Basic Auditory Processing Research Articles

Adults with dyslexia are impaired in categorizing speech and nonspeech sounds on the basis of temporal cues

Developmental dyslexia is characterized by severe reading and spelling difficulties that are persistent and resistant to the usual didactic measures and remedial efforts. It is well established that a major cause of these problems lies in poorly specified representations of speech sounds. One hypothesis states that this phonological deficit results from a more fundamental deficit in auditory processing. Despite substantial research effort, the specific nature of these auditory problems remains debated. A first controversy concerns the speech specificity of the auditory processing problems: Can they be reduced to more basic auditory processing, or are they specific to the perception of speech sounds? A second topic of debate concerns the extent to which the auditory problems are specific to the processing of rapidly changing temporal information or whether they encompass a broader range of complex spectro-temporal processing. By applying a balanced design with stimuli that were adequately controlled for acoustic complexity, we show that adults with dyslexia are specifically impaired at categorizing speech and nonspeech sounds that differ in terms of rapidly changing acoustic cues (i.e., temporal cues), but that they perform adequately when categorizing steady-state speech and nonspeech sounds. Thus, we show that individuals with dyslexia have an auditory temporal processing deficit that is not speech-specific.

Rise time and formant transition duration in the discrimination of speech sounds: the Ba-Wa distinction in developmental dyslexia

Across languages, children with developmental dyslexia have a specific difficulty with the neural representation of the sound structure (phonological structure) of speech. One likely cause of their difficulties with phonology is a perceptual difficulty in auditory temporal processing (Tallal, 1980). Tallal (1980) proposed that basic auditory processing of brief, rapidly successive acoustic changes is compromised in dyslexia, thereby affecting phonetic discrimination (e.g. discriminating /b/ from /d/) via impaired discrimination of formant transitions (rapid acoustic changes in frequency and intensity). However, an alternative auditory temporal hypothesis is that the basic auditory processing of the slower amplitude modulation cues in speech is compromised (Goswami et al., 2002). Here, we contrast children's perception of a synthetic speech contrast (ba/wa) when it is based on the speed of the rate of change of frequency information (formant transition duration) versus the speed of the rate of change of amplitude modulation (rise time). We show that children with dyslexia have excellent phonetic discrimination based on formant transition duration, but poor phonetic discrimination based on envelope cues. The results explain why phonetic discrimination may be allophonic in developmental dyslexia (Serniclaes et al., 2004), and suggest new avenues for the remediation of developmental dyslexia.

On the neuro-cognitive foundations of basic auditory number processing: an fMRI study

BackgroundIt is widely agreed that numbers automatically activate a magnitude representation. Nevertheless, so far no systematic evaluation of the neuro-cognitive correlates has been provided for the case of auditorily presented numbers.MethodsTo address this question, we presented spoken number words in three different tasks (passive listening, magnitude comparison, parity judgement) as well as spoken pseudowords in an fMRI study.ResultsWe found IPS activation typically associated with magnitude processing in all tasks with numerical stimuli only. Interestingly, directly contrasting the two semantic tasks magnitude comparison (magnitude-relevant) and parity judgement (magnitude-irrelevant) revealed a left lateralized predominance within the IPS for the processing of parity information as compared to a right lateralization for number magnitude for auditorily presented number words.ConclusionsIn summary, our results suggest a highly automatic activation of number magnitude for spoken number words similar to previous observations for visually presented numbers, but also indicate that the issue of hemispheric asymmetries deserves specific consideration.

