The Modified Checklist for Autism in Toddlers (M-CHAT) has yielded elevated rates of screening failure for children born preterm or with low birthweight. We extended these findings with a detailed examination of M-CHAT items in a large sample of children born at extremely low gestational age. The sample was grouped according to children's current limitations and degree of impairment. The aim was to better understand how disabilities might influence M-CHAT scores. Fourteen participating institutions of the Extremely Low Gestational Age Newborns (ELGAN) Study prospectively collected information about 1086 infants who were born before the 28th week of gestation and had an assessment at age 24-months. The 24-month visit included a neurological assessment, the Bayley Scales of Infant Development, Second edition (BSID-II), M-CHAT and a medical history form. Outcome measures included the distribution of failed M-CHAT items among groups classified according to cerebral palsy diagnosis, gross motor function, BSID-II scores and vision or hearing impairments. M-CHAT items were failed more frequently by children with concurrently identified impairments (motor, cognitive, vision and hearing). In addition, the frequency of item failure increased with the severity of impairment. The failed M-CHAT items were often, but not consistently, related to children's specific impairments. Importantly, four of the six M-CHAT 'critical items' were commonly affected by presence and severity of concurrent impairments. The strong association between impaired sensory or motor function and M-CHAT results among extremely low gestational age children suggests that such impairments might give rise to false positive M-CHAT screening.
© 2011 Blackwell Publishing Ltd.