Defining Pain (Part 2/2)

The physiological process in which the perception of pain becomes surfaced is complex, however, this section will provide a brief oversimplification of the neuroscience of pain.

Nociception refers to the detection of a noxious stimuli by nociceptors. When thermal, mechanical or chemical stimuli reach an intensity or a threat that is suggestive of injury, there is a transduction and transmission of sensory information from the periphery relaying information to the brain through the spinal cord. (Martucci, KT 2016) (Boadas-Vaello P, 2016). This signal continues to regions of the midbrain responsible for perceiving pain (somatosensory cortex via the thalamus) and provide the information regarding spatial features of the stimulus and the intensity of the signal (acute response/reflex). Nociception, as distinguished from pain perception, is a continuous neuronal mechanism of detection for protection. To negate the notion that nociceptors are painful stimuli, there is sufficient data that indicates that nociceptive activity can be present in the absence of pain perception. Nociceptors can have a close correspondence to painful stimuli, however, there are complexities that involve disassociations and insensitivities with many nociceptive inputs and inhibitory outputs in the brain. (Baliki, MN 2015). Pain on the other hand, is the product of the brain processing, referring to the emotional and sensory experience. (Chen, JS et al 2019) (Basbaum, A. 2009). It is manifested through subjective measures, that reflect a conscious experience based on pre-existing vulnerabilities mandated by emotional and physical learning. (Baliki, MN 2015).

We currently understand is that pain sensations begin when nociceptors experience a painful stimulus. Each individual has a different sensitivity threshold to the network of systems and pathways determining their experience of pain. Individual behaviors and perception can be modulated by habits, giving rise to new peripheral nociceptive learning and sensitization. (Basbaum et al 2009)(Biliki MN 2015) For example, many individuals would agree that applying a 50kg weight on 1 cm of skin would be relatively painful. Yet, it is evident that experienced ballerinas dance on their toes while carrying the weight of their bodies with no symptoms suggestive of pain or injury. The continuous influx of nociceptive activation yields evidence that we are capable of disassociating pain from nociception. (Baliki, MN 2015) This experience can be conditioned and/or influenced by biological (neurogenic inflammation, hormonal), physical, psychological/emotional (fear/anxiety, depression), social and environmental factors in which neuronal pathways are inputted and interpreted. Through continuous CNS updating, neuronal inputs are amenable to progressive adaptations to lessen error for better future sensory predictions. (Ongaro G, 2019)

Nociceptors in our tissues can detect potential threats in our skin, joints, organs, muscles, etc, and facilitate receptor potentials to mediate pathways. (Chen, JS et al 2019) (Basbaum, A. 2009)

(Chen, JS et al 2019)

Turk DC, Wilson HD. Fear of pain as a prognostic factor in chronic pain: conceptual models, assessment, and treatment implications. Curr Pain Headache Rep. 2010;14(2):88-95. doi:10.1007/s11916-010-0094-x

This is to reinforce the notion that there is NO single pain-generator. The existential relations to pain are both internal and external. Many researchers have dedicated investigations to the fear of onset, development and maintenance of pain. This data suggested that the anticipation of pain/injury produces a strong negative reinforcement, likely greater than the noxious stimuli that is associated to pain. Often, this augments a persistent fear-avoidance behavior, leading to physical and psychological consequences contributing to personal limitations. (McCracken, LM 1993) (Vlaeyen, JW 1995) (Turk, DC 2010). The anticipated behaviors and beliefs have shown to relate to reoccurring pain and may be predictive of persistent disability.  (Boersma, K 2005) This is often how the transition of acute pain/injury leading to chronic pain occurs. In chronic pain, ‘central sensitization’ is the result of sensitized receptors in the skin causing abnormal or increased signals from the peripheral nerves, and/or the lack of inhibition and/or the increased excitation within the central nervous system. (Martucci, KT 2016). This persistence re-frames our threshold and increases sensitivity, this better discussed in the Chronic Pain section in Defining pain.

SO, what do we do?

It’s become a societal norm to coddle oneself from the inevitable discomforts of life. We cannot disconnect the comfort of pain. Pain is real. It is not only the outcome of psychological or psychosocial factors. In order to establish a congruency when dealing with your own or one’s pain, enabling a mutual exploration of one’s beliefs, expectations, emotions and perceived understandings of pain is imperative. Recognizing environmental and contextual factors, as well as identifying internal influences and stressors. Research suggests that pain-related fear is in fact a risk factor for the development of chronic pain and long-term illness. (Boersma, K 2005). Depletion of fundamental factors, such as nutrition and sleep, as well as cognitive reserves, fatigue, depression and anxiety may result from communal factors and perpetuate catastrophizing tendencies, therefore, must be identified early on. Moderating patient stigmatization as opposed to solely focusing on mitigating pain, will in turn build therapeutic relationships for better outcomes.