Developmental learning impairments in a rodent model of nodular heterotopia

Developmental malformations of neocortex—including microgyria, ectopias, and periventricular nodular heterotopia (PNH)—have been associated with language learning impairments in humans. Studies also show that developmental language impairments are frequently associated with deficits in processing rapid acoustic stimuli, and rodent models have linked cortical developmental disruption (microgyria, ectopia) with rapid auditory processing deficits. We sought to extend this neurodevelopmental model to evaluate the effects of embryonic (E) day 15 exposure to the anti-mitotic teratogen methylazoxymethanol acetate (MAM) on auditory processing and maze learning in rats. Extensive cortical anomalies were confirmed in MAM-treated rats post mortem. These included evidence of laminar disruption, PNH, and hippocampal dysplasia. Juvenile auditory testing (P21–42) revealed comparable silent gap detection performance for MAM-treated and control subjects, indicating normal hearing and basic auditory temporal processing in MAM subjects. Juvenile testing on a more complex two-tone oddball task, however, revealed a significant impairment in MAM-treated as compared to control subjects. Post hoc analysis also revealed a significant effect of PNH severity for MAM subjects, with more severe disruption associated with greater processing impairments. In adulthood (P60–100), only MAM subjects with the most severe PNH condition showed deficits in oddball two-tone processing as compared to controls. However, when presented with a more complex and novel FM sweep detection task, all MAM subjects showed significant processing deficits as compared to controls. Moreover, post hoc analysis revealed a significant effect of PNH severity on FM sweep processing. Water Maze testing results also showed a significant impairment for spatial but not non-spatial learning in MAM rats as compared to controls. Results lend further support to the notions that: (1) generalized cortical developmental disruption (stemming from injury, genetic or teratogenic insults) leads to auditory processing deficits, which in turn have been suggested to play a causal role in language impairment; (2) severity of cortical disruption is related to the severity of processing impairments; (3) juvenile auditory processing deficits appear to ameliorate with maturation, but can still be elicited in adulthood using increasingly complex acoustic stimuli; and (4) malformations induced with MAM are also associated with generalized spatial learning deficits. These cumulative findings contribute to our understanding of the behavioral consequences of cortical developmental pathology, which may in turn elucidate mechanisms contributing to developmental language learning impairment in humans.

Auditory processing in children with language-based learning problems: a magnetencephalography study

We examined basic auditory temporal processing in children with language-based learning problems (LPs) applying magnetencephalography. Auditory-evoked fields of 43 children (27 LP, 16 controls) were recorded while passively listening to 100-ms white noise bursts with temporal gaps of 3, 6, 10 and 30 ms inserted after 5 or 50 ms. The P1m was evaluated by spatio-temporal source analysis. Psychophysical gap-detection thresholds were obtained for the same participants. Thirty-two percent of the LP children were not able to perform the early gap psychoacoustic task. In addition, LP children displayed a significant delay of the P1m during the early gap task. These findings provide evidence for a diminished neuronal representation of short auditory stimuli in the primary auditory cortex of LP children.

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.

Learning novel phonological representations in developmental dyslexia: associations with basic auditory processing of rise time and phonological awareness

Across languages, children with developmental dyslexia are known to have impaired lexical phonological representations. Here, we explore associations between learning new phonological representations, phonological awareness, and sensitivity to amplitude envelope onsets (rise time). We show that individual differences in learning novel phonological representations are related to individual differences in both rise time categorization and rise time discrimination when non-verbal IQ and short-term memory skills are controlled. This is consistent with the developmental claim that difficulties in the basic auditory processing of rise time cause difficulties in setting up the phonological lexicon from infancy, leading to impairments in phonological awareness.

Attention effects on auditory scene analysis in children

Auditory scene analysis begins in infancy, making it possible for the baby to distinguish its mother's voice from other noises in the environment. Despite the importance of this process for human behavior, the question of how perceptual sound organization develops during childhood is not well understood. The current study investigated the role of attention for perceiving sound streams in a group of school-aged children and young adults. We behaviorally determined the frequency separation at which a set of sounds was detected as one integrated or two separated streams and compared these measures with passively and actively obtained electrophysiological indices (mismatch negativity (MMN) and P3b) of the same sounds. In adults, there was a high degree of concordance between passive and active electrophysiological indices of stream segregation that matched with perception. In contrast, there was a large disparity in children. Active electrophysiological indices of streaming were concordant with behavioral measures of perception, whereas passive indices were not. In addition, children required larger frequency separations to perceive two streams compared to adults. Our results suggest that differences in stream segregation between children and adults reflect an under-development of basic auditory processing mechanisms, and indicate a developmental role of attention for shaping physiological responses that optimize processes engaged during passive audition.

