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There are different theories cited as the cause of Motion Sickness. Asymmetrical otolithic organ function is one of the etiology theories of motion sickness. In our study, the aim was to reveal whether there is a cause originating from the sacculocolic reflex pathway in the physiopathology of seasickness. The patient group included 15 man sailors with diagnosis of seasickness and the control group included 15 man sailors without seasickness in our study. Cervical evoked myogenic vestibular potential (cVEMP) findings were compared between the groups. In the right and left ears of sailors with seasickness, the mean latencies of the p13 and n23 waves at 100, 95, and 90 dB normal hearing level (nHL) levels were found significantly shorter than in the control group (p < 0.05, for all). In the seasickness group, cVEMP interaural wave amplitude asymmetry ratio at 100 nHL level were found significantly higher than the control group (p = 0.001). The findings of our study indicated that there may be reasons arising rom the sacculocolic reflex pathway in the pathophysiology of seasickness. [ABSTRACT FROM AUTHOR]

Disorders related to labyrinth irritation (kinetosis) constitute a significant problem in sea travel, especially in sea service. A team of military researchers conducted research on a very large group (over 200 people) regarding the possibility of preventing seasickness through physical training. An original set of exercises was developed and performed by the study group. Then, the sensitivity of the test group and the control group to rocking was checked in laboratory and real conditions (sea cruise). The method has been shown to be over 50% effective in preventing and alleviating the symptoms of seasickness. The use of selected physical exercises may be an effective training against the risk of kinetosis. [ABSTRACT FROM AUTHOR]

Human passive motion during boat, car or airplane travel may trigger motion sickness. Seasickness is the most provoking manifestation of motion sickness. It imposes major constraints on quality of life and human performance. Based on seasickness susceptibility the population is usually categorized into susceptible (S) and non-susceptible (NS). During repeated exposure some susceptible individuals undergo habituation and obtain symptoms relief, reflecting a third group of habituating (H) individuals. Recently, accumulative evidence suggests that the vestibular time constant (Tc) is associated with motion sickness susceptibility and attenuation of symptoms. These studies demonstrated that repeated passive motion stimuli lead to temporary short-term (days) changes in Tc, whereas sea sickness habituation process lasts 3 to 6 months. Therefore, the goal of the present study was to examine the behavior of Tc during the entire span of the seasickness habituation process between the H, S and NS groups to find an objective test for seasickness severity prediction. Tc of 30 subjects was prospectively evaluated pre, 3 and 6 months post exposure to sea environment using a computerized rotatory chair system protocol. Seasickness severity was evaluated by Wiker questionnaire. Significantly shorter Tc was found in the S group compared with the NS and H groups. Further analysis revealed lower maximal Slow Phase Velocity (mSPV) and nystagmus frequency (total number of beats/second) in the S group. Our results suggest that Tc, mSPV and nystagmus frequency might serve as a prediction for seasickness severity. This study was retrospectively registered on December 7th 2022 and assigned the identifier number NCT05640258. [ABSTRACT FROM AUTHOR]

Available decision-support tools rarely account for the welfare of technicians in maintenance scheduling for offshore wind farms. This creates uncertainties, especially since current operational limits might make a wind farm accessible but the vibrations from transits might be unacceptable to technicians. We explore technician exposure to vibration in transit based on the levels of discomfort and the likelihood of seasickness occurring on crew transfer vessels (CTVs). Vessel motion monitoring systems deployed on CTVs operating in the North Sea and sea-state data are used in a machine learning (ML) process to model the welfare of technicians based on operational limits applied to modelled proxy variables including composite weighted RMS acceleration (aWRMS) and motion sickness incidence (MSI). The model results revealed poor to moderate performance in predicting the proxies based on selected model evaluation criteria, raising the possibility of more data and relevant variables being needed to improve model performance. Therefore, this research presents a framework for an ML approach towards accounting for the wellbeing of technicians in sailing decisions once the highlighted limitations can be addressed.

