Biodynamic Hypothesis for the Frequency Tuning of Motion Sickness

INTRODUCTION Motion sickness is often provoked by oscillatory translational (linear) acceleration. For humans, motion frequencies around 0.2-0.3Hz are the most provocative. A current explanation for this frequency band is that it spans a region of maximum ambiguity concerning the interpretation of vestibular signals. Below 0.2-0.3Hz linear accelerations are interpreted as ‘tilt’ whereas at higher frequencies accelerations are interpreted as ‘translation’, i.e., linear motion through space. This is termed the ‘tilt-translation’ hypothesis. However the origin of this particular frequency range is unclear. We investigated whether the differential perceptions of oscillations at different frequencies derives from the biodynamics of active self-initiated whole body motion. METHODS Video-films were taken of subjects running slaloms of various combinations of lengths/amplitudes to provoke a range of temporal frequencies of slalom (reciprocal of time to run a cycle). RESULTS The usual tactic for cornering at frequencies 0.4Hz lateropulsion of the legs with torso erect was observed. Between these frequencies subjects showed variable tactics, mixing components of both tilt and lateropulsion. CONCLUSIONS This uncertainty in selecting the appropriate tactic for movement control around 0.2-0.3Hz is the possible origin of ‘tilt-translation’ ambiguity. It also follows that externally imposed motion around these frequencies would challenge both perception and motor control; with the consequence of motion sickness

Meniere’s, Migraine & Motion Sickness

CONCLUSION Elevated MSS in MD is likely to be a consequence of the onset of MD and not migraine per se. OBJECTIVES Pathologies of the vestibular system influence motion sickness susceptibility (MSS). Bilateral vestibular deficits lower MSS, vestibular neuritis or benign paroxysmal positional vertigo have little overall effect, whereas vestibular migraine elevates MSS. However, less is known about MSS in Meniere’s disease (MD), a condition in which many patients experience vestibular loss and migraine symptoms. METHODS We conducted an online survey that posed diagnostic and disease questions before addressing frequency of headaches, migraines, visual display dizziness (VDD), syncope, social life and work impact of dizziness (SWID4) and motion sickness susceptibility (MSSQ). The two groups were: diagnosed MD individuals with hearing loss (n=751) and non-MD individuals in the control group (n=400). RESULTS The MD group showed significantly elevated MSS, more headache and migraine, increased VDD, higher SWID4 scores, and increased syncope. MSS was higher in MD than controls only after the development of MD but not before, nor in childhood. Although elevated in MD compared with controls, MSS was lower than migraine patients from past data. Multivariate analysis revealed VDD, SWID4 and MSS in adulthood as the strongest predictors of MD, but not headache nor migraine

Predicting individual susceptibility to Visually Induced Motion Sickness (VIMS) by Questionnaire

BACKGROUND The introduction of new visual technologies increases the risk of visually induced motion sickness (VIMS). The aim was to evaluate the 6-item Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ; also known as the VIMSSQ-short) and other predictors for individual susceptibility to VIMS. METHODS Healthy participants (10M+20F), mean age 22.9 (SD 5.0) years, viewed a 360° panoramic city scene projected in the visual equivalent to the situation of rotating about an axis tilted from the vertical. The scene rotated at 0.2Hz (72° s-1), with a ‘wobble’ produced by superimposed 18° tilt on the rotational axis, with a field of view of 83.5°. Exposure was 10 min or until moderate nausea was reported. Simulator Sickness Questionnaire (SSQ) was the index of VIMS. Predictors/correlates were VIMSSQ, Motion Sickness Susceptibility Questionnaire (MSSQ), Migraine (scale), Syncope, Social & Work Impact of Dizziness (SWID), Sleep quality/disturbance, Personality (‘Big Five’ TIPI), a prior multisensory Stepping-Vection test, and Vection during exposure. RESULTS The VIMSSQ had good scale reliability (Cronbach’s alpha=0.84). and correlated significantly with the SSQ (r=0.58). Higher MSSQ, Migraine, Syncope & SWID also correlated significantly with SSQ. Other variables had no significant relationships with SSQ. Regression models showed that the VIMSSQ predicted 34% of the individual variation of VIMS, increasing to 56% as MSSQ, Migraine, Syncope and SWID were incorporated as additional predictors. CONCLUSIONS The VIMSSQ is a useful adjunct to the MSSQ in predicting VIMS. Other predictors included Migraine, Syncope & SWID. No significant relationship was observed between Vection and VIMS

Measuring the susceptibility to visually induced motion sickness and its relationship with vertigo, dizziness, migraine, syncope and personality traits

