Wow...I can also relate a little bit to so many of the things being mentioned here. I agree that these mystery neurological complaints and symptoms can be caused by so many different things!
I had many hand/forearm complaints... I couldn't WRITE anymore without moving my entire arm with a pen stuck in 'frozen' position in my hand. I had sharp stabbing pains in the wrists and forearms especially thumb and first finger (among other places in my body), very stiff hands, aching painful forearms etc.. I dropped things out of nowhere all the time. Vitamin B6 deficiency can cause carpal tunnel type symptoms, too, and for me...I think that was it. When my B12 deficiency was uncovered, I went on an overal supplement plan, which included extra P5P B6, magnesium, fish oil, and also a multivitamin. I had so many symptoms, too, just like the rest of you, that could "fit" with a number of conditions.....like fibromyagia, lyme disease, thyroid disease, etc. The only symptoms I have left are periods of brainfog and some lingering memory and concentration problems (still could not ever remember a number from a glance in the phone book to dialing it), but they are not nearly as bad as they were...still very frustrating at times. I also have very occasional and mild buzzing and twitching.
When I was at my worst, I could not, for example, add two two digit numbers together; it was mentally exhausting just to read; I couldn't process verbal conversations around me at all (just heard blah, blah, blah); I couldn't articulate well, stuttered and often dropped off mid sentence with no recollection of what I was talking about; word finding problems..wrong words popping out all the time (this still happens but not every other sentence..maybe just a couple times a day); and a couple of times I even got lost/disoriented when driving when I was going to what should be a familiar place....and that is getting into scary cognitive problems. I had the couple of vertigo attacks (lasting days each time), also episodes of feeling like I was dropping from the sky, etc, all that stuff.
Just from a vitamin deficiency.
My early symptoms were on and off over the course of 3-5 years more like flares (like the urninary tract symtpoms...had several 'flares' of that over a couple of years). My ear ringing, buzzing, and clicking noises was definitely on and off over many years, but the "phantom" ear pressure and pain came near the end. I say "phantom", because on exam there was no fluid or infection. But, then, everything started worsening rapidly, with new symptoms piling on at more rapid pace during the last six months before my problme was finally uncovered.
My oldest daughter, who we now know was B6 deficient, had "morning hands" during her childhood, and especially in the morning (hence us calling it 'morning hands'), couldn't button, tie shoes, dropped things, etc.
My youngest daughter had a fleeting episode of slurred speech once just before we discovered her gluten sensitivity, but had more episodes of sporadic weakness (limp body fatigue), leg drag, staggering, droopy eyelids (she couldn't lift them open on occasion, usually in the morning shortly after arising, but it would happen, say, while eating breakfast...and last a couple of minutes) and a lazy eye. All as a result of gluten sensitivity~ all resolved on a gluten free diet. She does not have Celiac Disease. If you haven't had a chance to check out The Gluten File yet, I hope you will. Especially the pages on neurological manifestations of gluten sensitivity/gluten ataxia, and the diagnostic pages.
Alena, just keep on looking~ and I hope you will find some answers one day soon. It can be a big long process of elimination and continued testing, and very hard to keep on going to the next doctor, next doctor, next doctor. Take breaks from it when you need to, but you may need to be very persistent to find answers. I agree with rose who suggests you take B12 and supporting vitamins (multivitamin, B-complex) while you continue to search... and of course always keep in touch with your doctor and keep him informed of things you are taking, including supplements

. Lots of information on safety/dosing on roses' pages or mine.
Do you have any family history of autoimmune disease?
Good luck!
Cara