| Abstract |
| This study quantitatively investigated the effects of the sampling frequency of eye-tracking equipment on gaze metrics and response classification performance in a saccade-based eye movement task. Thirty healthy older adults performed an interleaved prosaccade and antisaccade task. Eye gaze data were collected at a baseline frequency of 300 Hz and then downsampled to a range of 30-200 Hz for analysis. The lower sampling frequencies led to significant changes in gaze metrics. Specifically, saccade latency increased by more than 27 ms, whereas saccade amplitude decreased by approximately 2-3°. Additionally, peak velocity dropped by 90-120°/s. Fixation duration increased by as much as 397 ms, and fixation variability rose sharply by approximately three-fold in the prosaccade condition and up to 10-fold in the antisaccade condition. Conversely, the position error relative to the target remained mostly stable. The performance of gaze response classification was assessed using evaluation metrics. At sampling frequencies of ≥90 Hz, the performance remained stable, with accuracy ≥.98, precision ≥.99, F1 score ≥.99, and Cohen’s kappa ≥.95. However, at sampling frequencies of ≤60 Hz, the F1 score dropped to ≤.91, and Cohen’s kappa fell to ≤.63. These findings suggest that the sampling frequency substantially affects the accuracy and reliability of gaze analysis in eye tracking-based saccadic movement studies. A minimum sampling frequency of 90 Hz is recommended to ensure the extraction of gaze metrics and the performance of response classification. |
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| Key Words |
| Eye Tracking, Sampling Frequency, Interleaved Saccade Task, Gaze Analysis, Response Classification, 시선추적, 샘플링 주파수, 혼합형 신속보기 과제, 안구운동 분석, 반응 분류 |
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