An automated saccade analysis system
James Robert Brown · OhioLink ETD Center (Ohio Library and Information Network) · 1977
subjects wearing eyeglasses, and.design and write the entire computer software package to manage data input, output, and processing for saccadic response data.Present capablilities of the system are such that (l) subjects view the test target with normal binocular vision and the monitored eye is not touched in any way, (2 ) untrained subjects, even those wearing eyeglasses, may be tested with relative ease, (3 ) computer analysis of recorded responses to step target deflections will extract response latency and settling times, and (4-) rapid testing may be done -total system efficiency, including the subject's time (with rest periods) and all processing time, is about one saccade per minute for large batches of deflection trials.Preliminary testing of the saccade analysis system has been done, recording and analyzing nearly 1 6 0 0 saccadic responses made by four subjects.The system performs well and is easy to use for both experimenter and subject.Results from these preliminary trials indicate that saccadic responses to target step deflections are not the same for different directions, nor are they the same for all subjects.These results are presented later.Ho attempt will be made to generalize the data presented to include the populace as a wholej the subject sample is much too small.THE AUTOMATED SACCADE ANALYSIS SYSTEM System Overview The automated saccade analysis systea la a rapid, highly accurate, easy to use, computer based system, providing the researcher with the means to evaluate human saccadic eye rotation responses to two-dimensional step deflections of a point target* Subjects may be untrained, and within broad limits, may, if necessary, wear their own eyeglasses during tests* The system measures two-dimensional angular rotation of the subject's right eyo while the subject views the target, a very small, bright spot on an oscillosobpe screen.Binocular vision is permitted* During testing, the subjeot is instructed to fixate on the target as well as possible and each saccade trial consists of a step target deflection from the center of the screen* Target deflections may be generated along any of twenty-four fixed angular directions and out to four fixed radii from the central position* Deflections may be preassigned by the experimenter or sets of deflections may be generated at random by the saccade target deflector circuitry* The subject's "step?1 response to each target deflection Is monitored, encoded, and itored by the system computer for latex analysis.Computer analysis of each response yields first saccade latency and response settling times to four different radii about the target position, as well as performing regularity checks to insure "normalcy" of each response 5 analysed* Special plotting programs allow the user to plot these results for hatches of responses as either functions of deflection angle or deflection radius* Total system efficiencyv from seating the subject to plotting results, is about one saccadic response per minute for large batches of trials.Major hardware conponents of the saccade analysis system are (l) the saccade target deflector and oscilloscope, to provide visual stimuli to the subject, (2) a modified Comsweet-Crane eyetracker, to monitor the angular rotations of the subject* s eye movement response, (3 ) a FDP-8 /E computer, to collect and analyze response data, (If) a dual flexible disk system to provide mass data storage, and (5 ) & digital plotter, to plot raw response data or the results of computer processing of many resonses* Software components develped specifically for the saccade analysis system Include the four major programs ADIS01, APLOTO, SHI OUT, and SSPLOT* All programs are FORTRAN II with intermixed SABR (Digital Equipment Corporation assembly language) programming, and all programs are called and controlled by teletype keyboard commands* ADI SOI programming manages computer collection and disk data file storage of eyetracker output data and AFLCTO is a plotter package used to plot the raw data stored in this data files* SIR OUT processes batches of ADI301-created data files of saccade responses to target deflections, storing the results as a summary data file on disk* SSELOT is a special plotter program designed to plot the summarized data stored in a SPRCUT-created saccade summary data file*