Trying to stack cups in a certain order. Can identify people, but does not seem to know to play with his sister. Does not use toys as other kids do unless tower. If distracted with other toys, she sometimes forgot the concept. Fine motor skills seemed lower (at age 3 potentially) Had to get close to tap sisters head (if. Thumb sucking someone asked where she was) instead of just pointing across the room. Pre-occupation with a specific topic (trains, bugs, cars, etc. ) Cognitive: normal to above normal: a key component for diagnosing. Regression of social, intellectual and developmental skills. Only one with a specific genetic basis. Symptoms are: decreased head size, loss of movement, fine motor skills are lost. Quantitative delay: less of a particular skill, often related to the individuals chronological age and normative expectations, academic skills, mathematics, comparing to how much a normally developed child should be able to do.