Gender-specific development of auditory information processing in children: An ERP study

Objectives The aim of the present study was to evaluate the effects of gender on sensory and cognitive information processing in children by analyzing auditory event-related potentials (ERPs). The major questions were: (1) do ERPs differ between girls and boys aged 7–10 years, (2) do gender differences in ERPs depend on the development with age, on task-processing demands, and on the development of neuroelectric networks as reflected by the spontaneous EEG? Methods Thirty-six healthy children (18 girls and 18 boys) were divided in two age groups (7- to 8- and 9- to 10-year-old). Boys and girls were pairwise matched for age. Auditory ERPs were analyzed in a passive listening condition (PLC), a simple reaction task (SRT) and a serial learning reaction task (SLRT), in which memory and sensorimotor processes were varied in a balanced way. Cognitive performance, reaction times (RTs), and the spontaneous electroencephalogram (EEG) were also measured. Results Cognitive performance improved earlier in girls than boys, whereas response speed was not affected by gender. Independent of processing demands, ERP components within 300 ms after stimulation (N1, P2, N2 and P3) increased with development only in the group of girls. For later components, the developmental speeding of the parietal P3b component to task-relevant stimuli also tended to be more expressed in girls than boys, whereas a late frontal negative wave N400–700 was shorter in the girls than boys from the two age groups. Likewise, independently of age, the spontaneous EEG manifested a larger theta activity in girls than boys. Conclusions Developmental changes of basic auditory processing mechanisms strongly depend on gender in children between 7 and 10 years by being faster in girls. This gender-specific development of early ERP components is not modulated by processing demands, cannot be attributed to a faster cognitive maturation of girls, nor can it be explained with the gender-specific maturation of background neuroelectric networks. Rather, it reflects an accelerated functional activation of auditory processing networks in girls. Interestingly, the cognitive development was also faster in girls, but it occurred earlier than the functional activation of auditory processing networks. Significance This study provides evidence for accelerated neuroelectric (as reflected by spontaneous EEG), neurofunctional (as reflected by auditory ERPs), and neurocognitive (as reflected by learning performance) development in 7- to 10-year-old girls than boys.

Increasing CREB in the auditory thalamus enhances memory and generalization of auditory conditioned fear

Although the lateral nucleus of the amygdala (LA) is essential for conditioned auditory fear memory, an emerging theme is that plasticity in multiple brain regions contributes to fear memory formation. The LA receives direct projections from the auditory thalamus, specifically the medial division of the medial geniculate nucleus (MGm) and adjacent posterior intralaminar nucleus (PIN). While traditionally viewed as a simple relay structure, mounting evidence implicates the thalamus in diverse cognitive processes. We investigated the role of plasticity in the MGm/PIN in auditory fear memory. First we found that auditory fear conditioning (but not control manipulations) increased the levels of activated CREB in both the MGm and PIN. Next, using viral vectors, we showed that exogenously increasing CREB in this region specifically enhanced formation of an auditory conditioned fear memory without affecting expression of an auditory fear memory, formation of a contextual fear memory, or basic auditory processing. Interestingly, mice with increased CREB levels in the MGm/PIN also showed broad auditory fear generalization (in contrast to control mice, they exhibited fear responses to tones of other frequencies). Together, these results implicate CREB-mediated plasticity in the MGm/PIN in both the formation and generalization of conditioned auditory fear memory. Not only do these findings refine our knowledge of the circuitry underlying fear memory but they also provide novel insights into the neural substrates that govern the degree to which acquired fear of a tone generalizes to other tones.