Motion sickness is known under several names in different domains, such as seasickness, carsickness, cybersickness, and simulator sickness. As we will argue, these can all be considered manifestations of one common underlying mechanism. In recent years, it has received renewed interest, largely due to the advent of automated vehicles and developments in virtual reality, in particular using head-mounted displays. Currently, the most widely accepted standard to predict motion sickness is ISO 2631-1 (1997), which is based on studies on seasickness and has limited applicability to these newer domains. Therefore, this paper argues for extending the ISO standard to cover all forms of motion sickness, to incorporate factors affecting motion sickness, and to consider various degrees of severity of motion sickness rather than just emesis. This requires a dedicated standard, separate from other effects of whole-body vibration as described in the current ISO 2631-1. To that end, we first provide a sketch of the historical origins of the ISO 2631-1 standard regarding motion sickness and discuss the evidence for a common mechanism underlying various forms of motion sickness. After discussing some methodological issues concerning the measurement of motion sickness, we outline the main knowledge gaps that require further research.

Disorders related to labyrinth irritation (kinetosis) constitute a significant problem in sea travel, especially in sea service. A team of military researchers conducted research on a very large group (over 200 people) regarding the possibility of preventing seasickness through physical training. An original set of exercises was developed and performed by the study group. Then, the sensitivity of the test group and the control group to rocking was checked in laboratory and real conditions (sea cruise). The method has been shown to be over 50% effective in preventing and alleviating the symptoms of seasickness. The use of selected physical exercises may be an effective training against the risk of kinetosis. [ABSTRACT FROM AUTHOR]

Thresholds that guide diagnoses of probable and acceptable seasickness levels on board ships are scarcely reported in literature. Motion sickness incidence and motion sickness dose value thresholds exist, but are defined for specific environments, such as naval, or offered merely as optional criteria for ship performance metrics. The presented work communicates a novel means of developing seasickness diagnostic criteria during ship operation, based on observations from shipboard measurement systems and seafarers using an innovative platform. The innovative platform provides personalised seasickness criteria that are accessible during ship operation to estimate the probable level of seasickness on board. Results are compared to that from a traditional method of data acquisition and analyses, post operation, revealing a similar trend in diagnostic threshold magnitudes (13–85 m/s1.5) that can be applicable to voyages with different durations (0.5–6 hr) considering desired levels of seasickness (10–50 %). The seasickness criteria are envisioned to be pertinent for the prediction of probable seasickness levels based on sea state forecasts and ship motion estimation. [ABSTRACT FROM AUTHOR]

Motion sickness is the cause of major physical discomfort and impaired performance in many susceptible individuals. Some habituate to sea conditions, whereas others remain chronically susceptible, requiring lifelong pharmaceutical treatment. The present study sets out to investigate whether galvanic vestibular stimulation (GVS) coupled with rotatory chair stimulation could mimic sea conditions and alleviate motion sickness symptoms in individuals deemed chronically susceptible. Thirty seasickness susceptible subjects, after at least six months of regular sailing, were enrolled in a prospective, single-blind, randomised controlled study. The treatment group underwent GVS coupled with inverse phase rotatory chair impulse in sinusoidal harmonic acceleration protocol. The control group underwent a sham procedure. All subjects performed repeated velocity step tests to determine the vestibular time constant (Tc) and completed a seasickness questionnaire. The GVS rotatory chair procedure decreased the prevalence of severe seasickness. The number of motion sickness clinic visits and anti-motion sickness drug consumption were reduced in the treatment group three-month post intervention as compared to control. In addition, there was significant reduction of Tc in the treatment group. GVS coupled with rotatory chair impulse could decrease motion sickness severity, induce neurophysiological learning processes and promote habituation to seasickness in chronic susceptible subjects. This is a novel and promising non-pharmacological method to treat motion sickness susceptible individuals. Furthermore, the investigation demonstrated that adaptation to sea conditions may take place even after years of susceptibility to seasickness. This study was retrospectively registered on August 10th 2021 and assigned the identifier number NCT05004818. [ABSTRACT FROM AUTHOR]

