Abstract
Although it has been suggested that intraoperative monitoring with off response (OFR) in visual evoked potential (VEP) is possible, a stimulus preparation device for recording is not yet available. This paper reports on a prototype of a stimulator allowing for OFR recording to be more widely possible. The stimulation device needs to have a function of allowing the light emitting diode (LED), a stimulation device, to emit a constant light amount for a certain period of time. However this stimulation is difficult with existing products. In the new stimulator, heat generation accompanying the extension of the light emission time needs to be considered. The stimulus range which is the most effective and safe is set accordingly, and effective OFR recording is considered possible. In order to effectively record OFR, a very large amount of light is not required, so it was necessary to ensure sufficient light-off time while setting it, as stimulation intensity in a range not accompanied by heat generation. For stimulation, we set an output limit of 3/4 or less of the capability of the light emitting device and provided a safety device and light emission check function. In addition, the shape of the light emitting device was newly devised. Recording with a new stimulator can be easily set in comparison to the conventional design. In addition, the response waveform was well depicted. Recording of VEP off response was thought to be much easier with this stimulator. Easy recording greatly contributes to the progress of monitoring and leads to an improvement in surgical results. Since it can contribute to widening the scope of the recording of off response, it is expected that studies employing this technique will be conducted for various diseases in the future.