N1 and P2 components of auditory event-related potentials in children with and without reading disabilities

Objective The effects of within stimulus presentation rate and rise time on basic auditory processing were investigated in children with reading disabilities and typically reading children. Methods Children with reading disabilities (RD; N = 19) and control children ( N = 20) were studied using event-related potentials (ERPs). Paired stimuli were used with two different within-pair-intervals (WPI; 10 and 255 ms) and two different rise times (10 and 130 ms). Each stimulus was presented with equal probability and long between-pair inter-stimulus intervals (1–5 s). The study focused on N1 and P2 components. Results The P2 responses to the first tone in the pair showed differences between children with RD and control children. Also, children with RD had larger N1 response than control children to stimuli with short WPI and long rise time. Conclusions These results provide evidence for basic auditory processing abnormalities in children with RD. This processing difference could be related to extraction of stimulus features from sounds or to attentional mechanisms. Significance Our results show support for behavioral findings that children with RD and control children process rise times differently. More than half of children with RD showed atypical auditory processing.

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.

Basic Auditory Processing Skills and Specific Language Impairment: A New Look at an Old Hypothesis

To explore the sensitivity of children with specific language impairment (SLI) to amplitude-modulated and durational cues that are important for perceiving suprasegmental speech rhythm and stress patterns. Sixty-three children between 7 and 11 years of age were tested, 21 of whom had a diagnosis of SLI, 21 of whom were matched for chronological age to the SLI sample, and 21 of whom were matched for language age to the SLI sample. All children received a battery of nonspeech auditory processing tasks along with standardized measures of phonology and language. As many as 70%-80% of children diagnosed with SLI were found to perform below the 5th percentile of age-matched controls in auditory processing tasks measuring sensitivity to amplitude envelope rise time and sound duration. Furthermore, individual differences in sensitivity to these cues predicted unique variance in language and literacy attainment, even when age, nonverbal IQ, and task-related (attentional) factors were controlled. Many children with SLI have auditory processing difficulties, but for most children, these are not specific to brief, rapidly successive acoustic cues. Instead, sensitivity to durational and amplitude envelope cues appear to predict language and literacy outcomes more strongly. This finding now requires replication and exploration in languages other than English.

Cross‐cultural music phrase processing: An fMRI study

The current study used functional magnetic resonance imaging (fMRI) to investigate the neural basis of musical phrase boundary processing during the perception of music from native and non-native cultures. German musicians performed a cultural categorization task while listening to phrased Western (native) and Chinese (non-native) musical excerpts as well as modified versions of these, where the impression of phrasing has been reduced by removing the phrase boundary marking pause (henceforth called "unphrased"). Bilateral planum temporale was found to be associated with an increased difficulty of identifying phrase boundaries in unphrased Western melodies. A network involving frontal and parietal regions showed increased activation for the phrased condition with the orbital part of left inferior frontal gyrus presumably reflecting working memory aspects of the temporal integration between phrases, and the middle frontal gyrus and intraparietal sulcus probably reflecting attention processes. Areas more active in the culturally familiar, native (Western) condition included, in addition to the left planum temporale and right ventro-medial prefrontal cortex, mainly the bilateral motor regions. These latter results are interpreted in light of sensorimotor integration. Regions with increased signal for the unfamiliar, non-native music style (Chinese) included a right lateralized network of angular gyrus and the middle frontal gyrus, possibly reflecting higher demands on attention systems, and the right posterior insula suggesting higher loads on basic auditory processing.

Issues in human auditory development

The human auditory system is often portrayed as precocious in its development. In fact, many aspects of basic auditory processing appear to be adult-like by the middle of the first year of postnatal life. However, processes such as attention and sound source determination take much longer to develop. Immaturity of higher-level processes limits the processing of both simple and complex sounds by infants and children. Young listeners with impaired hearing may be at a particular disadvantage, in that they must make sense of sounds on the basis of a degraded representation using immature perceptual strategies. Learning outcomes: (1) Readers will be able to describe three stages of human auditory development. (2) Readers will be able to describe how experience with sound is important in auditory development. (3) Readers will be able to describe the role of attention and other higher-level processes in early audition.

Mismatch response is absent in 2-month-old infants at risk for dyslexia

This study examined auditory processing in 2-month-old infants at genetic risk for dyslexia and in controls. Manipulated natural speech stimuli (/bAk/ and /dAk/), at either side of the phoneme boundary, were presented to these infants and their automatic cortical deviance responses were recorded. Control infants showed two distinct mismatch responses, thus extending similar findings reported with kindergartners in terms of topographical distribution and cortical sources. The absence of such mismatch responses in the infants at risk supports the hypothesis of basic auditory (temporal) processing impairments in the disorder. The results suggest that these early signs of deficient auditory processing may point to problematic categorical perception at a later age.

