order discrimination was better for both groups of listeners at long than at short ISIs, but no group differences in performance were observed at either ISI. Performance on the ABRM task was also better at long than at short ISIs and was influenced by variability in masker frequency and by the spectral proximity of target and masker. The only significant group difference was found in one condition of the ABRM task when the target–masker interval was 200 ms, but this difference was not reliable when the measure was of optimal performance. Moderate correlations were observed between auditory thresholds and phonological skill for the sample as a whole and within the dyslexic and control groups. However, although a small subgroup of dyslexic listeners with poor phonology was characterized by elevated thresholds across the auditory tasks, evidence for an association between auditory and phonological processing skills was weakened by the finding of a subgroup of control listeners with poor auditory processing and normal phonological processing skills.

 

 

Hautus, M. J., Setchell, G. J., Waldie, K. E., & Kirk, I. J. (2003). Age-related improvements in auditory temporal resolution in reading-impaired children. Dyslexia, 9(1 ), 37-45.(click here)

Individuals with developmental dyslexia show impairments in processing that require precise timing of sensory events. Here, we show that in a test of auditory temporal acuity (a gap- detection task) children ages 6–9 years with dyslexia exhibited a significant deficit relative to age-matched controls. In contrast, this deficit was not observed in groups of older reading- impaired individuals (ages 10–11 years; 12–13 years) or in adults (ages 23–25 years). It appears, therefore, that early temporal resolution deficits in those with reading impairments may significantly ameliorate over time. However, the occurrence of an early deficit in temporal acuity may be antecedent to other language- related perceptual problems (particularly those related to phonological processing) that persist after the primary deficit has resolved. This result suggests that if remedial interventions targeted at temporal resolution deficits are to be effective, the early detection of the deficit and early application of the remedial programme is especiallycritical.

 

 

Heath, S. M., & Hogben, J. H. (2004). Cost-effective prediction of reading difficulties. Journal of Speech, Language, and Hearing Research, 47, 751-765. (click here)

This study addressed 2 questions: (a) Can preschoolers who will fail at reading be more efficiently identified by targeting those at highest risk for reading problems? and (b) will auditory temporal processing (ATP) improve the accuracy of identification derived from phonological processing and oral language ability? A sample of 227 preschoolers was screened for Performance IQ and was tested on phonological awareness (PA). The upper and lower quartiles of the PA distribution were selected as being at lowest and highest risk, respectively, for reading failure. Children with good and poor PA were tested on ATP, phonological short-term memory, rapid automatized naming, oral language, receptive vocabulary, and 2 measures of listening comprehension. Reading outcomes were measured at the end of Year 2. Only 1 child in the good-PA group became a poor reader by the end of Year 2, confirming that being in the top quartile for PA predicts positive reading outcomes. Discriminant analysis using the authors’ test battery within the poor-PA group identified poor readers with sensitivity of .91 and specificity of .84, but ATP did not improve classification accuracy afforded by phonological and oral language. A brief screening procedure was formulated using only PA, phonological short-term memory, and demographic variables, with which 80% of children with poor PA who are at risk of reading problems can be identified. Further refinements of this screening procedure would increase accuracy of identification at the cost of only a small increment in required testing time.

 

 

Heath, S. M., & Hogben, J. H. (2004). The reliability and validity of tasks measuring perception of rapid sequences in children with dyslexia. Journal of Child Psychology and Psychiatry, 45(7), 1275- 1287.(click here)

Background: Claims that children with reading and oral language deficits have impaired perception of sequential sounds are usually based on psychophysical measures of auditory temporal processing (ATP) designed to characterise group performance. If we are to use these measures (e.g., the Tallal, 1980, Repetition Test) as the basis for intervention in language and literacy deficits, we need to demonstrate that they can effectively quantify individual differences. Therefore, questions of standardisation, reliability and construct validity can no longer be ignored. Method: We explored these issues in three studies: (i) 52 Dyslexics and Good Readers aged 8 to 11 years performed a task requiring perception of rapid sequences (PRS) based on the Tallal Repetition Test; (ii) a subgroup of the initial sample was retested on the task three to four months later, and after extended practice; (iii) a further subgroup then completed a rate of auditory processing task using a backward recognition masking paradigm. Results: With a standardised methodology, we were able to replicate previous results with the PRS task, and demonstrate moderate reliability of measurement across time and practice. However, there were large effects of exposure and practice, and the task did not seem useful for identifying absolute and continuing deficits in given individuals. Conclusions: Our results call into question the use of this type of task as an individual measure of ATP. Neither is it certain that it is capturing what is currently understood as ATP. Keywords: Auditory temporal processing, auditory backward recognition masking, dyslexia, language impairment. Abbreviations: ATP: auditory temporal processing; PRS: perception of rapid sequences; SLI: specific language impaired/impairment; RAP: rate of auditory processing; LLI: language learning impaired; PIQ: performance IQ; ID: intensity discrimination.

