Many times behaviour problems are associated with children with autism. These can include incidents of tantrums, self injury, property destruction, and acts of aggression. Some behaviours are the result of developmental deficits (e.g. a child cannot speak and engages in misbehaviour as a form of communication).
Episodes of self injury can be in response to abnormal response to sensory. In some cases it serves the purpose of sensory stimulation and perseverations can result that are exceedingly challenging to terminate. Regardless of the cause, when a child is performing self stimulating behaviours (e.g. hand flapping, twirling, finger posturing, etc.) it is counterproductive to his/her learning.