Browsing by Subject "MMN"

Objectives. The aim of the current study was to explore whether there is an association between phonological processing and neural auditory discrimination in 5–6-years-old children. Phonological processing is defined by the ability to recognize and modulate small units of words, like phonemes. Neural auditory discrimination is defined by brain's automatic and preconscious ability to discriminate changes in auditory stimuli. Both phonological processing and neural auditory discrimination are important factors in the language development and deficits in those factors are known to be related to many language impairments. Single studies have reported an association between phonological processing and neural auditory discrimination but this theme is not well studied. In addition to group differences, we also studied differences in the ability to discriminate different sound deviants. Methods. The sample consisted of 38 children, whose mean age was 5 years and 10 months. The study was executed by dividing children into two groups by Nepsy-II phonological processing scores and comparing these two groups with the amplitudes of the brain's mismatch negativities (MMN) and late discriminative negativities (LDN). The comparison was made with repeated measures analysis of variance. Brain's event-related potentials were recorded with multifeature-paradigm in which the stimuli were modulated by vowel, consonant, duration of the vowel, intensity and frequency. Results and conclusions. The results of this current study demonstrate that differences in the phonological processing can be seen in the neural auditory discrimination. Both MMN- and LDN-potentials were stronger in those children, whose ability to process phonemes was better. In MMN-potentials the group difference was only seen in frequency, vowel and consonant deviants, whereas in LDN-potentials group differences were seen across all deviant types. In this study the phonological processing seems to be associated particularly to stronger LDN-potentials, which can provide information about the cognitive processes related to LDN-potentials. No previous studies about the association between phonological processing and LDN-potentials are known to be done.

Aim of study. The aim of this study was to determine how the processing of pitch cues in spoken words is affected by listeners' native language. In previous studies, listeners' have shown a better sensitivity to acoustic features that are linguistically relevant in the native language. It has also been shown that the processing of pitch information is lateralized to the left hemisphere when the information is linguistically distinctive and lateralized to the right hemisphere when it is not carrying linguistically relevant information. The processing of lexical pitch has been shown to be language specific. Pitch is lexically discriminating in Estonian, but not in Finnish. Therefore, native speakers of Estonian were hypothesized to show a better sensitivity to changes in pitch than the native speakers of Finnish. They were also hypothesized to show a lateralization to the left when processing linguistically discriminating changes in pitch. Methods. 12 native speakers of Estonian and 12 native speakers of Finnish participated in the study. Mismatch negativity (MMN) components of event-related potentials (ERP) were measured with electroencephalography (EEG). Stimuli consisted of Estonian words, which showed differences in duration and pitch. Results and conclusions. Scalp maps of neural activation suggested a larger sensitivity for small changes in pitch for the Estonian group, as well as a tendency towards lateralization of the processing of pitch cues to the left hemisphere for the Estonian group, and to the right for the Finnish group. These observations were supported by a significant interaction effect between language group, lateralization, and stimulus type. However, further pairwise comparisons were only marginally significant. Due to large variation in the Estonian group, the group was split based on geographical background information, since the use of pitch cue has been shown to vary regionally in Estonia. This analysis indicated regional variation in the processing of the pitch cue; the western Estonian group showed lateralization to the left hemisphere while processing stimuli with a small change in pitch. The findings of this study are in line with previous studies, showing that the native language affects the processing of pitch. It also suggests that the local language variety has an impact on these processes.