The Multimodal Assessment Model of Pain (MAP) is a developing pain assessment model, emphasizing the aforementioned constructs on individualistic experiences of pain through contextual and environmental factors. This model identifies three principal observable attributes related to pain: pain experience, pain expression and pain measure. Pain experience involves the sensory and emotional connection associated with one’s pain that cannot be observed by third parties. Pain expression narrates nonverbal and para-verbal behaviors, as well as word description. Pain measure is the quantitative aspect, in which pain is reports through self- and non-self-measures. (Wideman, TH 2019) (P Stillwell, K Harman 2019)

Though, its acknowledged that there is much ambiguity in subjective measures, it seems to be relatively more reliable than some objective measures. For clarity, objective measures are purposeful for guiding mechanism-based management. (Wideman, TH 2019).  In addition to this, self-reported measures do more than just scale a numerical pain level. It supports individual autonomy to personalize communication-based practice, it reveals information about how that patient may perceive their pain (e.g. hyper-analgesia or fearful from chronic pain) and it can be used as a baseline progress outcome measure. Essentially, utilizing a comprehensive pain assessment can help consolidate ones environmental and contextual factors. Clinicians can reframe patient narratives by shifting their own thoughts about pain, removing it as a symptom or diagnosis and acknowledging it as a subjective experience. This best described through an analogy of recognizing the difference between feelings of sadness and clinical depression. (Wideman, TH 2019). Not every hungry person is suffering from starvation. 

Due to the high inter-individual variability, there is no general consensus on how to treat one’s pain, but current evidence supports the use of education, encouraging movement, and minimizing healthcare utilization. (Louw, 2016). Allowing an individual to re-gain autonomy and self-sufficiency through opportunities of action and reframed perception. The only contraindication I can suggest through the rehabilitative phase of pain is absolute rest. Through the above-mentioned articles, some suggestions in moderating patient experience are listed below:

(Woby SR 2007)

With this being said, words matter. Many individuals have admitted that their learned beliefs about their pain came from their health professionals. (Setchell 2017) Perspective and framing information to patients/clients should be aimed to minimize dependencies of learned helplessness and to gain autonomy of the experience that drives their reality. Utilizing frameworks that account for fundamentally complex situations fosters a clinically relevant treatment strategy to target pain-related experiences. Identifying one’s learned tendencies allows the treating clinician to focus on internal and external stimuli, giving greater attention to the patient during encounters. Subsequent avoidance coping may reflect a failure in healing and rehabilitation from injury, so proper engagement of appropriate therapies should be taken cautiously to desensitize anxiety provoking stimuli. Treatment goals should be centered to improving daily functioning and increasing the quality of one’s life through self-efficacy and decreasing fear-avoidance behaviors.

Should you use other therapies? 

All other forms of therapy can be beneficial for some individuals, but are not necessary, but if used, they are highly recommended to be used in conjunction to the above listed suggestions. Therapeutic exercise, graded exposure, and overcoming challenges are key constructs in rehabilitation. Resisted exercise, endurance and power are influential staples in performance. This is where biomechanics is fundamentally important to understand when prescribing appropriate weight to patients/clients; being able to prescribe exercise requires knowledge of the external loads applying forces onto tissues. A graded exposure to (re)gaining strength allows the body to adapt and builds a resiliency to reduce the risk of (re)injury.

Manual therapy and joint mobilization are widely used interventions; although we know that we cannot change one’s muscular physiology with our bare hands, there is empirical evidence indicating a short-term activation of brain-orchestrated endogenous analgesia (Louw, A et al 2017).  To use this method is entirely up to the treating clinician, however, facilitating transient techniques to paradoxically shift passive treatment into active treatment may be beneficial to some and root dependency to others. This form of treatment warrants further investigation and studies. Other interventions such as e-stim, percussion, cupping, foam rolling, ultrasound, needling, taping, among many others have shown little to no efficacy in comparison to movement/exercise.

However, if one finds ‘relief’ using these modalities in conjunction with the above-listed suggestions, one should seek independence by reducing the frequency of passive care and transition to active care with a healthcare professional.  

Literature continuously reveals the importance of movement and regular exercise, making it a priority in rehabilitation. Even in context where we see exercise as a priority, the appropriate dosage is still undetermined. Increasing dose is measured by load, frequency and volume. Manipulating these factors to a threshold that is tolerable for the patient allows for better psychological and physiological adaptations. (Polaski 2019). Given the information provided in this series, we can be more mindful when discussing pain/injury and providing optimal therapies for desired goals. Fully grasping the fundamental concept of pain will allow for better management of patients/clients for all clinicians, coaches and trainers.

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