BACKGROUND: The widespread use of visual technologies such as Virtual Reality increases the risk of visually induced motion sickness (VIMS). Previously, the 6-item short version of the Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ short form) has been validated for predicting individual variation in VIMS. The aim of the current study was to investigate how the susceptibility to VIMS is correlated with other relevant factors in the general population. METHODS: A total of 440 participants (201M, 239F), mean age 33.6 (SD 14.8) years, completed an anonymous online survey of various questionnaires including the VIMSSQ, Motion Sickness Susceptibility Questionnaire (MSSQ), Vertigo in City questionnaire (VIC), Migraine (scale), Social & Work Impact of Dizziness (SWID), Syncope (faintness), and Personality (‘Big Five’ TIPI). RESULTS: The VIMSSQ correlated positively with the MSSQ (r = .50), VIC (r = .45), Migraine (r = .44), SWID (r = .28), and Syncope (r = .15). The most efficient Multiple Linear Regression model for the VIMSSQ included the predictors MSSQ, Migraine, VIC, and Age and explained 40% of the variance. Factor analysis of strongest correlates with VIMSSQ revealed a single factor loading with VIMSSQ, MSSQ, VIC, Migraine, SWID, and Syncope, suggesting a common latent variable of sensitivity. CONCLUSIONS: The set of predictors for the VIMSSQ in the general population has similarity with those often observed in patients with vestibular disorders. Based on these correlational results, we suggest the existence of continuum of underlying risk factors for sensitivity, from healthy population to patients with extreme visual vertigo and perhaps Persistent Postural-Perceptual Dizziness

Visual Vertigo, Motion Sickness and Disorientation in vehicles

The normal vestibular system may be adversely affected by environmental challenges which have characteristics that are unfamiliar or ambiguous in the patterns of sensory stimulation they provide. A disordered vestibular system lends susceptibility even to quotidian environmental experiences as the sufferer becomes dependent on potentially misleading, non-vestibular sensory stimuli. In both cases the sequela may be dizziness, incoordination, imbalance and unpleasant autonomic responses. Many forms of visual environmental motion, particularly busy places such as supermarkets, readily induce inappropriate sensations of sway or motion and imbalance referred to as visual vertigo. All people with intact vestibular function can become motion sick although individual susceptibility varies widely and is partially determined by inheritance. Motorists learn to interpret sensory stimuli in the context of the car stabilised by its suspension and guided by steering. A type of motorist disorientation occurs in some individuals that develop a heightened awareness of false perceptions of car orientation, readily experiencing stereotypical symptoms of threatened rolling over on corners and veering on open highways or in streaming traffic. This article discusses the putative mechanisms, consequences and approach to managing patients with visual vertigo, motion sickness and motorist disorientation syndrome in the context of chronic dizziness and motion sensitivity

The Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ): Estimating Individual Susceptibility to Motion Sickness-Like Symptoms When Using Visual Devices

Objective Two studies were conducted to develop and validate a questionnaire to estimate individual susceptibility to visually induced motion sickness (VIMS). Background VIMS is a common side-effect when watching dynamic visual content from various sources, such as virtual reality, movie theaters, or smartphones. A reliable questionnaire predicting individual susceptibility to VIMS is currently missing. The aim was to fill this gap by introducing the Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ). Methods A survey and an experimental study were conducted. Survey: The VIMSSQ investigated the frequency of nausea, headache, dizziness, fatigue, and eyestrain when using different visual devices. Data were collected from a survey of 322 participants for the VIMSSQ and other related phenomena such as migraine. Experimental study: 23 participants were exposed to a VIMS-inducing visual stimulus. Participants filled out the VIMSSQ together with other questionnaires and rated their level of VIMS using the Simulator Sickness Questionnaire (SSQ). Results Survey: The most prominent symptom when using visual devices was eyestrain, and females reported more VIMS than males. A one-factor solution with good scale reliability was found for the VIMSSQ. Experimental study: Regression analyses suggested that the VIMSSQ can be useful in predicting VIMS (R2 = .34) as measured by the SSQ, particularly when combined with questions pertaining to the tendency to avoid visual displays and experience syncope (R2 = .59). Conclusion We generated normative data for the VIMSSQ and demonstrated its validity. Application The VIMSSQ can become a valuable tool to estimate one’s susceptibility to VIMS based on self-reports

Factors influencing clinical outcome in vestibular neuritis – A focussed review and reanalysis of prospective data

