19115
M-CHAT-R with Follow-up Phone Interview (M-CHAT-R/F): Analysis of Changed Responses
The M-CHAT-R is a screening instrument developed for the detection of autism spectrum disorder (ASD) in children ranging from 16 to 30 months of age. It is a parent-completed measure consisting of 20 yes/no items. When a child screens positive on the M-CHAT-R, a more comprehensive follow-up phone interview can be conducted to confirm a parent’s answers and rule out potential false positives. A recent validation study suggests that the completion of the follow-up phone interview is most critical for children who fall in a medium risk category, failing between three and seven items on the M-CHAT-R. Despite the importance of the follow-up phone interview, the performance of individual items has not yet been examined. As the American Academy of Pediatrics recommends screening for ASD at 18- and 24-month well-child visits, the current study proposes to compare item performance on the follow-up phone interview (PI) for children who screen positive on the M-CHAT-R at 18- and 24-months.
Objectives:
To examine item performance on the M-CHAT-R Follow-up phone interview at 18 and 24 months.
Methods:
Parents completed the M-CHAT-R at their child’s 18- or 24- month well-child visit. The parents of children who screened positive on the M-CHAT-R were contacted, and PIs were conducted. The demographics of the 18-month (n = 400) and 24-month (n = 213) samples that screened positive on the M-CHAT-R were compared using Chi Square or t-tests, as appropriate. The percentage of times each item was asked on the PI (i.e., failed on the M-CHAT-R) was compared between the 18- and 24-month samples using Chi Square. The percentage of answers changed when each item was asked (i.e., fail on M-CHAT-R to pass on PI) was also compared using Chi Square.
Results:
Although samples differed on gender, they did not differ on ethnicity or informant characteristics, such as relationship to child and maternal education. PIs were conducted with over 80% of each sample, and were completed approximately a month and a half after the M-CHAT-R, on average. Items reflecting early development, such as imitation, were asked more often in the 18- than 24-month sample. Responses to twelve of twenty items changed (i.e., Fail to Pass) more than 60% of the time when asked on the PI. The most frequently changed items included encouraging parents to watch him/her, making unusual finger movements, and engaging in pretend play. Three items, pointing to direct attention, interest in peers, and response to name, were significantly more likely to change in the 24- than 18-month sample.
Conclusions:
Results suggest that the performance of individual M-CHAT-R and PI items may differ depending upon the age at completion. High frequency of change in response for more than half of the items reinforces the importance of the PI in the screening process. Parents may be cued to look for certain behaviors after completing M-CHAT-R leading to changed responses on the PI. Alternatively, parents may not understand the question as intended. Further research examining the predictive nature of change in item response for diagnosis is warranted.