I have recently visited a few labs that are using Tobii eye trackers, an EEG system from EGI and E-Prime and in this blog post I want to share some information about how you can be combined these in the same E-prime experiment.
E-Prime supports both Tobii eye trackers and EGI EEG equipment via two different extensions (E-Prime Extensions for Net Station and E-prime Extensions for Tobii). By using the Tobii extension E-Prime is able to communicate directly with a Tobii eye tracker and also record the eye tracking data in E-prime (as a tab delimited text file). The Net Station extension for E-Prime is able to send events, such as responses and stimuli names, from E-prime to the EEG acquisition computer running the Net Station software from EGI.
To be able to use a Tobii eye tracker and an EGI EEG system in the same experiment a two computer setup is needed: one PC running E-prime with both extensions installed and one Mac running Net Station (see picture below). The eye tracker is connected to the E-prime computer via Ethernet (for example by using the USB-Ethernet adapter provided by Tobii) additionally the Net Station and the E-prime computers are connected via another Ethernet connection (a direct LAN cable connection is recommended). In this setup E-prime will present the stimuli, collect and save the eye tracking data, and send information about the trials to Net Station containing information about which stimuli has been presented when. See the setup overview below:
In E-prime both the Tobii eye tracker and the Net Station extension should be installed and configured correctly; adding the IP address of the Net Station Mac and the name/serial number of the Tobii eye tracker is a minimum. In the E-prime experiment both Tobii and the Net Station Package calls should be combined as well as a few additional InLine scripts for both Net Station and Tobii. The Net Station package calls will send information about the trials to the Net Station Mac, while the Tobii package calls will calibrate the eye tracker and record the eye tracking data. This enables you to get two different data files (eye tracking data and EEG data) with identical event information (time stamps and when a certain stimuli was presented) in both files which should make the combined analysis of the data easier.
You can download my Tobii_eyetracking_EGI_EEG_integration_sample HERE (zip)
See E-prime sample experiment below:
Disclaimer! Please note that I have only tested this script and this setup in a couple of different labs. If you intend to use the experiment for real please make sure you conduct adequate testing of your setup and the script. I also do not know if this way of combining the Netstation and the Tobii extension in E-prime is officially supported and tested by E-prime. To be able to run the sample script you must have purchased and installed both the Netstation and the Tobii extensions for E-prime.
To learn more about how to combine eye tracking and different EEG systems and similar devices please visit Estefania Dominguez blog on http://gazesync.com