Technique of Evoked Potential Recordings from a Radiofrequency-Transmitted Spinal Cord Stimulating System

Summary

Radiofrequency (RF) transmitted spinal cord stimulation, as it has been used for clinical purposes (Long 1981; Meglio et al. 1981; Read et al. 1980) for more than a decade, offers the possibility of recording cortical (and peripheral) responses to spinally-delivered impulses, not just during the test stimulation period. Recordings can be obtained using conventional EMG averager devices, with the EMG machine triggering the RF stimulator unit or vice versa. For that purpose a home made electronic interface was developed. Registration of evoked responses using this method permits fast assessment of neurologic status. Comparison of components recorded with the methods described and by direct stimulation of the spinal cord during the test stimulation period showed no statistically significant changes using Student’s t-test for paired data.

The techniques described allow for continuing recordings to be made for clinical and neurophysiological purposes in the great majority of patients who have an RF-transmitted stimulating system implanted.