I have two conditions which are similar - but not the same.

1. Due to my MS, I have "equilibrium problems." My understanding is that this is probably due to nerve damage of the nerves leading to and from the cerebellum. I've learned to be very careful when walking in an unfamiliar location, when rising from a seated position, and especially when turning. I'm most disoriented when I cannot see the ground or am climbing stairs and momentarily on one foot. I have to be especially careful in crowds and climbing bleachers in sports stadiums. Walking on ice is nearly impossible because I don't have the ability to recover from a tilt. My advice to my elderly friends who are new to this, is to go slow and always have one hand ready for a handrail or the wall. When rising from a chair, wait for the stiffness to subside before taking a step. Vision is extremely important in balance, so always use the ability to see the ground. One other thing - anecdotal MS stories refer to purposeful "swaying" in order to keep control of the equilibrium. Also, a wide walking and standing stance helps. (MS people often wear their shoes out on the outsides of the soles first.)

2. The other condition is severe vertigo. I've only had it the last few years. An attack only lasts 15 seconds at the most, but it is similar to extreme seasickness. I always have it when I have a respiratory infection, and since I live in the world's number one area for springtime allergies (accoring to Claritin), I assume it is related to fluid on my ears. (middle ear, common among allergy sufferers) So far an antihistamine helps the condition. The worst thing is when I'm lying in bed and have to turn over. I just brace myself for several seconds of severe nausea. If your mother has a treatable condition, she should not waste time getting help.

As far as the doc - IMO, any doctor worth his/her salt will welcome a second opinion. All mine do, and I've certainly used the option. I do understand the hesitation with changing docs; that can cause lost time. I think you can tell the doc that you are concerned and want to pursue this further. My doc hates it when I ask questions, but I finally learned to get her talking about her dogs or kids, then laughing, then zap her with a direct question. Ususally I have to ask it three times before I get an answer!