Letting smokers look at ultrasound images of their own atherosclerotic plaques improves smoking cessation rates

Half of 155 smokers recruited from a community based heart health study were randomly assigned to either receive or not receive ultrasonography of their left and right carotid and femoral arteries. Of those receiving ultrasonography, those individuals who were found to have one or more atherosclerotic plaques were shown photos of their plaques. Thus there were 3 groups of smokers:

1. smokers not randomized to ultrasonography,
2. smokers randomized to ultrasonography with no plaques evident and therefore not shown any photos, and
3. smokers randomized to ultrasonography with plaques and shown their photos along with a 5-min explanation of the significance of the plaques and their impact on health. All participants received 10 mins quit-smoking counseling by a physician.

Six months after the interventions, 5% of smokers who were not shown ultrasonography photos quit, but 22% of smokers who were shown photos of their plaques quit. This is quite an impressive difference!

It may be that seeing what their smoking did to their bodies was somewhat of a wakeup call for many these smokers; that smoking was no longer viewed as a remote hazard but rather the cause of a current and very real problem.

DiClemente, C. C., Marinilli, A. S., Singh, M., & Bellino, L. E. (2001). The role of feedback in the process of health behavior change. American Journal of Health Behaviour, 25(3), 217-227.

Using the power of feedback to change your behavior

Our behavior is actually a very complex system. It consists of a collection of components that work together in order to achieve some goals. You eat and drink to survive, walk and drive in order to get where you need to go, befriend others so that you can enjoy the protection and pleasures of a social network, work to have money so that you can eat in order to survive, and so on. But if behavior serves as a slave to the master of goals, why is it that we cannot simply change goals and have our behavior fall in line? Why is it that we can’t simply declare that our goal is now to exercise vigorously for 30 minutes and sit back and watch our bodies go at it? Why is it so hard to change?

I know how most of you have probably explained your difficulties. In fact there are a few ultra-common ones:

No willpower. Many people tell themselves that they lack will-power or perhaps don’t want the goal (lose weight, get fit, learn new skill, etc.) enough. They kick themselves again and again, every time their behavior doesn’t match the noble goals they’ve ordained for themselves, declaring that they’re weak, miserable, wretched creatures who will always be fat, poor, late, unliked, tired, unhappy, or whatever.

No time. Another popular explanation is that you didn’t do x, y, or z because you just don’t have the time. After all, they’re a busy mom, employee, student, daughter, coach, wife, volunteer, playmate, and maybe all of the above. You’re just too busy to cook a meal of steamed vegetables, too tired to drag yourself to the gym, too short on time to sit quietly and meditate.

No time, no money, no way. Sometimes people will declare that the goals themselves are perhaps not so noble, practical, or even desirable. They question their motives (“Why should I lose weight; people should love me the way I am”), justify their current behaviors (“I’m just not a social person — I don’t really need to build my social network. In fact being too friendly would not be genuine!”), and consider alternatives (“I’ll go on the Atkins diet — sure, that’s perfect this way I can pig out on all the pork I want and I’ll still be following a ‘diet’”).

I also know the most likely responses to these explanations:

Fortify will-power. After kicking themselves for being so damn weak, these people are sure that if they just keep at it and try harder they’ll eventually be successful (“I’ve just got to try harder, harder, harder, dammit!”).

Change goals. Sometimes people believe that if you can’t hit the target, well then just move the target to make it easier to hit (“Exercising 30 minutes a day for three times a week is just not practical given all my multitude of obligations — a walk around the block every Saturday morning should be enough”).

Give up. Unfortunately, many people just give up and accept their current situation as if etched in granite (“I’m never going to be skinny, energetic, popular, great at a sport, happy, a non-smoker, or whatever, so why keep trying?”).

The reason why behavior change is so difficult is because most people have characterized the problem incorrectly. Behavior is a system. You might not have thought about it that way but that’s exactly what it is. Like all systems, its existence is defined in terms of 3 components: goals, output, and input. Most people attempt change through concentrating on goals and output. That’s why change is so hard. They focus on the wrong thing.