BackgroundGreater affluence and cheaper travelling have enabled a rapid increase in the number of people travelling around the world. About two thirds of travelers have experienced symptoms of motion sickness at least once. A known type of motion sickness is sea sickness.In extreme situations can concern as many as 60 % of even an experienced crew andas many as from 60 to 90% inexperienced sailors. Growing number research of is linking this disease to a psychosomatic reaction. The aim of the study was to review the literature on psychosomatic aspects of motion and seasickness and to evaluate them according to QUADAS-2 tool.Materials and methodsMaterials for this literature review were found by two authors using PubMed, ResearchGate, and Google Scholar databases. A combination of the keywords „seasickness”, „motion sickness”, „psychology” (according to Medical Subjects Headings- MeSH) was used to identify relevant studies. Finally, five publications were qualified for literature review. Each publication qualified for review was evaluated in accordance with the Quality Assessment Tool for Diagnostic Accuracy Testing (QUADAS-2).ResultsThe knowledge gained from 4 studies indicated that there is a relationship between the symptoms of motion- and seasickness and psychological conditions, and one of them suggests that these relationships are small.According to the QUADAS-2 tool, there is low possibility of making mistakes in patient selection and test indexes, but the studies are at risk of bias in terms of time and flow.ConclusionsConsidering all the reports on this subject, it is suggested that psychological factors related to personality traits, self-control and neuroticism have a significant impact on motion sickness, including seasickness. It is recommended to conduct further research on the subject.

Objectives The role of the cardiovascular system in the development of seasickness remains uncertain. Material and Methods Overall, 18 healthy students (10 males and 8 females) aged 18–24 years volunteered in the project, spending 2–7 h on life rafts. The cardiovascular system was examined with impedance cardiography. Susceptibility and symptoms of seasickness were evaluated by the Motion Sickness Susceptibility Questionnaire Shortform (MSSQ-Short) and the Motion Sickness Assessment Questionnaire (MSAQ). The Visual Analogue Scale (VAS), ranging 0–10, was used to assess nausea, dizziness and mood. The parameters were assessed at 2 time points. Results Differences in the heart rate (HR), the thoracic fluid content index (TFCI), the stroke index (SI) and the Heather index (HI) before launching the life rafts and after leaving them were observed (78.6, 20.8, 55.6 and 15.9 vs. 70.1, 19.7, 60.5 and 17.9, with p-values of 0.002,

BACKGROUND: The objectives were to assess the prevalence, severity, and medication taken, and to look for predictive factors in order to better identify characteristics of passengers at risk of motion sickness during transport from Hobart in Tasmania to the French polar stations in Antarctica. METHODS: There were 239 passengers who were surveyed over 4 yr with 4 round trips per year using the Motion Sickness Susceptibility Questionnaire (MSSQ), Simulator Sickness Questionnaire (SSQ), state-trait anxiety test (STAI -Trait and STAI - State), and general parameters (age, gender, number of trips, jet-lag, direction of the trip), medication, calculation of the distance of each passenger's cabin to the center of gravity (CoG). RESULTS: While the passengers had a low intrinsic sensitivity to motion sickness (MSSQ), 94% reported at least one SSQ symptom of motion sickness, and 38% vomited. Five associated factors were discovered: greater initial sensitivity (MSSQ), anticipation of being ill, younger age, higher level of anxiety at midtrip, and greater distance from the CoG. Of the passengers, there were 54% who took anti-motion sickness medication at different times of the trip, however, these passengers experienced more nausea. This could be due to self-selection since they were more sensitive to motion sickness. CONCLUSION: We identified three predictive factors of motion sickness (greater intrinsic susceptibility, younger age, and greater cabin distance from the CoG). For preventive purposes, two associated factors of MS (anticipation of being ill, MSSQ score) were determined to classify three groups of risk of MS to improve passenger care during the trip. [ABSTRACT FROM AUTHOR]

BACKGROUND: The effects of seasickness on working performance during motion exposure have been reported, while the aftereffects on working ability and life quality decline (WLD) still remain unclarified. METHODS: Two cohorts of healthy male Chinese subjects received either a single (SSV) or repeated (RSV) sea voyage training program on different vessels. A seasickness incidence (SSI) questionnaire was administered to assess the prevalence of seasickness symptoms (vomiting, nausea, other, or no symptoms). A WLD questionnaire was used to survey the general feeling of WLD (severe, moderate, slight, and none) by a 4-point score as well as the incidence rate (IR) of specific WLD items within 24 h after landing. RESULTS: The RSV cohort had lower overall IR of WLD than the SSV cohort (54.64% vs. 63.78%, N = 657 for both cohorts). The landing ship trainees in both cohorts showed higher general WLD score and higher IRs of physical fatigue, sleep disorder, and spontaneous locomotion decrement than those trained on the small vessels. Subjects with vomiting or nausea had higher general WLD score and higher IRs of concentration distraction, physical fatigue, anorexia, and spontaneous locomotion decrement than those with no symptoms. Higher IRs of firing accuracy decline (SSV: 21.35% vs. 7.13%, 9.14%; RSV: 22.11% vs. 9.28%, 5.27%), equipment operation disturbance (SSV: 16.85% vs. 3.57%, 6.85%; RSV: 20.47% vs. 7.85%, 7.03%) were also observed in the vomiting subjects than those with other symptoms and no symptoms. DISCUSSION: Significant WLD after landing was associated with transportation types, seasickness severity, and habituation during sea voyage training. [ABSTRACT FROM AUTHOR]

