New diagnostic tests for diabetic distal symmetric polyneuropathy

Neuropathy needs to be diagnosed early to prevent complications, such as neuropathic pain or the diabetic foot. It is obvious that diagnosis of neuropathy needs to be improved. New peripheral nerve function tests that appear to facilitate diagnosis are now emerging. This review outlines the new tests that have been proposed for the diagnosis of diabetic distal symmetric polyneuropathy, the commonest form of neuropathy in diabetes. New tests are classified into those mainly assessing large-fiber function (tactile circumferential discriminator, steel ball-bearing, and automated nerve conduction study) and those mainly assessing small-fiber function (NeuroQuick and Neuropad). Emerging tests are promising but must be evaluated in prospective studies. Moreover, their cost-effectiveness needs more careful appraisal. The clinician should, therefore, still rely on established modalities to diagnose neuropathy, but wider use of the new tests is expected in the near future.