The name is absent

Autism prodrome 85 of 89

Table 2 (continued)

Prospective screening studies

Reference		Age (Months)	Study design	Administration	Key items/content	Instrument parameters
Robins et al. (2001); Kleinman et al. (2008)_________	M- CHAT	24m	Combined high-risk: early intervention referrals (n = 484) and population screening (n = 3,309)_________	Parent questionnaire	Most discriminating items: joint attention behaviors and social relatedness	Positive predictive value = 36% (1-stage); Positive predictive value = 74% (2-stage)
Wetherby et al. (2004, 2008)	Ict	9-24m	Population screening (n = 5,385); multiple stage follow- ups________________________	Parent questionnaire	Early social communication behaviors; emotional response	Positive and negative predictive value at or higher than 70% for all age groups except 6 to 8m
Reznik et al. (2007); Watson et al. (2007)	^^FYI	12m	Pilot population study (n = 1,496)	Parent questionnaire	Full range of possible early autism abnormal signs	Follow-up studies not yet conducted

CHAT (Checklist for Autism in Toddlers); ESAT (Early Screening of Autistic Traits); M-CHAT (Modified- Checklist for Autism in Toddlers); ITC (Infant

Toddler Checklist); FYI (First Year Inventory)