BACKGROUND: The vestibular system is important in the pathogenesis of seasickness. Our objective is to investigate whether routine vestibular tests detect seasickness. METHODS: Included were 17 professional naval personnel (mean age of 29.76 ± 4.73 yr) diagnosed as having seasickness and 29 healthy age- and gender-matched controls. Cervical (c) vestibular evoked myogenic potentials (VEMP) and ocular (o) VEMP and bithermal caloric tests were performed after ear, nose, and throat examination, pure tone audiometry, and magnetic resonance imaging. Severity of seasickness was evaluated based on the Graybiel scale. P1 latency, N1 latency, P1N1 amplitude, and interaural asymmetry ratios (IAR) of cVEMP and oVEMP were compared between the patients and control groups. Abnormal findings in the caloric test were noted. Presence of an abnormality in any of the three vestibular tests (cVEMP, oVEMP, or caloric test) was accepted as a positive vestibular finding. RESULTS: According to the Graybiel Scale, severe malaise and frank sickness were observed in 3 patients (18.7%) and 13 patients (81.3%), respectively. Graybiel scoring could not be performed in one patient due to general discomfort and bad general condition. In the caloric test, each of three patients (17.65%) showed canal paresis, an incomplete test because of severe nausea, and vomiting and hyperactive response. There were no significant differences in P1 latency, N1 latency, P1N1 amplitude, or IAR of cVEMP and oVEMP (P > 0.05). There were three patients (17.65%) and two patients (11.76%) who had abnormal IAR for cVEMP and oVEMP, respectively. CONCLUSION: Routine vestibular tests may detect some findings in only a minority of patients with seasickness. [ABSTRACT FROM AUTHOR]

Introduction: Novel therapies are needed for the treatment of motion sickness given the inadequate relief and bothersome and dangerous adverse effects of currently approved therapies. Neurokinin-1 (NK1) receptor antagonists have the potential to be effective in improving the symptoms of motion sickness, given the involvement of Substance P in nauseogenic and emetic pathways and the expression of NK1 receptors in the gastrointestinal system. Here we evaluated the efficacy of tradipitant, a novel NK1 receptor antagonist, in preventing motion sickness in variable sea conditions.Methods: A total of 126 adults participated in the Motion Sifnos study. Groups of participants were assigned to one of seven boat trips lasting ~4 h on the Pacific Ocean. Participants were randomized 1:1 to tradipitant 170 mg or placebo and completed the Motion Sickness Severity Scale (MSSS) every 30 min, in addition to other assessments. Severity of motion sickness was assessed with the incidence of vomiting and the MSSS.Results: Participants on tradipitant had a significantly lower incidence of vomiting as compared to those on placebo across all boat trips (tradipitant = 17.5%, placebo = 39.7%, p = 0.0039). For trips exposed to rough sea conditions, the difference in the incidence of vomiting between the groups was more dramatic (tradipitant = 15.79%, placebo = 72.22%, p = 0.0009). Across these trips, motion sickness symptoms were significantly lower in the tradipitant group compared to the placebo group (tradipitant = 3.19, placebo = 4.57, p = 0.0235).Discussion: Tradipitant has the potential to be an effective therapy for the prevention of vomiting and treatment of nausea in people with motion sickness.

