Relationship between postural control and motion sickness in healthy subjects.

Owen N, Leadbetter AG, Yardley L.

Department of Psychology, University College London, UK.

This study examined the relationship between reported susceptibility to motion sickness, anxious personality and postural control. Postural stability was assessed in 34 healthy subjects standing with eyes open, eyes closed and viewing a disorienting virtual reality display. These measures were repeated with vibration of the calf muscles to distort the somatosensory feedback from the legs. Susceptibility to motion sickness and anxious personality were evaluated by questionnaire. Greater postural instability was correlated with susceptibility to motion sickness. Motion sickness susceptibility correlated most strongly with increased sway when the visual and somatosensory feedback was absent or distorted. Anxiety was correlated with reported susceptibility to motion sickness but not with postural stability. These findings suggest that deficient perceptual-motor responses to disorienting conditions may contribute to motion sickness susceptibility.

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Cabin location and the likelihood of motion sickness in cruise ship passengers.

Gahlinger PM.

Rocky Mountain Center for Occupational and Environmental Health, University of Utah, Utah, USA.

BACKGROUND: The prevalence of motion sickness approaches 100% on rough seas. Some previous studies have reported a strong association between location on a ship and the risk of motion sickness, whereas other studies found no association. This study was undertaken to determine if there is a statistical association between the location of the passenger cabin on a ship and the risk of motion sickness in unadapted passengers. METHODS: Data were collected on 260 passengers on an expedition ship traversing the Drake Passage between South America and Antarctica, during rough sea conditions. A standard scale was employed to record motion sickness severity. RESULTS: The risk of motion sickness was found to be statistically associated with age and sex. However, no association was found with the location of the passenger cabin. CONCLUSIONS: Previous research reporting a strong association of motion sickness and passenger location on a ship, studied passengers in the seated position. Passengers who are able to lie in a supine position are at considerably reduced risk of motion sickness. Expedition or cruise ships that provide ready access to berths, allow passengers to avoid the most nauseogenic positions. The location of the passenger cabin does not appear to be related to the likelihood of seasickness.

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Motion sickness susceptibility questionnaire revised and its relationship to other forms of sickness.

Golding JF.

Department of Psychology, University of Westminster, London, UK. goldinj westminster.ac.uk

The Reason and Brand Motion Sickness Susceptibility Questionnaire (MSSQ) has remained unchanged for a quarter of a century. The primary aims of this investigation were to improve the design of the MSSQ, simplify scoring, produce new adult reference norms, and analyse motion validity data. We also considered the relationship of sickness from other nonmotion causes to the MSSQ. Norms and percentiles for a sample of 148 subjects were almost identical to the original version of this instrument. Reliability of the whole scale gave a Cronbach's standardised item alpha of 0.86, the correlation between Part A (child) and Part B (adult) was r = 0.65 (p < 0.001), and test-retest reliability may be assumed to be better than 0.8. Predictive validity of the MSSQ for motion sickness tolerance using laboratory motion devices averaged r = 0.45. Correlation between MSSQ and other sources of nausea and vomiting in the last 12 months, excluding motion sickness itself, was r = 0.3 (p < 0.001), migraine was the most important contributor to this relationship. In patients (n = 101) undergoing chemotherapy, there were significant correlations between MSSQ and chemotherapy-induced nausea and vomiting. Migraine also appeared as a predictor of chemotherapy-induced sickness. It was concluded that the revised MSSQ can be used as a direct replacement of the original version. The relationship between motion sickness susceptibility and other causes of sickness, including migraine and chemotherapy, points to the involvement of the vestibular system in the response to nonmotion emetogenic stimuli. Alternatively, this relationship may reflect individual differences in excitability of the postulated final common emetic pathway.

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Influence of different conditions for tilt compensation on symptoms of motion sickness in tilting trains.

Forstberg J, Andersson E, Ledin T.

