Claudia Männel

Pauses and intonational phrasing: Erp studies in 5-month-old german infants and adults

In language learning, infants are faced with the challenge of decomposing continuous speech into relevant units, such as syntactic clauses and words. Within the framework of prosodic bootstrapping, behavioral studies suggest infants approach this segmentation problem by relying on prosodic information, especially on acoustically marked intonational phrase boundaries (IPBs). In the current ERP study, we investigate processing of IPBs in 5-month-old infants by varying the acoustic cues signaling the IPB. In an experiment in which pitch variation, vowel lengthening, and pause cues are present (Experiment 1), 5-month-old German infants show an ERP obligatory response. This obligatory response signals lower level perceptual processing of acoustic cues that, however, disappear when no pause cue is present (Experiment 2). This suggests that infants are sensitive to sentence internal pause, a cue that is relevant for the processing of IPBs. Given that German adults show both the obligatory components and the closure positive shift, a particular ERP component known to reflect the perception of IPBs, independent of the presence of a pause cue, the results of the current ERP study indicate clear developmental differences in intonational phrase processing. The comparison of our neurophysiological data from German-learning infants with behavioral data from English-learning infants furthermore suggests cross-linguistic differences in intonational phrase processing during infancy. These findings are discussed in the light of differences between the German and the English intonation systems.

Auditory perception at the root of language learning

Learning a spoken language presupposes efficient auditory functions. In the present event-related potential study, we tested whether and how basic auditory processes are related to online learning of a linguistic rule in infants and adults. Participants listened to frequent standard stimuli, which were interspersed with infrequent pitch deviants and rule deviants, violating a nonadjacent dependency between two syllables. Only infants who showed the more mature mismatch response for the pitch deviants (i.e., a negativity) showed a mismatch response to the rule deviants. Concordantly, the small group of adults who showed evidence of rule learning showed larger mismatch effects for pitch processing. We conclude that the ability to extract linguistic rules develops in early infancy and is tightly linked to functional aspects of basic auditory mechanisms.

Intonational phrase structure processing at different stages of syntax acquisition: ERP studies in 2‐, 3‐, and 6‐year‐old children

This study explored the electrophysiology underlying intonational phrase processing at different stages of syntax acquisition. Developmental studies suggest that childrens syntactic skills advance significantly between 2 and 3 years of age. Here, children of three age groups were tested on phrase-level prosodic processing before and after this developmental phase, while their brain activity was recorded. The Closure Positive Shift (CPS), which indexes the perception of intonational phrasing in adults, served as dependent variable. The event-related brain potentials of 3- and 6-year-olds, but not of 21-month-olds, showed a CPS. These results suggest that prosodic phrase processing, as indicated by the CPS, is established only later during childrens development, pointing to a close interaction of prosody and syntax acquisition.

The role of pause as a prosodic boundary marker: Language ERP studies in German 3- and 6-year-olds

Spoken language is hierarchically structured into prosodic units divided by prosodic breaks. The largest prosodic breaks in an utterance are intonational phrase boundaries (IPBs), which are defined by three acoustic cues, namely, pitch change, preboundary lengthening, and pausing. Previous studies have revealed that the electrophysiological marker of IPB perception, the Closure Positive Shift (CPS), is established between 2 and 3 years of age. Here, we examined the neural activity underlying IPB perception in children by targeting their reliance on pausing; hypothesized to be a key boundary cue in German. To evaluate the role of pausing, we tested IPB perception without the boundary pause, but with pitch change and preboundary lengthening. We tested children at the age of 3 years, when the CPS in response to IPBs has just emerged, and at 6 years, when language abilities are further developed. Results revealed that 6-year-olds, but not 3-year-olds, show the CPS in response to IPBs without full prosodic marking. These results indicate developmental differences with respect to the role of pausing as a prosodic boundary cue in German. The correlation of childrens IPB perception and their syntactic abilities further corroborates the close prosody-syntax interaction in childrens advancing ability to process phrase structure.

Evolutionary origins of non-adjacent sequence processing in primate brain potentials

There is considerable interest in understanding the ontogeny and phylogeny of the human language system, yet, neurobiological work at the interface of both fields is absent. Syntactic processes in language build on sensory processing and sequencing capabilities on the side of the receiver. While we better understand language-related ontogenetic changes in the human brain, it remains a mystery how neurobiological processes at specific human development stages compare with those in phylogenetically closely related species. To address this knowledge gap, we measured EEG event-related potentials (ERPs) in two macaque monkeys using a paradigm developed to evaluate human infant and adult brain potentials associated with the processing of non-adjacent ordering relationships in sequences of syllable triplets. Frequent standard triplet sequences were interspersed with infrequent voice pitch or non-adjacent rule deviants. Monkey ERPs show early pitch and rule deviant mismatch responses that are strikingly similar to those previously reported in human infants. This stands in contrast to adults’ later ERP responses for rule deviants. The results reveal how non-adjacent sequence ordering relationships are processed in the primate brain and provide evidence for evolutionarily conserved neurophysiological effects, some of which are remarkably like those seen at an early human developmental stage.