Propofol attenuates responses of the auditory cortex to acoustic stimulation in a dose‐dependent manner: A FMRI study

Functional magnetic resonance imaging (fMRI) using blood-oxygen-level-dependent (BOLD) contrasts is a common method for studying sensory or cognitive brain functions. The aim of the present study was to assess the effect of the intravenous anaesthetic propofol on auditory-induced brain activation using BOLD contrast fMRI. In eight neurosurgical patients, musical stimuli were presented binaurally in a block design. Imaging was performed under five conditions: no propofol (or wakefulness) and propofol plasma target concentrations of 0.5, 1.0, 1.5, and 2.0 microg ml(-1). During wakefulness we found activations in the superior temporal gyrus (STG) corresponding to the primary and secondary auditory cortex as well as in regions of higher functions of auditory information processing. The BOLD response decreased with increasing concentrations of propofol but remained partially preserved in areas of basic auditory processing in the STG during propofol 2.0 microg ml(-1). Our results suggest a dose-dependent impairment of central processing of auditory information after propofol administration. These results are consistent with electrophysiological findings measuring neuronal activity directly, thus suggesting a dose-dependent impairment of central processing of auditory information after propofol administration. However, propofol did not totally blunt primary cortical responses to acoustic stimulation, indicating that patients may process auditory information under general anaesthesia.

Sensory Contributions to Impaired Prosodic Processing in Schizophrenia

Deficits in affect recognition are prominent features of schizophrenia. Within the auditory domain, patients show difficulty in interpreting vocal emotional cues based on intonation (prosody). The relationship of these symptoms to deficits in basic sensory processing has not been previously evaluated. Forty-three patients and 34 healthy comparison subjects were tested on two affective prosody measures: voice emotion identification and voice emotion discrimination. Basic auditory sensory processing was measured using a tone-matching paradigm and the Distorted Tunes Test (DTT). A subset of subjects was also tested on facial affect identification and discrimination tasks. Patients showed significantly impaired performance on all emotion processing tasks. Within the patient group, a principal components analysis demonstrated significant intercorrelations between basic pitch perception and affective prosodic performance. In contrast, facial affect recognition deficits represented a distinct second component. Prosodic affect measures correlated significantly with severity of negative symptoms and impaired global outcome. These results demonstrate significant relationships between basic auditory processing deficits and impaired receptive prosody in schizophrenia. The separate loading of auditory and visual affective recognition measures suggests that within-modality factors may be more significant than cross-modality factors in the etiology of affect recognition deficits in schizophrenia.

The mismatch negativity (MMN) response to complex tones and spoken words in individuals with aphasia

