It's good that this diagnosis actually isn't SM, it's a kind of indication that he could eventually develop a syrinx and SM (hence being on cimetidine which can halt progression at this stage in some dogs). But if that's all he has at this age, you probably don't have any major worry that it would become a highly symptomatic level of SM and may never go beyond where it is now. Perhaps it is CM that is bothering him a bit in which case the cimetidine could also help. I have herd some great reports about Kate, the new neurologist there. Glad Murphy's bloods came back OK!