Prevalence and correlates of susceptibility to motion sickness

Nutritional and Behavioral Countermeasures as Medication Approaches to Relieve Motion Sickness: A Comprehensive Review

The mismatch in signals perceived by the vestibular and visual systems to the brain, also referred to as motion sickness syndrome, has been diagnosed as a challenging condition with no clear mechanism. Motion sickness causes undesirable symptoms during travel and in virtual environments that affect people negatively. Treatments are directed toward reducing conflicting sensory inputs, accelerating the process of adaptation, and controlling nausea and vomiting. The long-term use of current medications is often hindered by their various side effects. Hence, this review aims to identify non-pharmacological strategies that can be employed to reduce or prevent motion sickness in both real and virtual environments. Research suggests that activation of the parasympathetic nervous system using pleasant music and diaphragmatic breathing can help alleviate symptoms of motion sickness. Certain micronutrients such as hesperidin, menthol, vitamin C, and gingerol were shown to have a positive impact on alleviating motion sickness. However, the effects of macronutrients are more complex and can be influenced by factors such as the food matrix and composition. Herbal dietary formulations such as Tianxian and Tamzin were shown to be as effective as medications. Therefore, nutritional interventions along with behavioral countermeasures could be considered as inexpensive and simple approaches to mitigate motion sickness. Finally, we discussed possible mechanisms underlying these interventions, the most significant limitations, research gaps, and future research directions for motion sickness.

Correlation between anxiety and chronic motion sensitivity

BACKGROUND

Chronic motion sensitivity (CMS) is a combination of autonomic symptoms provoked by exposure to motion. The correlation between anxiety and CMS is not yet well understood.

OBJECTIVES

1) To compare median anxiety levels between young adults with and without CMS. 2) To examine the effect of anxiety on postural stability with immersion virtual reality. 3) To compare anxiety levels between sexes.

METHODS

Participants included 60 adults (20-40 years), with and without CMS. After determining their current and general anxiety levels, postural stability was measured.

RESULTS

There were significant differences in median (minimum, maximum) state- and trait-anxiety scores between participants with and without CMS, but no significant differences in median state- and trait-anxiety scores between males and females with CMS. There was a significant inverse relationship between state- and trait-anxiety scores and postural stability (ρ= -0.28, p = 0.03, and ρ= -0.32, p = 0.01, respectively). The stepwise regression analysis showed the Motion Sickness Susceptibility Questionnaire-Short Form score to be the only variable contributing significantly to postural stability (R2 = 26.2%; t = -4.5, p <  0.001).

CONCLUSIONS

Young adults with CMS are more anxious, although anxiety does not contribute to postural stability in this group. Anxiety levels do not appear to differ between young adult males and females with CMS.

A novel method for reducing motion sickness susceptibility through training visuospatial ability - A two-part study

Everyone can be susceptible to motion sickness (except those with complete loss of labyrinth function) and around one in three are known to be servery susceptible. Motion sickness can be experienced in many domains, including car travel, on a boat, using virtual reality headsets and simulator use amongst others. It is expected that due to potential designs and use cases, self-driving cars will increase motion sickness onset likelihood and severity for many car travellers. Besides medication, there are limited methods through which one can actively reduce their motion sickness susceptibility. This research develops a novel visuospatial training tool and explores the effect of visuospatial training on motion sickness. With a combined sample of 42 participants split between driving simulator trials (n = 20), and on-road trials (n = 22) baseline visuospatial skills and motion sickness were first measured. After a 14-day training period where participates completed 15-min of pen and paper tasks per day, it was found that visuospatial skills improved by 40%. This increase in visuospatial ability was shown to be directly responsible for a reduction in motion sickness by 51% in the simulator (with a 60% reduction in participant dropouts) and a 58% reduction in the on-road trial. This research has successfully identified a new method to reduce motion sickness susceptibility and the impact of these findings have wide reaching implications for motion sickness research, especially in the field of self-driving vehicles.

