Auditory discrimination profiles of speech sound changes in 6-year-old children as determined with the multi-feature MMN paradigm

ObjectiveA linguistic multi-feature mismatch negativity (MMN) paradigm with five types of changes (vowel, vowel-duration, consonant, frequency (F0), and intensity) in Finnish syllables was used to determine speech-sound discrimination in 17 normally-developing 6-year-old children. The MMNs for vowel and vowel-duration were also recorded in an oddball condition in order to compare the two paradigms. Similar MMNs in the two paradigms would suggest that they tap the same processes. This would promote the usefulness of the more time-efficient multi-feature paradigm for future studies in children.MethodsMMNs to five deviant types were recorded in the multi-feature paradigm in which these deviants (total of 50%) were presented in an alternating fashion with standards (50%). An oddball condition with vowel and vowel-duration deviants served as a control.ResultsThe linguistic multi-feature paradigm elicited significant MMN responses to all changes used and the responses were comparable to the ones recorded with the traditional oddball paradigm. Compared to a previous adult study (Pakarinen S, Lovio R, Huotilainen M, Alku P, Näätänen R, Kujala T. Fast multi-feature paradigm for recording several mismatch negativities (MMNs) to phonetic and acoustic changes in speech sounds. Biol Psychol, submitted for publication), the MMN amplitudes seemed to be smaller and of longer latencies in general in children than in adults.ConclusionsThe new time-efficient paradigm can be used in studies addressing cortical speech-sound discrimination in young children.SignificanceThe multi-feature paradigm enables fast (20 min) recording of MMNs for five speech-sound features. In future, it might be useful in detecting abnormalities in speech discrimination profiles of children with possible language-related disorders.     

Infants’ brain responses for speech sound changes in fast multifeature MMN paradigm

ObjectiveWe investigated whether newborn speech-sound discrimination can be studied in 40 min using fast multifeature mismatch negativity (MMN) paradigm and do the results differ from those obtained with the traditional oddball paradigm.MethodsNewborns’ MMN responses to five types of changes (consonant identity, F0, intensity, vowel duration and vowel identity) were recorded in the multifeature group (N = 15) and vowel duration and vowel identity changes in the oddball group (N = 13), after which the MMNs from both groups were compared with each others.ResultsStatistically significant MMNs in the 190–600 ms time range from the stimulus onset were found for most change types in both paradigms. Newborn MMN responses were predominantly positive but a small number of participants elicited negative MMNs instead. MMN amplitudes did not differ between the multifeature and oddball groups.ConclusionsNewborn speech-sound discrimination can be assessed in a short recording time using the fast multifeature paradigm.SignificanceThe paradigm presented here can be used to record extensive auditory discrimination profiles in newborns and assess development of speech-sound discrimination and its difficulties.     

Children’s brain responses to sound changes in pseudo words in a multifeature paradigm

ObjectiveThe multifeature mismatch negativity (MMN) paradigm has previously been used to study MMN responses to changes in tones or isolated syllables. We tested 4–12 year old children’s MMNs to changes in a naturally produced pseudo word context.MethodsWe studied preschoolers’ (under the age of 7 years, N = 15, mean age 5 years 4 months) and school childrens’ (over the age of 7 years, N = 15, mean age 9 years 3 months) MMNs to five types of changes (vowel duration, fundamental frequency, gap, intensity, vowel identity) in the middle syllable of a pseudo word [tɑtɑtɑ] using a multifeature paradigm.ResultsVowel duration and gap changes elicited larger frontocentral MMN responses than other change types and the vowel identity change also produced an early positive p-MMR. The presence of the MMN was also determined at the individual level, and it was found that vowel duration and gap deviants produced MMNs in most of the participants.ConclusionsThe current study shows that children’s neural speech sound discrimination can be assessed in a word context in a short recording time (30 min) by using the multifeature paradigm.SignificanceA paradigm which can be used to investigate the discrimination of several change types of speech-sounds in a natural context can be useful for investigating speech development and deficits.     

