Document Type : Research Article
Authors
1
Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran.
2
. Djavad Mowafaghian Research Center for Intelligent Neuro-rehabilitation Technologies, Sharif University of Technology, Tehran, Iran.
3
.Djavad Mowafaghian Research Center for Intelligent Neuro-rehabilitation Technologies, Sharif University of Technology, Tehran, Iran.
10.24200/sci.2026.68732.11350
Abstract
While Parkinson’s disease (PD) is widely recognized for its motor symptoms, it also significantly impacts eye movements. Consequently, researchers are exploring saccade parameters as potential diagnostic biomarkers. However, current literature suggests that standard metrics—specifically latency, amplitude, and peak velocity—lack the sensitivity to serve as standalone diagnostic tools. This limitation likely stems from the inherent complexity of PD, coupled with the high intra-trial variability and the demanding "high-speed, high-accuracy" nature of saccadic movements.
This study investigated pro-saccade parameters in 15 individuals with PD (on medication) and 15 age- and sex-matched neurologically healthy controls (HC). Aimed to explore dynamic characteristic of saccades, landing-error-to-amplitude ratio, amplitude and area under curve (AUC) of saccade displacement trajectory, along with peak, median, and average velocity, and high-velocity-percentage (HVP), i.e. percent of saccade duration with velocity above median, were examined in distinguishing PD patients from HC group.
We found that high-velocity-percentage (HVP) was significantly higher (p = 0.015) and landing-error-to-amplitude ratio was significantly lower (p = 0.002) in the HC group. However, peak, median and average velocity, amplitude and AUC of saccade displacement did not show significant differences between the two groups. Although sensitivity and specificity values were not high, the two introduced parameters provided some discriminatory ability compared to standard metrics with no discrimination. These findings suggest that parameters offering a holistic perspective on saccadic position and velocity profiles may be more effective at distinguishing between PD patients and healthy controls (HC).
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