Electrophysiological correlates of rapid auditory and linguistic processing in adolescents with specific language impairment

Low-Level Auditory Processing Correlates With Language Abilities: An ERP Study Investigating Sequence Learning and Auditory Processing in School-Aged Children

Auditory processing and procedural learning deficits have been associated with language learning difficulties. We investigated the relationship of these skills and school-age language abilities in children with and without a history of late talking using auditory event related potentials (ERPs). Late talking (i.e., slow early language development) increases the risk of persistent language difficulties, but its causes remain unknown. Participants in this study were children with varying language abilities (n = 60). Half of the participants (n = 30) had a history of late talking. We measured procedural learning by manipulating the predictability of sine tone stimuli in a passive auditory ERP paradigm. Auditory processing was tested by examining how the presence of noise (increasing perceptual demands) affected the ERPs. Contrary to our hypotheses on auditory processing and language development, the effect of noise on ERPs did not correlate with school-age language abilities in children with or without a history of late talking. Our paradigm failed to reveal interpretable effects of predictability leaving us unable to assess the effects of procedural learning. However, better language abilities were related to weaker responses in a 75-175 ms time window, and stronger responses in a 150-250 ms time window. We suggest that the weak early responses in children with better language ability reflect efficient processing of low-level auditory information, allowing deeper processing of later, high-level auditory information. We assume that these differences reflect variation in brain maturation between individuals with varying language abilities.

Number agreement processing in adolescents with and without developmental language disorder (DLD): evidence from event-related brain potentials

In morphologically richer languages, including French, one must learn the specific properties of number agreement in order to understand the language, and this learning process continues into adolescence. This study examined similarities and differences between French-speaking adolescents with and without developmental language disorder (DLD) when processing number agreement, and investigated how morpho-syntactic regularity affected language processing. Using event-related potentials (ERP) and only grammatical sentences with audio-visual mismatches, we studied ERP correlates to three types of number agreement: (1) regular determiner agreement in noun phrases, (2) regular subject-verb plural liaison, and (3) irregular subject-verb agreement. We also included a lexico-semantic mismatch condition to investigate lexico-semantic processing in our participants. 17 adolescents with DLD (M = 14.1 years) and 20 (pre)teens with typical language (TL, M = 12.2 years) participated in the study. Our results suggest three patterns. First, French-speaking teenagers without DLD are still consolidating their neurocognitive processing of morpho-syntactic number agreement and generally display ERP profiles typical of lower language proficiency than adult native speakers. Second, differences in morphosyntactic processing between teenagers with and without DLD seem to be limited to rule-based (regular) number agreement. Third, there is little evidence for corresponding differences in lexico-semantic processing.

Neural patterns elicited by lexical processing in adolescents with specific language impairment: support for the procedural deficit hypothesis?

Background

Deficits in procedural memory have been proposed to account for the language deficits in specific language impairment (SLI). A key aspect of the procedural deficit hypothesis (PDH) account of SLI is that declarative memory is intact and functions as a compensatory mechanism in the acquisition of language in individuals with SLI. The current study examined the neural correlates of lexical-phonological and lexical-semantic processing with respect to these predictions in a group of adolescents with SLI with procedural memory impairment and a group of chronologically age-matched (CA) normal controls.

Methods

Participants completed tasks designed to measure procedural and declarative memory and two ERP tasks designed to assess lexical-semantic and lexical-phonological processing in the auditory modality. Procedural memory was assessed using a statistical learning task. Lexical-semantic processing was assessed using a sentence judgment task modulating semantic congruency and lexical-phonological processing was assessed using a word/nonword decision task modulating word frequency. Behavioral performance on the tasks, mean amplitude of the cortical response, and animated topographs were examined.

Results

Performance on the statistical word-learning task was at chance for the adolescents with SLI, whereas declarative memory was no different from the CA controls. Behavioral accuracy on the lexical-semantic task was the same for the adolescents with SLI and CA controls but accuracy on the lexical-phonological task was significantly poorer for the adolescents with SLI as compared to the CA controls. An N400 component was elicited in response to semantic congruency on the lexical-semantic task for both groups but differences were noted in both the location and time course of the cortical response for the SLI and CA groups. An N400 component was elicited by word frequency on the lexical-phonological task for the CA controls not for the adolescents with SLI. In contrast, post hoc analysis revealed a cortical response based on imageability for the adolescents with SLI, but not CA controls. Statistical word learning was significantly correlated with speed of processing on the lexical decision task for the CA controls but not for the adolescents with SLI. In contrast, statistical word learning ability was not correlated with the modulation of the N400 on either task for either group.