Cortical speech and non‐speech discrimination in relation to cognitive measures in preschool children

Effective speech sound discrimination at preschool age is known to be a prerequisite for the development of language skills and later literacy acquisition. However, the speech specificity of cortical discrimination skills in small children is currently not known, as previous research has either studied speech functions without comparison with non‐speech sounds, or used much simpler sounds such as harmonic or sinusoidal tones as control stimuli. We investigated the cortical discrimination of five syllable features (consonant, vowel, vowel duration, fundamental frequency, and intensity), covering both segmental and prosodic phonetic changes, and their acoustically matched non‐speech counterparts in 63 6‐year‐old typically developed children, by using a multi‐feature mismatch negativity (MMN) paradigm. Each of the five investigated features elicited a unique pattern of differentiating negativities: an early differentiating negativity, MMN, and a late differentiating negativity. All five studied features showed speech‐related enhancement of at least one of these responses, suggesting experience‐related neural commitment in both phonetic and prosodic speech processing. In addition, the cognitive performance and language skills of the children were tested extensively. The speech‐related neural enhancement was positively associated with the level of performance in several neurocognitive tasks, indicating a relationship between successful establishment of cortical memory traces for speech and enhanced cognitive functioning. The results contribute to the understanding of typical developmental trajectories of linguistic vs. non‐linguistic auditory skills, and provide a reference for future studies investigating deficits in language‐related disorders at preschool age.     

Measurement of extensive auditory discrimination profiles using the mismatch negativity (MMN) of the auditory event-related potential (ERP)

ObjectiveMismatch negativity (MMN), a change-specific component of the auditory event-related potential (ERP), is sensitive to deficits in central auditory processing associated with many clinical conditions. The aim of this study was to obtain a comprehensive multi-dimensional profile of central auditory processing by extending the recently developed fast multi-feature MMN paradigm [Näätänen R, Pakarinen S, Rinne T, Takegata R. The mismatch negativity (MMN): towards the optimal paradigm. Clin Neurophysiol 2004;115:140–144].MethodsMMN responses to changes in sound duration, frequency, intensity, and perceived sound-source location at six different magnitudes of deviation were recorded from healthy young adults by using the multi-feature MMN paradigm. In addition, behavioural discrimination accuracy and speed were measured to examine the relationship between MMN and behavioural performance.ResultsAll the 24 sound changes elicited significant MMNs. MMN amplitude increased and latency decreased with increasing magnitude of sound change. Furthermore, the MMN amplitude and latency predicted the subjects’ accuracy and speed in detecting these deviations.ConclusionsThis new paradigm provides an extensive auditory discrimination profile for several auditory attributes at different deviation magnitudes in a minimal recording time.SignificanceThe auditory discrimination profiles can offer a comprehensive view of the development, plasticity, and deficits of central auditory processing.     

The right profile: mismatch negativity in schizophrenia with and without auditory hallucinations as measured by a multi-feature paradigm.

ObjectiveTo examine pre-attentive acoustic change detection in schizophrenia patients with and without auditory hallucinations via mismatch negativity (MMN) extracted from a multi-feature paradigm.MethodsThis study examined the electroencephalograph (EEG)-derived MMN, recorded across 32 sites, in 12 hallucinating patients (HPs) with schizophrenia, 12 non-hallucinating patients (NPs) with schizophrenia and 12 healthy controls (HCs). MMN was recorded in response to a multi-feature MMN paradigm [Näätänen, R., et al., 2004. The mismatch negativity (MMN): towards the optimal paradigm. Clin. Neurophys. 115, 140–144] which employs frequency, duration, intensity, location and gap deviants. Differences in source localization were probed using standardized low resolution brain electromagnetic tomography (sLORETA).ResultsHPs showed significantly smaller MMNs to duration deviants compared to HCs and NPs, as well as smaller MMNs to intensity deviants compared to HCs. Regionalized differences between HCs and each of the patient groups were observed in response to frequency deviants. There were no significant group effects for location or gap deviants, or for MMN latency. Source localization using sLORETA showed no significant differences in MMN generator location across groups for any of the deviant stimuli.ConclusionsThe often-reported robust MMN deficit to duration deviants may be specific to schizophrenia patients afflicted with auditory hallucinations. Furthermore, by using symptom-specific groups, novel deficits of pre-attentive auditory processing, such as that observed to intensity deviants in HPs, may be revealed.SignificanceThe differential responding observed between both groups of patients with schizophrenia has implications for automatic processing within the auditory cortex of hallucinating patients and suggests that care must be taken when recruiting participants in studies involving schizophrenia to ensure consistent, replicable results.     

