A new pilot study has revealed that children with Rett syndrome, who were thought to be unable to understand and process information, exhibit meaningful visual search whereby they can process and prioritize information. The findings lead researchers to believe that conventional testing is not robust enough and underestimates the cognitive abilities of this population.
Rett syndrome is a nervous system disorder, caused by mutation on the MECP2 gene located on the X chromosome, that leads to development reversals - loss in previously acquired language, hand use, and in most cases walking. The disorder overwhelmingly affects young girls, who develop normally for the first year of life with initial signs of regression occurring between 6 and 18 months. One in 10,000 females is affected by Rett syndrome, leaving them aware and alert but often without the ability to express themselves.
Unable to communicate through speech or hand movement, children with Rett syndrome have not been able to demonstrate their intellectual abilities. Researchers at Montefiore Medical Center, in New York City, have shown that standardized testing, often used to diagnose autism, underestimates the abilities of girls with Rett syndrome. Their results demonstrate that the children's capabilities surpass the current understanding of the disorder.
"It has been 46 years since the first clinical description of Rett syndrome, and until now there has been little indication whether sufferers can understand and process information," said study leader Aleksandra Djukic, MD, PhD, associate professor of clinical neurology and clinical pediatrics at Montefiore and director of the Tri-State Rett Syndrome Center. "The results of our study highlight that more customized testing is needed for girls with Rett syndrome to more accurately assess their intellectual abilities and psychological state. It is a medical necessity for these girls to have access to eye-gaze speech-generating computers in order for them to be able to demonstrate their mental ability and to communicate with their families."
With eye-gaze technology, a monitor tracks eye movements using cameras and reflected infrared light and allows patients to answers questions by fixing their gaze on the answer, which is represented by an image. Dr. Djukic uses the technology with her patients, and while they cannot communicate verbally, many are able to point to something, understand a question, and communicate through their eyes.
The study involved 49 girls with Rett syndrome and a control group of typical subjects. Researchers examined their nonverbal cognitive abilities and visual preferences by analyzing the pattern of visual fixation through eye-gaze technology.
The girls with Rett syndrome exhibited a preference for socially weighted stimuli, preferring to look at a face - in particular looking longer at the eyes of a person - than objects. This offers a new insight about their neurodevelopmental profile, their preferences and ability to process and discriminate visual stimuli.
The results also demonstrate a striking difference between children with Rett syndrome and those with autism who avoid social and eye contact, indicating that further research is needed to better understand the "hidden" thoughts and feelings of these girls.
Rett syndrome often is confused with autism, and girls affected by the disorder frequently are grouped in the same educational classes. This presents a problem since girls with Rett syndrome require a different teaching method that is targeted to their specific communication capabilities and needs. The key difference between children with autism and Rett syndrome is that girls with Rett show a preference for eye contact, whereas children with autism tend to avoid eye contact.
The results of the new study highlight the need for more comprehensive investigation, including direct comparisons of visual fixation patterns between girls with Rett syndrome and children with autism, Dr. Djukic said. The study, which is one in a series, should be considered in future intervention strategies so girls with Rett ultimately can be treated specifically to suit their disorder with the goal of enhancing their communication capabilities.
The Rett Syndrome Center at the Children's Hospital at Montefiore treats 250 patients from all over America and as far afield as Pakistan, Italy, Cyprus, Argentina and Venezuela.