Intra-epidermal Stimulation (IES) of Small Nerve Fibers (A-delta Fibers)

Intra-epidermal Stimulation (IES) of Small Nerve Fibers (A-delta Fibers)

The purpose of the study is to determine whether a particular type of nerve fibers, A-delta fibers, can be tested in an Electromyography (EMG) lab on a routine basis. Normal, healthy volunteers will be enrolled in this study.

The epidermis is the outermost layer of the skin that includes skin cells and small nerve fibers called A-delta fibers. A-delta fibers send signals to the brain about pin-prick type of pain and temperature. The investigators want to study whether the investigators can stimulate A-delta fibers and document this by recording electrical potentials from the nerves in subjects' limbs.

Study Procedures:

A small piece of plastic will be applied to your foot and your hand. A tiny sharp tip protrudes from this piece of plastic. You will be barely able to feel this sharp tip when touching the piece of plastic. This is the electrode for intra-epidermal stimulation.

With stimulation, you will feel a pin-prick type of sensation. The stimulus will be adjusted so that you barely feel the pin-prick type of sensation. The investigators will record responses of stimulation from nerves in your skin.

Inclusion Criteria:

• Individuals aged 21 through 60 years with no history or clinical signs of neuropathy.

Exclusion Criteria:

1. History of peripheral nerve disease or disease of somatosensory pathways.
2. Abnormalities on neurologic examination.
3. Prior or current exposure to known neurotoxins, such as excessive alcohol use or chemotherapy.
4. Neurologic or psychiatric conditions that would prevent the subject from being able to cooperate with testing.