Conclusion

The behavioral data suggests intact semantic conceptual knowledge, but impaired lexical phonological processing for the adolescents with SLI, consistent with the PDH. The pattern of cortical activation in response to semantic congruency and word frequency suggests, however, that the processing of lexical-semantic and lexical-phonological information by adolescents with a history of SLI may be supported by both overlapping and nonoverlapping neural generators to those of CA controls, and a greater reliance on declarative memory strategies. Taken together, the findings from this study suggest that the underlying representations of words in the lexicons of adolescents with a history of SLI may differ qualitatively from those of their typical peers, but these differences may only be evident when behavioral data and neural cortical patterns of activation are examined together.

Syntactic Gender Agreement Processing on Direct-Object Clitics by Spanish-Speaking Children with Developmental Language Disorder: Evidence from ERP

Children with developmental language disorder (DLD) have a psycholinguistic profile evincing multiple syntactic processing impairments. Spanish-speaking children with DLD struggle with gender agreement on clitics; however, the existing evidence comes from offline, elicitation tasks. In the current study, we sought to determine whether converging evidence of this deficit can be found. In particular, we use the real-time processing technique of event-related brain potentials (ERP) with direct-object clitic pronouns in Spanish-speaking children with DLD. Our participants include 15 six-year-old Mexican Spanish-speaking children with DLD and 19 typically developing, age-matched (TD) children. Auditory sentences that matched or did not match the gender features of antecedents represented in pictures were employed as stimuli in a visual–auditory gender agreement task. Gender-agreement violations were associated with an enhanced anterior negativity between 250 and 500 ms post-target onset in the TD children group. In contrast, children with DLD showed no such effect. This absence of the left anterior negativity (LAN) effect suggests weaker lexical representation of morphosyntactic gender features and/or non-adult-like morphosyntactic gender feature checking for the DLD children. We discuss the relevance of these findings for theoretical accounts of DLD. Our findings may contribute to a better understanding of syntactic agreement processing and language disorders.

P300 development from infancy to adolescence

This article provides an overview of P300 research from infancy through adolescence. First, a brief historical overview is provided highlighting seminal studies that began exploration of the P300 component in developmental groups. Overall, these studies suggest that the P300 can be detected in children and appears to reflect similar cognitive processes to those in adults; however, it is significantly delayed in its latency to peak. Second, two striking findings from developmental research are the lack of a clear P300 component in infancy and differential electrophysiological responses to novel, unexpected stimuli in children, adolescents, and adults. Third, contemporary questions are described, which include P300-like components in infancy, alteration of P300 in atypically developing groups, relations between P300 and behavior, individual differences of P300, and neural substrates of P300 across development. Finally, we conclude with comments regarding the power of a developmental perspective and suggestions for important issues that should be addressed in the next 50 years of P300 research.

An Initial Investigation of the Neural Correlates of Word Processing in Preschoolers With Specific Language Impairment

Purpose

Previous behavioral studies have found deficits in lexical-semantic abilities in children with specific language impairment (SLI), including reduced depth and breadth of word knowledge. This study explored the neural correlates of early emerging familiar word processing in preschoolers with SLI and typical development.

Method

Fifteen preschoolers with typical development and 15 preschoolers with SLI were presented with pictures followed after a brief delay by an auditory label that did or did not match. Event-related brain potentials were time locked to the onset of the auditory labels. Children provided verbal judgments of whether the label matched the picture.

Results

There were no group differences in the accuracy of identifying when pictures and labels matched or mismatched. Event-related brain potential data revealed that mismatch trials elicited a robust N400 in both groups, with no group differences in mean amplitude or peak latency. However, the typically developing group demonstrated a more robust late positive component, elicited by mismatch trials.

Conclusions

These initial findings indicate that lexical-semantic access of early acquired words, indexed by the N400, does not differ between preschoolers with SLI and typical development when highly familiar words are presented in isolation. However, the typically developing group demonstrated a more mature profile of postlexical reanalysis and integration, indexed by an emerging late positive component. The findings lay the necessary groundwork for better understanding processing of newly learned words in children with SLI.

