Francis J. Keefe, PhD
Duke University
Dr. Keefe has no significant financial interest or relationships to disclose.
Release Date: May 20, 2010
Expiration Date: January 1, 2011
For CME credit,TAKE POST-TEST & EVALUATION
Objectives
After completing this activity, you’ll be able to:
- Explain how theories of pain have evolved over time and how this evolution influences psychosocial approaches to pain management
- Discuss results of randomized clinical trials of pain coping skills training for arthritis pain
- Recognize future directions for clinical and research efforts in arthritis pain management
Background
Pain is as old as humankind. The earliest records of ancient civilization referred to pain and methods of pain relief. From what we can determine from these records, ancient civilizations understood pain that was associated with a disease or injury that you could see (acute pain). What they could not understand was pain that persisted. The earliest explanations for persistent pain were mystical or religious in nature. The breakthrough in our modern views of pain came as a result of Rene Descartes, a famous French scientist, mathematician and philosopher. He had an intense interest in sensory phenomena, including pain. Unlike the ancients, he encouraged empirical research. He was fascinated with the developments that were occurring in the Renaissance–how things could be machined and mechanical devices.
Descartes:
- Begins a systematic study of the physiology
- Nerves were hollow tubular structures with wires or filaments
- Exposure to heat would cause changes in the nerves and set of an alarm system in the brain
This is an illustration Rene Descartes put in his treatise on sensation and is fascinated by pain. This diagram posited: if you get too close to a fire, not just stimulus, it activates a thread that goes up a pathway and opens a port in the brain, and then you experience pain. He used the analogy of a bell ringer, like the bell ringing when the rope is pulled, so too does pain occur.
In subsequent centuries we learned a lot more about this pathway. We know there are specific receptors to pick up pain signals—instead of a thin thread—that we call nerves that go to the brain and there are centers of the brain that respond to pain sensation. This model was supported by investigation after investigation.
By the mid 1950s, this model had a lot of support, and it was believed that there must be something going wrong–damage, injury, disease, etc., if a patient had pain. Much like Descartes believed, the brain was acting as a telephone; when signals go off: pain. It is a very simplistic model. This is the model most arthritis patients still attend to, the model they bring into clinics despite efforts to educate them. Insurance carriers also subscribe to this model; they do not see the limitations. Clinicians know that there are a lot of problems with this model.
One example from the osteoarthritis (OA) literature involves how x-ray evidence correlates with pain levels. One of the nice things about working with OA is that the disease severity can be documented. The magnitude of the correlation is 0.1 to 0.17. In fact, the knee joint was the only joint in the body where there was a consistent and significant correlation with pain. This is significant because the sample sizes were huge. The clinical significance of the correlation of 0.1 to 0.17 is not very impressive. Clinically, the situation of 2 patients with the same severity of OA arises; one patient reported no pain, moderate to severe disease, the other patient reported extreme pain and is limited to a wheelchair. How do we deal with this? How do we account for this? This is one of the central things about pain and their individual differences. It is this kind of finding that led people to think about pain in a different way.
Gate Control Theory
The primary event really occurred with Ron Melzack and Pat Wall’s gate control theory in the mid 1960s. The basic notion was that the system is not hardwired; the brain does not just sit back and receive pain signals (like Descartes said). In fact, the brain is very active in modulating pain on a moment-to-moment basis. Ron Melzack’s contribution was to say that the brain is heavily involved. Pat Wall’s contribution was to say that involvement takes place at the spinal cord level in the substancia gelatinosa. Gate functioning is based on:
1) Descending influences from brain
- Cognitive processes (expectations, memories, etc.)
- Motivational-affective processes
2) Activity in large and small diameter fibers
There was a lot of research attempting to prove the theory false. In fact, what happened was exactly the opposite. Much evidence emerged that there is pain modulation occurring in the central nervous system, and it is related to what is going on in the brain. That has very important implications for pain management, it becomes more than addressing what is happening at the sensory level peripherally.