Effect of Gaze Stability Exercises on Chronic Motion Sensitivity: A Randomized Controlled Trial

BACKGROUND AND PURPOSE

Motion sensitivity is a common condition among the general population and may be accompanied by postural instability and anxiety. Preliminary studies suggest that minimal dosage of gaze stability exercises improves postural stability in young adults with chronic motion sensitivity. The aim of this study was to investigate the effect of progressive gaze stability exercises on postural stability, motion sensitivity, and anxiety in healthy young adults with chronic motion sensitivity.

METHODS

We conducted a single-blind randomized controlled trial to assess the effect of gaze stability exercises on chronic motion sensitivity. Forty-one participants of both genders ages 20 to 40 years with chronic motion sensitivity were randomly assigned to 2 groups. The intervention group performed gaze stability exercises while the sham group performed saccadic eye movement exercises for 6 weeks. Computerized Dynamic Posturography with Immersion Virtual Reality (CDP-IVR)-condition 1 (C1) and condition 2 (C2)-Motion Sensitivity Quotient (MSQ), Motion Sickness Sensitivity Susceptibility Questionnaire Short Form (MSSQ-Short: MSA, MSB), and State-Trait Anxiety Inventory for Adults (STAI Form Y-2) were the outcome measures used.

RESULTS

There was no significant group × time interaction for MSA, MSB, MSSQ percentile, STAI, MSQ, C1 mean, or C2 mean. However, posttreatment a significant difference in the mean CDP-IVR score of C2 was identified between the 2 groups. For C2, the intervention group demonstrated a 117% increase in the mean CDP-IVR score compared with a 35.2% increase in the sham group. MSQ reduced significantly from baseline to 6 weeks postintervention in the intervention group (4.0 ± 1.2 vs 1.9 ± 0.9). Anxiety was significantly reduced in the sham group only (38.2 ± 1.9 vs 35.8 ± 2.2).

DISCUSSION AND CONCLUSIONS

Based on the results of this study, progressive gaze stability exercises appear to have value for managing chronic motion sensitivity in healthy young adults. Further research with larger sample size and broader age range is needed to generalize these findings.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A203).

Clinical Characteristics of Benign Recurrent Vestibulopathy: Clearly Distinctive From Vestibular Migraine and Menière's Disease?

OBJECTIVE

We aimed to systematically investigate the clinical characteristics of benign recurrent vestibulopathy (BRV), vestibular migraine (VM), and Menière's disease (MD) and to assess whether clinical symptoms exist that are unique to BRV.

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary referral center.

METHODS

Between January 2015 and November 2016, patients were prospectively recruited at a specialized dizziness clinic. Patients were included if they met the diagnostic criteria for BRV, VM, or MD which was evaluated by simultaneous consultation of an otorhinolaryngologist and neurologist. All patients received a comprehensive clinical examination that included vestibular tests and pure-tone audiometry. A questionnaire was designed to systematically document symptoms of the three vestibular disorders.

RESULTS

A total of 122 patients were included in our study, 65 (53%) were females in whom 29 (24%) were postmenopausal. The mean age was 55.5 ± 13.7 years and the mean age of onset of vertigo attacks was 49.2 ± 14.8 years (n = 119). Forty-five (37%) patients had a clinical diagnosis of BRV, 34 (28%) of VM, and 43 (35%) of MD. No symptom could be identified which was specifically linked to BRV. In patients with BRV, similar to those with VM, we found a female preponderance (p = 0.05 in BRV, p = 0.001 in VM). Patients with VM reported significantly more often a positive history of motion sickness (p = 0.01). In addition, canal paresis was most profound in patients with MD (p = 0.001).

CONCLUSION

We found no clinical characteristics that were distinctive for BRV. However, we did find several distinctive clinical features for VM and MD which may assist the physician in their history taking.