Neural patterns elicited by sentence processing uniquely characterize typical development, SLI recovery, and SLI persistence

Background

A substantial amount of work has examined language abilities in young children with specific language impairment (SLI); however, our understanding of the developmental trajectory of language impairment is limited. Along with studying the behavioral changes that occur across development, it is important to examine the neural indices of language processing for children with different language trajectories. The current study sought to examine behavioral and neural bases of language processing in adolescents showing three different trajectories: those with normal language development (NL), those exhibiting persistent SLI (SLI-Persistent), and those with a history of SLI who appear to have recovered (SLI-Recovered).

Methods

Through a sentence judgment task, we examined semantic and syntactic processing. Adolescents judged whether or not each sentence was semantically and syntactically correct. Stimuli consisted of naturally spoken sentences that were either correct, contained a semantic verb error, or contained a syntactic verb agreement error. Verb agreement errors consisted of omission and commission violations of the third-person singular -s. Behavioral button-press responses and electroencephalographic recordings were collected. Behavioral judgments and mean amplitude of the N400 and P600 components were examined.

Results

Adolescents in the SLI-Persistent group had lower sentence judgment accuracy overall, relative to the NL and SLI-Recovered groups. Accuracy in judging omission and commission syntactic errors were marginally different, with marginally lower accuracy for commission errors. All groups demonstrated an N400 component elicited by semantic violations. However, adolescents in the SLI-Persistent group demonstrated a less robust P600 component for syntactic violations. Furthermore, adolescents in the SLI-Recovered group exhibited a similar neural profile to the NL group for the semantic and syntactic omission violations. However, a unique profile with initial negativity was observed in the SLI-Recovered group in the commission violation condition.

Conclusions

Adolescents with persistent language impairment continue to demonstrate delays in language processing at the behavioral and neural levels. Conversely, the adolescents in the SLI-Recovered group appear to have made gains in language processing skills to overcome their initial impairments. However, our findings suggest that the adolescents in the SLI-Recovered group may have compensatory processing strategies for some aspects of language, as evidenced by a unique event-related potential profile.

Electrophysiology of Perception and Processing of Phonological Information as Indices of Toddlers' Language Performance

PURPOSE

The toddler years are a critical period for language development and growth. We investigated how event-related potentials (ERPs) to repeated and novel nonwords are associated with clinical assessments of language in young children. In addition, nonword repetition (NWR) was used to measure phonological working memory to determine the unique and collective contribution of ERP measures of phonemic discrimination and NWR as predictors of language ability.

METHOD

Forty children between the ages of 24-48 months participated in an ERP experiment to determine phonemic discrimination to repeated and novel nonwords in an old/new design. Participants also completed a NWR task to explore the contribution of phonological working memory in predicting language.

RESULTS

ERP analyses revealed that faster responses to novel stimuli correlated with higher language performance on clinical assessments of language. Regression analyses revealed that an earlier component was associated with lower level phonemic sensitivity, and a later component was indexing phonological working memory skills similar to NWR.

CONCLUSION

Our findings suggest that passive ERP responses indexing phonological discrimination and phonological working memory are strongly related to behavioral measures of language.

Semantic Processing of Sentences in Preschoolers With Specific Language Impairment: Evidence From the N400 Effect

PURPOSE

Given the complexity of sentence processing and the specific problems that children with specific language impairment (SLI) experience, we investigated the time course and characteristics of semantic processing at the sentence level in Dutch preschoolers with SLI.

METHOD

We measured N400 responses to semantically congruent and incongruent spoken sentences (e.g., "My father is eating an apple/*blanket") in a group of 37 Dutch preschoolers with SLI and in a group of 25 typically developing (TD) peers. We compared the time course and amplitude of the N400 effect between the two groups.

RESULTS

The TD group showed a strong posterior N400 effect in time windows 300-500 ms and 500-800 ms. In contrast, the SLI group demonstrated only a reliable N400 effect in the later time window, 500-800 ms, and did not show a stronger presence at posterior electrodes.

CONCLUSION

The findings suggest that the neuronal processing of semantic information at sentence level is atypical in preschoolers with SLI compared with TD children.

Cortical Auditory Event Related Potentials (P300) for Frequency Changing Dynamic Tones

BACKGROUND AND OBJECTIVES

P300 has been studied with a variety of stimuli. However, the nature of P300 has not been investigated for deviant stimuli which change its characteristics from standard stimuli after a period of time from onset.

