Fear of Pain Triggers Crippling Anxiety for Some but Not All
Pain-related fear has a neural signature based on personalized fear constructs.
Posted December 25, 2018
"You can hide 'neath the covers and study your pain," is a classic line from Bruce Springsteen's seize-the-day anthem, "Thunder Road." Unfortunately, people with extreme lower back pain can lose their carpe diem mindset and zest for life.
In some cases, individuals with a pain-related fear (PRF) condition called "kinesiophobia" (fear of movement) become psychologically paralyzed. This condition is marked by crippling anxiety due to fear of movement (and the possibility of re-injury) experienced by someone with chronic pain who is afraid to exercise or perform activities of daily life.
"Why is pain-related fear much more debilitating for some people with lower back pain (LBP) than others?" Swiss researchers recently set out to answer this question using advanced fMRI neuroimaging technology. Their findings were published Dec. 24 in a paper, “Pain-Related Fear – Dissociable Neural Sources of Different Fear Constructs.”
“This is the first time that multivariate brain response patterns are used to better understand and dissect a psychological construct, here, pain-related fear, conventionally assessed by self-report (questionnaires). The [fear-avoidance] scale demonstrated strong predictive power with high sensitivity to the harmful condition and was associated with subcortical fear processing regions (amygdala, thalamus, hippocampus)," the authors said.
Pain Is Subjective
Because pain-related fear is subjective, asking patients to self-report the intensity of clinical pain often forces doctors to second-guess how much a patient’s free-floating anxiety or overall fear constructs are influencing how that particular patient self-assesses his or her degree of pain.
This pioneering study is a first step towards giving pain specialists neuroscientific tools for measuring the extent that a generalized fear response and trait anxiety might be influencing how a patient self-reports pain in a questionnaire.
Using self-report questionnaires has always presented problems for doctors trying to gauge precisely how much pain a patient is experiencing objectively. As we all know, some people have higher pain thresholds than others. For example, one person might describe an episode of stabbing back pain as a "9" on the 1-to-11 pain scale, whereas another might rate the same intensity of pain a "6" out of 11 on his or her self-reported questionnaire.
Each of us also has a unique explanatory style for coping with pain. Some people are hardwired to grin and bear it; these patients are prone to downplay how much their pain hurts. The downside of this explanatory style is that if an injury really does require temporary bed rest, trying to go about day-to-day activities despite the warning sign of pain may cause self-harm and exacerbate a debilitating injury.
On the flip side, some patients hyperbolize and exaggerate their pain; for people with a combination of lower back pain and kinesiophobia, bed rest is often an automatic (albeit unnecessary) default response. Unfortunately, in many cases, the lack of daily physical activity and complete immobility can make lower back pain worse and undermines someone's quality of life over time.
For their recent study on PRF (Meier et al., 2018), the researchers juxtaposed "harmless" versus "harmful" role-playing videos of actors performing everyday activities (e.g., casually walking down the street vs. picking up a heavy box without bending the knees) while patients with LBP were in an fMRI undergoing a real-time brain scan. The researchers were able to identify distinctive neural patterns in fear-processing brain regions that corresponded with how patients had self-assessed their pain-related fear in various questionnaires.
As you can see in the image by Meier and colleagues below, different brain regions were engaged when study participants viewed harmful or harmless videos of actors performing everyday tasks. These neural responses were then compared to each patient's self-reported answers to the Fear-Avoidance Beliefs Questionnaire (FABQ) and the Tampa Scale of Kinesiophobia (TSK).
The TSK is a kinesiophobia survey that asks patients to rate the degree that they "agree" or "disagree" with statements such as: "I’m afraid that I might injure myself if I exercise," "If I were to try to overcome it, my pain would increase," "My body is telling me I have something dangerously wrong," "It’s really not safe for a person with a condition like mine to be physically active," "No one should have to exercise when he/she is in pain."
If you are someone living with lower back pain, how would you respond to the statements above on a scale of (1) strongly agree, (2) agree, (3) disagree, (4) strongly disagree?
What makes this neuroscience-based approach and the brain scans below significant is that these images represent the first time researchers have correlated self-reported emotions relating to pain with specific neural signatures.
Although more research is needed to fully understand the correlation between a patient's brain activity and various scores on self-reported questionnaires, this research is an exciting leap forward in terms of gauging how different emotional states are linked to distinctive neural patterns in fMRI brain scans. With some fine-tuning, the authors of this study are optimistic that, sometime soon, their research findings will be applied in ways that help clinicians pinpoint commonalities and deconstruct differences between how each patient copes with pain-related fear.
The authors conclude, "While self-reports still represent the best and direct measure of subjective feelings of fear and anxiety (LeDoux and Hofmann, 2018), the current results emphasize the need to carefully consider the different pain-related fear questionnaires in research and clinical settings as their constructs are not interchangeable.”
Michael Lukas Meier, Barry Kim Humphreys, Andrea Vrana, Erich Seifritz, Philipp Staempfli, Petra Schweinhardt. " Pain-Related Fear - Dissociable Neural Sources of Different Fear Constructs." eNeuro (First published online: December 24, 2018) DOI: 10.1523/ENEURO.0107-18.2018
Joseph E. LeDoux and Stefan G. Hofmann. "The Subjective Experience of Emotion: A Fearful View." Current Opinion in Behavioral Sciences (First published online: November 16, 2017) DOI: 10.1016/j.cobeha.2017.09.011
Caroline Larsson, Eva Ekvall Hansson, Kristina Sundquist, and Ulf Jakobsson. "Kinesiophobia and Its Relation to Pain Characteristics and Cognitive Affective Variables in Older Adults with Chronic Pain." BMC Geriatr (First published online: July 7, 2016) DOI: 10.1186/s12877-016-0302-6