A PERSONAL COMPUTER-BASED VISUAL-EVOKED POTENTIAL STIMULUS AND RECORDING-SYSTEM

A system for recording electroretinograms and visual evoked cortical p otentials has been constructed with the use of a personal computer and a digital signal processing card. The system is based on widely avail able commercial hardware. It has been designed to be capable of perfor ming routine visual electrophysiology as well as allowing the developm ent of novel visual stimuli and signal detection techniques. The syste m enables both transient and steady-state stimulation rates. Pattern s timuli can be presented in pattern-reversal, pattern-onset, pattern-of fset or motion-onset modes. In addition to conventional signal averagi ng, the digital signal processing card can also provide on-line Fourie r analysis and is facilitating the development of adaptive filtering t echniques for the detection of steady-state visual evoked cortical pot entials. This versatile system is in regular clinical use for the meas urement of electroretinograms and visual evoked cortical potentials.