Neuromatrix theory. In 1999, Ron Melzack updated this theory, primarily because of the incoming data from imaging studies. When a pain stimulus is delivered to someone in an imaging device, many different areas light up. What Melzack proposed was that each of us has a neural signature of pain, a matrix of areas of the brain that are involved. When those areas are activated, we experience pain. Those are areas that are responsible for sensation and for visual input. If you are looking at the stimulus versus looking away, you can influence it. Cognitive and emotional endpoints that are both chronic and phasic are possible. The stress regulation system can be activated by pain, and can influence pain control. No matter what the influences, the output is what we clinically call pain.
Patients are often asked to put a number on it. Think about this; this is a complex experience. An orchestra is a good way to think about what is happening in the brain when pain experience occurs. There is a lot going in even though the audience hears one continuing sound. Why is this so important? Any one of these areas is a point for intervention. Pain can be modified by altering sensory input, by altering visual effects, by altering sound or by altering someone’s chronic emotional state with medications or psychotherapy. This gives hope for what can be done for people with persistent pain, because this type of pain is not well-managed using conventional strategies.
Stress and Coping Theory:
This leads to some work that looks particularly at interventions based on the stress and coping theory. One of the first questions when working with arthritis patients is how do people cope with arthritis pain? It turns out that, if you look at the literature, there are essentially two questions:
1. How do you cope?
(Coping skills)
- Distraction
- Rest breaks
- Relaxation
- Avoid negative thinking
2. How effective is your coping?
(Appraisal skills)
- “I can manage”
- “I can’t tolerate this”
Does coping matter in OA patients? Using data from OA patients with documented knee pain and x-ray grading of their knee, we looked at the disability compensation status, the chronicity of pain and some background variables. We asked: “Would these coping variables tell us anything about their pain and disability that you would not know from conventionally clinical measures?” Yes, even after controlling for these variables, patients who appraised their pain and coping skills as effective had significantly less pain. Even when controlling for pain level, there are significantly lower levels of psychological distress and less physical disability. Patients with better coping mechanisms walk and transfer from one position to another faster. This suggests that the appraisal dimension is also important.
Later studies have concluded that there are different ways that people cope: cognitive coping (working, distracting), or behavioral coping (changing day-to-day activities). Another way of parsing this is active coping versus passive coping. Also, the appraisal dimension has been investigated in a number of different ways using a number of different constructs. The factor that we were looking at in our work is called pain control and rational thinking. There are extensive studies looking at catastrophizing. Catastrophizing is to assume the worse possible outcome. Pain catastrophizing is not just something that happens in chronic pain patients. Everyone has variations; some of us people are very confident and never catastrophize; other people catastrophize quite a bit. It turns out to be one of the most consistent and significant predictors of disability, pain, and pain-related outcomes. Related concepts–self-efficacy, arthritis helplessness–tap into that appraisal dimension.
This is all correlational research, and there is a real problem with correlational research. Is it coping or appraisal that is driving pain, or pain driving appraisal? Most studies try to control for this statistically. These concerns have basically led most researchers who are doing this work into another area, which is: “What if we try to systematically alter coping? What would happen?”
Can pain coping skills be enhanced?
The basic model is:
- Pick people with some type of disease or injury, ideally one where severity can be documented.
- Control for that; make sure there are an equal number of people in the different conditions.
- In one of the treatment conditions in the randomized study, develop an intervention that systematically tries to alter how people cope and the perceived effectiveness of that coping. You cannot just alter appraisal; you have to work with the skills.
Coping skills involve:
- Helping patients reconceptualize pain and reappraise their ability to cope with arthritis pain. People respond so positively to this rationale
- Training in a variety of pain coping skills (e.g. relaxation, activity pacing, distraction, imagery)
- Behavioral rehearsal and guided practice
- Applying skills during pain episodes
What happens when you do this? Improvements were seen in:
- Pain
- Psychological distress
- Anxiety
- Depression
- Active coping
- Self-efficacy
- Physical functioning
- Physical disability
- Joint swelling)
Challenges to pain coping
One of the real challenges we are interested in is the intersection of obesity and OA. There are a number of reasons this is a challenge. Certainly, if you look around you in restaurants and most public places, you will see people who are obese with over-large portion sizes.
The obesity trend nationally, 1985 to 2003.
