Abstract: Objective To analyze the differences in accuracy of different eye movement parameters in distinguishing the cooperation and non-cooperation during image completion test of patients with mental disorders caused by craniocerebral trauma. Methods One hundred and forty cases of patients with mental disorders caused by craniocerebral trauma who took psychiatric impairment assessments were collected. The 21 pictures from “image completion” of Wechsler intelligence test were used as stimulating pictures, then divided into cooperation group and non-cooperation group according to binomial forced-choice digit memory test and expert opinions. The eye movement parameters of research subjects during completion of images were obtained by the SMI eye-tracker. The accuracy of eye movement parameters in distinguishing the cooperation or non-cooperation of patients with mental disorders caused by craniocerebral trauma in psychiatric impairment assessments were evaluated by the ROC curve. Results During the process of the image completion test, the area under curve （AUC） value of frequency of blink, frequency of fixation, pupil size, frequency of saccade, latency of saccade, average acceleration of saccade, the average and peak longitudinal velocity of saccade was above 0.5. When it comed to a specific stimulating picture, the AUC value of frequency of blink in looking at a specific stimulating picture could be above 0.8, and the AUC value of X axis diameter of pupil size could be above 0.7. Conclusion The accuracy of eye movement parameters in distinguishing the cooperation or disguise of patients with mental disorders caused by craniocerebral trauma is related with the stimulating picture. The accuracy of frequency of blink in distinguishing cooperation and non-cooperation is better than that of other eye movement parameters.

Key words: forensic psychiatry, disability evaluation, eye movements, cooperative behavior, accuracy