Hi welcome to the health care magic You have not mentioned which test has been done.. Here vitamin b 12 and calcium deficiency usually ruled out first But as you have history since three year, the organic causes has to be ruled out by cranial nerves examination and MRI scan like investigation Than according to cause further specific treatment can be prescribed The neuropathy can be cause secondary to bulged disc or by any systemic illness... Alcohol, smoking and diabetes also leading cause for neuropathy If needed nerve biopsy or NCV like testing useful Take care Consult neurophysician for examination