Schade, C.M., Sasaki J., Schultz D., et al. Voltage versus current stimulation pulse trains in patients undergoing spinal cord stimulation (SCS) trial. North American Neuromodulation Society, 12th Annual Meeting 2008; Ref Type: Abstract
Commercially available SCS devices control the energy delivered to neural tissue through constant voltage (CV) or constant current (CC) stimulation. Both activate neural tissue, causing the sensation of paresthesia. This study was designed to determine 1) whether patients could correctly identify identical and different pulse trains, and 2) if patients prefer voltage- or current-controlled stimulation.
In this IRB-approved multicenter feasibility study, 14 patients received 20 pairs of 15-second pulse trains. Pulse train pairs were randomly presented as: CC-CV. CV-CC, CV-CV, or CC-CC. Patients identified whether the two pulse trains were the same or different, and if different, if they preferred the first or second train. Patients were blinded to the type of stimulation presented.
Patients performed at chance level in identifying identical pulse pairs (55.7 ± 24.1% correct, 10 trials) and slightly better in identifying different pulse pairs (67.1 ± 25.2% correct, 10 trials). Three patients were below this percent (average) for both identical and different pulses. Four patients performed above average only in identifying identical pulses and felt that most different pulses were the “same.” Four patients thought that a majority of pulses felt different and performed below average in identifying identical pulses. Finally, three patients performed above average in identifying “same” and “different” pulse pairs. Of these, two preferred voltage and one preferred current.
In general, patients have a difficult time determining that two identical pulse pairs are
the same, and/or that different pulse pairs are different. Patients tend to fall into four categories: 1) Unable to correctly identify pulse pairs, 2) most pulse pairs feel the same, 3) most pulse pairs feel different, and 4) able to correctly identify pulse pairs. Of the three patients in category four, two preferred voltage stimulation and one preferred current stimulation.
C. Schade, Medtronic; Medtronic; J. Sasaki, Medtronic; Medtronic; QRX2Pharma; D. Schultz, Medtronic; Lilly; Pfizer; Medtronic; J. Greenberg, Medtronic employee; L. Johanek, Medtronic Disclosures: employee; G. King, Medtronic employee.