Consider the problem of trying to convince your dog (if you don’t have a dog, imagine that you have one) to not lie on your fancy couch. What would you do? Well you’d probably reward her for staying off the couch and withhold treats or even punish her when she sits on it it. Your reinforcements and punishments amount to feedback. Notice that there’s no discussion, no will-power, no change of the dog’s goals (or your goals). The dog is still a dog and still behaves like a dog, except that she will jump up on the couch less and less as your repeat the feedback more and more. I’d like to dwell on this point a bit more because it’s crucial.

The dog’s behavior, like yours, is a system. Perhaps her behavioral system is not as complex as yours but it’s still a system and remarkably complex nonetheless. The dog behavioral system has certain goals (food, water, protection, sticking with the pack, fun, etc.) and is designed to accomplish certain actions to satisfy those goals (eating, drinking, seeking shelter, staying close, play). By reinforcing staying off the couch you alter neither their goals nor their behaviors, for if you tried, you’d be pursuing the fool’s errand (not to mention giving yourself a heart attack). You are simply altering environmental feedback such that sitting on the couch produces feedback that the dog’s behavior is not achieving its goals (no treats, stern looks from you, which threatens her social standing in the pack). It would be foolhardy to make the dog any less a dog and it is no less foolhardy to make you any less you.

Thus, while most people focus on the goals and the output directly, it’s the feedback that deserves the attention. Just as a driver must see the road to drive, the thermostat must sense temperature to control the heating, and the hypothalamus must receive hormone concentration signals to know whether to continue or halt its activity, the behavioral system relies on feedback. This fact represents an entirely new class of possibilities for improving health and wellness that aim to relieve pain through altering feedback to the pain system. To compel the driver to steer left, make her believe she is too far to the right. To elevate the temperature, make it appear to the thermostat that it’s cooler than it is. Likewise to alter the our health-related behaviors, craft feedback to compel the system to respond in desired ways.

So what is feedback?

Before answering the question, what is feedback, it is necessary to understand what a system is. A system is a collection of elements that work together to achieve a common function or objective, where the elements that comprise the system can themselves be other systems. For example, the nervous and immune systems function together as when immune function is altered during times of stress. So the parts of a system work together to achieve some goal. But how does the system know it’s doing the right thing? Put another way, how do systems regulate themselves? How does the endocrine system know when to stop (or begin) releasing a particular hormone? How does the muscular system know how much force to apply to the muscles of the leg? How does the cardiovascular system know what should be the appropriate heart rate and blood pressure? And in a question of particular interest to me, being a researcher in pain, how does the pain system know how much pain is necessary? The answer to all these questions is feedback.

Feedback is, quite simply information that is returned to a system that enables it to regulate further output. Feedback is not just a nice-to-have icing on a system’s cake, but rather is a critical, integral component of all systems. Since almost everything in nature is ultimately hooked into a system, and since feedback is such a crucial component of all systems, it behooves us to understand feedback. Let’s look at some examples to get a feel for how critical feedback is to almost everything.

Try to imagine driving a car without being able to see. You, the driver, are a system. You consist of a collection of elements working together to achieve an objective — driving. But without being able to see where you’re going, you would not be able to function, to drive. You’d try your best to get all the initial conditions correct — you’d get the steering wheel as straight forward as possible, press down with a force that you’d known from the past should produce a particular acceleration. But deprived of feedback you’d soon drive into a wall, or worse.

How do you know you’re a good person, a smart person, a worthwhile person? That’s right: feedback. Over time, you received feedback to consistent with these evaluations. You know you’re worthwhile because you befriended other people who wanted to spend time with you. You know you’re smart because you received good grades in school and you seem to be able to make your way in the world reasonably well. You know you’re a good person because you like to help others whenever possible and you’ve received many  “thank-yous” from the recipients of your generosity. Now let’s do a thought experiment. Imagine that you never received any such feedback. Imagine that you went through life without any feedback from the world? How would you know who you are, what you are, why you are? Indeed it is fair to say that your entire identity has been forged through the operation of feedback.

Now, let’s take a look at the problem of pain. Pain is a system like any other system of the body, and like all systems, it relies on feedback. One of the most intriguing demonstrations of this reliance on feedback is the phenomenon of phantom limb pain (PLP). PLP refers to the perception of pain in a limb that has been amputated or deafferented. Notwithstanding its name, PLP is very real, impacts the majority of amputees and can be extremely severe. How could a limb that is no longer present possibly be painful?

