Reduced eye gaze fixation during emotion recognition among patients with temporal lobe epilepsy

To investigate the facial scan patterns during emotion recognition (ER) through the dynamic facial expression task and the awareness of social interference test (TASIT) using eye tracking (ET) technology, and to find some ET indicators that can accurately depict the ER process, which is a beneficial supplement to existing ER assessment tools.

Ninety-six patients with TLE and 88 healthy controls (HCs) were recruited. All participants watched the dynamic facial expression task and TASIT including a synchronized eye movement recording and recognized the emotion (anger, disgust, happiness, or sadness). The accuracy of ER was recorded. The first fixation time, first fixation duration, dwell time, and fixation count were selected and analyzed.

TLE patients exhibited ER impairment especially for disgust (Z =  - 3.391; p = 0.001) and sadness (Z =  - 3.145; p = 0.002). TLE patients fixated less on the face, as evidenced by the reduced fixation count (Z =  - 2.549; p = 0.011) of the face and a significant decrease in the fixation count rate (Z =  - 1.993; p = 0.046). During the dynamic facial expression task, TLE patients focused less on the eyes, as evidenced by the decreased first fixation duration (Z =  - 4.322; p = 0.000), dwell time (Z =  - 4.083; p = 0.000), and fixation count (Z =  - 3.699; p = 0.000) of the eyes.

TLE patients had ER impairment, especially regarding negative emotions, which may be attributable to their reduced fixation on the eyes during ER, and the increased fixation on the mouth could be a compensatory effect to improve ER performance. Eye-tracking technology could provide the process indicators of ER, and is a valuable supplement to traditional ER assessment tasks.