What are the diagnostic criteria for Autism Spectrum Disorder (ASD) in a toddler?

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Last updated: May 13, 2025View editorial policy

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From the Guidelines

Identifying autism in toddlers involves watching for specific developmental delays and behavioral patterns, and the American Academy of Pediatrics recommends autism-specific screening at 18 and 24 months for all children, regardless of whether concerns exist. Look for limited eye contact, lack of response to their name by 12 months, reduced social smiling, minimal babbling or speech development, absence of pointing or showing objects by 14 months, and limited interest in social interactions 1. Repetitive behaviors like hand flapping, unusual body movements, or intense focus on specific objects may also be present. Some toddlers with autism might have sensory sensitivities, becoming upset by certain sounds, textures, or lights. Early identification is crucial because intervention during these formative years can significantly improve outcomes. If you notice these signs, consult your pediatrician promptly for a formal evaluation.

Key Signs to Look Out For

  • Limited eye contact
  • Lack of response to their name by 12 months
  • Reduced social smiling
  • Minimal babbling or speech development
  • Absence of pointing or showing objects by 14 months
  • Limited interest in social interactions
  • Repetitive behaviors like hand flapping or unusual body movements
  • Sensory sensitivities to certain sounds, textures, or lights

Importance of Early Screening

The USPSTF concludes that there is insufficient evidence to assess the balance of benefits and harms of screening for ASD in young children for whom no concerns of ASD have been raised 1. However, the American Academy of Pediatrics recommends autism-specific screening at 18 and 24 months for all children, regardless of whether concerns exist. The Modified Checklist for Autism in Toddlers (M-CHAT) and its subsequent revisions are commonly used tools for screening 1.

Next Steps

If you notice any of the signs mentioned above, consult your pediatrician promptly for a formal evaluation. Remember that development varies among children, and these signs don't definitively confirm autism, but they warrant professional assessment. A comprehensive diagnostic evaluation, including a thorough medical assessment, psychological assessment, and communication assessment, may be necessary to determine the presence of ASD 1.

From the Research

Identifying Autism in Toddlers

To identify a toddler with autism, several screening tools and methods can be used, including:

  • The Modified Checklist for Autism in Toddlers (M-CHAT) 2, 3, 4, 5
  • The Parents' Evaluation of Developmental Status 2
  • The Ages and Stages Questionnaires 2
  • The Pervasive Developmental Disorders Screening Test, Second Edition 2
  • The Screening Tool for Autism in Two-year-olds 2

Screening Tools and Methods

The M-CHAT is a widely used screening tool for autism in toddlers, with a pooled sensitivity of 0.83 (95% credible interval [CI] 0.75-0.90) and specificity of 0.51 (95% CI 0.41-0.61) in high-risk children 4. The M-CHAT-R/F has a pooled positive predictive value (PPV) of 57.7% (95% confidence interval [CI] 48.6-66.8) 5.

Key Considerations

When using screening tools to identify autism in toddlers, it is essential to consider the following:

  • Age at screening: Sensitivity was higher for screening at 30 months compared with 24 months 4
  • Study design: Validation studies reported differences in psychometric properties across sample populations 4
  • Proportion of males: Meta-regressions covariates were age at screening, study design, and proportion of males 4
  • Risk level: PPV was higher among high-risk (75.6% [95% CI 66.0-85.2]) than low-risk samples (51.2% [95% CI 43.0-59.5]) 5

Implementation and Quality of Care

Implementation of a digital version of the M-CHAT-R/F can improve the quality of care for children at risk for autism spectrum disorders (ASD) 6. Accurate documentation of screening results and appropriate action for positive screens can increase with the use of digital screening forms 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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