The mismatch negativity (MMN) with no standard stimulus

ObjectiveThe recent fast multi-feature mismatch negativity (MMN) paradigms rest on the assumption that the deviant stimuli, alternating with the standard tone, strengthen the memory trace of the standard in respect to those attributes they have in common. In the present study, we tested whether the MMN can be recorded even without the standard stimulus, with the invariant properties of the deviant stimuli serving as a standard against which to detect the sound changes.MethodsMMN was recorded for changes in sound duration, frequency, intensity, location, gap, brightness, density, and noise level in a new multi-feature paradigm where no standard stimuli were used. In addition, these MMNs were compared with those recorded in the conventional multi-feature paradigm.ResultsAll sound changes elicited significant MMN responses that were highly similar between paradigms.ConclusionsThe MMN can be recorded even without the standard stimulus, as an accurate memory trace is constructed for the invariant features of the auditory input.SignificanceOmitting the standard stimuli results in almost 50% shorter recording time and the larger selection of deviant types with the newly introduced brightness, density, and noise-level changes provides even more information on the individual perceptual profiles than conventional multi-feature paradigms.     

The neurophysiological basis of the integration of written and heard syllables in dyslexic adults

ObjectiveLetter-speech sound integration in fluent readers takes place automatically and is dependent on temporal synchrony between letters and sounds. In developmental dyslexia, however, letter-speech sound associations are hard to learn, compromising accurate and fluent reading. We studied the effect of printed text on processing speech sounds in dyslexic and fluent adult readers.MethodsVisual stimuli were presented with sequences of spoken syllables including vowel or consonant changes, or changes in syllable intensity, frequency, or vowel duration. As visual material, written syllables or their scrambled images were used. The auditory stimuli were presented either synchronously with the visual stimuli or time delayed. The mismatch negativity (MMN), an index of automatic neural change detection, was recorded.ResultsMMN amplitudes were larger to syllable changes in combination with written syllables than with scrambled images in fluent readers. However, dyslexic readers showed no difference between syllables vs. scrambled image condition. Furthermore, MMNs to consonant and frequency changes peaked later in dyslexic than fluent readers.ConclusionsOur results suggest deficient and sluggish audiovisual integration in dyslexic individuals, which is not dependent on the phonological relevance of the deviant type.SignificanceUnlike previous studies, our study included several different types of syllable changes presented with concurrent print, enabling us to determine in more detail the nature of the audiovisual deficit in dyslexia.     

Early integration of vowel and pitch processing: A mismatch negativity study

ObjectiveSeveral studies have explored the processing specificity of music and speech, but only a few have addressed the processing autonomy of their fundamental components: pitch and phonemes. Here, we examined the additivity of the mismatch negativity (MMN) indexing the early interactions between vowels and pitch when sung.MethodsEvent-related potentials (ERPs) were recorded while participants heard frequent sung vowels and rare stimuli deviating in pitch only, in vowel only, or in both pitch and vowel. The task was to watch a silent movie while ignoring the sounds.ResultsAll three types of deviants elicited both an MMN and a P3a ERP component. The observed MMNs were of similar amplitude for the three types of deviants and the P3a was larger for double deviants. The MMNs to deviance in vowel and deviance in pitch were not additive.ConclusionsThe underadditivity of the MMN responses suggests that vowel and pitch differences are processed by interacting neural networks.SignificanceThe results indicate that vowel and pitch are processed as integrated units, even at a pre-attentive level. Music-processing specificity thus rests on more complex dimensions of music and speech.     

Deficit in the preattentive processing of syllabic duration and VOT in children with dyslexia

The aim of this experiment was to examine the preattentive processing of syllables in 9-11-year-old children with dyslexia and matched controls using the Mismatch Negativity (MMN), an auditory Event-Related brain potential (ERP) related to preattentive discrimination. Children were presented with a sequence of syllables that included standards (the syllable "Ba") and deviants in vowel frequency, vowel duration and Voice Onset Time (VOT) that were either close to or far from the standard (Small and Large deviants). No between-group differences were found for frequency deviants. However, whilst normal-reading children showed larger MMNs to Large than to Small deviants in vowel duration and VOT, no such deviance size effect was found in children with dyslexia. These results are taken to indicate that the preattentive processing of vowel duration and VOT is impaired in children with dyslexia, with no impairment in the processing of vowel frequency deviants. By revealing processing deficits of both duration and VOT deviants, these results suggest a strong link between acoustical and phonological processing.     