Introduction: Novel therapies are needed for the treatment of motion sickness given the inadequate relief and bothersome and dangerous adverse effects of currently approved therapies. Neurokinin-1 (NK1) receptor antagonists have the potential to be effective in improving the symptoms of motion sickness, given the involvement of Substance P in nauseogenic and emetic pathways and the expression of NK1 receptors in the gastrointestinal system. Here we evaluated the efficacy of tradipitant, a novel NK1 receptor antagonist, in preventing motion sickness in variable sea conditions. Methods: A total of 126 adults participated in the Motion Sifnos study. Groups of participants were assigned to one of seven boat trips lasting ~4 h on the Pacific Ocean. Participants were randomized 1:1 to tradipitant 170 mg or placebo and completed the Motion Sickness Severity Scale (MSSS) every 30 min, in addition to other assessments. Severity of motion sickness was assessed with the incidence of vomiting and the MSSS. Results: Participants on tradipitant had a significantly lower incidence of vomiting as compared to those on placebo across all boat trips (tradipitant = 17.5%, placebo = 39.7%, p = 0.0039). For trips exposed to rough sea conditions, the difference in the incidence of vomiting between the groups was more dramatic (tradipitant = 15.79%, placebo = 72.22%, p = 0.0009). Across these trips, motion sickness symptoms were significantly lower in the tradipitant group compared to the placebo group (tradipitant = 3.19, placebo = 4.57, p = 0.0235). Discussion: Tradipitant has the potential to be an effective therapy for the prevention of vomiting and treatment of nausea in people with motion sickness. [ABSTRACT FROM AUTHOR]

Objectives: The role of the cardiovascular system in the development of seasickness remains uncertain.Material and Methods: Overall, 18 healthy students (10 males and 8 females) aged 18-24 years volunteered in the project, spending 2-7 h on life rafts. The cardiovascular system was examined with impedance cardiography. Susceptibility and symptoms of seasickness were evaluated by the Motion Sickness Susceptibility Questionnaire Shortform (MSSQ-Short) and the Motion Sickness Assessment Questionnaire (MSAQ). The Visual Analogue Scale (VAS), ranging 0-10, was used to assess nausea, dizziness and mood. The parameters were assessed at 2 time points.Results: Differences in the heart rate (HR), the thoracic fluid content index (TFCI), the stroke index (SI) and the Heather index (HI) before launching the life rafts and after leaving them were observed (78.6, 20.8, 55.6 and 15.9 vs. 70.1, 19.7, 60.5 and 17.9, with p-values of 0.002, <0.001, 0.003 and 0.004, respectively). Females reacted with changes in SI and HR more vividly, whereas males regulated more HI and TFCI. In addition, HR correlated significantly with the central and peripheral symptoms in MSAQ, stroke volume (SV) with peripheral and sopite-related ones, SI with overall ones, and pulse pressure with overall, gastrointestinal and central ones (Spearman's rank correlation coefficient [ρ] was -0.478, -0.711, 0.476, 0.472, 0.525, -0.476, -0.579 and -0.584, respectively). As regards MSSQ-Short, it correlated negatively with sopite-related symptoms in MSAQ (ρ= -0.486). Mood in VAS correlated significantly with gastrointestinal symptoms, SI and the cardiac index (CI) (ρ = -0.752, -0.492 and -0.489, respectively).Conclusions: It was found that HR correlated negatively, and SV/SI correlated positively, with the severity of seasickness symptoms measured with MSAQ. Gender is probably an independent factor influencing reactions to motion. Women react with SI increase whereas men react with increased heart contractility (HI rise). Negative mood in seasickness evaluated with VAS seems to be mostly determined by gastrointestinal symptoms assessed with MSAQ and diminished cardiovascular indices (both CI and SI). Int J Occup Med Environ Health. 2020;33(4):467-77. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Individual motion sickness susceptibility can be rapidly estimated by the motion sickness susceptibil ity questionnaire (MSSQ), but its stability is affected by various factors. The purpose of this study was to investigate the involved predictive factors of motion sickness screened with uniform samples of Chinese college students and to verify the individual susceptibility difference in marine navigation. METHODS: A total of 1051 college students (719 men, 332 women; mean age: 18.32 ± 0.65 yr) completed the MSSQ. Another 42 men (mean age: 21.12 ± 1.10 yr) took part in 2 separate voyages. MSSQ data were collected before saiiing and Graybiel motion sickness questionnaire (GMSQ) data were collected within 24 h after saiiing and 24 h before landing. RESULTS: The internal consistency of the MSSQ was 0.685. The mean subscore of the MSSQ-A (18.47 ± 19.49) was significantly higher than that of the MSSQ-B (12.69 ± 14.97). Women had significantly higher MSSQ scores (38.29 ± 33.49) than men (27.87 ± 30.27). The mean MSSQ score of the inland subjects (33.97 ± 33.35) was significantly higher than that of the coastal subjects (27.81 ± 29.24). Nearly 93% of new seafarers experienced seasickness during their first navigation. The MSSQ score was positively correlated with seasickness symptoms (r = 0.706). CONCLUSION: Gender, age, and birthplace appear to be important predictors of motion sickness for Chinese college students. Specifically, women, younger people, and people who were born in inland China seem more prone to the syndrome. A high MSSQ score is a risk factor for seasickness. However, long-term voyages can lead to habituation, which reduces the occurrence of seasickness. [ABSTRACT FROM AUTHOR]