Brain Activation by H1 Antihistamines Challenges Conventional View of Their Mechanism of Action in Motion Sickness: A Behavioral, c-Fos and Physiological Study in Suncus murinus (House Musk Shrew)

Motion sickness occurs under a variety of circumstances and is common in the general population. It is usually associated with changes in gastric motility, and hypothermia, which are argued to be surrogate markers for nausea; there are also reports that respiratory function is affected. As laboratory rodents are incapable of vomiting, Suncus murinus was used to model motion sickness and to investigate changes in gastric myoelectric activity (GMA) and temperature homeostasis using radiotelemetry, whilst also simultaneously investigating changes in respiratory function using whole body plethysmography. The anti-emetic potential of the highly selective histamine H₁ receptor antagonists, mepyramine (brain penetrant), and cetirizine (non-brain penetrant), along with the muscarinic receptor antagonist, scopolamine, were investigated in the present study. On isolated ileal segments from Suncus murinus, both mepyramine and cetirizine non-competitively antagonized the contractile action of histamine with pK _b values of 7.5 and 8.4, respectively; scopolamine competitively antagonized the contractile action of acetylcholine with pA₂ of 9.5. In responding animals, motion (1 Hz, 4 cm horizontal displacement, 10 min) increased the percentage of the power of bradygastria, and decreased the percentage power of normogastria whilst also causing hypothermia. Animals also exhibited an increase in respiratory rate and a reduction in tidal volume. Mepyramine (50 mg/kg, i.p.) and scopolamine (10 mg/kg, i.p.), but not cetirizine (10 mg/kg, i.p.), significantly antagonized motion-induced emesis but did not reverse the motion-induced disruptions of GMA, or hypothermia, or effects on respiration. Burst analysis of plethysmographic-derived waveforms showed mepyramine also had increased the inter-retch+vomit frequency, and emetic episode duration. Immunohistochemistry demonstrated that motion alone did not induce c-fos expression in the brain. Paradoxically, mepyramine increased c-fos in brain areas regulating emesis control, and caused hypothermia; it also appeared to cause sedation and reduced the dominant frequency of slow waves. In conclusion, motion-induced emesis was associated with a disruption of GMA, respiration, and hypothermia. Mepyramine was a more efficacious anti-emetic than cetirizine, suggesting an important role of centrally-located H₁ receptors. The ability of mepyramine to elevate c-fos provides a new perspective on how H₁ receptors are involved in mechanisms of emesis control.

Are some people suffering as a result of increasing mass exposure of the public to ultrasound in air?

New measurements indicate that the public are being exposed, without their knowledge, to airborne ultrasound. Existing guidelines are insufficient for such exposures; the vast majority refers to occupational exposure only (where workers are aware of the exposure, can be monitored and can wear protection). Existing guidelines are based on an insufficient evidence base, most of which was collected over 40 years ago by researchers who themselves considered it insufficient to finalize guidelines, but which produced preliminary guidelines. This warning of inadequacy was lost as nations and organizations issued 'new' guidelines based on these early guidelines, and through such repetition generated a false impression of consensus. The evidence base is so slim that few reports have progressed far along the sequence from anecdote to case study, to formal scientific controlled trials and epidemiological studies. Early studies reported hearing threshold shifts, nausea, headache, fatigue, migraine and tinnitus, but there is insufficient research on human subjects, and insufficient measurement of fields, to assess what health risk current occupational and public exposures might produce. Furthermore, the assumptions underpinning audiology and physical measurements at high frequencies must be questioned: simple extrapolation of approaches used at lower frequencies does not address current unknowns. Recommendations are provided.

Opioid-Induced Nausea Involves a Vestibular Problem Preventable by Head-Rest

Background and Aims

Opioids are indispensable for pain treatment but may cause serious nausea and vomiting. The mechanism leading to these complications is not clear. We investigated whether an opioid effect on the vestibular system resulting in corrupt head motion sensation is causative and, consequently, whether head-rest prevents nausea.

