This appears to be infantile myoclonic epilepsy. Valproate is a good drug but it clearly is not successful. There are several other good drugs for this condition including: ACTH Inj., Spasil, and Toperamate and it would be desirable for you to see a neurologist or a good pediatrician. In the meantime start Toperamate (Tab Topaz or Topirol) 25 mg 1/2 twice a day; observed for 6 days if not better, increase to 1 tab twice a day. Inform me what happens. It is certain we can reduce the jerks. The mental state will depend on what his condition is at present and the cause of the problem e.g. birth difficulty, hereditary etc.