SUBJECTS AND METHODS

Nine young adults with normal hearing participated in the study. The P300 was elicited using an oddball paradigm, the probability of standard and deviant stimuli was 80% and 20% respectively. Six stimuli were used to elicit P300, it included two pure-tones (1,000 Hz and 2,000 Hz) and four tone-complexes (tones with frequency changes). Among these stimuli, 1,000 Hz tone served as standard while others served as deviant stimuli. The P300 was recorded in five separate blocks, with one of the deviant stimuli as target in each block. Electroencephalographic was recorded from electrode sites Fz, Cz, C3, C4, and Pz. Latency and amplitude of components of the cortical auditory evoked potentials were measured at Cz.

RESULTS

Waveforms obtained in the present study shows that, all the deviant stimuli elicited obligatory P1-N1-P2 for stimulus onset. 2,000 Hz deviant tone elicited P300 at a latency of 300 ms. While, tone-complexes elicited acoustic change complex (ACC) for frequency changes and finally elicited P300 at a latency of 600 ms. In addition, the results showed shorter latency and larger amplitude ACC and P300 for rising tone-complexes compared to falling tone-complexes.

CONCLUSIONS

Tone-complexes elicited distinct waveforms compared to 2,000 Hz deviant tone. Rising tone-complexes which had an increase in frequency elicited shorter latency and larger amplitude responses, which could be attributed to perceptual bias for frequency changes.

Cortical inhibition effect in musicians and non-musicians using P300 with and without contralateral stimulation

Introduction

Musicians have more robust and efficient neural responses in the cortical and sub-cortical regions, demonstrating that musical experience benefits the processing of both non-linguistic and linguistic stimuli.

Objective

This study aimed to verify P300's latency and amplitude behavioral using contralateral stimulation in musicians and non-musicians.

Methods

This was a case–control study. Subjects were divided in two groups: musicians, comprising 30 professional musicians, and non-musicians, comprising 25 subjects without musical experience.

Results

The present study showed that the musicians had lower latencies and higher amplitudes than the non-musicians in the P300 without contralateral noise. For the P300 amplitude values, the difference between groups persisted, and the musicians presented significantly higher amplitude values compared with the non-musicians; additionally, the analysis of the noise effect on the P300 response showed that the latency values were significantly increased in the musicians.

Conclusion

The central auditory nervous system of musicians presents peculiar characteristics of electrophysiological responses probably due to the plasticity imposed by musical practice.

Children with a history of SLI show reduced sensitivity to audiovisual temporal asynchrony: an ERP study

PURPOSE

The authors examined whether school-age children with a history of specific language impairment (H-SLI), their peers with typical development (TD), and adults differ in sensitivity to audiovisual temporal asynchrony and whether such difference stems from the sensory encoding of audiovisual information.

METHOD

Fifteen H-SLI children, 15 TD children, and 15 adults judged whether a flashed explosion-shaped figure and a 2-kHz pure tone occurred simultaneously. The stimuli were presented at 0-, 100-, 200-, 300-, 400-, and 500-ms temporal offsets. This task was combined with EEG recordings.

RESULTS

H-SLI children were profoundly less sensitive to temporal separations between auditory and visual modalities compared with their TD peers. Those H-SLI children who performed better at simultaneity judgment also had higher language aptitude. TD children were less accurate than adults, revealing a remarkably prolonged developmental course of the audiovisual temporal discrimination. Analysis of early event-related potential components suggested that poor sensory encoding was not a key factor in H-SLI children's reduced sensitivity to audiovisual asynchrony.

CONCLUSIONS

Audiovisual temporal discrimination is impaired in H-SLI children and is still immature during mid-childhood in TD children. The present findings highlight the need for further evaluation of the role of atypical audiovisual processing in the development of SLI.

Decreased sensitivity to long-distance dependencies in children with a history of specific language impairment: electrophysiological evidence

PURPOSE

One possible source of tense and agreement limitations in children with specific language impairment (SLI) is a weakness in appreciating structural dependencies that occur in many sentences in the input. This possibility was tested in the present study.