Swedish National Road and Transport Research Institute, Railway Systems, Linkoping. johan.forstberg vti.se

Increased speeds of trains can be achieved by using tilting trains that decrease the lateral acceleration experienced by passengers on curves, thereby allowing trains to run typically 25-30% faster on existing curved track and maintaining good ride comfort. Unfortunately, motion sickness in tilting trains is a major problem for some passengers. To investigate the incidence of motion sickness and the extent to which different tilt compensation strategies influence its occurrence, tests were conducted with a tilting train on a track with a large number of curves. Eighty healthy volunteers were studied, selected partly for their susceptibility. Three different cars were evaluated during 3 test days, with each test ride lasting about 3 h. On four occasions per test ride, the subjects answered a questionnaire concerning activities during the ride, ride comfort, ability to work and read, vegetative symptoms, fatigue, sleepiness, nausea and well-being. Subjects estimation of average ride comfort and ability to work and read was good in all conditions. However, 10% of the test subjects reported various symptoms of motion sickness (SMS). A 55% degree of tilt compensation of the lateral acceleration instead of the normal 70% reduced the symptoms of motion sickness incidence (SMSI) by 25-40%. SMSI correlated poorly with motion doses, which integrates vertical or lateral acceleration but correlated well with roll acceleration motion dose (r2 = 0.43, p < 0.001). For women, riding backward (p < 0.001) minimized SMSI, but men were insensitive to direction. Future railway design will have to optimize tilt systems by both minimizing motion sickness and avoiding excessive lateral acceleration or jerk.

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Coriolis effects and motion sickness modelling.

Bles W.

TNO Human Factors Research Institute, Soesterberg, The Netherlands. Bles TM.TNO.NL

Coriolis effects are notorious in relation to disorientation and motion sickness in aircrew. A review is provided of experimental data on these Coriolis effects, including the modulatory effects of adding visual or somatosensory rotatory motion information. A vector analysis of the consequences of head movements during somatosensory, visual and/or vestibular rotatory motion stimulation revealed that the more the sensed angular velocity vector after the head movements is aligned with the gravitoinertial force vector, the less nauseating effects are experienced. It is demonstrated that this is a special case of the subjective vertical conflict theory on motion sickness that assumes that motion sickness may be provoked if a discrepancy is detected between the subjective vertical and the sensed vertical as determined on the basis of incoming sensory information.

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Impaired gastric slow waves induced by spatial disorientation and effect of domperidone.

Kono T, Tokumaru O, Mizumoto C, Tatsuno J, Chen JD.

The Department of Physiology, 2nd National Defense Medical College, Tokorozawa, Japan.

OBJECTIVES: Our aims were to investigate the dominant frequency and regularity of gastric myoelectrical activity during motion sickness induced with the advanced spatial disorientation demonstrator (ASDD) and to evaluate the effect of domperidone on gastric myoelectrical activity and gastrointestinal symptoms during motion sickness. METHODS: Thirteen healthy volunteers participated in this study. This study was executed using the ASDD, which could duplicate several spatial disorientation phenomena in a safe, controlled environment. Each subject participated in two sessions and received oral administration of 10 mg domperidone before the study in one of the sessions. In each session, three 15-min EGG recordings were made before, during, and after rotation. The symptoms were scored by Graybiel's scale of motion sickness before and after rotation. All EGG data were subjected to computerized spectral analysis to obtain the percentage of normal 2-4 cycles/min (cpm) slow waves, percentage of tachygastria, EGG dominant frequency and power, and instability coefficient of the dominant frequency. RESULTS: We have found that the percentage of normal gastric slow wave was decreased (control session: 86.2 +/- 4.0% vs 70.0 +/- 5.4%, p < 0.01; domperidone session: 82.7 +/- 4.6% vs 69.8 +/- 5.6%, p < 0.03) and the percentage of tachygastria was increased (control session: 8.7 +/- 3.2% vs 17.8 +/- 5.6%, p < 0.01; domperidone session: 9.2 +/- 3.3% vs 18.1 +/- 3.5%, p < 0.01) after rotation in both sessions. The minute-by-minute variation of the gastric slow wave frequency was significantly increased during rotation in both sessions (control: 0.74 +/- 0.16 vs 1.35 +/- 0.19, p < 0.01; domperidone: 0.90 +/- 0.20 vs 1.47 +/- 0.17, p < 0.01). Domperidone did not prevent dysrhythmia or the symptoms of motion sickness. CONCLUSIONS: The percentage of normal gastric slow waves is decreased and the percentage of tachygastria is increased with spatial disorientation. Domperidone does not prevent gastric dysrhythmia or the symptoms of motion sickness induced with spatial disorientation.