 

 

Heim, S., Keil, A., & Ihssen, N. (2006). The relationship between temporal attention and literacy skills in classroom children. Zeitschrift Fur Psychologie, 214(4), 196- 206.

 

Hill, P. R., Hogben, J. H., & Bishop, D. M. V. (2005). Auditory frequency discrimination in children with specific language impairment: A longitudinal study. Journal of Speech Language and Hearing Research, 48(5), 1136-1146.(click here)

 

Hood, M., & Conlon, E. (2004). Visual and auditory temporal processing and early reading development. Dyslexia, 10(3), 234-252. (click here)

This study investigated the ability of temporal processing measures obtained before school entry to predict early reading development in an unselected sample of 125 children (68 males, 57 females). Visual and auditory temporal order judgement (TOJ) tasks measured at Preschool (mean age 5.36 years) significantly predicted letter and word identification (accuracy) and reading rate (fluency) in early Grade 1 (mean age 5.94 years), even after the effects of age, environment, memory, attention, nonverbal ability, and speech/ language problems were accounted for. There were no significant differences in the overall variance accounted for in reading between TOJ measures taken before or after reading had emerged. Both Preschool and Grade 1 measures of auditory TOJ accounted for significant independent variance in reading. However, only visual TOJ performance measured at Grade 1 accounted for unique variance in reading rate. This was discussed in terms of developmental changes in the role of visual temporal processing as reading develops. Reliability of the temporal measures from Preschool to Grade 1 was moderate. The results showed that measures of visual and auditory temporal processing obtained close to school- entry would be a useful addition to predicting risk of early reading difficulties.

 

 

Klein, R. M., & Farmer, M. E. (1995). Dyslexia and a temporal processing deficit:A reply to the commentaries. Psychonomic Bulletin and Review, 2(4), 515-526.(click here)

A number of points and criticisms were raised in the commentaries on our review paper (Farmer & Klein, 1995), and in this reply we address the most pertinent and major of those points. First, we clarify and expand upon what we mean by a temporal processing deficit. We then address Studdert- Kennedy and Mody’s (1995) major claims, which are confined to the auditory modality, that (1) a discriminative deficit underlies what they see as a rate of processing deficit, and (2) discriminative/rate deficits for speech and nonspeech materials are independent. We explain why we believe the first proposal is unlikely to provide an explanation of the temporal processing deficits that we reviewed, and we present a simple framework within which speech and nonspeech perceptual codes are viewed as higher level isolable subsystems that depend on a common, lower level, auditory input system. The speech and nonspeech systems may be influenced similarly by damage to, or impairments of, their common input system, but they can be selectively influenced by insults after the pathways diverge. Then we address some of the issues raised by Rayner, Pollatsek, and Bilsky (1995), relating to visual deficits and oculomotor behavior, and we point to the rapidly growing evidence to diminish skepticism about the occurrence of a transient system deficit in dyslexia. Next, while agreeing that case studies are valuable, we dispute Martin’s (1995) endorsement of the case study as the preferred methodology for studying a heterogeneous deficit such as developmental dyslexia. Finally, we affirm our original conclusion that more research aimed at revealing the nature and generality of the visual and auditory temporal processing deficits is warranted, and we reiterate some of our suggestions for the types of study that might help elucidate if and how these deficits might be causally related to the dyslexia with which they are frequently associated.

