Monday, September 18, 2006
Friday, September 01, 2006
Evaluation Points You Must Know For Pain
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.
Managing and Controlling Pain
One important approach to pain management is the operant view. This is best represented in the writings of Fordyce (1976). According to this view of pain, there is an initial response to pain stimulation that produces certain behaviors. These pain behaviors might include avoidance of work, staying in bed, and verbal descriptions of pain. In addition, pain behaviors might include taking medications. Initially, these pain behaviors are a response to pain stimulation. However, according to the principles of learning, behaviors can be strengthened through reinforcement. If pain behavior is reinforced or followed by positive consequences, its probability will increase in the future.
Flor, Kerns and Turk (1987) used questionnaire reports by pain patients and their spouses to assess how the patients' behaviors were related to their spouses' being solicitous, that is, reacting to pain behaviors by giving attention and care. Higher levels of solicitousness by the spouse were associated with patients showing more pain behavior and less activity, such as in visiting friends or going shopping.
Therefore the operant approach to pain requires that 'well behaviour' activities be reinforced and that pain behaviors be extinguished. Thus, families might be taught to ignore pain behaviors, but to provide reinforcement for functional activity/'well behaviours'.
Cognitive Behavioural Approaches
A cognitive-behavioural approach to pain regards pain as a perception that involves an integration of four sources of pain-related information:
- Cognitive, e.g. the meaning of the pain ('it will prevent me from working').
- Emotional, e.g. the emotions associated with the pain (T am anxious that it will never go away').
- Physiological, e.g. the impulses sent from the site of physical damage.
- Behavioural, e.g. pain behaviour that may increase the pain (such as not doing any exercise) and pain behaviour which may decrease the pain (such as doing sufficient exercise).
Cognitive-Behavioural approaches are popular because they integrate techniques that deal with the experience of pain on a number of levels, rather than viewing pain as a simple experience. This can be seen in a study by Basler and Rehfisch (1990) in which sixty chronic pain sufferers, who had experienced chronic pain in the head, shoulder, arm or spine for at least 6 months, were recruited. Ps were allocated to either (1) the immediate treatment group or (2) the waiting list control group.
All Ps completed measures at baseline (time 1), after the 12-week treatment intervention (time 2) and at 6-month followup (time 3). Ps in the control group completed the same measures at comparable time intervals. At times 1, 2 and 3, all Ps completed a 14-day pain diary, which included measures of: Intensity of pain, mood, functional limitation and pain medication.
The treatment programme consisted of weekly 90-minute sessions, which were carried out in a group 1 up to 12 patients. All Ps in the treatment group received a treatment manual. The following components were included in the sessions:
- Education. This component aimed to educate the subjects about the itionale of cognitive behaviour treatment. The subjects were eniraged to take an active part in the programme, they received formation about the vicious circle of pain, muscular tension, demoralization and about how the programme would improve their sense of self-control over their thoughts, feelings and behaviour.
- Relaxation. The subjects were taught how to control their responses pain using progressive muscle relaxation. They were given a home relaxation tape, and were also taught to use imagery techniques and visualization to distract themselves from pain and to further improve their relaxation skills.
- Modifying thoughts and feelings. The subjects were asked to complete coping cards to describe their maladaptive thoughts and adaptive coping thoughts. The groups were used to explain the role of fear, depression, anger and irrational thoughts in pain.
- Pleasant activity scheduling. The subjects were encouraged to use distraction techniques to reduce depression and pain perception. They were encouraged to shift their focus from those activities they could no longer perform to those that they could enjoy. Activity goals were scheduled and pleasant activities were reinforced at subsequent groups.
The results showed significantly different changes between the two groups in all their ratings. Compared with the control group, the subjects who had received cognitive behavioural treatment reported lower pain intensity, lower functional impairment, better daily mood, fewer bodily symptoms, less anxiety, less depression, fewer pain-related bodily symptoms and fewer pain-related sleep disorders.
(Reported in Ogden, 2000)
Perhaps the most obvious approach to measuring people's pain is to ask them to describe their discomfort, either in their own words or by filling out a rating scale or questionnaire. In treating a patient's pain, health care workers ask where the pain is, what it feels like, how strong it is, and when it tends to occur. With chronic pain patients, medical and psychological professionals often incorporate this kind of questioning within the structure of a clinical interview.