Methods

Thirty-six healthy men (26.6±4.3 years) received an opioid remifentanil infusion (45 min, 0.15 μg/kg/min). Outcome measures were the vestibulo-ocular reflex (VOR) gain determined by video-head-impulse-testing, and nausea. The first experiment (n = 10) assessed outcome measures at rest and after a series of five 1-Hz forward and backward head-trunk movements during one-time remifentanil administration. The second experiment (n = 10) determined outcome measures on two days in a controlled crossover design: (1) without movement and (2) with a series of five 1-Hz forward and backward head-trunk bends 30 min after remifentanil start. Nausea was psychophysically quantified (scale from 0 to 10). The third controlled crossover experiment (n = 16) assessed nausea (1) without movement and (2) with head movement; isolated head movements consisting of the three axes of rotation (pitch, roll, yaw) were imposed 20 times at a frequency of 1 Hz in a random, unpredictable order of each of the three axes. All movements were applied manually, passively with amplitudes of about ± 45 degrees.

Results

The VOR gain decreased during remifentanil administration (p<0.001), averaging 0.92±0.05 (mean±standard deviation) before, 0.60±0.12 with, and 0.91±0.05 after infusion. The average half-life of VOR recovery was 5.3±2.4 min. 32/36 subjects had no nausea at rest (nausea scale 0.00/0.00 median/interquartile range). Head-trunk and isolated head movement triggered nausea in 64% (p<0.01) with no difference between head-trunk and isolated head movements (nausea scale 4.00/7.25 and 1.00/4.5, respectively).

Conclusions

Remifentanil reversibly decreases VOR gain at a half-life reflecting the drug’s pharmacokinetics. We suggest that the decrease in VOR gain leads to a perceptual mismatch of multisensory input with the applied head movement, which results in nausea, and that, consequently, vigorous head movements should be avoided to prevent opioid-induced nausea.

Assessment of otolith function using cervical and ocular vestibular evoked myogenic potentials in individuals with motion sickness

The involvement of otolith organs in motion sickness has long been debated; however, equivocal findings exist in literature. The present study thus aimed at evaluating the otolith functioning in individuals with motion sickness. Cervical and ocular vestibular evoked myogenic potentials were recorded from 30 individuals with motion sickness, 30 professional drivers and 30 healthy individuals. The results revealed no significant difference in latencies and amplitudes between the groups (p>0.05). Nonetheless, thresholds were significantly elevated and inter-aural asymmetry ratio significantly higher in motion sickness susceptible group (p < 0.001) for both the potentials. All the individuals in the motion sickness group had high asymmetry ratio at least on one of the two potentials. Thus, reduced response and/or asymmetric otolithic function seem the likely reasons behind motion sickness susceptibility.

Is there a relationship between odors and motion sickness?

The aim of this study was to evaluate the relationship between olfaction and motion sickness. A sample of 18 participants was recruited and submitted to three sessions of nauseogenic stimulations: off vertical axis rotation (OVAR), performed under conditions of olfactory stimulation with limonene (pleasant odor), petrol (unpleasant odor) or distilled water (as a control). Motion sickness was assessed before, during and after each OVAR session. In addition, participants were asked to evaluate the intensity and hedonic valence of four odors (geraniol, limonene, butanol, petrol) as well as distilled water (as a control) before and after each OVAR session. Our analysis showed that OVAR has consistently increased the induced-motion sickness. However the addition of an odor that is pleasant or unpleasant during the rotation did not affect the occurrence of motion sickness symptoms compared to the control condition. Our results also showed that intensity of odors was significantly increased after OVAR and the intensity was significantly higher for unpleasant odors than for pleasant one. For the hedonicity, OVAR made unpleasant odors more unpleasant (p<0.0001) while it made limonene odor slightly more pleasant (p<0.05). The present study highlighted the lack of influence of odors in motion-induced sickness but an impact of a nauseogenic test on olfactory perception.

Phenylthiocarbamide taste perception and susceptibility to motion sickness: linking higher susceptibility with higher phenylthiocarbamide taste acuity

OBJECTIVE

This study is the first attempt to link quantified phenylthiocarbamide bitter taste recognition threshold with susceptibility to motion sickness.