Following vestibular neuritis (VN), long term prognosis is not dependent on the magnitude of the residual peripheral function as measured with either caloric or the video head-impulse test. Rather, recovery is determined by a combination of visuo-vestibular (visual dependence), psychological (anxiety) and vestibular perceptual factors. Our recent research in healthy individuals has also revealed a strong association between the degree of lateralisation of vestibulo-cortical processing and gating of vestibular signals, anxiety and visual dependence. In the context of several functional brain changes occurring in the interaction between visual, vestibular and emotional cortices, which underpin the aforementioned psycho-physiological features in patients with VN, we re-examined our previous published findings focusing on additional factors impacting long term clinical outcome and function. These included: (i) the role of concomitant neuro-otological dysfunction (i.e. migraine and benign paroxysmal positional vertigo (BPPV)) and (ii) the degree to which brain lateralisation of vestibulo-cortical processing influences gating of vestibular function in the acute stage. We found that migraine and BPPV interfere with symptomatic recovery following VN. That is, dizziness handicap at short-term recovery stage was significantly predicted by migraine (r=0.523, n=28, p=.002), BPPV (r=0.658, n=31, p0.05). In left-sided VN patients, we observed a negative correlation between visual dependence and ipsilesional oculomotor thresholds (R2 0.459; p0.05). To summarise, our findings illustrate that in VN, neuro-otological co- morbidities retard recovery, and that measures of the peripheral vestibular system are an aggregate of residual function and cortically mediated gating of vestibular input

Impairment of spatial cognitive function with preservation of verbal performance during spatial disorientation

Spatial disorientation, which is responsible for up to 30% of aircraft accidents causes impairment of cognitive function which may further compromise a pilot's ability to think his way out of the situation and regain control [1,]. The functional-anatomical separation of spatial and verbal processing [10,11] raises the possibility of selective interference between the task of resolving spatial disorientation and the ability to perform concurrent spatial, as opposed to verbal, secondary tasks. We report for the first time a degradation of spatial task performance with preservation of verbal performance when subjects in a simulator are disoriented by conflict between self- motion and visual flow in the view of the external environment

Prevalence, Predictors & Prevention of Motion Sickness in Zero-G Parabolic Flights

INTRODUCTION Zero-G parabolic flight reproduces the weightlessness of space for short periods of time. However motion sickness may affect some fliers. The aim was to assess the extent of this problem and to find possible predictors and modifying factors. METHODS Airbus Zero-G flights consist of 31 parabolas performed in blocks. Each parabola consisted of 20s 0g sandwiched by 20s hypergravity of 1.5-1.8g. The survey covered n=246 person-flights (193 Males 53 Females), aged (M+/-SD) 36.0+/-11.3 years. An anonymous questionnaire included motion sickness rating (1=OK to 6=Vomiting), Motion Sickness Susceptibility Questionnaire (MSSQ), anti-motion sickness medication, prior Zero-G experience, anxiety level, and other characteristics. RESULTS Participants had lower MSSQ percentile scores 27.4+/-28.0 than the population norm of 50. Motion sickness was experienced by 33% and 12% vomited. Less motion sickness was predicted by older age, greater prior Zero-G flight experience, medication with scopolamine, lower MSSQ scores, but not gender nor anxiety. Sickness ratings in fliers pre-treated with scopolamine (1.81+/-1.58) were lower than for non-medicated fliers (2.93+/-2.16), and incidence of vomiting in fliers using scopolamine treatment was reduced by half to a third. Possible confounding factors including age, sex, flight experience, MSSQ, could not account for this. CONCLUSION Motion sickness affected one third of Zero-G fliers, despite being intrinsically less motion sickness susceptible compared to the general population. Susceptible individuals probably try to avoid such a provocative environment. Risk factors for motion sickness included younger age and higher MSSQ scores. Protective factors included prior Zero-G flight experience (habituation) and anti-motion sickness medication

Reliability of functional outcome measures in adults with neurofibromatosis 1

Objectives: To determine intra-rater and inter-rater reliability of functional outcome measures in adults with neurofibromatosis 1 (NF1) and to ascertain how closely objective and subjective measures align. Methods: Forty-nine ambulant adults with NF1 aged 16 years and over were included in this observational study. Median age 31 years (range 16-66), 29 females, 20 males. Participants were video-recorded or photographed performing four functional outcome measures. Four raters from the Neurofibromatosis centre multi-disciplinary team independently scored the measures to determine inter-rater reliability. One rater scored the measures a second time on a separate occasion to determine intra-rater reliability. The measures evaluated were the functional reach, timed up and go, ten metre walk and a modified nine-hole peg tests. Participants also completed a disease specific quality of life questionnaire (INF1-QOL). Results: Inter-rater reliability and intra-rater reliability scores (intra-class coefficient, ICC) were similar for each outcome measure. Excellent rater agreement (ICC r ≥ 0.9) was found for the functional reach, timed up and go and the 10 metre walk tests. Rater agreement was good for the modified 9-hole peg test; ICC r= 0.75 for intra-rater reliability and 0.76 for inter-rater reliability. The timed up and go and the 10 metre walk tests correlated highly with perceived mobility challenges in the quality of life questionnaire (INF1-QOL). Conclusions: The functional reach, timed up and go and 10 metre walk tests are potentially useful outcome measures for monitoring NF1 treatment and will be assessed for validity and reliability in future multi-centre studies