Neurotological Evaluation of Susceptibility to Seasickness of Inexperienced Sailors

To clarify the relationship between susceptibility to seasickness and the function of the vestibular system, we examined 35 healthy male students in the second year of Toyama Fisheries High School (16 or 17 years old) before and after their first voyage, using the bithermal caloric test and the pendular rotational test (0.05 and 0.1 Hz). The results of the two tests were correlated with the severity of sea sickness, duration of sea sickness and the number of vomiting episodes. Thirty-three of 35 subjects (94%) suffered from sea sickness. The mean duration of sea sickness was 5.3 days, and the mean number of vomiting episodes was 5.5. In both the number of beats and the maximum slow phase velocity of caloric nystagmus, a significant correlation was found between the pre-voyage test results and the difference between the pre-vs. post-voyage test results (p< 0.05). Furthermore, these two parameters in the pre-voyage test were significantly correlated with the duration of sea sickness (p