SUBJECTS

The study was conducted on a sample of 291 teenage Rajput children (146 males and 145 females; age range 13-19 years) from the Sirmour district of Himachal Pradesh, India. Phenylthiocarbamide taste sensitivity was measured by administering a serial dilution of a freshly prepared phenylthiocarbamide solution, following the method of Harris and Kalmus. Motion sickness susceptibility was assessed retrospectively via interview.

RESULTS

About 40 per cent of the subjects had experienced motion sickness in the past. The mean and standard deviation of phenylthiocarbamide taste thresholds in non-tasters and tasters were 0.83 +/- 0.87 and 7.98 +/- 1.86, respectively. A bimodal distribution test (D/S) index of 5.24 confirmed bimodality of phenylthiocarbamide taste threshold distribution. The Mann-Whitney U test rejected the null hypothesis of mu 1 = mu 2 and thus confirmed the existence of differences in the distributions of phenylthiocarbamide taste threshold between individuals susceptible and not susceptible to motion sickness. Individuals susceptible to motion sickness had lower mean and median taste thresholds, indicating higher phenylthiocarbamide taste sensitivity, compared with non-susceptible individuals. The frequency of non-tasters was about 10 per cent in both motion sickness susceptible and non-susceptible individuals. The simple division of phenylthiocarbamide tasting ability into tasters and non-tasters was a less sensitive criterion with which to measure the association of this ability with motion sickness susceptibility. However, further differentiation of tasters into weak threshold, medium threshold and super threshold ('supersensitive') tasters clearly revealed a highly significantly increased risk of motion sickness in super threshold tasters (i.e. threshold solution number >or=12). The ratio of motion sickness susceptible individuals to non-susceptible individuals was 1:1.7 for non-tasters (threshold solution numbers zero to three) and weak and medium tasters (threshold solution numbers four to 11), but the trend was reversed for super threshold tasters (threshold solution numbers 12 and 13), in whom the ratio was 2:1.

CONCLUSION

Individuals exhibiting greater phenylthiocarbamide taste acuity (i.e. supersensitive tasters) had a higher susceptibility to motion sickness than did non-, weak and medium phenylthiocarbamide tasters, as measured in terms of their taste thresholds (i.e. threshold solution numbers zero to 11).

Motion and space sickness: intestinal and autonomic correlates

The purpose of this paper is to provide an overview of autonomic nervous system and gastrointestinal changes that occur during motion sickness. It is important to consider that motion sickness is a syndrome that can vary between individuals and within individuals and between and within motion sickness-inducing stimuli. Vomiting should be considered a discrete event of the motion sickness syndrome. Given so much variability in motion sickness symptoms, it should be expected that the physiological response to motion sickness will vary as well. This appears to be the case with the autonomic nervous system and gastrointestinal changes during motion sickness. Although much research remains to be done, it appears undeniable that the physiological expression of motion sickness is mediated by the autonomic nervous system, and when nausea is a predominant symptom, the stomach in general shuts down in a response characterized by decreased normal gastric myoelectrical activity and delayed gastric emptying.

The relationship between susceptibility to nausea and vomiting and the possession of conditioned food aversions

Because nausea and vomiting play an important role in the formation of conditioned food aversions, individual differences in susceptibility to nausea and vomiting may contribute to interindividual variation in conditioned food aversion acquisition. Two surveys reveal that, among female participants, self-reported motion sickness susceptibility is positively correlated with the number of conditioned food aversions possessed, but no such correlation appears among male participants.

