I think you're not misunderstanding, it's exactly what the term "Medical Reversal" is trying to capture. I.e. of course it's only a symptom, but it's something

I think you're not misunderstanding, it's exactly what the term "Medical Reversal" is trying to capture. I.e. of course it's only a symptom, but it's something that can be measured to show there's a problem early on.