Background: Motion sickness, is the onset of a series of clinical signs when travelling in a means of locomotion. Boats are the most common source of kinetosis, causing seasickness. Although this condition is often benign, it can severely affect the quality of life of seafarers, as well as the quality of their work. The aim of this study is to focus on the point prevalence and characteristics of seasickness in a population of French civilian seafarers from all shipping sectors., Materials and Methods: During two months in 2023, we conducted a cross-sectional study based on a questionnaire containing 28 questions., Results: One hundred nine men and 10 women completed the questionnaire. Of these, 34% said they were seasick. The main symptoms described by the sailors were nausea and cold sweats in 87.5% and 50% of cases, respectively. The prevalence of naupathy appears to be higher in women (60% compared with 31% in men). Women also seem to be less accustomed to the marine environment than men, with 71% of men and only 33% of women indicating that they get accustomed to life at sea. However, the symptoms of seasickness seem to disappear more slowly in men than in women. In terms of treatment, men (38%) were more likely to take medication than women (17%)., Conclusions: Our study shows a greater susceptibility to seasickness among women. This interpretation should be treated with caution given the small number of women who took part in the study. The relatively low point prevalence of seasickness (34%) could be due to under-reporting. Although ways of thinking are changing, seasickness is still a taboo subject for many sailors. Yet seasickness has major professional and personal repercussions. So it's important to raise the subject and discuss strategies for improving well-being at work.

Abstract Ship motions and their adverse effects have always been studied with the aim of reducing motions and accelerations using whatsoever plausible ways during both the ship design process and operating lifetime. In the present work, a simulation study is carried out by taking into consideration the passengers in several locations of the selected motor yacht in an intermediate sea state with Hs = 1 m. Irregular head wave scenario at Fn = 0.25 is investigated and a controller design is implemented to ensure that the calculated RMS vertical acceleration values are decreased to tolerated levels in terms of motion sickness index. First, wave loads are obtained in the time domain by using strip theory, linear superposition technique, and the most common realization technique. Then, using a linear two-degree-of-freedom mathematical model, in which pitch and heave motions are considered together with the direct solution of convolution integrals, the uncontrolled motions and accelerations are obtained. Then, the linear matrix inequalities based on robust static output feedback controller are designed to mitigate the vertical acceleration of the ship. Finally, the results obtained with the robust static output feedback control design are presented in numerical simulation studies to demonstrate the effectiveness of the proposed control approach. Highlights • Cummins' equation is used for the mathematical model in irregular waves. • Direct solution of the convolution integral is used for fluid memory effects. • It is aimed to mitigate vertical ship motions by designing a robust controller. • The results obtained with the static output feedback controller are presented. [ABSTRACT FROM AUTHOR]

The author consider the problem of motion sickness, analyze the causes of dizziness, and suggest various solutions.

Seasickness and its triggers, symptoms, and preventive measures were well known in antiquity. This chapter is based on an analysis of descriptions of motion sickness, in particular seasickness, in ancient Greek, Roman, and Chinese literature. A systematic search was made from the Greek period beginning with Homer in 800 BC to the late Roman period and ending with Aetios Amidenos in 600 AD, as well as in the Chinese medical classics dating from around 300 AD. Major aspects are the following: body movements caused by waves were identified in all cultures as the critical stimuli. The ancient Greeks and Romans knew that other illnesses and the mental state could precipitate seasickness and that experienced sailors were highly resistant to it (habituation). The Chinese observed that children were particularly susceptible to motion sickness; they first described the type of motion sickness induced by traveling in carts (cart-sickness) or being transported on a litter or in a sedan chair (litter-sickness). The western classics recommended therapeutic measures like fasting or specific diets, pleasant fragrancies, medicinal plants like white hellebore (containing various alkaloids), or a mixture of wine and wormwood. The East knew more unusual measures, such as drinking the urine of young boys, swallowing white sand-syrup, collecting water drops from a bamboo stick, or hiding earth from the kitchen hearth under the hair. The Greek view of the pathophysiology of seasickness was based on the humoral theory of Empedokles and Aristoteles and differed from the Chinese medicine of correspondences, which attributed malfunctions to certain body substances and the life force Qi. Many sources emphasized the impact of seasickness on military actions and famous naval battles such as the Battle of the Red Cliff, which marked the end of the Han dynasty in China, or the defeat of the Spanish Armada by the English in 1588. A peculiar form of motion sickness is associated with Napoleon's camel corps during the Egyptian campaign of 1798/1799, a sickness induced by riding on a camel. Thus, motion sickness in antiquity was known as a physiological response to unadapted body motions during passive transportation as well as a plague at sea. [ABSTRACT FROM AUTHOR]

