They provide an objective, repeatable means of measuring relevant afferent sensory nerve function. This may have resulted in artificially reducing reported sensitivity. Typically, peripheral nerves are electrically stimulated with a bipolar electrode. The propagation of the impulses are then recorded at specific sites along the course of the neurological pathway and over the corresponding area of the sensory cortex assi gned to receive such impulses. These signals are generally small, and buried within background endogenous cardiac, motor, and EEG activity, as well as surrounding exogenous electrical and radio frequency noise factors.
Peripheral nerves are repeatedly st imulated at a specific rate, and the impulses are recorded.
These recordings are then averaged together to eliminate random noise. The summation of recorded neurological impulses produces repeatable waveforms as illustrated in figure 1. This is referred to as the latency. Latency is measured at several landmarks or intervals. Nerve condition velocities can be calculated by measuring the distance between simulation and recording sites.