Simultaneous Recording and Stimulation Instrumentation for Closed Loop Spinal Cord Stimulation

Chronic neuropathic pain is a debilitating disorder. Many patients receive pain relief when implanted with a Spinal Cord Stimulation (SCS) system. However, there is currently no way to automatically determine the most effective parameters to use in stimulation, so some patients must return to the clinic periodically to have their device re-programmed. Further, postural changes can shift the position of the stimulating electrodes and require programming changes to optimize pain relief. Evoked compound action potentials (ECAPs) could be used as feedback signals to determine optimal patient stimulation parameters. To determine the feasibility of closed-loop feedback in SCS, we have designed a recording system that simultaneously records evoked compound action potentials (ECAPs) during stimulation. Using differential recording and high dynamic range amplifiers, this system is capable of simultaneous stimulation and recording without saturating. Here we show in vitro the capability of this system to record simulated evoked compound action potentials across all channels during stimulation without saturation and with low noise. This data acquisition system provides the ability to add recording to existing clinical stimulation trial systems with minimal changes to standard clinical practice.