The connotation of “nausea” has changed across several millennia. The medical term ‘nausea’ is derived from the classical Greek terms ναυτια and ναυσια, which designated the signs and symptoms of seasickness. In classical texts, nausea referred to a wide range of perceptions and actions, including lethargy and disengagement, headache (migraine), and anorexia, with an awareness that vomiting was imminent only when the condition was severe. However, some recent articles have limited the definition to the sensations that immediately precede emesis. Defining nausea is complicated by the fact that it has many triggers, and can build-up slowly or rapidly, such that the prodromal signs and symptoms can vary. In particular, disengagement responses referred to as the “sopite syndrome” are typically present only when emetic stimuli are moderately provocative, and do not quickly culminate in vomiting or withdrawing from the triggering event. This review considers how the definition of “nausea” has evolved over time, and summarizes the physiological changes that occur prior to vomiting that may be indicative of nausea. Also described are differences in the perception of nausea, as well as the accompanying physiological responses, that occur with varying stimuli. This information is synthesized to provide an operational definition of nausea. [ABSTRACT FROM AUTHOR]

Objective Seasickness is a widespread problem among naval crew, and has a major impact on their performance at sea. The three pharmacological agents most commonly employed in the treatment of seasickness are dimenhydrinate, cinnarizine, and scopolamine. At present, the effectiveness of anti-seasickness drugs is tested by a process of “trial and error”, while sailing and exposed to sea conditions. A physiological test to evaluate the action of a drug might save crew members long periods of suffering, as well as simplifying the procedure of selecting the appropriate treatment for each individual. The cervical vestibular evoked myogenic potentials (cVEMP) test has come to be recognized as a reliable procedure for the objective evaluation of saccular function. It was the hypothesis of the present study that cVEMP otolith responses may be affected by anti-motion sickness drugs, which might thus make cVEMP a useful clinical neurophysiological tool for the assessment of drug absorption and efficacy. Methods Thirty male sailors who regularly took medication for the treatment of seasickness participated in the study. Participants underwent the cVEMP test pre- and 1 h post-drug administration. Results A statistically significant decrease in p13 latency was found after administration of scopolamine compared with baseline (14.46 ms vs. 15.09 ms, p = 0.0049), with significant prolongation of the binaural average inter-latency in this group. No differences were found in the dimenhydrinate and cinnarizine study groups. Conclusions This study demonstrated that scopolamine absorption can be verified by changes in cVEMP latencies. Significance The potential of the cVEMP test for predicting action of scopolamine on the vestibular system. [ABSTRACT FROM AUTHOR]

On land, body sway during stance becomes coupled with imposed oscillations of the illuminated environment or of the support surface. This coupling appears to have the function of stabilizing the body relative to the illuminated or inertial environment. In previous research, the stimulus has been limited to motion in a single axis. Little is known about our ability to couple postural activity with complex, multi-axis oscillations. On a ship at sea, we evaluated postural activity using measures of body movement, as such, and we separately evaluated a direct measure of coupling between body movement and ship motion. Participants were tested while facing fore-aft and athwartship. We compared postural activity between participants who had been seasick at the beginning of the voyage and those who had not. Coupling of postural activity with ship motion differed between body axes as a function of body orientation relative to the ship. In addition, coupling differed between participants who had been seasick at the beginning of the voyage and those who had not. We discuss the results in terms of implications for general theories of postural control, and for prediction of susceptibility to seasickness in individuals. [ABSTRACT FROM AUTHOR]

