[Clinical study on the mechanism of motion sickness--clinical examination based on trigger factors]

[Article in Japanese]

Fujita N.

Department of Otorhinolaryngology, Nara Medical College.

This report deals with factors which trigger motion sickness. The author has focused on the clinical examinations applied to motion sickness cases. Relationships between clinical data and susceptibility to motion sickness were investigated. The following results were obtained: 1. CV R-R(coefficient of variation of R-R intervals on EGG)in the frequent motion sickness group showed higher values than in the occasional motion sickness group. This result suggests a hyperfunction of the vagus nerve. 2. In caloric testing with ENG, the motion sickness group showed lower values of duration and eye speed than the occasional motion sickness group. On the other hand, the frequent group showed higher values of laterality in eye speed than the occasional group. 3. With the visual suppression test, the frequent motion sickness group showed higher values than the occasional motion sickness group. On the other hand, there was a significant difference between the frequent motion sickness group and the occasional motion sickness group in terms of laterality of visual suppression values. 4. In testing fluctuation of CV R-R in response to optokinetic stimuli, the frequent motion sickness group showed elevation of CV R-R values after optokinetic load. On the other hand, the occasional motion sickness group showed depression of CV R-R values after the same load. 5. Among clinical examinations designed to diagnose susceptibility to motion sickness, CV R-R, the caloric test, the visual suppression test and OKP testing can produce sufficiently accurate results for clinical investigation.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1403328&dopt=Abstract motion sickness




Motion sickness-like syndrome among tank simulator drivers.

Lerman Y, Sadovsky G, Goldberg E, Kedem R, Peritz E, Pines A.

Israel Defense Forces Medical Corps, Jerusalem.

A military tank driving simulator has recently been introduced as a training aid for tank drivers in the Israel Defense Forces. Reports of nausea and vomiting among the first users of the simulator launched our investigation of the possible existence of a motion sickness-like syndrome among simulator drivers. Although the 59 subjects drove the simulator without any report of vomiting, other motion sickness-like symptoms were frequently reported. A comparison of symptoms reported after simulator and real tank driving show that dizziness, nausea, disorientation and hypersalivation were more frequently reported by simulator drivers and were of greater intensity. However, sweating and drowsiness were more prevalent among real tank drivers. The objective effect of driving the simulator was evaluated by instability and performance tests that were conducted before, during and after driving the simulator. A greater decrement in test results was observed among subjects reporting higher frequency of motion sickness-like symptoms.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1428818&dopt=Abstract motion sickness




[Clinical and experimental studies of royal made ping an dan on treatment of motion sickness]

[Article in Chinese]

Chen KJ, Li CS, Zhang GX.

Xiyuan Hospital, China Academy of Traditional Chinese Medicine, Beijing.

This paper presents the results of clinical observation and experimental research of Royal Made Ping An Dan (RPAD) of the Imperial Hospital of Qing Dynasty. The clinical results showed that RPAD was effective in treating 343 patients with motion sickness, and their average time for producing effect was 24.1 +/- 13.5 minutes. The total effective rates of dramamine group and Ren Dan group were 69.4% and 67.7% respectively, the latter included 45.7% of basically cured and 55.0% of markedly effective cases. There were significant differences among these groups (P < 0.05-0.01). It revealed that the effect of RPAD was better than that of dramamine and Ren Dan. According to laboratory findings, RPAD had the ability of alleviating symptoms of motion sickness and inhibiting eyeball tremor and improving meningeal microcirculation of experimental animals.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1477502&dopt=Abstract motion sickness




Vestibular, central and gastral triggering of emesis. A study on individual susceptibility in rats.

Hasegawa S, Takeda N, Morita M, Horii A, Koizuka I, Kubo T, Matsunaga T.

Department of Otolaryngology, Osaka Sumitomo Hospital, Japan.

Using kaolin intake as a behavioral index of emesis in rats, we examined the relationship between susceptibility to motion sickness and to emesis induced by apomorphine or copper sulfate. Rats showed a wide variation in susceptibility to motion sickness. Significant positive correlations were found between susceptibility to motion sickness and to emesis induced by intraperitoneal administration of apomorphine and by oral administration of copper sulfate. Motion, apomorphine and copper sulfate induce emesis through different receptors, so these findings suggest that the sensitivity of a common locus of emesis, presumably the emetic center in the brain stem, is one determinant of individual differences in susceptibility to motion sickness.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1481662&dopt=Abstract motion sickness




Susceptibility of divers in open water to motion sickness.

Norfleet WT, Peterson RE, Hamilton RW, Olstad CS.

Marine Resources Development Foundation, Key Largo, Florida 33037.

