A simple method for estimating conduction velocity of the spinothalamic tract in healthy humans

Objectives: The object of this study was to establish a method for estimati ng the conduction velocity (CV) of the spinothalamic tract (STT) in relatio n to clinical application. Methods: The CV of the STT was estimated by an indirect method based on tha t reported by Kakigi and Shibasaki in 1991 (Kakigi R, Shibasaki H. Electroe nceph clin Neurophysiol 80 (1991) 39). Laser-evoked potentials (LEP) were m easured in 8 subjects following hand (LEPH) and foot (LEPF) laser stimulati on. The conduction times recorded at the scalp (P340, P400 and N150 potenti als) were considered as the summation of peripheral and central components. The peripheral conduction times were calculated by measuring the latency o f the electrical cutaneous silent period (from the same stimulus site of LE Ps), corrected for F- and M-wave latency values. Results: The CV of the STT ranged between 8.3 and 11.01 m/s and its mean Va lue was found to be approximately 9.87 +/- 1.24 m/s. The CV of the STT obta ined by the N150 latencies overlapped that obtained by the P340/P400 latenc ies. Conclusions: Our data suggest that our method appears appropriate and usefu l for practical clinical purposes, furnishing an additional tool for invest igating the physiological function of small-fiber pathways. (C) 2000 Elsevi er Science Ireland Ltd. All rights reserved.