Earlier this year, Pediatrics published an article on the Modified Checklist for Autism in Toddlers, Revised with Follow-up (M-CHAT-R/F).1 Clinicians working in primary care pediatrics quickly learn the art of developmental surveillance. We ask pointed questions to ascertain whether infants and toddlers are achieving developmental milestones as they age. Although at first glance this seems to be a good approach, studies have shown that significant numbers of children at risk for developmental delays are consistently missed. These kids fall through the proverbial cracks, and many times they aren't identified until the optimal window for early intervention has passed. Thus the need arises for developmental screening to evaluate children at various points over time, using validated instruments to identify those at risk.
For readers who aren't familiar with the tool, the M-CHAT is a screening instrument designed to identify toddlers at risk for autistic spectrum disorder (ASD). The original M-CHAT consisted of 23 questions designed to tag parental perceptions of childhood behavior. Six of these questions were considered critical and served as red flags, alerting the clinician to the possibility of a child at risk. Failure of two or more critical items (or failure of three or more total items) triggered a referral for a more indepth neurodevelopmental evaluation.
When cumulative research data demonstrated that significant numbers of referred children were subsequently found to be developmentally normal, the designers of the tool elected to revise it. They also added a follow-up questionnaire to break out the salient points, all in an effort to reduce the number of children who initially screened positive, while attempting to maintain a high level of sensitivity in the instrument. This resulted in the M-CHAT-R (revised) and the M-CHAT-R/F (revised with a follow-up questionnaire).
The Pediatrics article reports the results of a large cohort of children (16,115) who were screened using the revised tool. The new tool resulted in fewer children being referred for further evaluation and a higher rate of detection of children at risk for ASD. In other words, the revised instrument seemed to be a bit more sensitive and specific in rooting out those children truly at risk.
The authors conclude that “[w]idespread implementation of universal screening can lower the age of ASD diagnosis by 2 years compared with recent surveillance findings, increasing time available for early intervention.” Because early intervention is key in achieving good outcomes for kids with ASD, this conclusion is good news indeed.
In the revised M-CHAT-R/F, children who fail two critical responses are labeled at risk, but apart from following them clinically and repeating the M-CHAT at a later date (in 3 months' time or after 24 months of age, whichever comes first), little can be done. I wonder about the degree of parental anxiety that might be generated in the meantime.
The follow-up questionnaire seems like a good idea. Here the clinician is presented with an indepth algorithm of further questions and clinical decision points. It boggles the mind just reading through it. Personally, I could envision spending a good half-hour chatting with parents about these sorts of issues. What with everything else clinicians are expected to do during well-child visits—assess proper nutrition, sleep, elimination, and dental hygiene; tag developmental milestones; provide anticipatory guidance; explain potential adverse reactions to immunizations—I find myself wondering how easily this revised instrument with follow-up can be incorporated into clinical practice.
In my personal experience, ultimately most children with ASD are diagnosed through a combination of parental concern and continuity of care by their primary care provider. The clinician who evaluates a child consistently over time is much more likely to identify the at-risk child. And we all would do well to learn to repeatedly pose that most important crucial question to the parent: “Do you have concerns about your child's development today?”
1. Robins DL, Casagrande K, Barton M, et al. Validation of the modified checklist for Autism in toddlers, revised with follow-up (M-CHAT-R/F). Pediatrics