Neural evidence of allophonic perception in children at risk for dyslexia

Learning to read is a complex process that develops normally in the majority of children and requires the mapping of graphemes to their corresponding phonemes. Problems with the mapping process nevertheless occur in about 5% of the population and are typically attributed to poor phonological representations, which are – in turn – attributed to underlying speech processing difficulties. We examined auditory discrimination of speech sounds in 6-year-old beginning readers with a familial risk of dyslexia (n=31) and no such risk (n=30) using the mismatch negativity (MMN). MMNs were recorded for stimuli belonging to either the same phoneme category (acoustic variants of /b?/) or different phoneme categories (/b?/ vs. /d?/). Stimuli from different phoneme categories elicited MMNs in both the control and at-risk children, but the MMN amplitude was clearly lower in the at-risk children. In contrast, the stimuli from the same phoneme category elicited an MMN in only the children at risk for dyslexia. These results show children at risk for dyslexia to be sensitive to acoustic properties that are irrelevant in their language. Our findings thus suggest a possible cause of dyslexia in that they show 6-year-old beginning readers with at least one parent diagnosed with dyslexia to have a neural sensitivity to speech contrasts that are irrelevant in the ambient language. This sensitivity clearly hampers the development of stable phonological representations and thus leads to significant reading impairment later in life.     

A comparison of the mismatch negativity (MMN) event-related potential to tone and speech stimuli in normal and aphasic adults

Abstract

We evaluated the mismatch negativity (MMN) event-related potential (ERP) in normal and aphasic adults to tone and speech stimuli to determine aphasic patients' auditory discrimination and the relationship between MMN measures and severity of aphasia. MMNs were present in 89% of normal subjects and 79% of aphasic subjects to tone stimuli. MMNs were present in 100% of normal subjects and 54% of aphasic subjects to speech stimuli. The duration of the MMN ERP to speech stimuli was significantly related to severity of aphasia on the Western Aphasia Battery, Porch Index of Communicative Ability, and the Token Test. Thus, not all aphasic people show an early, preconscious orientation response to tone and speech stimuli. However, the duration of this response, when present, to speech stimuli appears to be related to the severity of aphasia.     

Mismatch negativity to different deviant changes in autism spectrum disorders: A meta-analysis

ObjectiveMismatch negativity (MMN) has been continuously used to evaluate the functional integrity of central auditory processing. However, it still remains inconclusive whether patients with autism spectrum disorder (ASD) demonstrate reduced MMN responses in all deviant types.MethodsTo reconcile the previous controversial findings, we performed a meta-analysis of peer-reviewed MMN articles concerning ASD. The potential moderators regarding different deviant types, diagnosis, and age on the effect sizes (Hedges’ g) were also assessed.ResultsCompared to the controls, ASD patients showed reduced MMN amplitudes (g = −0.37, p = 0.001) and prolonged latencies (g = −0.33, p = 0.041) in response to speech-sound deviants. Children/adolescents with ASD manifested reduced MMN amplitudes in response to tone-duration deviants (g = −0.46, p = 0.014). Furthermore, the results showed significantly shortened MMN latencies to tone-frequency deviants in patients with autism (g = 0.29, p = 0.038) and, in contrast, prolonged MMN latencies (g = −0.74, p = 0.001) in patients with Asperger syndrome.ConclusionMMN deficits are robust in ASD patients, suggesting an altered central ability in auditory discrimination.SignificanceMMN alterations were displayed in different profiles with respect to frequency, duration and phoneme changes.     

Processing of Affective Speech Prosody is Impaired in Asperger Syndrome

Many people with the diagnosis of Asperger syndrome (AS) show poorly developed skills in understanding emotional messages. The present study addressed discrimination of speech prosody in children with AS at neurophysiological level. Detection of affective prosody was investigated in one-word utterances as indexed by the N1 and the mismatch negativity (MMN) of auditory event-related potentials (ERPs). Data from fourteen boys with AS were compared with those for thirteen typically developed boys. These results suggest atypical neural responses to affective prosody in children with AS and their fathers, especially over the RH, and that this impairment can already be seen at low-level information processes. Our results provide evidence for familial patterns of abnormal auditory brain reactions to prosodic features of speech.     

