TEMPORAL PARAMETERS OF SACCADIC EYE MOVEMENTS IN PATIENTS WITH PARANOID SCHIZOPHRENIA AND PERSONS AT RISK OF FIRST PSYCHOSIS
The study was aimed at determining the eye fine motility in schizophrenic patients and in persons at a high risk of the first psychosis. The article presents the results of the saccade tests of 143 patients with paranoid schizophrenia, 46 patients with the first psychosis risk syndrome, and 61 mentally healthy individuals. We used a video-nystagmograph provided with a complex for registration and plotting. The average saccade speed (р) for all groups when the stimulus moved to the left was 449.57s and to the right 451.57s corresponding to the normal physiological values. A study of the accuracy of the saccades for a constant signal rate showed that this index was significantly impaired only in patients with predominantly negative disorders when the stimulus moved to the right (F 14.6, P<0.0001) and to the left (F21.4, P<0.001). The average saccadic latency for the eye movement was 284±5 ms to the left and 286±5 ms to the right in the patients of this group at a constant and random stimulus rate. The random signal during the nystagmography after 10 minutes of stimulation led to a gross violation of the saccades accuracy in all the subgroups of comparison and the high-risk group in comparison with the control. The most evident violation of the saccades accuracy was found in the schizophrenia group with the leading disorganization syndrome when the stimulus moved to the right (F 48.5; P<0.001) and to the left (F 60.3; P<0.0001). The accuracy reducing and horizontal prosaccades latency increasing might be considered a biological marker of negative symptoms in schizophrenia. The horizontal prosaccades accuracy violation under a random signal indicated at a deficiency in working of the brain detector of the saccade errors correction and in the organization of the total mental activity representing one of the basic neurocognitive deficits of schizophrenia.