Microcomputer-based recording system for clinical electrophysiology.

We developed a personal computer-based system for clinical electrophysiologic measurements. The computer interfaced with a commercially available A/D converter, a low-noise isolation preamplifier, filter circuits, pattern and Ganzfeld stimulators, and a hardcopy unit. Separate programs were developed for electroretinography (ERG), pattern ERG and simultaneous visual evoked potential (VEP), flash and pattern-shift VEP, and electro-oculographic measurements. The complete control of the applied hardware (eg, stimulus control, automatic gain, and filter selection) is a common feature of the computer programs. These programs provide oscilloscopic functions, overload protection, artifact elimination, averaging, automatic peak latency and amplitude determination, baseline correction, smoothing, and digital filtering. The results can be presented on matrix, laser printers, or digital plotters. The hardware components and the features of the driver software are demonstrated on normal and pathologic signals.