Motion sickness is provoked by passive motion of self, or of the visual environment, or of both, and commonly occurs while riding in cars, buses, boats, planes etc.1,2

Symptomatic motion sickness susceptibility (MSS) is common in migraine patients. Even between attacks, migraine patients3–5 especially those with vestibular migraine (VM)6,7 are particularly susceptible to motion sickness; they can have it when they try to read while riding in a car or bus.8,9

The aim of our study was to determine if being unable to read while riding in a car without developing motion sickness is a useful clinical approximation of formal MSS questionnaire scores.10

We studied 92 definite VM patients11 (ages 21–61 years) who did not have history of other neurological disorders and had normal audiogram, 58 migraine patients without a history of vertigo (MO)12 (aged 19–60 years) and 74 healthy control subjects (HC) (aged 19–81 years). VM patients were recruited from our neuro-otology outpatient clinic, MO patients and HCs by advertisement. HCs had normal neurological examination and did not have a history of headache or vertigo. Minimum number of participants in each group was estimated at 52, assuming medium effect size (f = 0.25) and 80% power).13 All participants gave their informed consent and local ethical committee approved the study.

Motion sickness was questioned by two methods.

• (A)

  This 2-item questionnaire: Question 1: Could you read while riding in a car or bus without becoming motion sick? Question 2: Do you have motion sickness while riding in a car or bus?

• (B)

  MSSQ Short questionnaire which investigates motion sickness with each mode of transportation. This questionnaire is in two sections: A (childhood-MSA) and B (adulthood-MSB). Each section consists of 9-items graded 0–3, with higher scores signifying higher motion sickness susceptibility. The score given depends on how much sickness or nausea is felt during travel. Sum of MSA and MSB forms MSSQ Short-Total (MST).10

There were no significant age (p = 0.308) or gender (p = 0.831) differences between VM, MO patients and HCs.

VM and MO patients were both more likely than HCs (p < 0.001) to report motion sickness (Question 1) and they were also more likely than HCs (p < 0.001) to report being unable to read in a moving car without becoming motion sick (Question 2) (Table 1).

Mean scores of both VM and MO patients were significantly higher on the MSA section than of HCs (p < 0.001) but the VM patients’ scores were not significantly different to MO patients’ scores of (p = 0.171).

On the other hand, mean MSB and MST scores were different between patient groups; VM patients had higher scores than MO patients (p < 0.001), and both had significantly higher scores than the HCs (p < 0.001) (Table 2).

Mean MSB scores were lower than MSA scores in MO patients (p < 0.001), but did not differ in VM patients (p = 0.81) or in HCs (p = 0.48) (Table 2).

The possible cutoff scores for motion sickness in the MSA is 4.25 (Sensitivity = 83.3%, 95% CI 75.2%‒89.1%) and for MSB 5.25 (Sensitivity = 89.8%, 95% CI 82.6%–94.2%). We suggest that the cutoff point MST scores is 8.50 (Sensitivity = 91.6%, 95% CI 84.9%–95.6%) (Table 3).

ROC curves and AUC values were derived (Fig. 1) with the corresponding 95% confidence interval (95% CI) using “not able read while riding in a car” as the gold standard. Graphs moving toward the upper left corner represent an increasing AUC value with progressively higher rates of true positives (sensitivity) and higher rates of true negatives (specificity). Higher AUC of each section of MSSQ-Short indicates a high diagnostic accuracy for motion sickness. MSB score had the hightest AUC (AUC = 0.909, 95% CI 0.86–0.94), followed by the MST score (AUC = 0.87, 95% CI 0.83–0.92) and then MSA score (AUC = 0.80, 95% CI 0.74–0.86).

Figure 1.

ROC curves of MSSQ scores (MSA, MSB, MST) with the response to the “reading in the car while riding” question as the gold standard.

(0.11MB).

Here we found that both VM and MO patients have much higher MSA, MSB and MST scores than HCs and that VM patients have significantly higher MSB and MST (but not MSA) scores than MO patients.

A possible explanation for this is that MO patients are able to adapt to motion sickness, whereas VM patients are not. This explanation is supported by our previous study comparing MSSQ scores with Dynamic Gait Index (DGI) and Dizziness Handicap (DHI) in VM and MO patients.14 Higher MSSQ scores were correlated with worse DGI and DHI scores supporting the notion of MSS as an indicator of vestibular hypersensitivity.

Around 2/3 of the population, will at some time, experience carsickness15 and with certain provocative manoeuvres almost anyone can be made motion sick.16 On the other hand, migraine patients, especially VM patients have decreased thresholds for angular acceleration perception and have higher MSS than HCs.17 Hypersensitivity of the vestibular system could be a mechanism for MSS in VM patients.4 Migraine, vertigo and motion sickness could share pathophysiology3 and migraine prevention treatment could reduce vertigo handicap and MSS of VM patients.18

Although an online survey of 277 unselected students, found no significant correlation between MSS scores in what was considered to be VM or MO,19 this negative finding might be the result of the methodology; an online survey in contrast to the face-to-face medical consultation in our study.

In order to read clearly while in a travelling car, it is necessary to suppress vestibulo-ocular reflexes triggered by vehicle motion.16 When a person’s vestibular system is sensitive,17 it is difficult read while riding in a car without developing motion sickness, perhaps because of the visual-vestibular conflict.1

We agree14 that it is useful to ask dizzy patients about MSS (2) but there is not always time in a busy dizzy clinic to administer a full MSS questionnaire. We routinely ask our patients if they consider if they are susceptible to motion sickness and also if they are able to read when travelling in a car or bus without becoming motion sick.

Here 6 of 92 VM patients (mean MSSQ total score of 29.8), 4 of 58 MO patients (mean MSSQ total score of 19.1) and 4 of 74 HCs (mean MSSQ total score of 4.8) denied being susceptible to motion sickness but nonetheless admitted to being unable to read while travelling without developing motion sickness.

The relevance of our observations for the clinician is that a long history of MSS preceding the development of recurrent spontaneous vertigo, can be reliably detected with a single question about reading while riding in a car.

Being unable to read while riding without getting motion sick is a useful indicator of vestibular migraine.

This study was not supported by any funding.

The authors declare no conflicts of interest.