Investigatión of the development of neural and behavioural auditory rhythmic sensitivity and of its contribution to reading acquisition

Resumen

The main goal of the current doctoral dissertation was to examine the contribution of brain and behavioural rhythmic sensitivity during pre-reading stages to the development of future reading. To achieve this goal, we conducted a longitudinal study in which typically developing children were tested three times: twice before they had received formal reading instruction (T1: 4-5 y.o.; T2: 5-6 y.o.) and once after reading instruction was introduced in the school curriculum (T3: 6-7 y.o.). Along these three testing times, we used EEG to measure the children¿s brain rhythmic (oscillatory) activity in response to natural speech and to auditory signals modulated at rates relevant for speech perception (at the stress, syllabic and phonemic rates). The children also ran a battery of behavioural tasks that included a measure of rhythmic skills (tapping to a beat in synchrony) and several classical reading predictors (e.g. phonological awareness, phonological short-term memory). The longitudinal nature of this work allowed us testing for the first time the trajectory of brain coherence to auditory signals during early childhood. Furthermore, this is the first study finding a long-hypothesized relation between brain oscillatory activity at low frequency bands (0.5 Hz) in pre-reading stages and later reading achievement, such that right-lateralized brain responses to speech at T2 correlated significantly with children¿s reading achievement at T3. Regarding behavioural rhythm sensitivity, whereas rhythmic skills were tightly related to other reading predictors before reading was acquired (T1 and T2), we found no evidence that it contributed significantly to final reading outcome. Differences among measures of brain vs. behavioural rhythmic sensitivity are discussed, especially in the context of early detection and intervention of children at risk of developing reading disorders.