I'm not a doctor, but I have lived and breathed music and made a good full time living out of singing and playing guitar for 30 years. One day...out of nowhere, I woke up and from my left elbow down had a strange tingling numb feeling. I thought I probably slept on my arm or something. After a week I was quietly and deep down REALLY starting to worry...I may never play the guitar again. By this stage I had already ruined my voice from overuse. To put this in perspective...there was no real pain, just the frustration of what I eventually pin pointed was my left thumb and index finger, where I could not make the 'ok' sign. The weakness was to the point there was no way with all my strength could I open a can of softdrink (soda). Not being able to play the guitar was too much to face, so I pretended in my own head that I was having a little break.
So I did what everyone does and I started going to specialists in this department. They did tonnes of tests and I was very impressed by their knowledge and it made sense. One specialists suggested it was coming right up from my shoulder. I always believed (and I could feel it)it was from the elbow down into those 2 fingers.
Months went by and treatments didn't improve at all.
Now this where I say....don't always follow the text books and degree on the wall. Not once did any of these 'specialists' even mention a Tens machine. A Health Herald Digital Therapy Machine. I'm sure you know what these machines do. So I started testing my pain threshold and turning up (over time) the tens machine almost into spasms. I eventually knew what exact setting, which area, what strength to set the machine. To cut a long story short, within 3 months I had all my feeling back in my left hand.