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Biomedical subjects

A Rolnick

Publications and source records attributed to A Rolnick.

8 recordsLinked to original sources
PubMed1991

Why is the driver rarely motion sick? The role of controllability in motion sickness.

The central hypothesis of the work is that the dimension of control-no control plays an important role in motion sickness. Although it is generally agreed that having control over a moving vehicle greatly reduces the likelihood of motion sickness, few studies have addressed this issue directly, and the theoretical explanation for this phenomenon is not completely clear. In this study, we equated groups differing in controllability for head movement, vision, activity, and predictability, which have often been suggested in the literature as explanations for the driver's immunity to motion sickness. Twenty-two pairs of yoked subjects were exposed to nauseogenic rotation. One subject of each pair had control over the rotation and head movements, while the other was exposed passively to the same motion stimulus. Subjects who had control reported significantly fewer motion sickness symptoms and less of a decrement in their well-being, as compared to the yoked subject without control. The results are discussed in relation to Reason's sensory rearrangement theory and the concept of feed-forward mechanisms in motion perception.

Adult↗
PubMed1989

Conditioned taste aversion in humans using motion-induced sickness as the US.

The purpose of the experiment was to demonstrate conditioned taste aversion (CTA) and latent inhibition (LI) of CTA in humans using rotation-induced motion sickness as the unconditioned stimulus. To accomplish this, flavour familiarity (familiar vs unfamiliar) and rotation (rotation vs no rotation) were manipulated in a 2 X 2 factorial design. Subjects consumed either a familiarly flavoured carbonated beverage or a novel one after which half of each group was rotated or not rotated. Two hours later the subjects were re-presented with the flavoured drink that they had previously drunk. The groups receiving rotation consumed less of the drink that the non-rotated groups, thus demonstrating CTA. The rotated group pre-exposed to the novel flavoured drink consumed less than the rotated group pre-exposed to the familiar drink, thus demonstrating LI. The effectiveness of the rotation procedure in producing motion sickness was confirmed by self-reports of general feelings and by symptom rating scales. In addition, it was found that, at the time of consuming the test drink the rotation groups' motion-sickness symptom scores were reduced to the level of the nonrotated groups. Applications of these data to the prophylactic treatment of chemotherapy-induced food aversions were discussed.

Adolescent↗
PubMed1989

Salivary changes associated with seasickness.

Salivary composition and flow rate were measured in 13 healthy male volunteers exposed to a real seasickness situation. The flow rates of whole unstimulated and stimulated saliva were significantly reduced at sea in about 80% of the subjects. Salivary flow rate was negatively correlated with seasickness severity. These results contrast with the classic concept of increased salivation during seasickness. At sea, the potassium concentration of both unstimulated and stimulated saliva was significantly reduced, while sodium concentration was consistently elevated. The sodium and protein concentrations were positively correlated with seasickness severity. Thus, objective measurements of salivary flow rate and composition may be recommended for evaluation of the seasickness syndrome.

Adolescent↗
PubMed1989

Performance and well-being under tilting conditions: the effects of visual reference and artificial horizon.

It is generally agreed that the incidence of motion sickness in sailors working below deck is higher than in sailors who have the horizon as a visual reference on the bridge. This study investigated the possible beneficial effect of a projected artificial horizon as a means to prevent seasickness. Twelve subjects were exposed to angular motion in a tilting room under three experimental conditions: a) With the windows covered, allowing no visual reference from the outside world; b) With the windows uncovered, thus allowing a partial view of the environment; and c) With the windows covered and a horizon projected on the walls by a rotating laser beam. Subjects were exposed for 35 min in each condition while performing different computerised tasks. There was a reduction in well-being and performance as a function of exposure time. These effects were clearly shown in the "closed cabin" condition. There were less motion sickness symptoms in the "artificial horizon" and "window" conditions. The presence of a visual reference prevented the decrement in performance found in the "closed cabin" condition. The results of this study suggest that a projected horizon might alleviate motion sickness aboard naval vessels, and thus improve the performance of sailors at sea.

Female↗
PubMed1988

Salivary changes associated with experimental motion sickness condition in man.

The effect of experimental motion sickness condition (rotation) on salivary flow and composition was studied in 34 healthy male volunteers. In most subjects, the flow rate of whole saliva was significantly decreased, while the potassium concentration was markedly increased during rotation. These results contrast with the classic reports of subjectively increased salivation in the first stages of motion sickness and may tentatively be explained in terms of sympathetic activation. The salivary protein concentration and secretion rate observed before and during rotation were consistently higher in those subjects categorized as moderately or severely sick during rotation. The salivary protein levels may perhaps be considered as an additional objective variable in the prediction of susceptibility to motion sickness.

Adolescent↗
PubMed1987

Efficacy of transdermal scopolamine against seasickness: a 3-day study at sea.

Transdermal scopolamine has been reported to provide protection against motion sickness, both while sailing at sea (7-8 h) and under experimental conditions. In this study, we tested the efficacy of transdermal scopolamine and evaluated its side effects during a 72-h cruise at sea. We tested 38 male volunteers, 20-25 years old, who were located on a 3000-ton vessel. The presence of seasickness, defined by Graybiel's diagnostic criteria, was used to calculate percent protection. When sickness was considered as malaise II or more, the drug provided 74, 73, and 39% protection during the three sailing days, respectively. There were no significant differences in the magnitude of the side effects reported by experimental and placebo groups. We conclude that transdermal scopolamine's efficacy against seasickness during a 3-day cruise was not associated with significant side effects and, therefore, we find the drug suitable for long-term use by sailing crews.

Administration, Cutaneous↗
PubMed1986

Transdermal scopolamine: human performance and side effects.

The effect of transdermal scopolamine on performance was tested on 23 naval volunteers. Performance was evaluated by using a battery of professional (naval-related) and cognitive tests. For all tests performed there were no significant differences between the scores obtained in placebo and transdermal scopolamine conditions. These results were in close agreement with subjective estimations of performance. Transdermal scopolamine significantly reduced salivary flow, whereas mood state, visual acuity, and eye accommodation for near vision were not affected. We conclude that transdermal scopolamine administration is not accompanied by decrement in performance abilities and can safely be used by naval crews.

Accommodation, Ocular↗