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Systematic investigation of physiological correlates of motion sickness induced by viewing an optokinetic rotating drum.

Hu S, McChesney KA, Player KA, Bahl AM, Buchanan JB, Scozzafava JE.

Department of Psychology, Humboldt State University, Arcata, CA 95521, USA. sh4 axe.humboldt.edu

PURPOSE: This study investigated the physiological correlates of motion sickness provoked by viewing an optokinetic rotating drum. METHOD: A total of 52 subjects viewed an optokinetic rotating drum for 16 min. Subjective symptoms of motion sickness (SSMS) and ratings of over-all sickness were measured during the drum rotation. Electrogastrogram (EGG), electroencephalogram (EEG), electrocardiogram, and skin conductance were measured as physiological correlates of motion sickness. RESULTS: Analysis by Pearson's correlation showed that the subjects who had higher scores of SSMS during the drum rotation generated the following: a) a higher rating of over-all sickness (r = 0.76); b) a higher ratio of spectral power of EGG at 4-9 cycles per minute (cpm) between drum rotation and baseline periods (r = 0.63); c) a higher net percent increase of spectral power in the EEG frequency band 0.5-4 Hz between drum rotation and baseline periods on C3 (r = 0.29) and C4 (r = 0.31); d) a higher ratio of spectral power of EEG frequency band 0.5-4 Hz between drum rotation and baseline periods on C3 (r = 0.31); and e) a higher level of net increase in skin conductance from baseline to drum rotation (r = 0.30). CONCLUSION: The increase of EGG at 4-9 cpm activity, gastric tachyarrhythmia, is the most sensitive physiological index of the severity of symptoms of motion sickness.

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The retention of adaptation to motion sickness eliciting stimulation.

Hu S, Stern RM.

Department of Psychology, Humboldt State University, Arcata, CA 95521, USA. sh4 axe.humboldt.edu

PURPOSE: This study compared the retention of adaptation to motion sickness eliciting stimulation after 1 mo and 1 yr. METHOD: A total of 34 subjects who developed nausea to an optokinetic rotating drum in a preliminary session repeatedly viewed the same rotation with an interval of 48 h between sessions until they had no feelings of nausea. For each session, subjects' electrogastrograms (EGGs) at 4-9 cycles per minute (cpm) were also recorded as a physiological index of the severity of motion sickness. Subjects were re-exposed to the optokinetic drum either after 1 mo or 1 yr. RESULTS: The mean ratings of nausea for the subjects who were re-exposed to the optokinetic drum after 1 mo were 9.23 for the initial exposure and 0.94 for the re-exposure session. EGG indicators of motion sickness were 6.65 for the initial exposure and 1.03 for the re-exposure session. The mean ratings of nausea for the subjects who were re-exposed to the optokinetic drum after 1 yr were 8.94 for the initial exposure and 6.88 for the re-exposure session. EGG indicators of motion sickness were 5.97 for the initial exposure and 4.05 for the re-exposure session. CONCLUSION: These results indicated that adaptation to the motion sickness eliciting stimulation of optokinetic rotation is almost completely retained for 1 mo and partially retained for 1 yr.

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