I agree with a couple of others that silent reflux may be an issue. One can have reflux with no symptoms, or with just a cough. One doesn't have to have traditional acid reflux symptoms for reflux to be an issue. Google "LPR" for more information. This is a good web site to learn more: http://www.jamiekoufman.com/2010/01/08/silent-reflux-laryngopharyngeal-reflux-lpr-is-ubiquitous/.
Also, look into "post viral vagal neuropathy." If this is what she has, a simple, inexpensive, pain killer called tramadol, can almost immediately stop this cough. I had a chronic cough related to acid reflux (LPR) and post viral vagal neuropathy, and within just a few days of taking tramadol, my cough was gone. Ask your mother's doctor if this could be the case. They can test her for it, or give her the tramadol (if not contraindicated) to see if it helps.
Post Edited (BaileyJane) : 1/14/2011 5:05:42 PM (GMT-7)