 

 

Laasonen, M., Service, E., & Virsu, V. (2002). Crossmodal temporal order and processing acuity in developmentally dyslexic young adults. Brain and Language, 80(3), 340- 354.(click here)

We investigated crossmodal temporal performance in processing rapid sequential nonlinguistic events in developmentally dyslexic young adults (ages 20–36 years) and an age- and IQ-matched control group in audiotactile, visuotactile, and audiovisual combinations. Two methods were used for estimating 84% correct temporal acuity thresholds: temporal order judgment (TOJ) and temporal processing acuity (TPA). TPA requires phase difference detection: the judgment of simultaneity/nonsimultaneity of brief stimuli in two parallel, spatially separate triplets. The dyslexic readers’ average temporal performance was somewhat poorer in all six comparisons; in audiovisual comparisons the group differences were not statistically significant, however. A principal component analysis indicated that temporal acuity and phonological awareness are related in dyslexic readers. The impairment of temporal input processing seems to be a general correlative feature of dyslexia in children and adults, but the overlap in performance between dyslexic and normal readers suggests that it is not a sufficient reason for developmental reading difficulties.

 

 

McAnally, K. I., Castles, A., & Stuart, G. W. (2000). Visual and auditory processing impairments in subtypes of developmental dyslexia: A discussion. Journal of Developmental and Physical Disabilities, 12(2), 145- 156. (click here)

There has been a large body of research exploring sensory processing deficits in dyslexia, in both the visual and the auditory domains. Recently, there has also been evidence to suggest that dyslexia may be a heterogeneous disorder, with different patterns of dyslexia being identifiable. In this paper, we examine the relationship between these two bodies of research. First, we briefly review the evidence for sensory processing impairments in dyslexia, in both the visual and the auditory domains. Second, we consider how such deficits ight affect the development of different component processes in reading and, therefore, be associated with different subtypes of dyslexia. Finally, we present some illustrative data, which points to the importance of considering different component processes of reading when investigating sensory processingdeficits in dyslexia.

 

 

Meng, X. Z., Sai, X. G., Wang, C. X., Wang, J., Sha, S. Y., &Zhou, X. L. (2005). Auditory and speech processing and reading development in Chinese school children: Behavioural and ERP evidence. Dyslexia, 11(4), 292-310. (click here)

By measuring behavioural performance and event-related potentials (ERPs) this study investigated the extent to which Chinese school children’s reading development is influenced by their skills in auditory, speech, and temporal processing. In Experiment 1, 102 normal school children’s performance in pure tone temporal order judgment, tone frequency discrimination, temporal interval discrimination and composite tone pattern discrimination was measured. Results showed that children’s auditory processing skills correlated significantly with their reading fluency, phonological awareness, word naming latency, and the number of Chinese characters learned. Regression analyses found that tone temporal order judgment, temporal interval discrimination and composite tone pattern discrimination could account for 32% of variance in phonological awareness. Controlling for the effect of phonological awareness, auditory processing measures still contributed significantly to variance in reading fluency and character naming. In Experiment 2, mismatch negativities (MMN) in event-related brain potentials were recorded from dyslexic children and the matched normal children, while these children listened passively to Chinese syllables and auditory stimuli composed of pure tones. The two groups of children did not differ in MMN to stimuli deviated in pure tone frequency and Chinese lexical tones. But dyslexic children showed smaller MMN to stimuli deviated in initial consonants or vowels of Chinese syllables and to stimuli deviated in temporal information of composite tone patterns. These results suggested that Chinese dyslexic children have deficits in auditory temporal processing as well as in linguistic processing and that auditory and temporal processing is possibly as important to reading development of children in a logographic writing system as in an alphabetic system.

 

 

Muneaux, M., Ziegler, J., Truc, C., Thomson, J., &Goswami, U. (2004). Deficits in beat perception and dyslexia. Evidence from French. Neuroreport, 15(7), 1-5.

 

Rayner, K., Pollatsek, A., & Bilsky, A. B. (1995). Can a temporal processing deficit account for dyslexia? Psychonomic Bulletin and Review, 2(4), 501-507. (click here)

In this comment, we argue that although Farmer and Klein (1995) have provided a valuable review relating deficits in nonreading tasks and dyslexia, their basic claim that a “temporal processing deficit” is one possible cause of dyslexia is somewhat vague. We argue that “temporal processing deficit” is never clearly defined. Furthermore, we question some of their assumptions concerning an auditory temporal processing deficit related to dyslexia, and we present arguments and data that seem inconsistent with their claims regarding how a visual temporal processing deficit would manifest itself in dyslexic readers. While we agree that some dyslexics have visual problems, we conclude that problems with reading caused by the visual mechanisms that Farmer and Klein postulate are quite rare.

