Possible cause is Head banging. Action to take This inexplicable behavior seems to comfort the child but distresses the parents, who fear that their baby will hurt himself. It usually starts at about 6 months and stops by the time a child is 2 years old. Possible cause is This harmless habit may also appear in a child who can sit up. It may start as early as 6 months and usually disappears before the child reaches 2 years Action to take Head rolling or rubbing.
Possible cause is Developmental disorder or autistic behavior.
Action to take Consult your pediatrician, who may prescribe a short-term medication to calm the child and recommend a helmet to protect her head. Coping with head banging Children are rarely, if ever, harmed by this behavior, but if you are concerned that your child may injure himself, or the behavior is not diminishing over months, consult your pediatrician. Your baby will eventually outgrow head banging and body rocking. In the meantime, however, the movement and noise that seem to give him pleasure may cause a great deal of wear and tear on your family's nerves. You can't restrain the baby or make him stop the activity, but you can take a few simple steps to keep the noise at the lowest possible level.