Shaky Science: Animals Still Used in Motion Sickness Experiments
By Jonathan Balcombe, Ph.D.
This column is part of a monthly “Beyond Animal Research” series.
If you’ve ever suffered motion sickness, you know that it’s a miserable feeling. Other animals are also vulnerable, and for at least 50 years scientists have been subjecting monkeys, dogs, cats, rats, and other species to experiments designed to make them ill. Here are some recent examples:
- At the University of Texas, female dogs had electric charges delivered directly to their small intestines via implanted electrodes. Depending on patterns of charges and drugs, dogs suffered different degrees of vomiting and other motion-sickness-like symptoms.1
- At the All India Institute of Medical Sciences, rats were rotated 1,350 times over 45 minutes to observe the effects of various antiemetic drugs on vomiting rates.2
- Experimenters at the University of Tokyo induced vomiting in house musk shrews by injecting vasopressin either into the bloodstream or into the brain.3
- Scientists at Shimane University in Japan force-fed tree frogs, then subjected them to “parabolic flight.” Motion sickness was measured as the presence of vomitus in a frog’s cage.4
Motion sickness is a subjective experience, and animals cannot report it. The only clear objective measure is vomiting. Unlike these cruel studies, there are many ways to study motion sickness ethically, with human volunteers. Here is a recent sample:
- At the University of Southampton, 20 human subjects rated motion sickness during a 30-minute car journey under conditions of artificially restricted view, restricted view due to seating position, and a video view of the road ahead. Car motions were also measured in three axes.5
- At the University of Arkansas, adults sat in a rotary chair to simulate space motion sickness to assess the effectiveness of four anti-nausea drugs with pre- or post-treatment.6
- University of Southampton researchers exposed 120 adults for up to 30 minutes to sinusoidal lateral oscillation to study the role of oscillation frequencies on motion sickness. Subjects provided ratings of motion sickness at one-minute intervals.7
- At Nanyang Technological University, Singapore, motion sickness was studied in 30 adults placed on a rotating platform with a head-mounted display that could produce conflicting self-motion cues.8
Studying motion sickness in humans avoids tenuous extrapolations between species, and subjects can verbally express their symptoms often and in great detail. Unlike animal subjects, people volunteer to participate, and they may terminate exposure at any point. Decisions to fund, conduct, review, and publish research don’t always follow a rational path, and it is unfortunate that these animal studies were conducted.
1. Liu J, Wang L, Chen JD. Effects of intestinal electrical stimulation on intestinal dysrhythmia and symptoms in dogs. Dig Dis Sci. 2004;49:720-728.
2. Gupta YK, Chaudhary G. Effect of antiemetic drugs on decrease in gastric emptying in experimental model of motion sickness in rats. Acta Pharmacol Sin. 2003;24:296-300.
3. Ikegaya Y, Matsuki N. Vasopressin induces emesis in Suncus murinus. Jpn J Pharmacol. 2002;89:324-326.
4. Naitoh T, Wassersug RJ, Yamashita N. Factors influencing the susceptibility of anurans to motion sickness. J Comp Physiol [A]. 2001;187:105-113.
5. Griffin MJ, Newman MM. Visual field effects on motion sickness in cars. Aviat Space Environ Med. 2004;75:739-748.
6. Dornhoffer J, Chelonis JJ, Blake D. Stimulation of the semicircular canals via the rotary chair as a means to test pharmacologic countermeasures for space motion sickness. Otol Neurotol. 2004;25:740-745.
7. Donohew BE, Griffin MJ. Motion sickness: effect of the frequency of lateral oscillation. Aviat Space Environ Med. 2004;75:649-656.
8. Duh HB, Parker DE, Philips JO, et al. “Conflicting” motion cues to the visual and vestibular self-motion systems around 0.06 Hz evoke simulator sickness. Hum Factors. 2004;46:142-153.
Jonathan Balcolmbe, Ph.D., is an ethologist and PCRM research consultant. He is the author of The Use of Animals in Higher Education, as well as many articles on humane life science education and scientific papers on animal behavior. He is the author of a recent scientific review showing that animal experiments are more stressful than previously understood.