Point 3: Interviews
To measure chronic pain effectively, professionals need more information than just a description of the pain. Interviews with the patient and key others, such as family members and co-workers, provide a rich source of background information in the early phases of treatment. These discussions ordinarily focus on such issues as:
- History of the pain problem, including when it started, how it progressed, and what approaches have been used for controlling it.
- The patient's emotional adjustment, currently and before the pain syndrome began.
- The patient's lifestyle—recreational interests, exercise patterns, diet, and so on—before the pain condition began.
- The pain syndrome's impact on the patient's current lifestyle, interpersonal relations, and work.
- The social context of pain episodes, such as happenings in the family before an attack and how family members respond when the pain occurs.
- Factors that seem to trigger attacks or make them worse.
- How the patient typically tries to cope with the pain.
Point 4: Rating Scales
One of the most direct, simple, and commonly used ways to assess pain is to have individuals rate some aspect of their discomfort on a scale (Chapman et al., 1985; Jensen et al., 1989; Karoly, 1985). One type is the visual analog scale, which has people rate their pain by marking a point on a line that has labels only at each end. This type of scale is very easy for people to use and can be used with children as young as 5 years of age (Karoly, 1985).
No pain ----------------------------------------------------------- Worst pain possible
The box scale has individuals choose one number from a series of numbers that represent levels of pain within a specified range. The verbal rating scale has people describe their pain by choosing a word or phrase from several that are given.
|No Pain||1||2||3||4||5||6||7||8||9||10||Worst pain possible|
Because rating scales are so easy and quick to use, people can rate their pain frequently. Repeated ratings would reveal how their pain changed over time, such as during everyday activities or during the ourse of an experiment. As an example, Dennis Turk and his colleagues have described how this approach can be used with chronic pain patients (Turk, Meichenbaum, & Genest, 1983). Each hour of a day the patients rate their pain on index cards, which have separate scales for each hour. They do this for, say, 2 weeks, also indicating whenever they take pain medication. Before starting this procedure, they leam what to say if someone sees them filling out the card and asks what they are doing, ways to remind themselves to do each hourly rating, and what to do if they forget. One use of repeated ratings is in showing the ebbs and flows of pain intensity that patients often experience.
Point 5: Behavioural Assessment
Because people tend to exhibit pain behaviors when they are in discomfort, it should be possible to assess their pain by observing their behavior.
Procedures are available whereby health care workers can assess the pain behavior of patients in structured clinical sessions. These sessions are usually conducted in hospital settings and are structured by the specific pain behaviors to be assessed and the tasks the patient is asked to perform. One approach of this kind has been developed into a pain assessment instrument—the UAB Pain Behavior Scale—for use by nurses during their standard routines, such as in early morning rounds (Richards, Nepomuceno, Riles, & Suer, 1982). The nurse has the patient perform several activities and rates each of 10 behaviors, such as ie patient's mobility and use of medication, on a three-point scale: "none," "occasional," and "frequent." These ratings are converted into numerical values and summed for a total score.
Assessing Pain Behavior in Everyday Activities: Family members or key others in the patient's life are usually the best people to make these everyday assessments of pain behavior. These people must,ph of course, be willing to help and be trained to make careful observations and keep accurate records. Pain researcher Wilbert Fordyce (1976) has recommended a procedure whereby the assessor—say, the client's spouse—compiles a list of five to ten behaviors that generally signal when the patient is in pain. Then the spouse receives training in watching for these behaviors and keeping track of the amount of time the patient exhibits them. Finally, the spouse is trained to monitor how people, including the assessor, react to the client's pain behavior. This procedure is useful not only in assessing the patient's pain experiences but in determining their impact on his or her life and the social context that may maintain pain behaviors.
The above material on assessing pain is sourced from Sarafino (1994).
Types and Theories of Pain
Types of Pain
Acute pain is typically associated with an active disease state or traumatic injury. When the damaged area heals, the pain typically goes away. Acute pain serves as an important signal identifying that there is damage. With this information, behavior change can be initiated so that further injury might be avoided.
Sometimes pain persists even after injuries have healed. This is usually referred to as chronic pain. Chapman and Bonica (1985) identify three types of chronic pain: (1) pain that lasts after the normal feeling of a disease or an injury; (2) pain associated with a chronic medical condition, such as a degenerative disease or a neurological condition; or (3) pain that develops and persists in the absence of identifiable organic problem.
