This gap has previously been filled by a histological method to evaluate cutaneous nerve fiber density. These fibers are small and many are unmyelinated with very slow conduction velocities therefore, their conduction responses cannot be captured and evaluated by routine nerve conduction studies. Since not all patients with small fiberopathy have both somatic and autonomic involvement, assessing somatic fibers is very much desired. Autonomic function can be assessed by quantifying sweat output and measuring cardiovascular regulation. They play key roles in cutaneous nociception, thermoreception, and autonomic function. Small caliber nerve fibers consist of somatic (type C and Ad fibers) and autonomic fibers. A sensitive and specific diagnostic tool is thus essential for making correct diagnosis and rendering appropriate subsequent management. Some patients may predominantly present with pain, which is subjective.

The clinical presentation usually consists of cutaneous pain, numbness and autonomic dysfunction, which can lead to significant functional impairment.

It is also not uncommon to be idiopathic, especially in elderly patients. Small fiber sensory neuropathy is a common neuromuscular disorder associated with many medical conditions, including diabetes mellitus, amyloidosis, HIV infection, connective tissue diseases, and pharmacological neurotoxicity. Cleveland Clinic Cutaneous Nerve Laboratory, one of only a few in the country, has been created to improve diagnosis and research in small fiber sensory neuropathy.

Pain fiber nerve conduction study