Fi, anyone who owns a cavalier and especially anyone breeding needs to know as much as possible about SM, as it looks as if at least 50%, and probably up to 80%, of cavaliers have it to some degree. It is in the minds of many researchers the single biggest threat to the future of the cavalier breed as at best it is likely causing discomfort to some degree in many, perhaps most, cavaliers; at worst, it causes hideous levels of pain to the dog eventually requiring the dog be put down.
There are no genetic tests but it can be determined whether an asymptomatic dog is likely carrying the genes for this condition by doing an MRI. This is the reason for the low cost MRI screening programme for cavaliers in the UK -- pprimarily, to help breeders see whether their dogs have the skull malformation and syrinxes (the spinal fluid pockets that give syringomyelia its name) and -- as this is likely -- the degree to which they are affected. One neurologist in the UK has come up with a breeding protocol for breeders to use in conjunction with MRIs until the point when there may be a genetic test (it is not certain there ever will be, in which case the situation is very serious for the breed, and it will probably not be able to continue as it is now).
I have a lot of background detail here on this site in the Health section and also in the SM forum. In addition I have lots of information on my SM Infosite --
http://sm.cavaliertalk.com -- which is entirely dedicated to making information on the condition more widely available to cavalier owners and breeders.
The breeding protocol is here:
http://sm.cavaliertalk.com/protocol.htm
Note that some of the prominent neurologists treating this condition feel no cavalier should be bred unless it has been MRI'd and is declared clear of both the malformation and syrinxes. However this would virtually eliminate genetic diversty in the breed -- which is necessary for the breed's future -- so the protocol is considered by most to be the most acceptable way forward until there is hopefully a genetic test or other ways of screening for the dogs most likely to pass along the worst genes.
BTW I know that breeder whose site you quote from, Gabriele Pollmeier; a woman who cares very deeply about cavaliers; she also used to live in Ireland where she bred ahnd showed a different breed than cavalier but I can;t remember which! Note I quoted her in my story for the Irish Times on puppy farms:
http://www.cavaliertalk.com/phpBB2/viewtopic.php?t=366