Peroneal nerve conduction velocity: the importance of temperature correction

The relationship between skin surface temperature, near nerve temperature and nerve conduction velocity (NCV) of the peroneal nerve was studied in normal and diabetic subjects to determine a peroneal NCV-treatment correction factor and to investigate whether temperature correction of NCV reduces its variability. Twenty normal subjects (age 21 to 72 years, mean 44, SD 17) were tested for peroneal NCV, skin and near nerve temperatures bilaterally at ambient temperature (mean 26.6C). Tests were repeated after cooling the lower extremity to a skin temperature of 26C, and at skin temperatures of 28 and 29C as the legs were allowed to gradually warm. An additional 20 normal and 20 diabetic subjects were tested weekly at ambient temperature for peroneal NCV and skin temperature, measured at 15cm above the lateral malleolus. The results showed a linear relationship between skin temperature, near nerve temperature and peroneal NCV (p less than 0.001). Peroneal NCV was altered 2.0 meters per second per degree (C) change in skin and near nerve temperature (p less than 0.001). When using our formula, peroneal motor NCV corrected = 2.0 [32 - skin temp(C)] + NCV (m/sec), for correction of peroneal NCV to a standard skin temperature of 32C, it was found that temperature corrected NCV were less variable (p less than 0.05) than noncorrected NCV in the same diabetic subjects. These results indicate that temperature corrected NCV should be calculated routinely during clinical NCV examinations of patients with peripheral neuropathies.