 

 

Rey, V., DeMartino, S., Espesser, R., & Habib, M. (2002). Temporal processing and phonological impairment in dyslexia: Effect of phoneme lengthening on order judgment of two consonants. Brain and Language, 80(3), 576-591. (click here)

The evidence of supporting phonological deficit as a cause of developmental dyslexia has been accumulating rapidly over the past 2 decades, yet the exact mechanisms underlying this deficit remain controversial. Some authors assume that a temporal processing deficit is the source of the phonological disorder observed in dyslexic children. Others maintain that the phonological deficit in dyslexia is basically linguistic, not acoustic, in nature. Three experiments were conducted and tested the impact of the temporal alteration and the impact of complex syllabic structure on consonant order judgments. Thirteen phonological dyslexics (age 10–13) and 10 controls matched for chronologial age were compared on a Temporal Order Judgment (TOJ) task using the succession of two consonants (/p/ /s/) within a cluster. In order to test the possible relevance of the temporal deficit hypothesis, the task also included two additional conditions where either the two stimuli were artificially slowed or two phonological structures were opposed (CCV and CVCV). As expected, the TOJ performance was significantly poorer in dyslexics than in controls. Moreover, in the ‘‘slowed speech’’ condition dyslexics’ performance improved to reach the normal controls’ level, whereas manipulating the phonological structure complexity provided no significant improvement. Finally dyslexics’ performances, especially on the slowed condition, were found correlated with several tests of phonological processing. These results lend support to the general temporal deficit theory of dyslexia.

 

 

Santos, A., JolyPottuz, B., Moreno, S., Habib, M., &Besson, M. (2007). Behavioural and event- related potentials evidence for pitch discrimination deficits in dyslexic children: Improvement after intensive phonic intervention. Neuropsychologia, 45(5), 1080-1090. (click here)

Although it is commonly accepted that dyslexic children have auditory phonological deficits, the precise nature of these deficits remains unclear. This study examines potential pitch processing deficit in dyslexic children, and recovery after specific training, by measuring event-related brain potentials (ERPs) and behavioural responses to pitch manipulations within natural speech. In two experimental sessions, separated by 6 weeks of training, 10 dyslexic children, aged 9–12, were compared to reading age- matched controls, using sentences from children’s books. The pitch of the sentence’s final words was parametrically manipulated (either congruous, weakly or strongly incongruous). While dyslexics followed a training focused on phonological awareness and grapheme-to-phoneme conversion, controls followed a non-auditory training. Before training, controls outperformed dyslexic children in the detection of the strong pitch incongruity. Moreover, while strong pitch incongruities were associated with increased late positivity (P300 component) in controls, no such pattern was found in dyslexics. Most importantly, pitch discrimination performance was significantly improved, and the amplitude of the late positivity to the strong pitch incongruity enhanced, for dyslexics after a relatively brief period of training, so that their pattern of response more closely resemble those of controls.

 

 

SchulteKorne, G., Deimel, W., Bartling, J., & Remschmidt, H. (1999). The role of phonological awareness, speech perception, and auditory temporal processing for dyslexia. European Child &Adolescent Psychiatry, 8, 28-34. (click here)

There is strong evidence that auditory processing plays a major role in the etiology of dyslexia. Auditory temporal processing of non-speech stimuli, speech perception, and phonological awareness have been shown to be influential in reading and spelling development. However, the relationship between these variables remains unclear. In order to analyze the influence of these three auditory processing levels on spelling, 19 dyslexic and 15 control children were examined. Significant group differences were found for all speech variables, but not for any non-speech variable. Structural equation modeling resulted in a fairly simple model with direct paths to the respective next lower level. One additional path from preattentive speech processing to spelling had to be included in order to improve the model fit. These results strengthen the role of speech and phonological processing for the etiology in dyslexia.

 

 

Strehlow, U., Haffner, J., Bischof, J., Gratzka, V., Parzer, P., & Resch, F. (2006). Does successful training of temporal processing of sound and phoneme stimuli improve reading and spelling? European Child & Adolescent Psychiatry, 15(1), 19-29. (click here)

