OBJECTIVETo investigate the effect of infrasonic field of minesweeper on psychology of minesweeper crews.

METHODSAn experimental ship was selected to conduct infrasonic minesweeping, a control ship of the same type was selected to operate likewise with the infrasound generator turned off, and another group of coast-servicemen was chosen as blank control. Attention-span test, digit memory test, two-digital numbers list and profile of mood states (POMS) were used to test the ship crews and coast-servicemen.

RESULTSThere were no significant differences in psychological parameters between the two ship crews before the experiment. But the scores of two-digit figures list in ship crews were significant lower than that in coast-servicemen, (31.2 +/- 11.8, 36.4 +/- 14.5 respectively vs 45.8 +/- 13.9, P < 0.05). POMS showed that the scores of anger-hostility, fatigue-inertia, and confusion-bewilderment in both ship crew groups [(15.5 +/- 6.4, 18.3 +/- 6.8), (12.1 +/- 5.0,12.3 +/- 4.9), (11.6 +/- 4.4, 12.5 +/- 4.8), respectively] were higher than those in coast-servicemen (13.9 +/- 7.0, 7.6 +/- 4.1, 8.2 +/- 4.3, respectively, P < 0.05 or 0.01), while vigor-activity in experimental group (15.0 +/- 5.9) was lower than that in coast-servicemen (19.7 +/- 4.7). After the experiment, the scores of experimental crews in digit memory test (14.5 +/- 5.0), vigor-activity (12.2 +/- 5.8), fatigue-inertia (15.8 +/- 6.2) were significantly different from those of control crews (17.3 +/- 4.8, 16.5 +/- 4.6, 11.3 +/- 5.1).

CONCLUSIONSThe infrasonic field from minesweeper may injure the crew's psychological health and some neurobehavioral function.