From the Guidelines
At 6 months old, the earliest signs of Autism Spectrum Disorder (ASD) may include limited eye contact, reduced social smiling, and minimal babbling or vocal sounds, as well as atypical body movements and motor development, although no definitive behavioral or diagnostic markers for ASD have yet been identified in infants aged < 12 months 1.
Early Signs of ASD
Some studies suggest that infants with ASD may exhibit differences in social attention, such as diminished orienting to the eye region of the face, as early as 2-6 months of age 1. Additionally, atypical sensory behaviors, repetitive or otherwise atypical motor behaviors, and nonverbal communication differences may be observed during the age range of 6 to 12 months 1.
Importance of Monitoring Development
It is essential for caregivers to be mindful of early developmental milestones, including social and emotional development, as well as motor, language, and problem-solving skills, and to raise questions if they have concerns that developmental goals are not being met 1.
Recommendations for Parents
If parents notice several of these patterns consistently, they should discuss their concerns with their pediatrician at their baby's next check-up. Early intervention services can begin even before a formal diagnosis and can significantly improve outcomes, as the young brain has greater neuroplasticity and ability to develop new neural pathways.
Key Findings
- No definitive behavioral or diagnostic markers for ASD have yet been identified in infants aged < 12 months 1
- Atypical body movements and motor development may be potential early markers of ASD 1
- Temperamental profiles, such as lower sensitivity to social reward cues, may distinguish high-risk siblings with a later diagnosis of ASD from high-risk siblings who do not receive an ASD diagnosis and siblings without a family history of ASD 1
- Repetitive behavior with objects, such as spinning or lining up, may be an early marker of ASD, as early as 12 months of age 1
From the Research
Earliest Signs of Autism Spectrum Disorder (ASD) in 6-Month-Old Infants
- Decline in eye fixation from 2 to 6 months of age, with infants later diagnosed with ASD exhibiting a mean decline in eye fixation during this period 2
- Functional connectivity magnetic resonance imaging at 6 months can correctly identify which individual children will receive a research clinical best-estimate diagnosis of ASD at 24 months of age 3
- Gaze behavior and affect at 6 months may not provide early markers for autism, but gaze to the mouth may be useful in predicting individual differences in language development 4
- Delays in early language and communication development, such as understanding fewer phrases and producing fewer gestures, may be apparent in infants later diagnosed with ASD 5
- Characteristic behaviors of autism may begin to be noticeable from the age of two, but there are no reliable predictors of autism in infancy, and early signs may be detectable in six-month-old babies 6
Key Findings
- Infants later diagnosed with ASD may exhibit a decline in eye contact from 2 to 6 months of age 2
- Functional neuroimaging at 6 months can predict a diagnosis of ASD at 24 months of age with high accuracy 3
- Gaze behavior at 6 months may not be a reliable predictor of autism, but may be related to language development 4
- Delays in language and communication development may be apparent in infants later diagnosed with ASD as early as 12 months 5