Neurophysiological evidence of impaired musical sound perception in cochlear-implant users

Objective

Music perception with a cochlear implant (CI) can be unsatisfactory because current-day implants are primarily designed to enable speech discrimination. The present study aimed at evaluating electrophysiological correlates of musical sound perception in CI users to help achieve the long-term goal of improved restoration of hearing in those individuals.

Methods

Auditory discrimination accuracy in adult CI users (n = 12) and matched normal-hearing controls (n = 12) was measured by behavioral discrimination tasks and mismatch negativity (MMN) recordings. Discrimination profiles were obtained by using a set of clarinet sounds (original/vocoded) varying along different acoustic dimensions (frequency/intensity/duration) and deviation magnitudes (four levels).

Results

Behavioral results and MMN recordings revealed reduced auditory discrimination accuracy in CI users. An inverse relationship was found between MMN amplitudes and duration of profound deafness.

Conclusions

CI users have difficulties in discriminating small changes in the acoustic properties of musical sounds. The recently developed multi-feature MMN paradigm (Pakarinen et al., 2007) can be used to objectively evaluate discrimination abilities of CI users for musical sounds.

Significance

Measuring auditory discrimination functions by means of a multi-feature MMN paradigm could be of substantial clinical value by providing a comprehensive profile of the extent of restored hearing in CI users.     

Event-related potential indices of auditory vowel processing in 3-year-old children

Objective: To determine the ERP characteristics and ERP indices of central speech sound encoding and discrimination in young children.Methods: Auditory sensory event-related potentials (ERPs) and the ERP index of auditory sensory discrimination (the mismatch negativity, MMN) were elicited by vowel stimuli in 3-year-old children. In an oddball paradigm, the standard stimulus was vowel /a/, one deviant stimulus was vowel /o/ (the across-category change), and the other was nasalized vowel /a/ (within-category change). In addition, the ERP changes occurring during the 14 min uninterrupted recording were examined.Results: As indexed by the sensory P1, N2, and N4 peaks, the 3-year-old children's transient neural encoding of vowels was comparable to that earlier registered in 1-year-old children but also showed vowel-specific characteristics observed in school-age children. The 3-year-old's MMN was comparable in amplitude to the school-age children's MMN and appeared to be sensitive to the across-category aspects of vowel changes. However, its latency was longer in the 3-year-olds than in school-age children. Among the sensory ERPs, only the N4 peak showed significant diminution during the experiment. The across-category change MMN diminished after 10 min of the recording, however, over the frontal areas only.Conclusions: In the 3-year-old children, the sensory processing of vowels exhibited transitional characteristics between those observed in infants and school-age children. The auditory sensory discrimination in the 3-year-olds appeared to be sensitive to the phonemic aspects of stimulus change. The frontally-predominant MMN diminution during the experiment might indicate the greater refractoriness of its frontal-lobe generators. In general, the auditory sensory ERPs show distinct maturational profiles from that of the MMN.     

Deficit of long-term memory traces for words in children with cochlear implants

ObjectiveLanguage experience can develop long-term memory traces for speech units in the brain, to ensure efficient processing of speech sounds. However, prelingually deafened children lack sufficient auditory input before cochlear implantation. Whether the experience-dependent long-term memory traces exist in prelingually deafened children with cochlear implants (CIs) remains unclear.MethodsWe presented CI and normal hearing (NH) children with Mandarin Chinese spoken disyllables in an oddball paradigm and recorded event-related potentials. Each disyllable was defined as a meaningful word or a meaningless pseudoword by the tonal information in the second syllable.ResultsThe amplitude of mismatch negativity (MMN) elicited by words was larger than that elicited by pseudowords in NH children. However, this enhancement of the MMN amplitude was not found in CI children. Behavioral results showed later recognition points for words and lower accuracies for speech comprehension in CI children than in NH children. Furthermore, increased theta power for words compared with pseudowords was only found in NH children.ConclusionsOur findings indicate a deficit of long-term memory traces for words in prelingually deafened children with cochlear implants.SignificanceEarly speech input may be crucial to the formation of long-term memory traces for speech units.     