Well, it appears that the reason has to do with the fact that there is a one-to-one mapping in the brain between regions of the body and the portion of the brain that represents that region. The hand, fingers, arm, face, legs, etc. are all represented somatotopically; that is, in they are represented by different and specific sections of somatosensory and motor cortical tissue. More than that, the amount of real estate reserved for the various parts of the body in these cortices is proportional to the sensory resolution required. For example, the mouth, lips and fingers take up relatively large proportions of cortical tissue compared to other parts such as the back and arms. The result is that we can distinguish between two points less than 1mm apart in our fingers but two points applied 1 cm apart on the back will feel as if it were a single point. Perhaps you have seen the sensory and motor homunclus (little man) figures depicting the representation of the body in the sensory and motor cortices (see figure below).

Ordinarily, signals (feedback) from the body reach their corresponding portion of the brain and all is good. But what happens if, say an arm is amputated? There are no longer any signals going from the arm to the brain. So what happens to the portion of the cortex that previously received signals from the arm? Well what happens is that the areas of the cortex neighboring the now idle tissue begin to migrate so that the tissue that previously represented the arm is now representing whatever its neighbor represents. As you can see from the sensory homunculus picture, the cortical tissue adjacent to the hand and arm is the face. That means that sensations in the face will begin to be represented in the cortical tissue previously representing the hand and arm. So what’s the problem, you ask? Wouldn’t it just mean that sensations in the face become even better? The answer is no. In fact, this cortical migration is often referred to as “maladaptive plasticity” and is associated with pain. In fact there is a very strong correlation between the magnitude of migration and severity of pain ratings. The exact reason why this remapping of cortical surface is associated with pain is unknown. But a particular treatment, mirror therapy, has been developed that compels a reversal of the migration and with it, a substantial reduction in pain.

Mirror therapy for missing upper body limbs typically entails the use of a device containing two compartments, one of which the individual places his intact hand or entire arm. The mirror reflects the activity in such a way that it conveys the impression that his amputated limb has been returned and it can be moved. To put it in the words of Ramachandran and Rogers-Ramachandran (2000), “When viewing the reflection of the intact hand in the mirror, “the reflection of his own right hand is optically superimposed on the felt location of his phantom limb so that he has the distinct visual illusion that the phantom limb had been resurrected. If he now made mirror symmetric movements while looking in the mirror, he received feedback that the phantom limb was obeying his command.” (Ramachandran & Rogers-Ramachandran, 2000, p. 319). The mirror in this case essentially alters the feedback presented back to individual. As far as his brain is concerned, he has both limbs intact. This feedback is so convincing, in fact, that it gradually leads to the reversal of the problematic cortical migration.

Image credit: http://uc.exteenblog.com/highwind/images/Know/brain_homunculus1.jpg

Feedback and anxiety

Imagine a child who suffers from social anxiety. He fears contact with others for he worries that he will be evaluated negatively. His anxiety, his fear, causes him to avoid social contact. Avoiding contact means that he is deprived of opportunities to have positive social experiences. With a good deal of his attention on the impression he is making and worry about how to act, he comes across awkward, stilted, perhaps ungenuine. In response, others feel uncomfortable and avoid contact with him. This means that the feedback this child receives is consistent with his anxieties. He doubts he will be evaluated positively, which in turn causes him to act in the very manner than brings about negative evaluations. Often referred to as a self-fulfilling prophesy, this situation is known as a positive feedback loop. In a positive feedback loop, the system responds by altering its function so as to increase or promote the situation that caused the feedback. An example of a natural positive feedback loop is the onset of contractions in childbirth labor. The occurrence of a contraction induces the release of oxytocin, which stimulates stronger and more frequent contractions.

Once we frame the problem of anxiety in terms of feedback, the solution becomes obvious: break the feedback loop by intervening to alter the feedback. Imagine now a socially anxious child who, has an interaction with someone who is trained to respond with warmth and acceptance despite the child’s awkwardness. This interferes with the positive feedback loop. The child gets a taste for being accepted regardless of his stilted behavior. Now the child may feel just a bit less anxious. Feeling more comfortable and more confident, he becomes less awkward and more socially appealing, which in turn invites more positive evaluations, which bring about greater comfort and confidence and so on. Notice that we have traded one positive feedback loop (an unfavorable one) for another (a favorable one).

