Construction of a reference table of values for a neurophysiology laboratory

Abstract

This is an study performed to develop a normal reference table of values for nerve conduction studies including sensory, motor and late responses (F Wave and H Reflexes) of the median, ulnar, radial, sural and peroneal nerves; same as also its correspondent late responses and the study of the median-flexor carpi radialis and tibial-soleus complexes in a neurophysiology laboratory located in an Andean city about 2600 m above the level of the sea. This consecutive study includes 100 patients referred for evaluation, free of neuropathic pathology same as also without risk factors associated to peripheral nerve disease. The mean age was 49 year old; with the lower and upper limits between 15 and 71 years old. The normal conduction values (and standard deviation) for sensory responses are (in meter by second): median nerve 53.3±2.2, ulnar nerve 55.2±3.6, radial nerve 54.8±4.2, sural nerve 57.5±5, and 53.1±4.5 in the superficial peroneal nerve. The motor conduction normal values are: 57.5±4.6 for the median nerve, 63.7±5.3 for the ulnar nerve, 57.9±4.2 the radial nerve, and 55.7±3.6 for the common peroneal nerve. The latency when we study the late responses showed as normal values (in milliseconds); 23.5±1.3 for the median nerve, 23.9±1.5 for the ulnar nerve, and, 40.0±2 for the peroneal nerve. The H Reflex latency also in milliseconds was 16.3±1.2 for the median-flexor carpi radialis complex; and 28.7±2 for the tibial-soleus complex. The results are very similar compared to the international published data, in relation to the height of the included subjects; the difference is related to this factor and shows normal responses once we eliminated the confound factors depending in the environment (skin temperature as the principal).