Objective The aim of this study was to measure and train auditory temporal processing in children with dyslexia and to examine whether there was a transfer of improved auditory temporal processing to reading and spelling skills. MethodsComputer-based procedures to measure and train temporal processing of sound and phoneme stimuli were developed. Test- scores for a normal control group consisting of 8-year- olds were established. Second graders with dyslexia were included in the training condition and divided into three groups: a control group, a group specifically trained in sound processing, and a third group specifically trained in phoneme processing. After an initial diagnostic procedure, both training groups received specific training every day for 4 weeks. All children, regardless of the group, received the same standard reading training programme designed for children with dyslexia at school. Outcome measures were assessed immediately after training as well as 6 and 12 months later. Results Tests for temporal processing of sound and phoneme stimuli proved to be highly reliable. Children with dyslexia (N=44) showed impaired auditory processing of sound and phoneme stimuli compared to normal controls (N=51). There was a specific significant improvement in sound, respectively phoneme, processing for the training groups immediately after the end of training. The improvement of phoneme processing remained stable after 6 months and as a trend after 12months. After 6 and 12 months of training, children of all three groups improved significantly in reading no matter what group. In spelling, the sound training group had a slight advantage after 6 months, which was not stable after 12 months. Conclusions Auditory temporal processing could be trained effectively at the sound and phoneme levels. However, no significant stable transfer of these improved abilities on reading and spelling exceeding the effect of the school-based standard training was demonstrated.

 

 

Talcott, J. B., Hansen, P. C., Assoku, E. L., & Stein, J. F. (2000). Visual motion sensitivity in dyslexia: evidence for temporal and energy integration deficits. Neuropsychologia, 38(7), 935-943. (click here)

In addition to poor literacy skills, developmental dyslexia has been associated with multisensory deficits for dynamic stimulus detection. In vision these de®cits have been suggested to result from impaired sensitivity of cells within the retino-cortical magnocellular pathway and extrastriate areas in the dorsal stream to which they project. One consequence of such selectively reduced sensitivity is a difficulty in extracting motion coherence from dynamic noise, a deficit associated with both developmental dyslexia and persons with extrastriate, dorsal stream lesions. However the precise nature of the mechanism(s)underlying these perceptual de®cits in dyslexia remain unknown. In this study, we obtained motion detection thresholds for 10 dyslexic and 10 control adults while varying the spatial and temporal parameters of the random dot kinematogram (RDK) stimuli. In Experiment 1 stimulus duration was manipulated to test whether dyslexics are speci®cally impaired for detecting short duration, rather than longer stimuli. Dot density was varied in Experiment 2 to examine whether dyslexics' reduced motion sensitivity was a€ected by the amount of motion energy present in the RDKs. Dyslexics were consistently less sensitive to coherent motion than controls in both experiments. Increasing stimulus duration did not improve dyslexics' performance, whereas increasing dot density did. Thus increasing motion energy assisted the dyslexics, suggesting that their motion detectors have a lower signal to noise ratio, perhaps due to spatial undersampling.

 

 

Tallal, P. (2004). Improving language and literacy is a matter of time. Nature Reviews:  Neuroscience, 5, 1-8. (click here)

Developmental deficits that affect speech perception increase the risk of language and literacy problems, which can lead to lowered academic and occupational accomplishment. Normal development and disorders of speech perception have both been linked to temporospectral auditory processing speed. Understanding the role of dynamic auditory processing in speech perception and language comprehensionhas led to the development of neuroplasticity-based intervention strategies aimed at ameliorating language and literacy problems and their sequelae.

 

 

Tallal, P. (2003). Language learning disabilities: Integrating research approaches. Current Directions in Psychological Science, 12(6), 206-211. (click here)

Developmental language learning impairments affect 10 to 20% of children and increase their risk of later literacy problems (dyslexia) and psychiatric disorders. Both oral- and written-language impairments have been linked to slow neural processing, which is hypothesized to interfere with the perception of speech sounds that are characterized by rapid acoustic changes. Research into the etiology of language learning impairments not only has led to improved diagnostic and intervention strategies, but also has raised fundamental questions about the neurobiological basis of speech, language, and reading, as well as hemispheric lateralization.

 

 

Tallal, P., & Gaab. N. (2006). Dynamic auditory processing, musical experience and language development. Trends in Neurosciences, 29(7), 382-390. (click here)

Children with language-learning impairments (LLI) form a heterogeneous population with the majority having both spoken and written language deficits as well as sensorimotor deficits, specifically those related to dynamic processing. Research has focused on whether or not sensorimotor deficits, specifically auditory spectrotemporal processing deficits, cause phonological deficit, leading to language and reading impairments. New trends aimed at resolving this question include prospective longitudinal studies of genetically at-risk infants, electrophysiological and neuroimaging studies, and studies aimed at evaluating the effects of auditory training (including musical training) on brain organization for language. Better understanding of the origins of developmental LLI will advance our understanding of the neurobiological mechanisms underlying individual differences in language development and lead to more effective educational and intervention strategies. This review is part of the INMED/TINS special issue Nature and Nurture in Brain Development and Neurological Disorders, based on presentations at the annual NMED/TINS symposium (http://inmednet.com/).