BACKGROUND: Motion sickness is an unpleasant physiological state that may be controlled via nonpharmacological methods. Controlled breathing has been shown to maximize parasympathetic nervous system (PNS) tone and may have the ability to decrease motion sickness symptoms. METHODS: The effects of slow diaphragmatic breathing (DB) in a motion sickness-inducing environment were examined w ithin motion sickness susceptible individuals. Subjects (A/ = 43) were assigned randomly to either an experimental group trained in slow DB or a control group breathing naturally at a normal pace. The experimental group was trained using a digital video that helped them pace th e ir diaphragmatic breathing at six breaths/min. During the study, subjects viewed a virtual reality (VR) experience of a boat in rough seas for 10 min. Motion sickness ratings along w ith heart rate and respiration rate were collected before, during, and after the VR experience. RESULTS: Results indicated that the experimental group was able to decrease their breathing to eight breaths/min during the VR experience. This breathing rate was significantly slower than those in the control group. We found that DB subjects, compared to those in the control group, displayed significantly greater heart rate variability and reported feeling less motion sickness during exposure to the VR experience than those in the control group. DISCUSSION: Results indicate possible benefits of using slow DB techniques in a motion sickness inducing environment, [ABSTRACT FROM AUTHOR]

The paper discusses the results of the author's experiment aimed at determining the effects of physical exercises, particularly rapid changes of head position, on susceptibility to motion sickness. Navy sailors underwent trainings followed by test cruises under real circumstances. The method was found to be of about 50% effectiveness; intensive physical training alleviated the complaints during cruises in about half of the study population. [ABSTRACT FROM AUTHOR]

BACKGROUND: Seasickness is a risk aboard a ship. Histamine is postulated as a causative agent, inversely related to the intake of vitamin C. Persons with mastocytosis experienced improvement of nausea after the intake of vitamin C. OBJECTIVE: To determine whether vitamin C suppresses nausea in 70 volunteers who spent 20 minutes in a life raft, exposed to one-meter-high waves in an indoor pool. METHOD: Double-blind placebo-controlled crossover study. Two grams of vitamin C or placebo was taken one hour before exposure. Blood samples were taken one hour before and after exposure to determine histamine, diamine oxidase, tryptase, and vitamin C levels. Symptom scores were noted on a visual analog scale. On the second day the test persons were asked which day they had felt better. RESULTS: Seven persons without symptoms were excluded from the analysis. Test persons had less severe symptoms after the intake of vitamin C (p< 0.01). Scores on the visual analog scale were in favor of vitamin C, but the difference was not significant. Twenty-three of 63 persons wished to leave the raft earlier: 17 after the intake of placebo and 6 after the intake of vitamin C (p< 0.03). Women (p< 0.02) and men below 27 years of age (p< 0.02) had less pronounced symptoms after the intake of vitamin C. Histamine (p< 0.01) and DAO levels were increased after the intake of vitamin C (p< 0.001) and after placebo (n.s.). The fact that the second test day was rated less stressful by most volunteers is indicative of habituation.CONCLUSIONS: Some of the data show that vitamin C is effective in suppressing symptoms of seasickness, particularly in women and men younger than 27 years of age, and is devoid of side effects. Histamine levels were initially increased after the test persons had been exposed to waves. [ABSTRACT FROM AUTHOR]

Highlights: [•] This prospective study examines the cervical vestibular evoked myogenic potential (cVEMP) test as an objective tool for the prediction of continued susceptibility and habituation to seasickness. [•] cVEMP thresholds differed significantly between crewmembers who had become habituated to seasickness and those remaining severely susceptible. [•] The lower cVEMP thresholds observed in the habituation group imply a broader dynamic range, which may facilitate the process of habituation to sea conditions. [Copyright &y& Elsevier]

Summary: Objectives: Seasickness corresponds to all of the clinical symptoms experienced by a subject at sea related to boat movements. The objective of this study was to evaluate the efficacy of optokinetic training versus placebo in the treatment of seasickness. Material and methods: Fifteen subjects were randomized to either an optokinetic training arm or a placebo arm. The impact of seasickness was evaluated for each subject before and after optokinetic training using the Graybiel scale. Results: Among the trained subjects, 71.4% were improved by optokinetic training versus 12.5% of control subjects. A significant difference was observed for Graybiel scores before and after optokinetic training in the training arm. Conclusion: Optokinetic training appears to be an effective modality for the management of disabling seasickness. This training can be further improved by more global patient management. [Copyright &y& Elsevier]