Recent data indicate that obesity is the number one preventable cause of OA. The exact mechanism of how obesity increases the incidence of OA is not known, but it appears to involve all three factors. Altered biomechanical loading of the joints has traditionally been thought to be the primary cause of the disease in obese people due to increased joint stress and altered loading pattern. Those factors appear to be part of the cause for increased knee OA, but they don’t explain the increased incidence of OA in the hand. This finding has led to the thought that a systemic, metabolic factor might be at work. Recent studies indicate that obesity is a mild inflammatory disease, as fat produces a number of pro-inflammatory cytokines (now being called adipokines). These inflammatory factors also appear to be related to a family of metabolic diseases called Metabolic X Syndrome (includes type II diabetes and heart disease). Yet cognitive factors also appear to be at play as obesity is associated with more pain and disability in people with OA. With obesity you get increases in IL-1, IL-6, and increased nitrous oxide and prostaglandins. There are clear changes in immune function, and we know that both with obesity and OA pain you get things like decreased self-efficacy; not only for pain control, but for controlling eating, and people find they feel helpless and activity hurts, so they cut back and avoid activity.
Can weight management enhance pain coping skills training?
Weight management is really about behavioral weight management: dieting, restrictive behavior, etc. The modern approach is essentially saying that weight loss takes a period of time. If patients are really going to lose weight and maintain it—there are a lot of studies that show people can lose weight, but they can’t maintain it—a variety of factors need to be addressed.
Lifestyle factors
Exercise (aerobic activity)
Attitudes (eating-related and pain-related)
Relationships
Nutrition
We run groups now in our rehab center that involve a combination of group sessions for education in these 5 factors, as well as education in pain control, and they go to an exercise facility to exercise together. The basic design of the study is to randomize patients where they receive either coping skills training alone, the LEARN weight loss program alone, the combination of both or a controlled condition. From these patients we are assessing their outcome in terms of self-report outcomes; however, we are also taking blood samples to look at immune changes (before and after and then follow-up).
Are treatment targets related to pain and disability in this population?
This is an ongoing study that has approximately 180 patients. I cannot tell you the outcome because we have not done an analysis yet. However, I will give you some hints from the baseline data that indicates we are on the right route. As I mentioned earlier, the idea of pain coping skills training is to change how people appraise their pain. We are indexing that in this study by their confidence that they can manage their pain. With the lifestyle behavioral weight management intervention you would expect that a major target would be reducing body mass index. The notion with both of this is that they are mediators so that patients who go through the pain coping skills training who have increased self-efficacy should have the best outcomes. Similarly, those patients who go through the weight management program and have the greatest weight loss should show the best outcomes. Self-efficacy is the belief that you have the capability to achieve pain control. What we found is that at baseline (these are obese OA patients), self-efficacy relates to lower pain, lower physical disability and lower psychological disability.
Gait Analysis. There is also a relationship with body mass index in terms of pain, not so much with physical and psychological skills. One of the features of the study is sophisticated gait analysis. We have a lab where there is a force plate. We have patients walk across the force plate, and we can quantify the gait on the force plate as well as with the markers. With the markers we get reflection. They can be picked up on cameras, and then you can digitize all of this and look at the person move through space and quantify all of the knee angles.
One of the things that we are interested in is how these target variables relate to gait variables. We are finding, not surprisingly, that if you are heavier, you walk slower; however, we have not yet done analysis looking at how these psychological factors might relate to gait. This is an interesting program project because these studies are not only being done clinically; they were mimicking similar studies in mouse models of OA, animals that are prone to get OA and obesity.
Can coping skills training benefit RA patients early in their disease course?
Coping skills training protocols for RA patients have been tested in a number of studies, but the average duration of disease prior to study was 10 to 20 years. Patterns of coping and appraisal develop over that time. One of the questions that I have is: If early aggressive medical intervention can make a difference with early RA, why aren’t we intervening with psychosocial approaches early? The benefits not only include reduced pain, but also reduced psychological distress and suffering that accompany pain. One finding was people who have an unexpected flare in their disease activity get depressed; they conclude these medications are not doing anything for them; they stop the medication; and the disease worsens. With coping skills training, we can actually inoculate people (stress inoculation); prepare them psychologically to anticipate they are going to feel like stopping, to anticipate that they will get depressed and so on. Then we can help them preemptively develop a strategy they can apply at the time of disease flare to prevent psychological stress and emotional reaction.