People's experience with chronic pain also depends on two factors: (1) whether the underlying condition is benign or is malignant and worsening and (2) whether the discomfort exists continuously or occurs in frequent and intense episodes. Using these factors, Dennis Turk, Donald Meichenbaum, and Myles Genest (1983) have described three types of chronic pain:
1. Chronic/recurrent pain stems from benign causes and is characterized by repeated and intense episodes of pain separated by periods without pain. Two examples of chronic/recurrent pain are migraine headaches and muscle-contraction (tension) headaches; another exampie is myofascial pain, a syndrome that typically involves shooting or radiating, but dull, pain in the muscles and connective tissue of the head and neck, and sometimes the back.
2. Chronic/intractable/benign pain refers to discomfort that is typically present all of the time, with varying levels of intensity, and is not related to an underlying malignant condition. Chronic low back pain often has this pattern.
3. Chronic/progressive pain is characterized by continuous discomfort, is associated with a malignant condition, and becomes increasingly intense as the underlying condition worsens. Two of the most prominent malignant conditions that frequently produce chronic/progressive pain are rheumatoid arthritis and cancer.
Theories of Pain
Specificity theory. Von Frey (1895) argued that the body has a separate sensory system for perceiving pain—just as it does for hearing and vision—and this system contains its own special receptors for de:ecting pain stimuli, its own peripheral nerves and pathway to the brain, and its own area of the brain for processing pain signals. But this structure is not correct.
Pattern theory. Goldschneider (1920) proposed that there is no separate system for perceiving pain, and the receptors for pain are shared with other senses, such as of touch. According to this view, people feel pain when certain patterns of neural ctivity occur, such as when appropriate types of activity reach excessively high levels in the brain. These patterns occur only with intense stimulation. Because strong and mild stimuli of the same sense modality produce different patterns of neural activity, being hit hard feels painful, but being caressed does not.
Gate Control Theory. Melzack has proposed a theory of pain that has stimulated considerable interest and debate and has certainly been a vasy improvement on the early theories of pain. According to his theory, pain stimulation is carried by small, slow fibers that enter the dorsal horn of the spinal cord; then other cells transmit the impulses from the spinal cord up to the brain. These fibers are called T-cells. The T-cells can be located in a specific area of the spinal cord, known as the substantial gelatinosa. These fibers can have an impact on the smaller fibers that carry the pain stimulation. In some cases they can inhibit the communication of stimulation, while in other cases they can allow stimulation to be communicated into the central nervous system. For example, large fibers can prohibit the impulses from the small fibers from ever communicating with the brain. In this way, the large fibers create a hypothetical "gate" that can open or close the system to pain stimulation. According to the theory, the gate can sometimes be overwhelmed by a large number of small activated fibers. In other words, the greater the level of pain stimulation, the less adequate the gate in blocking the communication of this information.
There are 3 factors which influence the 'opening and closing' of the gate -
- The amount of activity in the pain fibers. Activity in these fibers tends to open the gate. The stronger the noxious stimulation, the more active the pain fibers.
- The amount of activity in other peripheral fibers—that is, those fibers that carry information about harmless stimuli or mild irritation, such as touching, rubbing, or lightly scratching the skin. These are large-diameter fibers called A-beta fibers. Activity in A-beta fibers tends to close the gate, inhibiting the perception of pain when noxious stimulation exists. This would explain why gently massaging or applying heat to sore muscles decreases the pain.
- Messages that descend from the brain. Neurons in the brainstem and cortex have efferent pathways to the spinal cord, and the impulses they send can open or close the gate. The effects of some brain processes, such as those in anxiety or excitement, probably have a general impact, opening or closing the gate for all inputs from any areas of the body. But the impact of other brain processes may be very specific, applying to only some inputs from certain parts of the body. The idea that brain impulses influence the gating mechanism helps to explain why peopie who are hypnotized or distracted by competing environmental stimuli may not notice the pain of an injury.
Thus we can conclude that our experience of pain is dependent on the condition of 'the gate'. The more the gate is opened the greater the perception of pain. Melzack suggests that several factors can open the gate:
- Physical factors, such as injury or activation of the large fibres
- Emotional factors, such as anxiety, worry, tension and depression;
- Behvioural factors, such as focusing on the pain or boredom.
The gate control theory also suggests that certain factors close the gate.
- Physical factors, such as medication, stimulation of the small fibres;
- Emotional factors, such as happiness, optimism or relaxation;
- Behavioural factors, such as concentration, distraction or involvement in other activities.