Because autism is on a spectrum from severe cognitive and functional deficits to high functioning, these signs can vary significantly. Low functioning autism is usually easy to identify due to significant verbal, social, and cognitive impairment. High functioning autism can be trickier, as the child may function well in many areas. Early signs of high functioning autism are lack of social responsiveness or difficulties with social interactions, high rigidity and resistance to change, and getting “stuck” on topics or behaviors are common. Sensory difficulties and “odd” behaviors such as walking on tip toes, hand flapping, or rocking are also sometimes present.