Red Lights or Blue Lights: What Color Do You See?

Can you think of a time when your thoughts influenced how you felt about a situation? For example; have you ever heard a sound at night while you’ve been home alone? In a matter of seconds you can go from being relaxed on the couch to having a mild panic attack thinking that there is an intruder in the house with you. Did you actually see something? No, but your brain processed that information as potentially dangerous and kick started your body’s “fight or flight” response just in case.

This hypothetical situation can be applied to a variety of scenarios, including our perceptions of pain. In fact, Mosely and Arntz published a study in 2007 looking at how the context in which a noxious stimulus is delivered can alter the way people perceive pain. During the study, a cold metal rod (-20 degrees Celsius) was applied very briefly to the subject’s hand while they received various contextual information about the stimulus. This information was in the form of a light: red or blue. The subjects were told that the red light meant “hot” and the blue light stood for “cold.” The subjects were then asked to rate their pain intensity, pain unpleasantness, and the temperature that they perceived (on a 0-10 scale, with 0 indicating both no pain/unpleasantness, as well as being extreme cold).

Now the study was a little more complicated than just looking at the color light; the subjects were given different scenarios in which they rated their perception of the stimulus. For example, they either were provided a warning as to the color of the light versus no warning, or were allowed to look at the application of the rod versus being blinded to it (see the image below for a representation of the different scenarios).


blue light study

So what did they find? Well long story short, the subjects rated their pain intensity and unpleasantness as higher when looking at the red light versus the blue. In case you forgot…THE STIMULUS NEVER CHANGED! The rod stayed the same temperature; all that changed was the color of the light (see the graph below for the results of the study).

blue light graph

So what does this mean? Well Mosely and Arntz made the following conclusion, “the tissue damaging meaning of a noxious stimulus, warning about the stimulus and visual attention to the stimulus all affect the evoked experience.” That being said, our perceptions about an injury (whether they are accurate or not), can play a huge role in regards to our pain. This can be a game changer for us as physical therapists, as we have the opportunity to educate our patients not only about their injury, but about other factors that may be exacerbating their symptoms as well.

So what can we do about it? How many times have you had a patient tell you that they have imaging that shows they have arthritis, a torn rotator cuff, or a disc herniation? And obviously since there is evidence of these pathological tissues it must be the source of their pain, right? WRONG! One recent study published in 2015 by Nakashima et al examined the prevalence of abnormal findings on cervical spine MRIs. Over 1,200 healthy volunteers (key word, healthy, aka no symptoms) ranging in ages from 20 to 70 years were imaged. The findings? Over 85% of the subjects presented with disc bulges (even those subjects in their 20s, with over 70% of this population having evidence of some degree of bulging). Why is this information important? Well if you were a patient and you were told by a medical doctor that your MRI found degenerative changes, disc protrusions/herniations/bulges, narrowing, etc…what would you think? All of these words have such negative connotations associated with them, which may also serve as a “red light.” Could these “issues in your tissues” be causing the pain? Maybe, but we just saw how many “abnormal” findings were associated with individuals without symptoms. In fact, since the majority of the individuals presented with disc bulges wouldn’t it be “abnormal” not to have these changes…? Think about that.

Be mindful of how you talk to your patients, because the way you communicate to them may have the potential to change a few red lights to blue. For example, I love reviewing lumbar MRIs with my patients, because I feel that this can be a “make or break” point in regards to their fear of their prognosis. Often the images look like the following:

lumbar mriI choose my words very carefully at this point, and instead of pointing out the disc protrusions at L4/L5 and L5/S1 or the degenerative disc disease that they have, I may say that they have some “grey hairs” in their back (metaphorically speaking) which can be found in individuals without any symptoms at all. Now a once potentially red light may be slightly bluer. What I may highlight a little more closely would their multifidi, as you can see in the following example:


The above image shows fatty infiltration of the lumbar multifidi; a common finding in individuals with low back pain. Now I tend to describe these changes to their multifidi in regards to hamburger meat (once again, metaphorically speaking); image on the left has the good stuff, high quality lean beef. Image on the right on the other hand, may be closer to 60/40 beef. Which would you prefer to eat? Why do I show them these muscles? If their impairments include lumbopelvic stability (not all patients with low back pain need “core” exercises though, see the following post), then we can address this through physical therapy. BLUE LIGHT! The once depressing, scary MRI now shows the potential for an improvement in their symptoms, and you may have a better adherence to your plan of care now that the patient understands more about their “tissue issue.” Remember, knowledge is power.

Check out the following statements that I’ve heard used by patients or other medical professionals, and see how they could potentially switch from a red light to a blue:

  • “I have bone on bone arthritis that the doctor said was the worst he has ever seen.”
    • Thank you for instilling fear avoidant behaviors. Educating the patient that arthritic changes are a normal part of the aging process, and that they probably have had these changes for several years. Maybe discussing some of the research behind “abnormal” imaging findings in asymptomatic individuals can drive home the point that pain does not always equal tissue damage.
  • I hurt my back 20 years ago lifting a box off of the ground, so my doctor told me never to lift anything over 10 pounds again.
    • Sounds like a red light to me. Using words like “never,” “always,” or “worst,” really stick in a patient’s mind, so try and be mindful when making suggestions or recommendations (even if it is regarding something like posture or exercise technique). This would be a perfect patient to talk about tissue healing rates, and dive into some more pain science education (ex: their tissues have healed at this point, but their nervous system may still perceive lifting as a dangerous stimuli…aka red light).
  • “That knot in your muscle is as hard as a rock and keeps coming back.”
    • So now the patient thinks of their muscles as rocks, and that there symptoms are resilient. I often have patient’s ask if things “feel tight” when I’m performing soft tissue mobilizations, and if applicable, I tell them how it is normal for certain muscle groups to be “tighter” or “stiffer” than others (ex: upper trapezius when doing myofascial work, or thoracic spine when performing joint mobilizations). While each patient is special and unique, we do not necessarily want to verbalize that their tissues are that way.
  • “I was told that since I tore my rotator cuff I’d never be able to swim again.”
    • A few things to address in this one. Once again, discussing the normal “abnormalities” found during imaging would be a good start. Also, never say never. Never. Automatically the thought of not being able to return to a sport, work, or life activities can prove to be a huge blinking red light. Now this patient may not be able to swim for hours, but talking about the benefits of addressing the potential impairments that they may have, and relating that back to their ability to achieve their goals may increase their confidence.

Each time a patient walks into your clinic, they may have a few red lights in the back of their mind. While some may be brighter than others, cumulatively they can add up, and when they do, your patient’s symptoms may go through the roof. Thankfully we have the potential to turn these lights off, and maybe switch on a few of the blue ones while we are at it.


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