Browsing by Author "Salonen, Satu"

Objective: The objective of this study is to investigate how parent’s dyslexia and the severity of it affect the neural speech-sound discrimination of preschool-age children. The second aim is to study whether children’s pre-reading skills combined with familial dyslexia risk are associated with neural speech-sound discrimination. The association between dyslexia and speech-sound discrimination has been found in many studies before, but there is conflicting evidence regarding dyslexia risk, especially in preschool-age children. The hypotheses are that 1) more severe dyslexia of a parent and 2) familial dyslexia risk combined with weak pre-reading skills are both associated with smaller and less left lateralized mismatch negativity (MMN) and late discriminative negativity (LDN) responses. Methods: The sample of this study was a subsample (n = 94) of the DyslexiaBaby follow-up study. The children were 4–5 years old and 19 of them were controls that did not have dyslexia in the family. The severity of parent’s dyslexia was categorized to compensated, mild or moderate/severe. The pre-reading skills of children were assessed with the Finnish Lukiva test. The experimental setup was an oddball paradigm of /tata/ standard stimulus and five deviant stimuli that was presented during an electroencephalography (EEG) recording. The deviance in the stimuli was either in the vowel duration, consonant duration, latter vowel identity, or small or big change in the frequency of the second syllable. Results: The moderate/severe dyslexia group had smaller MMN amplitudes than the controls. Also, the moderate/severe dyslexia group had smaller LDN amplitudes only on the left hemisphere compared to the controls. There were preliminary, but not significant results of very weak pre-reading skills combined with familial dyslexia risk being associated with right-lateralized MMN and LDN responses. Conclusions: Children with familial dyslexia risk have difficulties in neural speech-sound discrimination especially in the left hemisphere compared to controls. However, no evidence was found of parent’s mild or compensated dyslexia being associated with weaker speech-sound discrimination. Therefore, moderate or severe dyslexia of a parent seems to be a higher risk for a child’s difficulties in speech-sound discrimination and targeting this group with interventions seems beneficial.