Cognitive-behavioral therapy (CBT) is a very commonly used approach to treating anxieties and its focus is on altering thoughts associated with anxiety provoking situations. An individual faced with a social situation would be asked to question why they are feeling anxious, what they fear, etc., and then are taught how to transform these thoughts so that they provoke less anxiety. Though it is not typically expressed in terms of feedback, CBT essentially amounts to altering feedback. It is important to realize that feedback is not absolute. In other words, it is every bit as open to interpretation as anything else that we perceive. CBT amounts to altering how one appraises feedback from the environment from more to less threatening. Its tight interweaving of feedback and behavior is likely one of the reasons for its success.

But I would like to suggest that we can go much further. As I depicted in the scenario above, involving the child, I think that systematically altering the environment so as to provide particular types of feedback can be a very effective way to bring about reduced anxiety. Essentially what I am proposing is to construct situations in which the individual can practice behaviors and receive the right kind of feedback. This is something that just can’t happen naturally due to the dastardly power of the positive feedback loop.

Without feedback we are reduced to a bumbling, twitching, aimless, lump of flesh!

Let’s do a thought experiment:

Imagine driving a car without any feedback. No feedback at all. Close your eyes and hold your hands out as if holding a steering wheel. You can’t see a thing. But you can still feel the location of your hands and arms in space through your proprioceptive sense. Try now to imagine that you can no longer feel where your hands and arms are. Oh sure, you may know that your brain commanded them into a particular position but how would you know they’re there. Perhaps they got tired and began to slip downward. You wouldn’t know. But you can still feel the vibrations, hear the rumble of the motor and the sound of the tires rolling on the pavement. Well, imagine that you are now in a special car with remarkable insulation that eliminates any and all vibrations and sounds. Try to visualize what it is like to drive like this. “Why, I can’t drive at all! How do you expect me to drive a car without seeing, feeling, or hearing anything!” Precisely, it’s impossible isn’t it? You the driver, a sophisticated system if ever there was one, is reduced to a bumbling, twitching, aimless, lump of flesh, without feedback. What I hope is now clear is that feedback is a crucial component of any system, without which the system simply cannot function. And that’s why, changing feedback can have profound effects on the behavior of any system.

Mirror therapy self-delivered at home can improve lower limb phamtom pain

In a recently published case study, Beth Darnall (Darnall, 2009) details the case of a 35 year old man who lost a log as a result of an auto accident. The patient began experiencing phantom limp pain immediately after surgery and a host of pharmacological and psychological treatments failed to adequately control the pain. Mirror therapy was then begun. He purchased a long mirror and laid it down on the floor and positioned his intact leg alongside the mirror so that it appeared that he was viewing two intact limbs.

For about 20-30 minutes 3 times per week, the patient followed an unstructured protocol of his own devising, in which he exercised his intact foot and watched the movements in the mirror. He reported decreased pain, increased control, and a sense of enjoyment. After engaging in the mirror therapy 20 mins daily for 1 month, he reported complete resolution of the phantom pain. Interestingly he reported that if he missed his regular mirror therapy practice the phantom pain would return within 1-2 days but resuming regular practice eliminated the pain once again.

I think these results couldn’t be cooler. Here was a super simple, low-cost, non-pharmacological therapy, self-administered at home, that was able to kill a severe pain, substantially reduce reliance on opioids and other pain meds, and enhanced the patient’s sense of self efficacy and control.

Mirror therapy shown to be effective at treating complex regional pain syndrome (CRPS)

Mirror therapy has been shown to successfully treat phantom limb pain but there is some evidence that it can also prove effective at treating CRPS as well.

In a recent study by Angelo Cacchio and colleagues in Italy (Cacchio et al, 2009) 24 stroke patients with CRPS type 1 of a paretic arm were randomly assigned to one of 3 groups: mirror therapy, covered mirror, and mental imagery.

In both the mirror and covered-mirror groups, patients performed several movements of the affected arm for 30 mins daily. The primary outcome was severity of pain upon movement, motor function, brush-induced allodynia, and edema after 4 weeks of therapy.