Background: The mismatch negativity (MMN) is a fronto-centrally distributed event-related potential (ERP) that is elicited by any discriminable auditory change. It is an ideal neurophysiological tool for measuring the auditory processing skills of individuals with aphasia because it can be elicited even in the absence of attention. Previous MMN studies have shown that acoustic processing of tone or pitch deviance is relatively preserved in aphasia, whereas the basic acoustic processing of speech stimuli can be impaired (e.g., auditory discrimination). However, no MMN study has yet investigated the higher levels of auditory processing, such as language-specific phonological and/or lexical processing, in individuals with aphasia.Aims: The aim of the current study was to investigate the MMN responses of normal and language-disordered subjects to tone stimuli and speech stimuli that incorporate the basic auditory processing (acoustic, acoustic-phonetic) levels of non-speech and speech sound processing, and also the language-specific phonological and lexical levels of spoken word processing. Furthermore, this study aimed to correlate the aphasic MMN data with language performance on a variety of tasks specifically targeted at the different levels of spoken word processing.Methods & Procedures: Six adults with aphasia (71.7 years ±3.0) and six healthy age-, gender-, and education-matched controls (72.2 years ±5.4) participated in the study. All subjects were right-handed and native speakers of English. Each subject was presented with complex harmonic tone stimuli, differing in pitch or duration, and consonant-vowel (CV) speech stimuli (non-word /de:/ versus real word /deI/). The probability of the deviant for each tone or speech contrast was 10%. The subjects were also presented with the same stimuli in behavioural discrimination tasks, and were administered a language assessment battery to measure their auditory comprehension skills.Outcomes & Results: The aphasic subjects demonstrated attenuated MMN responses to complex tone duration deviance and to speech stimuli (words and non-words), and their responses to the frequency, duration, and real word deviant stimuli were found to strongly correlate with performance on the auditory comprehension section of the Western Aphasia Battery (WAB). Furthermore, deficits in attentional lexical decision skills demonstrated by the aphasic subjects correlated with a word-related enhancement demonstrated during the automatic MMN paradigm, providing evidence to support the “word advantage effect”, thought to reflect the activation of language-specific memory traces in the brain for words.Conclusions: These results indicate that the MMN may be used as a technique for investigating general and more specific auditory comprehension skills of individuals with aphasia, using speech and/or non-speech stimuli, independent of the individual's attention. The combined use of the objective MMN technique and current clinical language assessments may result in improved rehabilitative management of aphasic individuals.

Assessment of auditory processing in 6-year-old language-impaired children: Evaluacion del procesamiento auditivo en niños de 6 años con trastornos del lenguaje

The performance of a group of twenty 6-year-old children with specific language impairment (SLI) on several behavioural auditory tests was compared to that of a group of twenty age-matched control children. The auditory test battery used in this study consisted of the following tests: a speech-in-noise test, a filtered speech test, a binaural fusion test, a frequency pattern test, a duration pattern test, a temporal integration test, an auditory word discrimination test, an auditory synthesis test, an auditory closure test and a number recall test. Our results show that the SLI children obtained scores on almost all tests that were significantly lower than those of the control group. Many of the basic auditory processing measures in our test battery correlated significantly with receptive and language scores, suggesting a (causal) relationship between auditory processing and language proficiency. Results from discriminant function analyses do not warrant deleting one or more tests from the test battery yet (with the exception of the auditory synthesis test and the temporal integration test, for which we did not find significant group effects). At present, we are conducting experiments with older (SLI and control) children and adults to find whether the significant performance deficits of the SLI children are also found in older SLI children, and to determine the influence of maturational effects on these auditory tests.SumarioSe comparó el rendimiento en varias pruebas conductuales auditivas de un grupo de veinte niños de 6 años de edad con deficiencies específicas del lenguaje (SLI), con el de un grupo control de veinte niños con edades similares. La batería de pruebas auditivas utilizada en este estudio consistió en: una prueba de lenguaje en ruido, una prueba de lenguaje filtrado, una prueba de fusión binaural, una prueba de patrones de frecuencia, una prueba de patroncs de duración, una prueba de integración temporal, una prueba de discriminatión auditiva del habla, una prueba de síntesis auditiva, una prueba de cierre auditivo y una prueba de memoria de números. Nuestros resultados muestran que los niños con SLI lograron, en casi todas las pruebas, puntuaciones significativamente más bajas que aquellas del grupo control. Muchas de las medidas básicas de procesamiento auditivo de nuestra batería de pruebas mostraron una correlación significaliva con las puntuaciones de recepción y del lenguaje, sugiriendo una relación causal entre el procesamiento auditivo y la competencia lingüística. Los resultados de los análisis de función discriminatoria no sugieren aún la eliminatión de una o más pruebas de la batería (con la excepción de la prueba de síntesis auditiva y la de integración temporal, para las cuáles no encontramos un cfecto significativo de grupo). Actualmente, estamos conduciendo experimentos con niños mayores (con SLI y en grupo control) y con adultos, para averiguar si las deficiencias significativas de rendimiento en los niños con SLI se encuentran también en niños mayores con SLI, y determinar así la influencia de un efecto de maduración en estas pruebas auditivas.