Smooth pursuit eye movements in psychiatric inpatients

Abstract

IntroductionEye movements are used in several studies as a biomarker in order to evaluate cortical alterations in psychiatric disorders. Pursuit eye movements’ deficits were found both in schizophrenia and in affective disorder patients. Nevertheless, these findings are still controversial.ObjectivesSet up a system to record and evaluate the eye movements in psychiatric patients.AimsTo verify the applicability of a smooth pursuit task in a sample of psychiatric inpatients and to prove its efficiency in discriminating patient and control group performance.MethodsA sample of psychiatric inpatients was tested at psychiatric service of diagnosis and care of AUSL Romagna-Cesena. Eye movement measures were collected at a sampling rate of 60 Hz using the eye tribe tracker, a bar plugged into a PC, placed below the screen and containing both webcam and infrared illumination. Subjects underwent to a smooth pursuit eye movement task. They had to visually follow a white dot target moving horizontally on a black background with a sinusoidal velocity. At the end of the task, a chart of the eye movements done is shown on the screen. Data are off-line analyzed to calculate several eye movement parameters: gain, eye movement delay with respect to the movement of the target, maximum speed and number of saccades exhibited during pursuit.ResultsPatients compared to controls showed higher delay and lower gain values.ConclusionsFindings confirm the adequacy of this method in order to detect eye movement differences between psychiatric patients and controls in a smooth pursuit task.Disclosure of interestThe authors have not supplied their declaration of competing interest.