what are the signs of autism in a 4 year old child?
['hyperactivity or short attention span.', 'impulsivity.', 'aggression.', 'self-injures (punching or scratching self)', 'temper tantrums.', 'irregular reaction to sounds, smells, tastes, sights, or textures.', 'irregular eating and sleeping habits.', 'inappropriate emotional reactions.']