Diagnosing sm
No, nothing on build and while there are some internal skull indications these are subtle and very hard to see externally (especially as hair reshapes the way the head looks). But several neurologists do think breeding for smaller cavaliers increases the risk of the problem across the breed as the consistent element in predisposed breeds is being a toy or otherwise miniatarised breed. Having a flatter face/shortened muzzle is also directly connected to incidence of SM. So it is really the breed, not the build of the individual dog, that is the issue. Crosses of affected breeds can also have SM.
On the main question: most cavaliers are definitely diagnosed by MRI, not examination. The only definite way to diagnose is by MRI. That said: I will differ here and say that if there are strong indications a dog has SM on clinical examination then I would ask my own vets to let me trial a range of medications. Or I'd ask to see a neurologist for a clinical exam if there are cost issues for example with having an MRI. Given the incidence in the breed certain clinical signs are most likely to be SM. If there's a belief the issue might be related to PSOM then I'd have the dog scoped for that to see if there's any external evidence. If gabapentin helps then it almost certainly is SM. Head tilt and facial droop is also connected to SM. I MRId almost all my cavaliers for one main reason: research. I was already quite sure one dog had SM and her MRI confirmed it but I wasn't planning surgery and her symptoms were mild so if I'd had to pay full cost I'd never have opted for an MRI. The research MRIs enabled me to find one asymptomatic dog had SM and he eventually went on to have symptoms. Having an MRI is very useful to know what you are dealing with, but consider how high the likelihood is of any MRI showing SM especially in any dog over 5 -- by that age, almost certainly well over a 50% chance. It can be very hard to determine whether PSOM or SM is causing any particular shared symptom if both turn out to be present, as well. Unfortunately the conditions are so complicated! So in summary: I'd have an MRI if there is a low cost one available, or insurance, as that is the definitive approach. Or I'd have one if I wanted to have all options, including surgery, available. But I do not think treatment varies at all based on the MRI, except for a recommendation of surgery in especially worrying cases. A mini MRI at low cost generally is not adequate for basing surgery on... so it can be hard to know which choice to make.
DIAGNOSING SM
I wonder if I could mention this .
This was Posted by Katie Eldred on another Cavalier Forum Recently.
She is I believe ,could be the Oldest Living Cavalier Breeder alive to-day.
This is what she said,HOMERBRENT CAVALIERS ,for her ,had Beautiful and RECOGNIZEABLE CORRECT HEADS.
If you can find a Photo of CH Homaranne Caption ,you will see his Head was like what a Dogs Head should be like, not like the Pretty Look that so many of Cavaliers' Dogs Heads have to-day.
I am back to my what I believe again, the SM Problem is all in the Genes, as Karlin says ,about SM being Predisposed to Cavaliers ,did Cavaliers carry the SM Gene/Genes since they originated in the late 1920's and 1930's, they when the Cavalier was starting to be Miniatarised in the early 1980's, did the different Genes come to-gether and SM appeared.
I think it's different for the Cavaliers and their MVD Problem, it is a Fact that there were Cavaliers dying at a young age from Heart Trouble in the 1940's and 1950's ,as the Generations of Cavaliers have come through the years with Heart Trouble,then as a Result it's likely why the Cavalier MVD Problem is not improving ,is because there are now so many Cavalier Carriers of the MVD GENES around in to-days' Cavaliers.
It is no use saying that a Cavalier is Long Lived ,that Cavalier could still be a Carrier of the MVD GENE.
The Future of our Cavalier Breed depends on the Finding of the SM and MVD Genes.
Bet