Slowly conducting potentials in human sensory nerves.

Area of Science:

• Neuroscience
• Clinical Neurophysiology
• Sensory Nerve Conduction

Background:

• Small myelinated sensory fibers, Aδ-fibers, transmit pain and temperature sensations.
• Current nerve conduction study techniques cannot examine Aδ-fibers.
• Existing methods are experimental, specialized, or indirect.

Purpose of the Study:

• To develop a clinical neurophysiology method for examining Aδ-fibers.
• To enable direct assessment of Aδ-fiber function in clinical practice.

Main Methods:

• Utilized standard clinical neurophysiology equipment.
• Recorded averaged responses to focal, non-painful epidermal nerve stimulation.
• Developed an algorithm to identify Aδ-fiber potentials by comparing averaged responses.
• Applied statistical thresholds (99th and 99.9th percentiles) to distinguish true potentials from noise.

Main Results:

• Identified numerous negative and positive potentials significantly different from controls.
• Conduction velocities ranged from 1.3-29.9 m/s.
• These velocities are consistent with those of Aδ-fibers.

Conclusions:

• The developed stimulation, recording, and data analysis methods are applicable in clinical EMG laboratories.
• This technique allows for the identification of Aδ-fibers in human sensory nerves.
• Facilitates clinical assessment of Aδ-fiber function.