Some older dogs get something called laryngeal paralysis. I haven't had a dog with it but several others have had labs with laryngeal paralysis, sometimes referred to as lar par. Maybe that's what your vet was referring to. You could try looking online to read more about it. I'd have to look it up myself before I could tell you more. If I find a good link before someone else gives you more info, I'll add it here.
Laryngeal Disease in Dogs | petMD