A coping skills training protocol that is tailored to people with early RA:
(Standard coping skills training plus)
1) Training in communication skills:
- How to engage in decision-making conversations with family members, health care providers, and co-workers
- How to address key issues such as the nature and limitations of their disease and their own preferences and needs.
2) Training in goal setting
- To better identify highly valued, realistic activity goals and work on accomplishing these goals.
3) Maintenance enhancement training
- Teach patients how to maintain frequent coping practice,
- Identify high risk situations and early warning signs of pain and symptom flares and,
- Cope with and prevent setbacks.
How does the patient maintain the skills? How can they anticipate high-risk situations like a disease flare and manage them? The study design for this trial is comparing this comprehensive training to a tension control that simply provides information and contact, and a standard care control. We are taking blood measures before and after, and at 18-month follow up in addition to the standard measure to see if we can alter biomarkers of disease activity in this population.
Pain Communication
Pain is not just a personal experience: it is a social experience.
This model focuses on patient-partner interactions when pain occurs. There are very few studies about caregivers. Almost everything looks at the pain experience. However, the pain experience leads to pain expression. How does the clinician know that someone is having increased pain? The only way is if they express it, both verbally and nonverbally. That expression can be influenced by a lot of things. If they think that you can help them, you may see a different pain expression than if they do not. If they feel discouraged, you may see a different pain expression. What is being communicated looks like pain, but it’s also the thoughts and feelings surrounding the pain.
In a pilot study of 24 OA patients having OA of the knees and 23 of their spouses (50% of the patients were female, average age was 63.9 years), we asked the patients’ spouses two things:
- How confident are you can actually communicate effectively about pain, and;
- Do you actually hold back, how much do you try to hold back from having discussions about this?
As far as self-efficacy, we found that people who felt they could not communicate the pain well had a lot more pain, physical disability and psychological distress. If a partner said, “I am not very good at picking up on and responding to this,” their positive affect is much lower.
Patients who held back had higher levels of pain or tended to have high levels of pain, and higher levels of physical and psychological disability. Partners who held back had much higher levels of caregiver strain, and negative affect. Here you have a very different perspective on pain, a sort of dyadic perspective where the degree to which patients and partners are able to communicate influences the person with the pain and the adjustment of the person around.
Training dyads in pain communication. Early approaches to managing chronic pain were to minimize attention to pain behavior and maximize attention to well behavior. It seemed to work as part of the package. However, this is not applied readily to disease-related pain because there are a lot more challenges.
Challenges for patient
- Emotions
- Patient pain catastrophizing
- Fear that pain expression will distress partner
- Concealing pain from partner
- Pain expression leads to unhelpful/negative partner responses
Challenges for partner
- Increases in negative emotion in response to pain expression
- Partner pain catastrophizing
- Problems overestimating or underestimating pain
- Responding in an unhelpful/negative fashion
Couples-based pain communication skills training
We are actually working with couples to train them how to communicate more effectively about pain. We have a six-session protocol.
Session 1: Rationale, couples’ interaction style
Session 2: Tailoring treatment goals
Session 3: Sharing thoughts and feelings
Session 4: Introduction to problem solving
Session 5: Decision-making/problem-solving guidelines
Session 6: Practice and application of problem solving skills and maintenance
The study design includes a control condition. We give them educational information with the partner involved and so on. We are seeking to alter communication patterns, and see if that has an effect on pain disability.
Overall conclusions
- Controlled studies have shown that coping skills training is effective in reducing pain and emotional distress, and enhancing self-efficacy in arthritis patients
Challenges remain:
- Overweight and obese OA patient
- Effects of CST in early stage disease
- Addressing pain communication
- Developing and refining Coping skills training approaches can lead to major advances
- Prevent pain
- Improve the quality of life
- Reduce the suffering of many individuals having arthritis
