Effect of daily linear acceleration training on the hypergravity-induced vomiting response in house musk shrew (Suncus murinus).

The effects of repeated linear acceleration training and the antimotion sickness drug, promethazine, on hypergravity-induced motion sickness were examined in musk shrew (Suncus murinus), which is known to show a vomiting response to motion stimulation. Animals were assigned into five groups: vestibular intact, untreated animals (Sham), vestibular lesioned (VL) animals, vestibular intact animals with promethazine hydrochloride administered as daily drinking water (Prom), vestibular intact animals who underwent horizontal linear accelerator motion training (Train), and vestibular intact animals treated with both promethazine hydrochloride and linear acceleration training (Prom+Train). In Sham animals, the number of vomiting episodes was 14±2 during 2 G exposure for 10min, and was accompanied by intense Fos expression in the medial vestibular nucleus (MVe), the nucleus of the solitary tract (NTS), the area postrema (AP), and the paraventricular hypothalamic nucleus (PVN). The vomiting response and Fos expression were completely abolished in VL animals, indicating that these responses are mediated via the vestibular system. Although Train and Prom animals experienced a significantly reduced number of hypergravity-induced vomiting episodes compared with Sham animals, the effect was significantly greater in Train animals than in Prom animals. Fos expression in the NTS, AP, and PVN were significantly more reduced in Train animals than in Prom animals. Higher dose of bolus injection of promethazine (50mg/kg, i.p.) completely abolished the vomiting episodes, although the animals were drowsy and sedated due to side effects. In conclusion, daily linear acceleration training and promethazine could prevent the hypergravity-induced vomiting episodes.

Stroboscopic vision as a treatment for motion sickness: strobe lighting vs. shutter glasses.

INTRODUCTION: Countermeasures (e.g., drugs, training, etc.) designed to combat the problem of space motion sickness (SMS) have had only limited successes. A possible solution for SMS and terrestrial motion sickness may rest in preventing retinal slip via stroboscopic vision. METHODS: There were 32 subjects who participated in a study to investigate the effect of stroboscopic illumination on motion sickness using either a strobe light or liquid crystal display (LCD) shutter glasses. There were 19 subjects who read text and made +/- 20 degrees head movements in the horizontal plane (yaw) at 0.2 Hz while wearing left-right reversing prisms and exposed to 4-Hz stroboscopic or normal room illumination (control condition). Motion sickness was scored using the Miller and Graybiel scale and subjective self-ratings. In a crossover design, testing was repeated using stroboscopic LCD shutter glasses with an additional 13 subjects and 6 subjects from the first condition. RESULTS: During the experiment with a strobe light, motion sickness scores were significantly lower than in the control condition (chi 0.32 strobe vs. chi 3.79 light = p < 0.003). Results with the LCD shutter glasses corresponded with those when the environment was strobed in an otherwise dark room (chi 1.0 glasses vs. chi 4.1 light = p < 0.001). CONCLUSIONS: Stroboscopic illumination reduced the severity of motion sickness symptoms, and shutter glasses with a flash frequency of 4 Hz are as effective as a strobe light. Stroboscopic illumination appears to be an effective countermeasure where retinal slip is a significant factor in eliciting motion sickness due to either self- or surround-motion.

The space mission MIR'97: operational aspects.

BACKGROUND: A German astronaut visited the MIR space station between 10 February and 2 March 1997. Together with his Russian colleagues, he conducted a series of scientific investigations before, during and after his stay aboard the MIR station. Research performed during this flight was part of a global space life sciences programme and focused on metabolic homeostasis, fluid balance, calcium homeostasis and cardiovascular regulatory mechanisms. The main goal of the scientific experiments was to use this mission as a milestone to establish international networks of scientific collaboration using space research as a tool for focused research in respective fields. Thus, in most cases the results obtained from the astronaut complemented a series of results obtained on ground and from other flights. In other cases, they extended previous results and opened new fields for future research. PARTICIPANTS: Human space flight with astronauts serving as operators and at the same time as test subjects is very complex. Many people, including mission control, a science management team, medical operations, ethics committees and a medical board, participated to harmonize the different requirements, thus making a maximal scientific outcome possible. CONCLUSION: In summary, this space mission may be seen as a model for focused long-term multidisciplinary international research, and demonstrates that space medicine is no longer adventure but science.

Cognitive-behavioral management of motion sickness.

This monograph is intended to provide health professionals with information on a cognitive-behavioral technique which was developed to teach individuals who are prone to motion sickness to better cope with motion environments. It includes an overview of motion sickness, describing the signs and symptoms, etiology and incidence of this malady. Prevention and treatment are then reviewed, including both pharmacological and non-pharmacological therapies. The historical background on the cognitive-behavioral technique is then discussed. This is followed by a review of supporting experimental work, and an account of how such counselling should be carried out. Finally, a number of current military desensitization programs are compared and contrasted with cognitive-behavioral therapy.

Spacelab experiments on space motion sickness.

Recent research results from ground and flight experiments on motion sickness and space sickness conducted by the Man Vehicle Laboratory are reviewed. New tools developed include a mathematical model for motion sickness, a method for quantitative measurements of skin pallor and blush in ambulatory subjects, and a magnitude estimation technique for ratio scaling of nausea or discomfort. These have been used to experimentally study the time course of skin pallor and subjective symptoms in laboratory motion sickness. In prolonged sickness, subjects become hypersensitive to nauseogenic stimuli. Results of a Spacelab-1 flight experiment are described in which four observers documented the stimulus factors for and the symptoms/signs of space sickness. The clinical character of space sickness differs somewhat from acute laboratory motion sickness. However SL-1 findings support the view that space sickness is fundamentally a motion sickness. Symptoms were subjectively alleviated by head movement restriction, maintenance of a familiar orientation with respect to the visual environment, and wedging between or strapping onto surfaces which provided broad contact cues confirming the absence of body motion.