Motion sickness is linked to nystagmus-related trigeminal brain stem input: a new hypothesis

Motion sickness is a common and distressing but poorly understood syndrome associated with nausea/vomiting and autonomic nervous system accompaniments that develops in the air or space as well as on sea or land. A bidirectional aetiologic link prevails between migraine and motion-sickness. Motion sickness provokes jerk nystagmus induced by both optokinetic and vestibular stimulation. Fixation of gaze or closure of eyes generally prevents motion sickness while vestibular otolithic function is eliminated in microgravity of space, indicating a predominant pathogenetic role for visuo-sensory input. Scopolamine, dimenhydrinate, and promethazine reduce motion-related nystagmus. Contraction of extraocular muscles generates proprioceptive neural traffic and can provoke an ocular hypertensive response. It is proposed that repetitive contractions of the extraocular muscles during motion-related jerk nystagmus rapidly augment brain stem afferent input by increasing proprioceptive neural traffic through connections of the oculomotor nerves with the ophthalmic nerve in the lateral wall of the cavernous sinus as well as by raising the intraocular pressure thereby stimulating anterior segment ocular trigeminal nerve fibers. This verifiable hypothesis defines the pathophysiological basis of individual susceptibility to motion sickness, elucidates the preventive mechanism of gaze fixation or ocular closure, advances the aetiologic link between MS and migraine, rationalizes the mechanism of known preventive drugs, and explores new therapeutic possibilities.

Plasma vasopressin, an etiologic factor of motion sickness in rat and human?

Arginine vasopressin (AVP) is considered as an etiologic hormone in motion sickness. However, the possible role of plasma AVP in motion sickness is still controversial. A number of studies have found a gender difference in susceptibility to motion sickness in humans and experimental animals, with female subjects being more susceptible. However, the existence of a gender difference in the AVP response to motion sickness is not known. This study was designed to verify the assumption that plasma vasopressin plays a role in motion sickness. Changes in plasma vasopressin were observed after motion sickness-inducing rotatory stimuli in both sexes in human subjects and rats receiving or not anti-motion-sickness treatments. Plasma vasopressin levels in motion sickness rats exhibited a decrease after rotation in female, but not in male rats. The vasopressin content of the pituitary increased in both sexes. Plasma vasopressin in rats of both sexes tended to increase after a 15-day adaptive training of rotation, but pituitary vasopressin content was not affected under this condition. In contrast, in human subjects, plasma vasopressin levels increased after rotation in all males, but not in females. When anti-motion-sickness drugs (domperidone 10 mg + flunarizine 5 mg) were administered, plasma vasopressin levels were elevated in both females and males. It is concluded that plasma vasopressin increases after motion sickness-induced stimulation provided subjects have become trained to motion sickness. These results do not support an etiologic role of plasma vasopressin in the genesis of motion sickness.

Habituation to galvanic vestibular stimulation for analysis of susceptibility to carsickness

OBJECTIVE

In a previous study we developed a standardized procedure for a reproducible quantification of galvanic-induced body sway (GBS). In line with other reports, GBS shows short-term (fast) habituation upon stimulus repetition. The aim of this study was to evaluate whether the degree of short-term habituation to galvanic vestibular stimulation (GVS) is correlated with susceptibility to carsickness.

MATERIAL AND METHODS

A total of 24 female subjects underwent computer-controlled GVS as part of a prospective experimental study conducted in a tertiary referral center. A binaural 1-cosinusoidal stimulus of 0.5 Hz and 1 mA was repeated five times. Binaural stimulation was chosen to obtain maximum responses, making possible habituation to repetitive GVS obvious. The groups consisted of 12 subjects suffering from carsickness and 12 healthy subjects.

RESULTS

Analysis of the repeated measurements test showed that the GBS-gain curve for the carsickness group was always superimposed on that for the healthy subjects. However, the (absolute) first to fifth GBS gains showed no significant differences (p = 0.134 - 0.995). When comparing short-term habituation in subjects suffering from carsickness versus healthy subjects, the results showed no differences in the mean values of the first (30.534% vs 27.024%), final (42.637% vs 38.544%) and average (35.544% vs 33.644%) habituations (p = 0.875, 0.991 and 0.951, respectively).

CONCLUSION

We did not observe any significant differences in sensitivity or habituation of the GBS in carsick subjects compared to healthy subjects. This implies that carsick subjects show a similar ability to discard an irrelevant, non-motion sickness-inducing galvanic stimulus as healthy subjects.