Assessments of Chronodispersion and Tacheodispersion of F Waves in Patients with Spinal Cord Injury

OBJECTIVE: To evaluate the chronodispersion and tacheodispersion of F waves in patients with spinal cord injury and to determine whether these parameters are more sensitive than those of standard F waves. DESIGN: F chronodispersion and F tacheodispersion as well as F wave latencies, amplitude, and persistence were measured in tibial nerves of 23 male patients with different scales of spinal cord injury and 23 normal subjects. Spasticity was measured and correlated with F chronodispersion in spinal cord injury patients. RESULTS: F chronodispersion of 6.4 +/- 1.9 msec (mean +/- SD) obtained in spinal cord injury patients was found to be significantly greater than the results of 3.9 +/- 1.6 msec in normal controls (P < 0.05). F chronodispersion was greater in spinal cord injury patients with complete cord lesion. A positive correlation was found between F chronodispersion and Ashworth Scores in spinal cord injury patients. There were no significant differences in minimal latency, amplitude, persistence of F waves, and F tacheodispersion between spinal cord injury patients and normal subjects. CONCLUSIONS: Measurement of F chronodispersion may provide a useful and sensitive electrophysiologic assessment in evaluation of spinal cord injury and serve as an evident tool for differentiating pathologic from normal state motoneuron excitability in spinal cord lesion.