Most children follow typical patterns of development from birth through adolescence. Children with autism spectrum disorder, ASD, do not. Differences are often detected early and become clearer as a child with ASD begins to drop behind the development of his peers. However, in some cases an infant appears to develop normally until age 1 to 3 years. Then, sudden changes may occur that indicate the presence of ASD, according to the National Institute of Mental Health.
Age 1 to 3 Months
Two 1-month milestones that children with autism may fail to display are responding to a voice and making adjustments in anticipation of being picked up and held, according to the University of Hawai’i’s developmental milestone guidelines. Other absent milestones include failure to recognize a caregiver and to smile in response to an adult’s smile at 2 months. At 3 months, an infant with autism may not react when a face disappears or be able to vocalize two different vowel sounds.
Age 4 Months to 1 Year
At 4 months, the child may still not turn toward a sound and at 6 months may not smile at a mirror image. At 8 months, there may be no sign the child can vocalize three different vowel sounds. Imitation of vocalizations may not appear at 10 months and the autistic child may not cooperate in games. The child may not use gestures when he or she wants something at 11 months and at 1 year, there may be no expressive jabbering that is characteristic of other children that age.
Age 13 Months to 60 Months
At 13 months, the autistic child may not imitate someone patting a toy or be able to make four different combinations of vowel sounds. There may be no imitation of single words at 16 months or use of words when he or she wants something at 19 months. At 22 months, there may be no indication the child can combine gestures and words or, at age 25 months, make a two-word utterance. At 34 months, the child may still not pose questions. Finally, at 60 months, the child may not be able to follow three commands.
Other Possible Indicators of Autism Spectrum Disorder
The National Institute of Mental Health’s list of possible indications a child may have a form of autism includes many included in the list of missed milestones as well as some others. For example, failure to point, babble or gesture meaningfully by 12 months, failure to speak by 16 months, failure to combine two words by 24 months, failure to respond to his or her own name and loss of social or language skills are all indications a child may have autism spectrum disorder.