Hello! My name is Dr. Aida and I am glad to attend you on Healthcaremagic! Unfortunately this is a neurodegenerative disorder, which is not very responsive to medication. Levodopa does not cause any improvement, but I would recommend trying it, under medical supervision and see if his situation improves. Regarding the spasticity, a muscle relaxant could help, coupled with physiotherapy. Regarding Keppra, it may help reduce the myoclonus (muscular jerks) in the spastic limbs, but it does not make any miracle. Hope you will find this information helpful! Best wishes!