The relationship between temperature and neuronal characteristics.

The purpose of this study was to determine a relationship between surface temperature of the limb and neuronal characteristics of the median and ulnar nerves in non-impaired individuals. Previous literature demonstrates that there is a negative correlation between distal latency and amplitude and temperature while a positive correlation exists between nerve conduction velocity and temperature. It is a common clinical practice to externally manipulate the temperature of a cold limb. Thirty-six participants (21 male, 15 female,) with an age range between 20-38 years old (mean age = 26.6) completed the study. Temperature of the limb was not manipulated by the researchers prior to testing and was measured at the distal wrist crease using a surface probe. Relationship was determined using a Pearson product-moment coefficient of correlation. A significant negative correlation existed for median distal sensory latency (DSL), ulnar DSL, ulnar motor amplitude (CMAP), and ulnar sensory amplitude (SNAP). The investigators conclude that temperature is a factor to consider when performing nerve conduction studies. The researchers suggest using mathematical correction factors to compensate for a cool limb rather than external heating.