The active mirror group enjoyed a substantial decrease in pain severity after 4 weeks. In this group 7 of 8 patients reported reduced pain. In the covered group, by contrast, only 1 of 8 participants reported reduced pain while 5 reported an increase in pain. In the mental imagery group only 2 patients reported a decrease in pain while 6 reported an increase in pain.

Subsequent to the initial 4-week randomization period, 12 patients from the covered mirror and mental imagery groups crossed over to active mirror therapy. Eleven out of these 12 patients subsequently reported a reduction of pain after 4 weeks.

Cacchio, A., De Blasis, E., Necozione, S., di Orio, F., & Santilli, V. (2009). Mirror therapy for chronic complex regional pain syndrome type 1 and stroke. N Engl J Med, 361(6), 634-6.

What happens in the brain during mirror therapy?

Although mirror therapy has been shown to be effective for treatment of phantom limb pain, complex regional pain syndrome and other pain conditions, little is known regarding the neural mechanisms responsible. In other words, to the extent that mirror therapy works, why does it work? A recent study imaged the brains of 18 healthy volunteers using fMRI while they moved their right hand. The study was divided into 2 experiments: a no-mirror experiment and a mirror experiment. In both experiments participants performed a series of right-hand finger taps alternating with rests. In the no-mirror experiment, participants could see both hands but were instructed to focus visually on the right hand. In the mirror experiment a mirror was placed between the hands such that it appeared that the right hand was superimposed on the position of the left hand, which was behind the mirror. Participants were instructed to focus visually on the mirror reflection of the right hand (the illusory left hand).

In both experiments, when activation during finger tapping was contrasted with rest, activation was seen in the left precentral gyrus (primary motor cortex) and postcentral gyrus (somatosensory cortex), the left precentral gyrus/superior frontal gyrus (premotor cortex), the right middle temporal gyrus, the left middle occipital gyrus, and the cerebellum.

When cortical activation during the no-mirror experiment was contrasted against activation during the mirror experiment it was found that there was more activation in the mirror experiment than in the no-mirror experiment within the right superior temporal gyrus (STG) and the right superior occipital gyrus.

The STG is an area shown to be involved during the observation of biological motion. The authors indicate that the coordinates of STG activation in this study are very similar to those obtained in a study on imitation of hand movements. It appears then that during the mirror experiment, when participants were observing an illusory left hand (ie. the reflection of their right hand), the mirror neuron system (Rizzolatti & Craighero, 2004) was activated and it was as if they were observing the movement of a left hand distinct from their own.

These results are interesting but run counter to what we might expect. Mirror therapy creates the illusion of the presence of a limb that is in fact missing and appears to result in the correction of the maladaptive cortical migration resulting from deafferentation. Therefore we would expect that mirror therapy would somehow produce activation patterns in the motor cortices contralateral to the illusory limb. Recent TMS (transcranial magnetic stimulation) studies have indeed produced results in support of this hypothesis (Garry, Loftus, & Summers, 2005; Funase, Tabira, Higashi, Liang, & Kasai, 2007). This study, however, found no increased activation of M1 in the right hemisphere (contralateral to the movement of the illusory limb). The authors point out that this divergence in results may be due to the fact that these other studies found increased M1 excitability only when the mirror condition was contrasted against a control condition in which participants moved the right hand but did not directly observe this movement.

Also, I have a feeling that there is something else. In this experiment participants were not asked to mentally image (visualize) the movement of the left hand while observing the illusory left hand. They were therefore not trying to envision movement themselves and this may have accounted for the fact that we only see activity in the mirror neuron system in this study.

So the upshot seems to be that we now have a somewhat better idea of what’s going on when people observe their limbs moving in mirrors but there are still many questions that remain.

• Funase, K., Tabira, T., Higashi, T., Liang, N., & Kasai, T. (2007). Increased corticospinal excitability during direct observation of self-movement and indirect observation with a mirror box. Neurosci Lett, 419(2), 108-12.
• Garry, M. I., Loftus, A., & Summers, J. J. (2005). Mirror, mirror on the wall: Viewing a mirror reflection of unilateral hand movements facilitates ipsilateral M1 excitability. Exp Brain Res, 163(1), 118-22.
• Matthys, K., Smits, M., Van der Geest, J. N., Van der Lugt, A., Seurinck, R., Stam, H. J., et al. (2009). Mirror-Induced visual illusion of hand movements: A functional magnetic resonance imaging study. Arch Phys Med Rehabil, 90(4), 675-81.
• Rizzolatti, G., & Craighero, L. (2004). The mirror-neuron system. Annu Rev Neurosci, 27, 169-92.

