Descrizione di un pacchetto software per l'analisi in frequenza del potenziale evocato visivo steady-state. A set of software procedures for the frequency analysis of the steady-state electroencephalographic (EEG) response

A set of software procedures for the frequency analysis of the steady-state electroencephalographic (EEG) response to periodic visual stimuli is described. This package is a prototype of videographic interface which can be easily handled by users who are not expert in computer science. The software has been implemented in Microsoft Visual Basic 3.0 under Windows for IBM-compatible PC's. The choice of this programming language allows the user to handle the application easily, selecting functions from the current window with a click of the mouse. The package was experimented for the analysis of the EEG traces obtained by 24 electrodes located on the scalp according to the 10/20 System, sampled at the frequency of 128 Hz. These traces were either recorded without any visual stimuli, both with eyes closed and open, or elicited by periodic flashes whose frequencies were 4, 6, 8, 12 and 16 Hz. The first I-s epoch following the stimulus was not subjected to analysis. Our objective was to test the efficiency of the package from two points of view: user-friendliness, and capability of providing parameters characterizing the signal in a significant way.