Hi
@Kenbob, yes my husband used to do the same. Initially he would make sporadic full body jerks overnight while he slept. Later, like your wife, they would happen sporadically during the day and he would spill hot drinks down him as a result.
He did take memantine but he took it right from the early stages of the disease as he wasn't able to take the normal dose of aricept (donepezil). However, he didn't get the sporadic body jerks right from the start - he was some four years into his diagnosis, once he was in the moderate stages, before they started to happen.
As these episodes became more and more frequent one consultant said it was the medication but another consultant said it was a natural part of the progression of the disease. In our case I tend to think it was the latter because it took several years before it started to materialise in my husband.
There wasn't much I could do but I did stop filling his mug up to the top. I also added a little extra milk or cold water so that it was still hot enough to enjoy, but not too hot that it would burn him should he splash any down himself. After I explained what was happening, the staff at the day centres and memory cafes we attended did the same.
Fortunately, the situation made him laugh rather than distress him (once I'd worked out the optimum temperature) but when it first started to happen he was, like your wife, very apologetic bless him.