Do Rett syndrome persons possess Theory of Mind? Some evidence from not-treated girls.

The aim of this research paper is to investigate Theory of Mind (ToM) capacities with Rett Syndrome (RS), which is similar to autism yet with more significant impairments. RS patients can best be described as hardly ever advancing past the sensorimotor stage, or the period described by Piaget between birth and eighteen months during which an infant's knowledge of the world is limited to sensory perceptions and motor activities with behaviours that consist of simple motor responses caused by sensory stimuli. Nevertheless, single-case studies have shown that RS patients can develop a mentalistic understanding of others if properly trained. To further advance this finding, non-trained RS female children completed a false belief task appositely devised with a non-verbal answering mode familiar to RS girls. Results show that RS girls are better on this type of false belief task than a control group of autistic children, whose deficit in ToM understanding is well-documented in literature. Our findings, though preliminary, may be a first step towards a better understanding of the differences between RS and autism in mental state reasoning, opening new topics of research and intervention in ToM with severe clinical conditions.