New method of visual disturbances assessment in pilots during tests in the Polish human centrifuge.
OBJECTIVE
Visual disturbances are commonly accepted criteria for acceleration tolerance assessment. Researchers during centrifuge experiments use them as a safe criterion for cessation of acceleration exposure. Visual disturbances analysis is a non-invasive method of assessing retinal blood flow. Limitation of visual stimuli perception is a measure of physiological state of the experiment participants before hemodynamic changes, which reach a critical level manifested by G-induced loss of consciousness. Detection of these disturbances play an important role during the acceleration tolerance assessment. In this study, an attempt was made to answer the question on how many mistakes or incorrect reactions had to be identified to classify the ability of the pilot to fly on military jets.


METHODS
A new computer-aided research apparatus of our own design was used to assess visual disturbances, being a criterion of +Gz tolerance. In the center of monitor screen, a line of 3 light points was projected. During the centrifuge test, green lateral lights randomly changed their shapes from circles to squares while central light, being a point of vision fixation, remained unchanged. To assess its efficacy, 14 volunteers participated in the tests with various stimuli exposure. The authors aimed at selecting parameters of stimuli and exposure so that the division of reactions presented in the table would correspond with the score scale appropriate for our goals.


RESULTS
Preliminary tests showed that appropriately selected light intensity of the exposed stimuli enables the use of test results to assess the number of erroneous reactions, and consequently the level of pilots' concentration during centrifuge tests.


CONCLUSIONS
It has been found that the chosen luminance range of the projected light points is correct as it allows to evaluate the reactions, which should be considered erroneous. Additionally, prolongation of the correct reaction time to the mean value of about 400 ms facilitates better differentiation of results. Proper results evaluation, depending on the number of errors, lack of reactions or prolonged reactions made the assessment easier with computer-aided methods.
Wołkanowski
Marek
M
Polish Air Force Institute of Aviation Medicine, Krasińskiego 54, 01-755 Warsaw, Poland. mwojtkow@wiml.waw.pl
Truszczyński
Olaf
O
Wojtkowiak
Mieczysław
M
D000054:Acceleration / Q000009:adverse effects*; D000328:Adult; D000337:Aerospace Medicine; D002498:Centrifugation / Q000379:methods*; D006801:Humans; D018471:Hypergravity / Q000009:adverse effects*; D009784:Occupational Diseases / Q000209:etiology* / Q000517:prevention & control; D010775:Photic Stimulation; D011044:Poland; D012171:Retinal Vessels; D012307:Risk Factors; D014474:Unconsciousness / Q000209:etiology / Q000517:prevention & control; D014786:Vision Disorders / Q000209:etiology* / Q000517:prevention & control