Several aspects of the environment of divers should increase their susceptibility to motion sickness: a) sensory conflicts, b) body fluid redistribution, and c) nitrogen narcosis. We tested motion sickness susceptibility by placing subjects on a rotating platform and having them perform stylized heat movements that produced cross-coupled angular accelerations in vestibular end organs until nausea developed. This test was performed once each day on 9 consecutive days while subjects were immersed at the end of 3-4 h of diving. The test was also carried out while subjects were nonimmersed with no preceding diving on the day immediately before and after this 9-day period. Compared with nonimmersed conditions, significantly fewer head movements were required to elicit nausea while immersed (P less than 0.01). We conclude that individuals are more susceptible to motion sickness while immersed in open water than while on dry land.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1536062&dopt=Abstract motion sickness




Phasic skin conductance activity and motion sickness.

Golding JF.

Royal Air Force Institute of Aviation Medicine, Farnborough, Hants, United Kingdom.

Sweating is commonly associated with motion sickness. Previous studies have attempted to relate sweating or the associated electrodermal activity to the degree of motion sickness symptoms. This study was aimed at improving methodology by study of 1) recording site--palmar finger versus forehead; and 2) signal analysis--tonic skin conductance level (SCL) versus phasic skin conductance responses (SCRs). Eleven subjects were exposed to a cross-coupled motion challenge, produced by repeated head movements (16 per minute) during rotation around the Earth vertical axis in which rotational velocity was incremented on a staircase profile from 3 degrees to 99 degrees.s-1 to an end point of moderate nausea. Six subjects underwent additional control conditions of rotation only and head movements only. A group of 12 subjects underwent sessions of vertical and horizontal sinusoidal linear motion through the head z-axis at 0.3 Hz, 1.8 ms-2 rms. Sweating responses were recorded in a further three subjects by mass spectrometry for water vapor from the skin using a dry N2 gas flow method. Phasic skin conductance activity at the forehead site provided the best correlate of motion sickness onset and recovery. Other combinations of signal analysis or recording site were less useful.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1567315&dopt=Abstract motion sickness




Investigation of anti-motion sickness drugs in the squirrel monkey.

Cheung BS, Money KE, Kohl RL, Kinter LB.

Defence and Civil Institute of Environmental Medicine, Ontario, Canada.

Early attempts to develop an animal model for anti-motion sickness drugs, using dogs and cats; were unsuccessful. Dogs did not show a beneficial effect of scopolamine (probably the best single anti-motion sickness drug for humans thus far) and the findings in cats were not definitive. The authors have developed an animal model using the squirrel monkey (Saimiri sciureus) of the Bolivian phenotype. Unrestrained monkeys in a small lucite cage were tested in an apparatus that induces motion sickness by combining vertical oscillation and horizontal rotation in a visually unrestricted laboratory environment. Signs of motion sickness were scored using a rating scale. Ten susceptible monkeys (weighing 800-1000 g) were given a total of five tests each, to establish the baseline susceptibility level. Based on the anticholinergic activity of scopolamine, the sensitivity of squirrel monkey to scopolamine was investigated, and the appropriate dose of scopolamine for this species was determined. Then various anti-motion sickness preparations were administered in subsequent tests: 100 ug scopolamine per monkey; 140 ug dexedrine; 50 ug scopolamine plus 70 ug dexedrine; 100 ug scopolamine plus 140 ug dexedrine; 3 mg promethazine; 3 mg promethazine plus 3 mg ephedrine. All these preparations were significantly effective in preventing motion sickness in the monkeys. Ephedrine, by itself, which is marginally effective in humans, was ineffective in the monkeys at the doses tried (0.3-6.0 mg). The squirrel monkey appears to be a good animal model for antimotion sickness drugs. Peripherally acting antihistamines such as astemizole and terfenadine were found to be ineffective, whereas flunarizine, and an arginine vasopressin V1 antagonist, showed significant activity in preventing motion sickness.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1613127&dopt=Abstract motion sickness




alpha-Fluoromethylhistidine but not diphenhydramine prevents motion-induced emesis in the cat.

Lucot JB, Takeda N.

Department of Pharmacology, Wright State University, Dayton, OH 45435.

PURPOSE: This study seeks to evaluate the comparative role of alpha-fluoromethylhistidine and diphenhydramine in the prevention of motion sickness. METHOD: The role of histaminergic mechanisms in motion sickness were evaluated in a feline model. Twenty-six female cats were studied. A variety of doses of fluoromethylhistidine and diphenhydramine were administered before motion testing. RESULTS: Fluoromethylhistidine was effective in preventing motion sickness. The efficacy was dose dependent. In contrast, diphenhydramine failed to prevent motion sickness in any of the tested doses. CONCLUSIONS: The failure of diphenhydramine to prevent motion sickness was unexpected. This may reflect the route of administration or the animal model studied. Depletion of histamine with fluoromethylhistidine prevented motion sickness in cats. Our results suggest that this drug may provide a very long duration of protection in cats.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1626619&dopt=Abstract motion sickness