Language Development Deficits and Early Interactive Music Intervention

Investigators compare effects of 6-month music versus circus group interventions on language development in infants and toddlers with or without familial risk for dyslexia (anticipated total N=200). Effects of intervention timing, dyslexia risk and genetics, and social-emotional factors on the intervention outcomes are investigated.

Infancy and early childhood lay the base for language and reading abilities, and this development can be compromised by heritable conditions such as the reading deficit developmental dyslexia. One of the earliest indices of language abilities is neural processing of native language speech, as it is associated both with familial risk for developmental language and reading deficits and with subsequent language and reading development. Previous work has shown that musical activities can promote auditory and language learning early on and even improve reading in dyslexic children. Large-scale randomized controlled trials are needed particularly in risk groups in order to give recommendations and design effective interventions to support language development and ameliorate later difficulties. The investigators will conduct such a trial to study the effects of a playful music training group compared to a similar circus training group on speech processing and language development in infancy and early childhood. It is investigated how these effects are moderated by familial risk for dyslexia and its genetic markers as well as timing of the intervention in relation to the children's age and developmental status. Investigators study how the expected social-emotional benefits of the interventions on the parent, child, and their interaction mediate the intervention effects on language. Approximately 8-12-month-old infants with confirmed parental dyslexia or without parental dyslexia will be randomized, using block randomization, to one of the two 6-month training groups, and outcome measures will be collected before and after the intervention and at follow-up \~1 year after the intervention has ended. The total anticipated sample size is 200, with approximately 100 infants in the music and circus interventions and within each intervention, approximately 50 infants with and 50 without parental dyslexia. Speech processing will be evaluated with speech-elicited auditory event-related potentials, and language skills and general development with standardized parental questionnaires and age-appropriate standardized tests. Social-emotional factors are evaluated with parental questionnaires. DNA samples are collected to study dyslexia genetics. The results can contribute to designing effective interventions for supporting language development in vulnerable groups early on.

Eligibility Criteria:
Inclusion Criteria:

* 8-12 months old at start of intervention (recruited between 0-11 months)
* Born healthy and at term (gestational age at least 37 weeks and birth weight at least 2500 g)
* Normal hearing at birth (evoked oto-acoustic emissions conducted to newborns routinely at the hospital)
* At least one caregiver living with the child is native speaker of Finnish and speaks Finnish to the child
* Risk group: At least one biological parent has developmental dyslexia according to a recent (\<5 years) diagnostic statement by a health care professional or according to a dyslexia test at study enrollment; symptoms have started in childhood

Exclusion Criteria:

* Medication affecting the central nervous system
* Sensory deficits
* Serious health conditions
* No-risk group: Suspected dyslexia or developmental language disorder due to symptoms that have started in childhood in either of the biological parents; diagnosis of a developmental or language disorder (incl. dyslexia, developmental language disorder, attention-deficit/hyperactivity disorder ADHD, attention-deficit disorder ADD) or neurological disorder in either of the biological parents
* Risk group: Diagnosis of ADHD, ADD, or other not-language-related developmental disorder in either of the biological parents; in the dyslexic parent, brain trauma in childhood that may indicate a non-heritable cause for the reading deficit or individualized school curriculum that may indicate broader developmental deficits.