Disorganized rhythm and synchrony: early signs of autism and Rett syndrome.

We interpret early age-related developments in intentions and socially responsive behaviour with data from home videos of infants who later develop autism or Rett syndrome. Detailed evidence is given from a micro-analytic study of videos of monozygotic twin girls at 11 months, one of whom became autistic in the second year. Changes in this twin's attention, motor tonus, initiative and emotion reduce her prospective control of movements and her anticipations in awareness compared to her sister. These changes were reflected in the child's asynchronous social behaviour, which frustrated the father's attempts to support her attempts to walk, share toys, or play a game, confusing his anticipations, and this further reduced mutual attention and joint activity. Observations of the development of girls with Rett syndrome in the first year reveal changes in motor coordination, attention and communicative initiative, indicative of a failure of intrinsic core brain regulations of neural development and conscious activity. Notwithstanding that the two conditions show clear differences in both brain growth and early development of skills and sociability, the first signs of autism and Rett syndrome have important similarities. We conclude with recommendations for an approach to early diagnosis and treatment, applicable for the whole range of developmental brain disorders, including Rett syndrome and autism, that attempts to identify residual capacities for sympathetic motivation and collaborative learning-an approach that deliberately tries to support weakened rhythmic impulses for motor, perceptual and communicative functions in the growing infant brain.