Thank you for your reply.
Unfortunately, I do not have access to the exact values of my studies at this point. I do remember, however, the doctor mentioning that the only parameter that had been significantly influenced was the amplitude. It was lower than the corresponding amplitude on my right hand by a factor of at least 20. The reaction latency was fine too, without temporal dispersion.
After taking vitamins, all amplitudes increased a little, but the big difference remained. I also recall the doctor asking about cramps; indeed, since the numbness started, I have been getting them occasionally. They usually resolve within 1-2 seconds though.
(I am aware that, without providing the study itself, you cannot produce a good reply. Maybe the above can still help in some way? )
I will look into the options you mentioned. Most importantly, I am now convinced to not rush into surgery.
Thank you very much!