Abstract:
Background and objective:
Pain is a universal, personal and subjective experience. Many factors are involved in the interpretation of this unpleasant sensation, including past experience, ethnicity and culture. Understanding these factors plays an important role in a comprehensive and multidimensional approach to the assessment and management of acute and chronic pain. The aim of this study is to determine experimental pain perception differences between Arab and western European healthy male subjects.
Method:
Fifty-six healthy Arab and western European male volunteers from Queen Margaret University College recruited to examine pain threshold using the method of limits in Quantitative Sensory Test (TSA 2001) and a Dolorimeter. Thermal and pressure pain threshold was measured on the thenar eminence of the non-dominant hand. Both ethnic groups were analysed separately.
Result:
Total fifty-six subjects (28 Arab and 28 European) subjects completed the study. In depended t-test result indicates that no statistically significant difference was found between Arabs and Europeans hot [t (54) =1.150; p>0.05], cold [t (54) =0.568; p>0.05], and pressure [t (54) =-0.279; p>0.05] pain threshold.
Conclusion:
No significant statistical difference in pain thresholds between Arab and Western European healthy male subjects was evident. More research is warranted in this field to access the perceptual and psychological aspects associated with pain.
Introduction
Pain is a subjective experience (French, 1989) and the protective function of life (Turk and Melzack, 1992). A number of factors may influence pain perception, including psychological, sociological and biological. Pain is the most common symptom in people who seek medical help, and is an important growing problem in the world (Strong, 2002).
One of the most important factors affecting the pain perception is Culture. Research indicates that socio-cultural factors have a great influence on pain and it varies across different social situations. Hence, it is important to study pain reactions keeping the socio-cultural factors in mind (Zborowski, 1952). To be able to assess the pain and its effect of the patients, normative data needed for each ethnic group and recorded their normal behaviour in pain stimulation in laboratory setting.
Various methods have been used in the past to induce experimental pain in varied cultural background populations to determine the influence of culture on perception of pain of an individual (Bates et al, 1994; Juarez et al, 1999; woolf et al, 2003; Ibrahim et al, 2003; Rotheram et al, 2000, Zaidi, 1994, Zborowski, 1952, Dunn, 2004).
However, determining cultural differences was not the primary aim of the research in many of these studies. Thus, there is need for further studies to determine the influence of culture on the perception of pain in individuals. (Janal et al, 1994; Mimi et al, 2002). Culture affects the perception of pain and response to pain in different ways (Bates et al, 1993). However, to our knowledge, there has been no research to determine the effect of culture factor on the pain thresholds in respect of Western European and Arab populations. The case study by Chatuverdi et al (1997) portrays the need for this research.
In a study on medical practice in south London showed that there is a delay in South Asians receiving treatment for heart conditions (Chatuverdi et al 1997). This delay was found to be due to the failure to recognise patient behaviour as appropriate for their illness by the assessing clinicians. In other words, the clinicians did not know the normal behaviour of this group and thus failed to recognise the importance of their symptoms.
Cultural diversity is a known risk factor for the under treatment of pain (Kagawa-Singer & Blackhall, L.J 2001). Therefore, understanding the cultural factor in pain management plays an important role in successful modern pain management programs.
The areas of ethnicity and pain seem to have been less well researched than pain related age and gender. The influence of these two latter variables in pain experience has been studies in both healthy subjects and those with pain. Research concerning ethnicity is almost all limited to chronic pain.
Various studies surrounding this topic suggest that there are different components to pain but, generally, they focus their attention on the social and behavioural dimensions. Westbrook et al (1984) and Chatuverdi et al (1997) compared the pain behaviour of Swedes, Australians, South Asians, and Europeans respectively. Despite the use of different methodologies and populations, both observed differences in pain behaviour in the ethnic groups.
Bates (1993, 1994) suggested that the attitudes, beliefs and emotional and psychological state of an individual play an important role in the variation in chronic pain experience in different ethnic groups. These factors, which affect the pain perception, should be encountered in any pain assessment and its effect. Regardless of the design or methodology used in the different studies, the researchers point to the importance of considering ethnic particularities if these is to be a better understanding of patients.
Different methods have been used in the past to induce experimental pain. These include the use of ischemic pain (Rosche et al, 1984), pinch pain (Simmonds et al, 1992) mechanical pain (Simmonds et al, 1992; Walsh et al, 1995) and cold pain (Johnson & Tabasam, 1999). However, the sensitivity and magnitude of stimulus response is poorly estimated with these methods (Price, 1996). Quantitative sensory test and Dolorimeter was used because its show reliability and validity in pain thresholds assessing.
The study was designed to investigate a limited area of pain perception in a closely defined population using apparatus in which the stimulus eliciting a response is quantified.
· The premising aim of the study is to determine the difference, if any, in thermal and pressure pain thresholds of western Europeans and Arab healthy male population using Quantitative sensory test and a Dolorimeter.
· A secondary aim was to obtain subjects normative data from healthy male Arab and Western European subjects for pain threshold. This may be useful for further research.
Method:
Prior to main study pilot study was conducted in order to test various determinants of the study design and methodology. The pilot study was conducted a week prior to the research study to prevent any previous experience, which may cause bias of the result. Two subjects who would not be involved in the main study were selected. The methodology followed during the pilot study was similar to that used in the research study. The results of the pilot study were satisfactory and indicated the feasibility of a full-scale research study.
After obtaining approval from the university ethics committee, 56 healthy volunteer subjects were recruited from Queen Margaret University College. No examinee had a history of significant medical problems or chronic painful conditions. Informed consent was obtained from all subjects before thermal and pressure threshold measurement was carried out. Heat, cold pain thresholds were measured using a thermal sensory test (Verdugo & Ochoa, 1992). Pressure pain threshold was measured using a Dolorimeter. The apparatus employed was a thermal sensory analyser (model TSA-2001Medoc Ltd). The Quantitative sensory threshold test device was programmed such that it would discharge five hot and cold stimulations alternately to the non-dominant hand (the thenar aspect was used) (Yarnitsky et al, 1995 & Shy et al, 2003). In order to improve the reliability of the results a starting point for the Thermode was set as 32?C (Yarnitsky & Ochoa, 1991; Hagander et al, 2000). A range of 0°C to 50° C was used during the study. The rate of change in temperature was set to 1° C/sec as the stimulus moved away from the base line (Yarnitsky, 1997). To increase intrarater reliability the rate of temperature change was increased gradually (Palmer et al, 2000) and a temperature change of 3°C/sec was set as the stimulus returned to the base line of 32°C (Yarnitsky, 1997).
The sensory feedback data of the pain threshold levels was automatically recorded on the computer by a simple push-button response of the subject at the point where he deems the stimulus painful. The Peltier Thermode was firmly strapped against the thenar eminence by using a tourniquet approximately 20cm in length and 2cm in width (Hagander et al, 2000; Dyck et al, 1993), and to standardise the contact between the Peltier Thermode and thenar eminence surface, the tourniquet was expanded for 2 cm before fixation to the application site. The subject was blinded to the aim of the study and, to prevent the effect of optical feedback, the subjects were prevented from seeing the monitor displaying the information.
The pressure test was performed five minutes after the quantitative sensory test was conducted to avoid possibility of
