Browsing by Author "Siikjärvi, Ella"

Objectives. The aim of this study was to examine with electroencephalography (EEG) the associations between speech-sound elicited mismatch negativity (MMN) and late discriminative negativity (LDN) and pre-reading skills. Exploring the neural base of pre-reading skills will benefit the development of interventions for reading difficulties. It was hypothesized that left-lateralized MMNs and LDNs are elicited by all changes and larger and left-lateralized responses are linked with better pre-reading skills. Children with dyslexia risk were assumed to have poorer pre-reading skills and their responses were assumed to be smaller and more right-lateralized than in controls. Methods. Twenty-three children (of whom 16 with dyslexia risk) participated in an assessment of language abilities and EEG recording around the age of four years seven months. MMN and LDN were recorded for vowel, phoneme duration and frequency changes occurring in the second syllable of the standard stimulus (/tata/). The Repeated-measures analyses of covariance and the correlation analyses were applied to examine the relationship between MMN and LDN amplitudes, scalp distributions and phonological awareness, rapid automatized naming (RAN), verbal short-term memory, letter knowledge and a parent’s evaluation of pre-reading skills. The effects of risk status on MMN and LDN responses and pre-reading skills were investigated with the Repeated-measures and the One-way analyses of variance. Results. MMNs in the right hemisphere for consonant duration and vowel change and LDNs for all changes were statistically significant. LDN for vowel duration change was associated with RAN, and LDN for large frequency change was associated with letter knowledge so that the responses were larger in children performing better. LDN for vowel change was larger in children with poor letter knowledge and RAN, and LDN for small frequency change was larger in children performing poorly in RAN. Children performing poorly in RAN had right-lateralized MMNs, whereas children performing better had larger amplitudes mainly in the left hemisphere. Dyslexia risk had no effect on MMNs, LDNs or pre-reading skills. Conclusions. Right-lateralized speech processing and possibly also difficulties of discriminating vowel and frequency changes are associated with poor reading skills. Strengthening the ability to discriminate and manipulate phonemes may be important when supporting reading skills, however this should be investigated with an intervention study.