Characterizing the morphosyntactic processing deficit and its relationship to phonology in developmental dyslexia

This study explores the morphosyntactic processing deficit in developmental dyslexia, addressing the on-going debate on the linguistic nature of the disorder, and directly testing the hypothesis that the deficit is based on underlying processing difficulties, such as acoustic and/or phonological impairments. Short German sentences consisting of a pronoun and a verb, either correct or containing a morphosyntactic violation, were auditorily presented to 17 German-speaking adults with dyslexia, and 17 matched control participants, while an EEG was recorded. In order to investigate the interaction between low-level phonological processing and morphosyntactic processing, the verbal inflections were manipulated to consist of different levels of acoustic salience. The event-related potential (ERP) results confirm altered morphosyntactic processing in participants with dyslexia, especially when morphosyntactic violations are expressed by both lexical and inflectional changes. Moreover, ERP data on phoneme discrimination and behavioural data on phonemic awareness and verbal short-term memory reveal phonological deficits in dyslexic participants. However, a causal relationship between phonological and morphosyntactic processing was not conclusive, because anomalous morphosyntactic processing in dyslexia is not directly mediated by acoustic salience, rather it correlates with high-level phonological skills and is mediated by lexical cues.

Present and past: Can writing abilities in school children be associated with their auditory discrimination capacities in infancy?

Literacy acquisition is highly associated with auditory processing abilities, such as auditory discrimination. The event-related potential Mismatch Response (MMR) is an indicator for cortical auditory discrimination abilities and it has been found to be reduced in individuals with reading and writing impairments and also in infants at risk for these impairments. The goal of the present study was to analyze the relationship between auditory speech discrimination in infancy and writing abilities at school age within subjects, and to determine when auditory speech discrimination differences, relevant for later writing abilities, start to develop. We analyzed the MMR registered in response to natural syllables in German children with and without writing problems at two points during development, that is, at school age and at infancy, namely at age 1 month and 5 months. We observed MMR related auditory discrimination differences between infants with and without later writing problems, starting to develop at age 5 months-an age when infants begin to establish language-specific phoneme representations. At school age, these children with and without writing problems also showed auditory discrimination differences, reflected in the MMR, confirming a relationship between writing and auditory speech processing skills. Thus, writing problems at school age are, at least, partly grounded in auditory discrimination problems developing already during the first months of life.

Facial speech gestures: The relation between visual speech processing, phonological awareness, and developmental dyslexia in 10-year-olds

Successful communication in everyday life crucially involves the processing of auditory and visual components of speech. Viewing our interlocutor and processing visual components of speech facilitates speech processing by triggering auditory processing. Auditory phoneme processing, analyzed by event-related brain potentials (ERP), has been shown to be associated with impairments in reading and spelling (i.e. developmental dyslexia), but visual aspects of phoneme processing have not been investigated in individuals with such deficits. The present study analyzed the passive visual Mismatch Response (vMMR) in school children with and without developmental dyslexia in response to video-recorded mouth movements pronouncing syllables silently. Our results reveal that both groups of children showed processing of visual speech stimuli, but with different scalp distribution. Children without developmental dyslexia showed a vMMR with typical posterior distribution. In contrast, children with developmental dyslexia showed a vMMR with anterior distribution, which was even more pronounced in children with severe phonological deficits and very low spelling abilities. As anterior scalp distributions are typically reported for auditory speech processing, the anterior vMMR of children with developmental dyslexia might suggest an attempt to anticipate potentially upcoming auditory speech information in order to support phonological processing, which has been shown to be deficient in children with developmental dyslexia.

Phonological abilities in literacy-impaired children: Brain potentials reveal deficient phoneme discrimination, but intact prosodic processing

Intact phonological processing is crucial for successful literacy acquisition. While individuals with difficulties in reading and spelling (i.e., developmental dyslexia) are known to experience deficient phoneme discrimination (i.e., segmental phonology), findings concerning their prosodic processing (i.e., suprasegmental phonology) are controversial. Because there are no behavior-independent studies on the underlying neural correlates of prosodic processing in dyslexia, these controversial findings might be explained by different task demands. To provide an objective behavior-independent picture of segmental and suprasegmental phonological processing in impaired literacy acquisition, we investigated event-related brain potentials during passive listening in typically and poor-spelling German school children. For segmental phonology, we analyzed the Mismatch Negativity (MMN) during vowel length discrimination, capturing automatic auditory deviancy detection in repetitive contexts. For suprasegmental phonology, we analyzed the Closure Positive Shift (CPS) that automatically occurs in response to prosodic boundaries. Our results revealed spelling group differences for the MMN, but not for the CPS, indicating deficient segmental, but intact suprasegmental phonological processing in poor spellers. The present findings point towards a differential role of segmental and suprasegmental phonology in literacy disorders and call for interventions that invigorate impaired literacy by utilizing intact prosody in addition to training deficient phonemic awareness.

Neural correlates of prosodic boundary perception in German preschoolers: If pause is present, pitch can go

Children׳s perception of prosodic phrasing provides a head start into the discovery of speech structure. Based on the close prosody-syntax correspondence, children can infer the underlying syntactic structure from the acoustic modulations of prosodic boundaries, typically consisting of co-occurring pitch changes, preboundary lengthening, and pausing. Previous electrophysiological studies revealed that listeners are to some degree flexible in the detection of major prosodic boundaries that are not marked with all three of the suprasegmental cues. Adults and 6-year-olds still showed the brain response for prosodic boundary perception, the Closure Positive Shift (CPS), when pauses marking boundaries were deleted. In contrast, younger children at 3 years did not show this ability yet, but required pausing to complement the other boundary cues. Following the hypothesis that German weights duration cues more heavily than pitch cues, we here examined 3-year-olds׳ brain responses to prosodic phrasing, testing the role of boundary-related pitch changes. Results revealed that children at this age even showed the CPS in response to pitch-neutralized boundaries with only pausing and preboundary lengthening being present. These results indicate differential roles of acoustic cues in boundary perception, with a preferential reliance on duration cues over pitch changes in 3-year-olds. This preference likely results from the characteristics of the German intonation system and furthers the discussion of cross-linguistic differences in the weighting of prosodic boundary cues.