Are there any new treatments for stiff person syndrome?

Not really: This curious and devastating autoimmune disease was newly-discovered when i was in medical school, and is very challenging for both patient and physician. You probably know much more about it than most doctors do. There's a helpful article at medscape http://emedicine.Medscape.Com/article/1172135-treatment good luck and don't give up hope.

SPS: Treatments include immune-modulating therapies such as ivig (intravenous immune-globulin) and plasmapheresis; pharmacological therapy, patient and staff education, behavioral and physical therapy. Benzodiazepines and other gaba-acting medications remain essential to managing the stiffness and spasms of sps.