Body feedback can influence how we evaluate the world around us

In a study by Jens Forster, college undergrads were asked to evaluate a series of food products that were previously identified as being highly positive (candy bar) or highly negative (beef lung). The names of the food products were presented on a screen in front of participants. By random assignment, 4 objects were presented with vertical movement, 4 with horizontal movement, and 5 with no movement. The movement back and forth or up and down lasted about 18 secs for each object. After the presentation of each object, participants rated the degree to which they liked it and the how much they would like to buy it.

Vertical head movements (nodding) increased liking for the positive stimuli (the foods that people like) compared to the control, whereas it did nothing to how much participants liked the negative foods. On the other hand, horizontal head movements (shaking) decreased liking for negative stimuli (foods that people dislike) compared to the control, but had no effect on positive stimuli. Similar results were obtained for desire to buy product. In other words, the motor action of nodding or shaking amplified existing response tendencies (liking or not liking).

Forster points out that these results are consistent with the so-called motor-compatibility model, which states that behaviors will have a greater affect on responses when the valence of stimuli and the emotional valence linked to the behavior match. In his words, “When the motivational orientation implied by participants’ head movements and target valence are compatible, judgments and behavior became more extreme. When the were incompatible, however, no significant effects of head movements on judgments of well-known products were observed. Mood did not mediate the effects.” (p. 421).

Förster, J. (2004). How body feedback influences consumers’ evaluation of products. Journal of Consumer Psychology, 14(4), 416-426.

Social anxiety is strongly affected by attention to, and misinterpretation of, internal bodily states

One question raised by researchers seeking to understand social phobia is why it persists in spite of the fact that socially  anxious individuals are no more likely to receive direct negative feedback in social situations than people who don’t suffer from this affliction. Well, a very compelling explanation is that social phobics are more likely to attend to, and misinterpret, internal bodily sensations. When in a social situation, social phobics are prone to shift attention from others and towards a detailed monitoring of themselves. They tend to notice slight changes in facial temperature or heart rate and then interpret those sensations as signs of their nervousness and become convinced that it is an indication that they are coming across poorly. Jennifer Wild and colleagues obtained particularly evidence in support of this model.

While high and low socially anxious college students were having a 10 min conversation with an experimental confederate they received false feedback about their level of physiological arousal. The feedback itself, which consisted of vibrations at set time intervals to the chest, was the same for all participants but some were told that the vibrations reflected an increase in arousal, others were told it meant a decrease in arousal, and a control group was told that only the comfort of the apparatus was being tested and that any vibrations they felt were irrelevant to the current experiment.

Participants told that their level of physiological arousal had increased during their conversation reported feeling considerably more anxious, and believed they came across more poorly in the conversation than those who where told that their arousal had decreased or whom received no feedback (controls).

So people told that their arousal had increased felt that they made a poorer impression but did they really? The data suggest that the answer to this question is, not really. As the researchers put it, “Believing one’s arousal is increasing during a social interaction has a large impact on the individual’s perception of how well the interaction is going and how well they come across, as these are influenced by anxiety level and perceived bodily sensations. However, this internal state is not necessarily obvious to the social interaction partner and other observers, as indicated by the absence of condition on the item “How anxious did the person look?”, and on negative items on the Behaviours Checklist for the independent assessor.” People led to believe that they were nervous were more likely to be judged not more negatively but rather lower on positive behaviors.

This is fascinating research because it strongly suggests that the anxiety as well as conviction that one has made a poor impression that marks social phobia is largely due to the greater attention to, and misinterpretation of, internal bodily states and other forms of feedback. And it suggest that treatments should help phobics focus attention outside themselves, away from self-montoring, and instead towards the interactions with others.

Wild, J., Clark, D. M., Ehlers, A., & McManus, F. (2008). Perception of arousal in social anxiety: Effects of false feedback during a social interaction. J Behav Ther Exp Psychiatry, 39(2), 102-16.