--if you are experiencing neuropathy as a result of impaired glucose tolerance, which is certainly possible (I've posted before a lot of links about neuropathic symptoms occurring well before people are diagnosed with frank diabetes), it would likely effect the small, unmyelinated fibers first, and these are not measurable by standard EMG/nerve conduction studies, which only measure gross abnormalities of larger, myelinated nerves.

There is other testing that might be brought to bear, including quantitative sensory testing, which is designed to ascertain the responsivity of the small fibers that subsume temperature sensation, and skin biopsy to determine density and condition of intraepidermal small fibers.