METHOD

Children with a history of SLI (H-SLI; n = 12; M = 9;7 [years;months]) and typically developing same-age peers (TD; n = 12; M = 9;7) listened to and made grammaticality judgments about grammatical and ungrammatical sentences involving either a local agreement error (e.g., "Every night they talks on the phone") or a long-distance finiteness error (e.g., "He makes the quiet boy talks a little louder"). Electrophysiological (ERP) and behavioral (accuracy) measures were obtained.

RESULTS

Local agreement errors elicited the expected anterior negativity and P600 components in both groups of children. However, relative to the TD group, the P600 effect for the long-distance finiteness errors was delayed, reduced in amplitude, and shorter in duration for the H-SLI group. The children's grammaticality judgments were consistent with the ERP findings.

CONCLUSION

Children with H-SLI seem to be relatively insensitive to the finiteness constraints that matrix verbs place on subject-verb clauses that appear later in the sentence.

Normative topographic ERP analyses of speed of speech processing and grammar before and after grammatical treatment

Typically developing (TD) preschoolers and age-matched preschoolers with specific language impairment (SLI) received event-related potentials (ERPs) to four monosyllabic speech sounds prior to treatment and, in the SLI group, after 6 months of grammatical treatment. Before treatment, the TD group processed speech sounds faster than the SLI group. The SLI group increased the speed of their speech processing after treatment. Posttreatment speed of speech processing predicted later impairment in comprehending phrase elaboration in the SLI group. During the treatment phase, change in speed of speech processing predicted growth rate of grammar in the SLI group.

Deconvolution of magnetic acoustic change complex (mACC)

OBJECTIVE

The aim of this study was to design a novel experimental approach to investigate the morphological characteristics of auditory cortical responses elicited by rapidly changing synthesized speech sounds.

METHODS

Six sound-evoked magnetoencephalographic (MEG) responses were measured to a synthesized train of speech sounds using the vowels /e/ and /u/ in 17 normal hearing young adults. Responses were measured to: (i) the onset of the speech train, (ii) an F0 increment; (iii) an F0 decrement; (iv) an F2 decrement; (v) an F2 increment; and (vi) the offset of the speech train using short (jittered around 135ms) and long (1500ms) stimulus onset asynchronies (SOAs). The least squares (LS) deconvolution technique was used to disentangle the overlapping MEG responses in the short SOA condition only.

RESULTS

Comparison between the morphology of the recovered cortical responses in the short and long SOAs conditions showed high similarity, suggesting that the LS deconvolution technique was successful in disentangling the MEG waveforms. Waveform latencies and amplitudes were different for the two SOAs conditions and were influenced by the spectro-temporal properties of the sound sequence. The magnetic acoustic change complex (mACC) for the short SOA condition showed significantly lower amplitudes and shorter latencies compared to the long SOA condition. The F0 transition showed a larger reduction in amplitude from long to short SOA compared to the F2 transition. Lateralization of the cortical responses were observed under some stimulus conditions and appeared to be associated with the spectro-temporal properties of the acoustic stimulus.

CONCLUSIONS

The LS deconvolution technique provides a new tool to study the properties of the auditory cortical response to rapidly changing sound stimuli. The presence of the cortical auditory evoked responses for rapid transition of synthesized speech stimuli suggests that the temporal code is preserved at the level of the auditory cortex. Further, the reduced amplitudes and shorter latencies might reflect intrinsic properties of the cortical neurons to rapidly presented sounds.

SIGNIFICANCE

This is the first demonstration of the separation of overlapping cortical responses to rapidly changing speech sounds and offers a potential new biomarker of discrimination of rapid transition of sound.

Abnormal functioning of the left temporal lobe in language-impaired children

Specific language impairment is associated with enduring problems in language-related functions. We followed the spatiotemporal course of cortical activation in SLI using magnetoencephalography. In the experiment, children with normal and impaired language development heard spoken real words and pseudowords presented only once or two times in a row. In typically developing children, the activation in the bilateral superior temporal cortices was attenuated to the second presentation of the same word. In SLI children, this repetition effect was nearly nonexistent in the left hemisphere. Furthermore, the activation was equally strong to words and pseudowords in SLI children whereas in the typically developing children the left hemisphere activation persisted longer for pseudowords than words. Our results indicate that the short-term maintenance of linguistic activation that underlies spoken word recognition is defective in SLI particularly in the left language-dominant hemisphere. The unusually rapid decay of speech-evoked activation can contribute to impaired vocabulary growth.

