Friday, September 01, 2006

Evaluation Points You Must Know For Pain

It is hard for a doctor to explain about pain other than relying on what the patient tells them. This means that there are many problems in investigating the experience of pain. Given the subjective nature of the experience of pain psychologists are limited in the methods they can use to investigate this phenomenon.

Point 1: Methodology

There are very few objective measures of pain. This is because pain is a subjective experience. Therefore, interviews are often used. The main problem with interviews is that of interviewer bias. The researcher may be looking for specific answers and details, thus they may be more likely to make suggestions to the patient and wrongly interpret what they say. This potentially makes the data biased and less reliable, and possibly affects validity.

In addition the interviewee may want to look good and attempt to improve their self presentation by underestimating or avoiding the complete truth about their experience of pain, e.g. men may not admit to the degree of pain they are experiencing as it may make them appear weak. To suffer stoically - to suffer in silence, without making too much fuss - may be viewed as a desirable quality in patients. A man who thinks that 'making a fuss' is a behaviour that women show, will be less likely to demonstrate this himself. Some patients may adopt the 'sick role' and be quiet, passive and acquesant. These factors may well alter the Ps behaviour towards the interviewer and thus bias the results.

In addition using a questionnaire causes certain problems, although it can be the most reliable measure of pain, as the questionnaire can show changes in pain over time and the success of treatment programs. They can have problems capturing the individual experience of pain and this can affect the validity of the measure. To an extent you are limiting people's responses. Further you need to be able to read and write, and some may not admit to not being able to read, and are unlikely to admit it due to embarrassment. Thus if a questionnaire is the main a method of investigation some groups of participants pain experience cannot be effectivley investigated, for example, young children, people with severe learning disabilities, and those with a low level of literacy.

Further, semantic differential scales (choosing wich words best describe your pain) are difficult and time consuming to complete and demand a sophisticated literacy level, a sufficient attention span, and a normal cognitive state. They therefore are less convenient to use in the clinical environment, but have value when a more detailed analysis of a patient's perception of pain is needed, as in a pain clinic or clinical research setting.

Point 2: Reliability.

A difficult aspect of reliability is that the patient may have developed a different understanding of the pain problem and may give a different response from one examination to the next. It is equally important for the examiner to ask himself or herself whether the interpretation of the patient's responses differs from one examination to the next. Both factors affect the reliability of the information being gathered.

Point 3: Interaction between interviewer and interviewee.

The quality of the interview and the data obtained is dependent on the interaction between researcher and P. This point has been highlighted by Labov in a study in which the participants were young black children. he found that more information and better quality data was elicited a from the participants when the interviewer was Black rather than White. Therefore the interviewer - participant interaction can affect the data found. We must be aware that who the interviewer is, in addition to whom the participant is, will have direct effects on the type and quality of interaction that takes place. These factors will affect the reliability and validity of any study that uses interviews as a method of investigation.

Point 4: Issues in measuring the effectiveness of pain management techniques.

Placebo effect: Diamond et al (1960) showed through mock operations for a heart bypass to cure angina (Ps actually went ‘under the knife’ but had nothing else done!) that this had similar effects in reducing feelings of pain as the real operation. Thus the placebo effect in pain control could be very real. It may be more to do with the Ps expectancy to experience reduced pain that is the most effective method. Thus any method of pain management needs to be invetigated with this factor kept in mind.

Given that pain is a subjective experience any truly objective measure is impossible, thus the data collected in regards to the effectiveness of any pain management method must be viewed in this light. That the information recorded is a partial and biased account of individual self-reports. Linked with the placebo effect this means that ever gaining a valid picture of the effectiveness, or otherwise, of any pain management technique will be problematic.


Blogger Aaron Grey said...

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Aaron Grey
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3:46 PM  

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