Pain and Unpleasantness Evoked by a Cold Pressor Test: DISCUSSION

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12 Mar 2010

Cold Pressor Test

In the literature, various distraction techniques have been shown to raise the pain threshold. As an experimental pain model, the cold pressor test has been widely used since it provides a standardized and relatively intense pain stimulus. If a significant effect on the perceived intensity of pain can be observed in a relatively small number of volunteers (10-15) with this model, the distracting technique may be suitable for further evaluation.

Pain tolerance to the cold pressor test has been shown to increase after watching a humorous movie for 30 minutes before the pain stimulus started, and distraction in the form of a mental task (subtraction) has recently been demonstrated to attenuate the pain sensation evoked by short C02 laser stimuli. The results of another previous study indicated that it was essential for the hypoalgesic effect that, first, the volunteer had a strong belief in the positive effect of music as distraction and, second, that he/she was allowed to control the volume and thereby create a feeling of controlling the pain. A more recent study evaluated the intensity of pain during dental treatment with music used as a distraction without any prior positive information and without giving the patient the possibility of controlling the volume and reported that patients listening to music experienced a stronger feeling of control of the pain than patients in the control group. cialis professional

The present study aimed to investigate video glasses as an easy way of implementing external distraction. A recent study demonstrated that audio and video both transmitted through video glasses reduced intensity of symptoms during sigmoidoscopy while sound per se did not have a significant effect. The interpretation of this result could be that the hypoalgesic effect is related to the intensity of the stimuli, which was the reason for including both 2D and 3D films in the present study. There was no possibility for the volunteer to manipulate the volume of sound once started or to choose favorite videos. The same film sequences were unfortunately not available in both 2D and 3D, and in the selection of the videos, weight was put on their neutral content.

The present data clearly indicated that the video glasses that transmitted 3D or 2D video and stereo sound reduced the perceived pain and/or unpleasantness from the cold pressor stimulus. Another interesting finding in the present study was the observed gender differences in the effect of video glasses (H3 had to be rejected). Three-dimensional video produced a significant reduction in pain and unpleasantness in the male group compared with the control condition, whereas there was no effect for 2D video. In the female group, there was a significant reduction only of unpleasantness for the 2D video compared with the control. Thus, hypothesis Нг had to be rejected with regard to the male group and H2 with regard to the female group. The different findings in the male and the female groups, however, are not likely to be explained by generally lower VAS scores in males than in females since there were no significant differences in their ratings of pain and unpleasantness in the control condition. Gender differences in pain threshold have been shown predominantly to originate in the experimental pain technique, but gender differences have been found by other authors using the cold pressor and other thermal test stimuli. Pain tolerance could not be measured because no volunteers withdrew their hand before the fixed maximum period of 3 minutes. The present results are in agreement with the findings in a study on relaxation and distraction during dental procedures that suggested that relaxation in the form of instructions through earphones was more effective in women than in men and that distraction in the form of a video game was more effective in men than in women. It must be emphasized that the male group consisted mainly of polytechnic students and the female group consisted of dental students, which could be a confounding factor. Nevertheless, it was a remarkable finding that everyone wanted to use video glasses, either 2D or 3D, if they were to repeat a cold pressor test, even if they had rated the lowest pain intensity in the condition without video glasses.

Three quarters of the volunteers actually did prefer the method in which they had rated the lowest pain intensity. It seems promising for the video glasses method that it was universally preferred by volunteers, and it seems that the individual is able to choose the method that gives the greatest relief of pain and in this way optimize the effect. cheap cialis canadian pharmacy

In conclusion, this study suggests that an external distraction technique, video glasses, could be effective as an easily implemented device to reduce pain and unpleasantness. Therefore, further studies may be warranted to reveal whether the effect of video glasses can be transferred to different clinical situations in dental practice.

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Blog invites submissions of review articles, reports on clinical techniques, case reports, conference summaries, and articles of opinion pertinent to the control of pain and anxiety in dentistry.