Patient-interactive, microprocessor-controlled neurological stimulation system.

Objectives. Recent technical improvements in implanted stimulation devices, in particular the development of programmable, multicontact devices, have facilitated their clinical application in the management of pain. If the capabilities of these devices are to be used to full advantage, adjustment after implantation demands a major investment of time and effort. Ideally, adjustment should be based upon psychophysical data of high quality; this imposes additional demands. Materials and Methods. We have developed a computerized system, designed for direct patient interaction and for greater ease of operation than the standard external devices provided with these implants. It rapidly tests the available contact combinations and stimulus pulse parameters, at a rate substantially greater than that of a skilled human operator using the standard device. At the same time, it records detailed, graphical data and patient ratings at varying thresholds. We have redesigned the system based upon our experience with a prototype interfaced to the bus of an IBM-compatible PC, c. 1983. The new system communicates through the serial port to a freestanding, dedicated interface, whose microprocessor in turn controls standard, commercial radiofrequency transmitters. This frees the host computer from stimulus timekeeping, allowing simultaneous entry of pain drawings and stimulation drawings by the patient, analysis of incoming data, and generation of complex "multichannel" stimuli. Furthermore, upgrades to the host computer to expedite these tasks generally will require no other hardware or software modifications. Results and Conclusions. Our patient-interactive computerized system has proven to be safe and effective clinically in adjusting implanted spinal cord stimulators. It offers advantages of data standardization and quality control, as well as delivery of novel pulse sequences and protocols to assess the treatment of pain and neurological disorders by electrical stimulation devices. 1998 Blackwell Science, Inc.