FROM 0 TO 3 MONTHS
• Does not react to sounds someone’s voice.
• Does not smile.
• Does not maintain eye contact.
• Does not emit vocalizations.
FROM 12 TO 18 MONTHS
• Irritability and frequent tantrums.
• The first words do not appear.
• Misunderstanding of orders accompanied by gestures.
• Does not communicate through gestures. “goodbye”, “no”.
FROM 3 TO 4 YEARS
• Displays an incoherent way of speaking outside of the family context.
• Does not use phrases with more than 2 words.
• Does not ask questions like What? Where?.
• Difficulty of stablish relationships with other children.