Studies have shown that early diagnosis and intervention significantly impact the prognosis of individuals with autism spectrum disorder (ASD): the earlier the detection and diagnosis, the better the prognosis and functional status later in life. Currently, the average age of diagnosis is approximately 3-4 years. However, ASD individuals show signs of the disorder as early as in their infancy and toddler years. For this reason, investigators are devoting considerable attention to the development of easily applied early detection tools and screening tests.
The standard evaluation methods for ASD today are the DSM-V classification criteria and tools such as the Autism Diagnostic Observation Schedule (ADOS), which provides the official diagnosis. However, while these methods are accurate and highly sensitive, they are typically both difficult and costly to administer and subjectively biased. Because providers often don’t have the resources to perform these tests, diagnosis and subsequent treatment of ASD are often delayed, contributing to worse prognoses for the individuals with ASD.
For these reasons, researchers have proposed easier and faster alternatives, and applied them with varying results in terms of feasibility and sensitivity. They should be thoroughly studied scientifically and statistically before being recommended to the first-front families, educators and healthcare providers. Eye tracking (ET) is an especially promising alternative because of its speed and comparative objectivity, the latter of which could greatly reduce the possibility of bias in traditional evaluations of ASD. Recent studies have shown that there are adequate observable differences in ET outcomes between ASD patients and neurotypical subjects. Additionally, and importantly, there is no risk of physical harm or potential biological contamination or infection with the method.
Individuals with ASD exhibit certain behaviors that can be detected with eye tracking, including difficulties in interpreting gaze cues, preferences in fixating on more highly systemized pictures, decreased attention to faces, and lack of right hemispheric dominance for face processing. The Martinos Center’s Xue-Jun (June) Kong and colleagues are working to optimize eye tracking for tracking these behaviors. To this end they sought to determine, first, whether the accuracy of the method can be improved by using new criteria, and, second, whether it can be enriched by modifying or adding more steps.
Kong and colleagues developed a short and simple paradigm that can be applied in infants, toddlers and children to detect early signs of ASD in eye gaze, eye following, joint attention, and emotion response. The paradigm can be used to observe early, subtle and unique cues for infants at risk to ASD. The total test lasts approximately two minutes.
The researchers have used this new paradigm to better reveal the psychological properties of ASD individuals and are now validating it against the standard DSM-V. Based on the results of the validation, they will select the more effective steps and cutoff scores in order to achieve the optimal protocol, with the best sensitivity and specialty. After confirming the efficacy of the protocol, they will use it to identify the diagnostic patterns and signs of ASD as early as infancy.
Kong and colleagues are now working to explore further the potential of the new paradigm. Over the long term, they hope to expand the project to include a comprehensive protocol using only behavioral and observational methods, which will facilitate evaluation and diagnosis of ASD and other mental conditions.
In the image above, Xue-Jun (June) Kong (center), director of the Synapse Research Project at the Martinos Center and head of the eye-tracking project, directs clinical research and patient consultation at the Shenzhen Maternity and Child Health Hospital.