Browsing by Author "Meriläinen, Jaana"

Developmental dyslexia is a heritable learning disorder which according to the predominant theories has its core problems in the processing of speech sounds. Auditory processing deficits have been found in dyslexics and in infants with a genetic risk for dyslexia. It has been shown that infants with a genetic risk for dyslexia have attenuated or more right-hemispheric lateralized auditory event-related potentials (ERPs) to changes in speech stimuli compared to infants with no genetic risk. It has been shown that interventions can ameliorate the reading and writing skills of dyslexics and concurrently influence their ERPs. The aim of the present study was to find out if an early musical intervention can ameliorate the auditory processing skills in infants. Altogether 58 infants with a genetic risk for dyslexia were assigned to three groups where one group listened to vocal music, second group listened to instrumental versions of the same music and the third one was a control group with no intervention. After six months of intervention, auditory ERPs of the infants were recorded while the infants were presented with a repetitive pseudoword /tata/ with random infrequent duration, frequency, or vowel changes in the latter syllable. It was also studied if the ERPs were correlated with the amount of music played during the intervention or with the parents' evaluations of their infant's degree of prelinguistic development. The groups differed from each other in the auditory processing of the repetitive standard sound so that in the control group the ERPs had a different hemispheric pattern compared to the intervention groups and the repetitive sound was processed faster in the control group than in the instrumental group. It was also found that the hemispheric pattern of the ERPs for the vowel changes was different in the instrumental intervention group compared to the other groups. The parents' evaluations of the prelinguistic development of their infant were correlated with the ERPs so that the ERPs to the repetitive standard stimuli were enhanced and reached their peak earlier in the infants who were evaluated to be more mature in their prelinguistic development. According to the results, the ERPs for the repetitive sounds are correlated with children's linguistic development and an early musical intervention can modify the neural network processing speech sounds in infants with a genetic risk for dyslexia. In the future, it should be followed if these intervention effects on brain functions also enhance the linguistic development of the children and it should be also explored how other parts of the auditory environment of the children besides the intervention have possibly affected their auditory skills.