STH MULTIDISCIPLINARY INTERNATIONAL

Conference of Biological Psychiatry

«Stress and Behavior»

Proceedings of the 9th International Multidisciplinary Conference «Stress and behavior» Saint-Petersburg, Russia, 16-19 May 2005 Editor: Allan V. Kalueff, PhD

CONFERENCE ABSTRACTS 2. SLEEP AND BEHAVIOR

EEG AND REACTION TIME: PERFORMANCES ANALYSES AT NIGHTTIME EXPERIMENTS

V.B. Dorokhov, T.M. Lavrova, P.V. Yakimovich,

V.V. Dementienko, A.G. Markov, V.M. Shakhnarovich

Institute of Higher Nervous Activity and Neurophysiology RAS; J-S Co. Neurocom, Moscow, Russia Impaired wakefulness in machine operators represents a danger for both themselves and the general public. While on duty, such persons are expected to be continuously, i.e., without interruption, on the alert. For this, we have designed experimental model of continuous vigilance monitoring using electroencephalography (EEG) and reaction time.

Method: The long lasting experiments took place at nighttime (22.00—05.00 h) on 6 young adult men (18—26 years) in 5 separate experiments (30 experiments). The participants were half-lying in an armchair in a darken room with open eyes and underwent psychomotor vigilance test (pressing the button of joystick the right or left hand). After a green-light flash, participants pressed the button by right hand, and after a red-light flash, they had to press button with the left hand. Inter-stimuli intervals varied from 2 to 4 s. The probability of occurrence was 70% (green flash) and 30% (red flash). For activity support during all night, the participants were allowed to have a break 4—5 times for 10—15 minutes. For data registration, we used digital 54-channel polygraph «SAGURA-2000» (MKE Medizintechnik GmbH, Germany). We registered: 6 channels of EEG (F3, F4, C3, C4, O1, 02), EOG (horizontal and vertical movements of eyes) and polygraphical parameters: EDR, ECG, EMG, breathing, SpO2, pressing buttons and the video-image of the subjects.

Data analyses. Reaction time varied rather widely, between 200 and 1000 ms. EEG power (FFT) in 6 standard EEG-ranges, for 5 s artifact free epoch was measured.

Results: At lengthening time of the reaction and error appearance, caused by development of a drowsy condition, the most indicative changes were observed in an alpha and theta/delta — ranges of EEG. The direction of changes EEG was similar in all subjects: at decrease of a level of wakefulness, the EEG power in an alpha and theta/delta ranges markedly increased. Importantly, the individual differences in character of these changes have to be taken into account while creating monitoring systems to control the level of wakefulness.

Psychopharmacol. Biol. Narcol. 2005. Vol. 5, N 2. P. 892—893 Psyhopharmacology & biological narcology

ISSN 1б0б—8181