Attentional but not pre-attentive neural measures of auditory discrimination are atypical in children with developmental language disorder

We examined neural indices of pre-attentive phonological and attentional auditory discrimination in children with developmental language disorder (DLD, n = 23) and typically developing (n = 16) peers from a geographically isolated Russian-speaking population with an elevated prevalence of DLD. Pre-attentive phonological MMN components were robust and did not differ in two groups. Children with DLD showed attenuated P3 and atypically distributed P2 components in the attentional auditory discrimination task; P2 and P3 amplitudes were linked to working memory capacity, development of complex syntax, and vocabulary. The results corroborate findings of reduced processing capacity in DLD and support a multifactorial view of the disorder.

Electrophysiological correlates of connotative meaning in healthy children

The affective, connotative meaning of words can be statistically quantified by the semantic differential technique. Words that are located clearly on one of the three dimensions called "Evaluation", "Potency", and "Activity" were used as visual stimuli in a topographic event related potential study (ERP). Stimuli had been statistically defined in a group of 249 children (Skrandies, Jpn Psychol Res 53: 65-76, 2011). We investigated electrical brain activity in 19 healthy children with normal intelligence and reading skills between 11 and 15 years of age. Words that belonged to different semantic classes were presented at random on a monitor, and EEG was measured from 30 channels. Evoked potentials were computed offline for each semantic class. In the ERP data we observed significant effects of word class on component latency, field strength and topography. Similar as with adult subjects such effects occurred at small latency of about 115 ms after word presentation. The language-evoked components in children were similar but not identical to those reported previously for various groups of adults. Our data show that visually evoked brain activity is modulated by connotative meaning of the stimuli at early processing stages not only in adults but also in children.

The influence of speech stimuli contrast in cortical auditory evoked potentials

Objective

Method

Results

Conclusion

Motor sequencing deficit as an endophenotype of speech sound disorder: a genome-wide linkage analysis in a multigenerational family

OBJECTIVES

The aim of this pilot study was to investigate a measure of motor sequencing deficit as a potential endophenotype of speech sound disorder (SSD) in a multigenerational family with evidence of familial SSD.

METHODS

In a multigenerational family with evidence of a familial motor-based SSD, affectation status and a measure of motor sequencing during oral motor testing were obtained. To further investigate the role of motor sequencing as an endophenotype for genetic studies, parametric and nonparametric linkage analyses were carried out using a genome-wide panel of 404 microsatellites.

RESULTS

In seven of the 10 family members with available data, SSD affectation status and motor sequencing status coincided. Linkage analysis revealed four regions of interest, 6p21, 7q32, 7q36, and 8q24, primarily identified with the measure of motor sequencing ability. The 6p21 region overlaps with a locus implicated in rapid alternating naming in a recent genome-wide dyslexia linkage study. The 7q32 locus contains a locus implicated in dyslexia. The 7q36 locus borders on a gene known to affect the component traits of language impairment.

CONCLUSION

The results are consistent with a motor-based endophenotype of SSD that would be informative for genetic studies. The linkage results in this first genome-wide study in a multigenerational family with SSD warrant follow-up in additional families and with fine mapping or next-generation approaches to gene identification.

Auditory deficit as a consequence rather than endophenotype of specific language impairment: electrophysiological evidence

Background

Are developmental language disorders caused by poor auditory discrimination? This is a popular theory, but behavioural evidence has been inconclusive. Here we studied children with specific language impairment, measuring the brain’s electrophysiological response to sounds in a passive paradigm. We focused on the T-complex, an event-related peak that has different origins and developmental course from the well-known vertex response.

Methods

We analysed auditory event-related potentials to tones and syllables from 16 children and 16 adolescents with specific language impairment who were compared with 32 typically-developing controls, matched for gender, IQ and age.

Results

We replicated prior findings of significant reduction in Ta amplitude for both children and adolescents with specific language impairment, which was particularly marked for syllables. The topography of the T-complex to syllables indicated a less focal response in those with language impairments. To distinguish causal models, we considered correlations between size of the Ta response and measures of language and literacy in parents as well as children. The best-fitting model was one in which auditory deficit was a consequence rather than a cause of difficulties in phonological processing.

Conclusions

The T-complex to syllables has abnormal size and topography in children with specific language impairment, but this is more likely to be a consequence rather than a cause of difficulties in phonological processing.