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Browsing by Subject "http://www.yso.fi/onto/yso/p3328"

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  • Äänteiden prosessointikyvyn yhteys hermostolliseen kuuloerottelukykyyn 5–6-vuotiailla lapsilla 
    Örmä, Ida-Lotta (2016)
    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.
  • Hidasaaltounen vahvistaminen unenaikaisilla äänillä ja sen vaikutus muistisuoritukseen 
    Yli-Kyyny, Iikka (2016)
    Objectives: In recent years, scientific inquiry has been able to dig into the effects of sleep on memory. More specifically, slow oscillations (SO) detected with EEG during deep sleep, have been found to reactivate memory representations which further enhances their processing and consolidation into long-term memory. In previous studies, auditory stimulation during deep sleep has been found to strengthen the brain's natural SO cycles and enhance consolidation of declarative memory but it has also been found to have unwanted side-effects on mood. This study is part of a research project, Sound Deep Sleep, where the objective is to develop a non-pharmacological method for home use to enhance the positive effects of deep sleep using auditory stimulation. In this study the effects of different auditory stimuli and their duration on memory consolidation and mood was investigated. Methods: 21 healthy adult volunteers took part in the study. The subjects slept in a sleep research lab in the Institute of Occupational Health for four nights with electrodes attached to the scalp and their memory performance and mood was tested once every evening and once every morning. Memory performance was tested with paired associative words, face-name test and with sequential finger tapping. Subject's mood was tested with POMS questionnaire and task load with NASA-TLX. During the four nights, subjects were presented with brief auditory noise or percussion sounds for the whole night of for the first four hours or with no auditory stimulation in a randomized order. The auditory stimulation was time locked to SO cycles according to online detection by a previously developed algorithm. The volume of the sound was adjusted according to online detection of sleep depth by the same algorithm. Results and conclusions: Auditory stimulation did not affect memory consolidation, mood, task load or subject's sleep architecture. The results on memory consolidation are contradictory to previously published data and possible explanations for the contradiction are discussed. The fact that this study had larger sample size and almost identical design than previous studies casts doubt that the effects size of auditory stimulation on memory consolidation might be smaller than previously expected or that it concerns only a sub-population of people. Based on the results of this study, suggestions for future research designs are introduced.

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