 

 

Valdois, S., Bosse, M. L., & Tainturier, M. J. (2004). The cognitive deficits responsible for developmental dyslexia: Review of evidence for a selective visual attentional disorder. Dyslexia, 10(4), 339-363. (click here)

There is strong converging evidence suggesting that developmental dyslexia stems from a phonological processing deficit. However, this hypothesis has been challenged by the widely admitted heterogeneity of the dyslexic population, and by several reports of dyslexic individuals with no apparent phonological deficit. In this paper, we discuss the hypothesis that a phonological deficit may not be the only core deficit in developmental dyslexia and critically examine several alternative proposals. To establish that a given cognitive deficit is causally related to dyslexia, at least two conditions need to be fulfilled. First, the hypothesized deficit needs to be associated with developmental dyslexia independently of additional phonological deficits. Second, the hypothesized deficit must predict reading ability, on both empirical and theoretical grounds. While most current hypotheses fail to fulfil these criteria, we argue that the visual attentional deficit hypothesis does. Recent studies providing evidence for the independence of phonological and visual attentional deficits in developmental dyslexia are reviewed together with empirical data showing that phonological and visual attentional processing skills contribute independently to reading performance. A theoretical model of reading is outlined in support of a causal link between a visual attentional disorder and a failure in reading acquisition.

 

Van Ingelghem, M., van Wieringen, A., Wouters, J., Vandenbussche, E., Onghena, P., & Ghesquiere, P. Psychophysical evidence for a general temporal processing deficit in children with dyslexia. Neuroreport, 12(16), 3603-3607.

             The hypothesis of a general (i.e. cross-modal) temporal processing deficit in dyslexia was tested by examining rapid processing in both the auditory and the visual system in the same children with dyslexia. Participants were 10- to 12-year-old dyslexic readers and age-  matched normal reading controls. Psychophysical thresholds were estimated for auditory gap and visual double flash detection, using a two-interval, two-alternative forced-choice paradigm. Significant group differences were found for the auditory and the visual test. Furthermore, temporal processing measures were significantly related to word and pseudo- word reading skills. As 70% of the dyslexic readers had significantly higher thresholds than controls for both auditory and visual temporal processing, the evidence tends to support the hypothesis of a general temporal processing deficit in children with dyslexia.

 

Virsu, V., Lahti-Nuuttila, P., & Laasonen, M. (2003). Crossmodal temporal processing acuity impairment aggravates with age in developmental dyslexia. Neuroscience Letters, 336(3), 151-154.(click here)

             Temporal processing has been found to be impaired in developmental dyslexia. We investigated how aging affects crossmodal temporal processing impairment with 39 dyslexic and 40 fluent 20-59-year-old readers. Cognitive temporal acuity was measured at millisecond levels in six tasks. They consisted of order judgments of two brief non-speech stimulus pulses, the stimuli being audiotactile, visuotactile and audiovisual, and of simultaneity/nonsimultaneity detection of the pulses in two parallel three-pulse trains. Temporal acuity declined with age in both reading groups and its impairment was observed in developmental dyslexia. A new finding was that the crossmodal temporal impairment, directly relevant to reading, increased with age. The age-related exacerbation suggests a developmental neuronal deficit, possibly related to magnocells, which exists before dyslexia and is its ontogenetic cause.

 

Walker, M. M., Givens, G. D., Cranford, J. L., Holbert, D., &Walker, L. (2006). Auditory pattern recognition and brief tone discrimination of children with reading disorders. Journal of Communication Disorders, 39(6), 442-455.(click here)

Auditory pattern recognition skills in children with reading disorders were investigated using perceptual tests involving discrimination of frequency and duration tonal patterns. A behavioral test battery involving recognition of the pattern of presentation of tone triads was used in which individual components differed in either frequency or duration. A test involving measurement of difference limens for long and short duration tones was also administered. In comparison to controls, children with reading disorders exhibited significantly higher error rates in discrimination of duration and frequency patterns, as well as larger brief tone frequency difference limens. These results suggest that difficulties in the recognition and processing of auditory patterns may co-occur with decoding deficits in children with reading disorders.