An extensive pattern of atypical neural speech-sound discrimination in newborns at risk of dyslexia

ObjectiveIdentifying early signs of developmental dyslexia, associated with deficient speech-sound processing, is paramount to establish early interventions. We aimed to find early speech-sound processing deficiencies in dyslexia, expecting diminished and atypically lateralized event-related potentials (ERP) and mismatch responses (MMR) in newborns at dyslexia risk.MethodsERPs were recorded to a pseudoword and its variants (vowel-duration, vowel-identity, and syllable-frequency changes) from 88 newborns at high or no familial risk. The response significance was tested, and group, laterality, and frontality effects were assessed with repeated-measures ANOVA.ResultsAn early positive and right-lateralized ERP component was elicited by standard pseudowords in both groups, the response amplitude not differing between groups. Early negative MMRs were absent in the at-risk group, and MMRs to duration changes diminished compared to controls. MMRs to vowel changes had significant laterality × group interactions resulting from right-lateralized MMRs in controls.ConclusionsThe MMRs of high-risk infants were absent or diminished, and morphologically atypical, suggesting atypical neural speech-sound discrimination.SignificanceThis atypical neural basis for speech discrimination may contribute to impaired language development, potentially leading to future reading problems.     

Alterations of mismatch negativity (MMN) in schizophrenia patients with auditory hallucinations experiencing acute exacerbation of illness

Auditory verbal hallucinations (AHs), or hearing 'voices', are one of the hallmark symptoms of patients with schizophrenia. The primary objective of this study was to compare hallucinating schizophrenia patients with respect to differences in deviance detection, as indexed by the auditory mismatch negativity (MMN). Patients were recruited during an acute psychotic episode requiring hospitalization, during which time symptoms of psychosis, including auditory hallucinations, are likely to be at their most severe. MMNs to duration, frequency, gap, intensity and location deviants (as elicited by the 'optimal' multi-feature paradigm) were recorded in 12 acutely ill schizophrenia patients (SZ) with persistent AHs and 15 matched healthy controls (HC). Electrical activity was recorded from 32 scalp electrodes. MMN amplitudes and latencies for each deviant were compared between groups and were correlated with trait (PSYRATS) and state measures of AH severity and Positive and Negative Syndrome Scale (PANSS) ratings in SZs. There were significant group differences for duration, gap, intensity and location MMN amplitudes, such that SZs exhibited reduced MMNs compared to HCs. Additionally, gap MMN amplitudes were correlated with measures of hallucinatory state and frequency of AHs, while location MMN was correlated with perceived location of AHs. In summary, this study corroborates previous research reporting a robust duration MMN deficit in schizophrenia, as well as reporting gap, intensity and location MMN deficits in acutely ill schizophrenia patients with persistent AHs. Additionally, MMN amplitudes were correlated with state and trait measures of AHs. These findings offer further support to previous work suggesting that the presence of auditory hallucinations may make a significant contribution to the widely reported MMN deficits in schizophrenia.     

Neural evidence of the allophonic mode of speech perception in adults with dyslexia

ObjectiveA growing body of evidence suggests that individuals with dyslexia perceive speech using allophonic rather than phonemic units and are thus sensitive to phonetic variations that are actually irrelevant in the ambient language. This study investigated speech perception difficulties in adults with dyslexia using behavioural and neural measurements with stimuli along a place-of-articulation continuum with well-defined allophonic boundaries. Adults without dyslexia served as control participants.MethodsCategorical perception of a /b? - d?/ place-of-articulation continuum was evaluated using both identification and discrimination tasks. In addition to these behavioural measures, mismatch negativity (MMN) was recorded for stimuli that came from either similar or different phoneme categories.ResultsThe adults with dyslexia exhibited less consistent labelling than controls, but no heightened sensitivity to allophonic contrasts was observed at the behavioural level. Neural measurements revealed that stimuli from different phoneme categories elicited MMNs in both the adults with dyslexia and controls, whereas stimuli from the same category elicited an MMN in the adults with dyslexia only.ConclusionThe finding that adults with dyslexia have heightened sensitivity to allophonic contrasts in the form of neural activation supports the allophonic explanation of dyslexia.SignificanceSensitivity to allophonic contrasts may be a valuable marker for dyslexia.