Many cognitive functions in human are based on asymmetric brain networks. For most adults, language is processed largely by the left hemisphere while other auditory treatments, such as voice recognition are rather based on the right hemisphere. Many studies helped to highlight the presence of anatomical and functional asymmetries both in the first months of life. What are the causes of these imbalances? How do they develop? Are they necessary for operation or for effective learning?

The investigators would like in this work, in collaboration with applied mathematics team of Compiègne and INSERM team, to determine from which period the development of hemispheric dominance is set up for recognition of language and in which brain structure it occurs in preterm infants whose sound environment is usually very different from that of the fetus. The impact of this environment on brain development of infants and their early learning will be assessed.

Inclusion Criteria:

• preterm gestational age over 26 weeks of gestation + 6 days and less than 42 weeks.
• normal group of children : A child meets the age criteria and without ductus arteriosus persistence ultrasound or detectable neurological disorders after clinical, neurophysiological and radiological (ETF , Scanner, MRI).
• Group of children meet the age criteria and with cerebral neurological pathology detectable after clinical, neurophysiological and radiological (ETF , Scanner, MRI).

Exclusion Criteria:

• severe congenital malformation
• Any refusal of a parent .
• Children with severe impairment of the general condition and vital functions
• Children with dermatitis of the face or scalp
• Children treated with ventilation High Frequency (HFO )
• Presence of intravenous access on the scalp ( preventing the realization of the ETF , EEG or NIRS .

The inclusion of patients in the study will be conducted in the intensive care unit and neonatal intensive care CHU Amiens .