My 9 year old does this along with other quirky things. We had him taken to Riley and evaluated. It came back that he has ADD, OCD, Sensory Integration and Aspergers like tendancies but not Aspergers. I think it's probably the OCD or SI that cause him to repeat things. SI symptoms
-- Loves to spin, swing and jump--this will seem to calm them down after several minutes.
-- Complains of how clothing feels, does not like tags left in their clothing and have to have their socks on just so, or a certain kind of sock.
-- Picky eaters--get stuck on one certain food and is basically impossible to get them to eat anything else.
-- Oversensitivity to smells. Or undersensitivity--may sniff people, objects, food.
-- Oversensitivity to sounds--will frequently cover ears. Or undersensivity.
-- May have an exceptionally high pain tolerance
-- May tire easily
-- Unusually high or low activity level
-- Resists new situations
-- Problems with muscle tone, coordination, motor planning
-- Can be very impulsive or distractible.
-- Persistently walks on toes to avoid sensory input from the bottom of the feet. This can also be a sign of cerebral palsy if the child is unable to bring their feet down flat when asked or trying.
These are just a few of the symptoms that children with SID/DSI can exibit.
Although OCD could be the cause for my son I think the SI affects how his brain processes things. By repeating stuff back to himself he is helping himself process the info. He repeats a lot of things! Good luck.