Biomedical subjects

Christiane Weber

Publications and source records attributed to Christiane Weber.

4 recordsLinked to original sources

PubMed2006

Prosodic processing at the sentence level in infants.

We investigate whether 8-month-old infants can detect prosodic cues relevant in sentence structuring. We recorded event-related potentials to examine online responses to the processing of prosodic boundaries. Prior studies in adults have validated the closure positive shift as reflecting prosodic boundary perception during speech processing. The current study shows that in the event-related potentials of 8-month-olds, a closure positive shift is elicited in relation to the prosodic boundaries in speech, suggesting that these infants are able to structure speech input into prosodic units on a neurophysiological basis similar to that seen in adults. A delay in latency of the infant closure positive shift, however, suggests that children's exploitation of prosodic boundaries for the segmentation of the speech stream is still developing.

Acoustic Stimulation↗

PubMed2005

Reduced stress pattern discrimination in 5-month-olds as a marker of risk for later language impairment: neurophysiologial evidence.

The study at hand investigates prosodic abilities of infants as early predictors of Specific Language Impairment (SLI), which is commonly diagnosed at a later age. The study is based on the hypothesis that the prosodic abilities of infants at risk for SLI are less elaborated than those of controls due to less efficient processing of the relevant acoustic cues. One of the most critical prosodic cues for word segmentation is stress pattern. In German as well as in English, the most frequent stress pattern of bisyllabics is the trochee, in which stress is placed on the first syllable. Using a passive oddball design, German 5-month-olds were examined with respect to their ability to discriminate different stress patterns of bisyllabics. Infants were grouped retrospectively based on their production performance at the ages of 12 and 24 months. In contrast to matched controls, infants with very low word production displayed event-related brain potentials with a significantly reduced amplitude of the discrimination response, i.e. a Mismatch Negativity (MMN), to the trochaic stress pattern. This amplitude difference indicates impaired prosodic processing of word stress during early development and may thus be taken as an early marker of risk for SLI.

Acoustic Stimulation↗

PubMed2004

Discrimination of word stress in early infant perception: electrophysiological evidence.

Language acquisition crucially depends on the ability of the child to segment the incoming speech stream. Behavioral evidence supports the hypothesis that infants are sensitive to the rhythmic properties of the language input. We recorded event-related potentials (ERPs) to varying stress patterns of two syllable items in adults as well as in 4- and 5-month-old infants using a mismatch negativity (MMN) paradigm. Adult controls displayed a typical MMN to the trochaic item (stress on the first syllable) as well as to the iambic (stress on the second syllable) item. At the age of 4 months, no reliable discrimination response was seen. However, at the age of 5 months, a significant mismatch response (MMR) was observed for the trochaic item, indicating that the trochee, i.e. the most common stress pattern in German, was separated consistently from the iambic item. Hence, the present data demonstrate a clear development between 4 and 5 months with respect to the processing of different stress patterns relevant for word recognition. Moreover, possible contributions of different filter settings to the morphology of the mismatch response in infants are discussed.

Acoustic Stimulation↗

PubMed2002

Neural manifestation of cognitive and precognitive mismatch detection in early infancy.

We recorded event-related potentials (ERPs) in 2-month-old infants in two different states of alertness: awake and asleep. Syllables varying in vowel duration (long vs short) were presented in an oddball paradigm, known to elicit a mismatch brain response. ERPs of both groups showed a mismatch response reflected in a positivity followed by a frontal negativity. While the positivity was present as a function of the stimulus type (present for long deviants only), the negativity varied as a function of the state of alertness (present for awake infants only). These data indicate a functional separation between precognitive and cognitive aspects of duration mismatch essential for the distinction between long and short vowels during early infancy.

Acoustic Stimulation↗