Evaluation of the Gate Control Theory
- Significance
Using Fawcett’s criteria to evaluate the significance of the theory, the theory appears significant, though many of the concepts, propositions, philosophical claims, and conceptual models are not explicitly stated. The metaparadigm of the Gate Control Theory of Pain is health, and the metaparadigm proposition the theory addresses is processes affecting health (Wenzel, n.d.). This metaparadigm or its proposition are not explicitly stated by the theory’s authors, however. The philosophical claims on which the theory are based are also not explicitly stated, rather they are implied. For example, the authors provide evidence from research studies for their theory but do not explicitly state their belief in the value of the scientific method. The authors also do not specify which, if any, of the three philosophical worldviews of nursing (reaction, reciprocal interaction, simultaneous action) which their theory fits (Butts, 2011). This is likely because the theory is not specifically a nursing theory. Another important question in evaluating the significance of a theory is whether the conceptual models are explicitly stated (Fawcett, 2005). There are seven conceptual models of nursing which Fawcett has recognized, and none of these are mentioned by Melzack & Wall (Butts, 2011). Again, this is likely because the theory is not a nursing theory. Instead, the authors present their theory using a diagrammatic conceptual model to communicate the three-fold mechanism of pain modulation (Melzack & Wall, 1965). The model is easy to understand and explicitly states the factors proposed to influence pain perception.
The authors of the Gate Control Theory of Pain are Ronald Melzack and Patrick D. Wall. Melzack is a psychologist and Wall is a biologist, both serving as professors in their respective disciplines (Melzack & Wall, 1965). These two disciplines are important to the study of pain which is felt physically through biological mechanisms and influenced by psychological states. Citations for other theories (i.e. specificity theory and pattern theory), clinical evidence, and physiological evidence are provided throughout Melzack and Wall’s original article about the Gate Control Theory of Pain (Melzack & Wall, 1965). In fact, there are over 70 citations dating back to 1894 included (1965). The author’s backgrounds and the supporting evidence they provided contribute to the significance of the Gate Control Theory of Pain according to Fawcett’s criteria (Wenzel, n.d.).
2. Internal Consistency
According to Fawcett’s criteria, determination of internal consistency requires the reviewer to consider four factors: the congruence of the elements of the work, semantic clarity and consistency of concepts, lack of redundancy, and structural consistency (Fawcett, 2005). Based on these components, the Gate Control Theory of Pain is internally consistent. The context, or conceptual model, of a three-fold mechanism of pain modulation is congruent with the theory that pain can be modulated by presynaptic inhibition (Melzack & Wall, 1965). However, the mechanism by which pain can be modulated at a presynaptic location remains unknown. Therefore, the theory is consistent in its proposition of the theory of pain control, however, the mechanism by which one can control that pain is less clear (Melzack & Wall, 1965). Despite opportunity for numerous definitions of “pain” the theory maintains semantic clarity by clearly defining pain and the three systems involved in its perception. Of note, this mechanism had increased clarity in following years as discussed below in regard to parsimony. Lastly, they are no redundant concepts in the theory.
3. Parsimony
Fawcett’s criteria for parsimony of a theory asks the reviewer to consider the clarity and conciseness of the stated theory (Fawcett, 2005). The Gate Control Theory of Pain clearly proposes that pain phenomena are determined by interactions between three systems: the substantia gelatinosa, the dorsal column and the T-cell activation which elicits response and perception (Melzack & Wall, 1965). While this theory was clearly stated in its original iteration in 1965, it was not necessarily concise. The original publication of this theory in the journal Science proposed that the three systems determine pain perception are complex systems and the theory does not clearly identify which interactions between those three systems may present opportunities for pain modulation. In the years since its original publication, the theory’s conciseness has improved, leading to the conclusion transmission of pain stimulus is modulated by the peripheral nervous system. Therefore, while the initial iteration of the Gate Control Theory may not have fully met Fawcett’s criteria for parsimony, the theory as it stands today, does (Dickinson, 2002)
4. Testability: Middle-Range Theories
Fawcett’s criteria for testability in middle-range theories questions whether a concept can be empirically observed or measured (Fawcett, 2005). Gate Control Theory of Pain can be classified as a middle range theory as it is specific, concrete, and its assertions are measurable (Fawcett, 2005). When Gate Control Theory of Pain was first presented in 1965 we were limited in our ability to test the theory. Our knowledge and tools were not sensitive enough for direct measurement of neural impulses along the fibers, receptors and within the brain of the human nervous system. Instead the theory was tested with clinical observation (Melzack & Wall, 1965). Research has progressed since then and we now have more sensitive tools and have expanded our knowledge of the nervous system. Recent research has expanded pain beyond the Gate Control Theory of Pain into multiple mechanisms (Dickenson, 2002). Gate Control Theory continues to be tested but now usually as a supportive concept, among many others, in developing interventions in pain control (Dickenson, 2002).
5. Empirical Adequacy: Middle-Range Theories
Fawcett’s criteria of empirical adequacy requires that the assertions in the theory are congruent with empirical evidence from all studies testing the theory (Fawcett, 2005). In other words, not only must the theory be able to be observed empirically and measured, as described above, but the evidence must be replicable. In the case of the Gate Control Theory of Pain, while many have criticized the physical and neural mechanisms of the theory, no one yet has been able to propose a comparable alternative or refute its basic principles (Sufka & Price, 2002). This is not to say that aspects of the theory have not been rightly contested. Neuroscience and pain research has grown exponentially since the release of the Gate Control Theory in 1965. In fact, many credit the theory for initiating such research. As more neurotransmitters and nerve pathways are examined, the exact mechanisms of the Gate Control Theory are muddied and become more complex (Sufka & Price, 2002). However, even if the Gate Control Theory is now considered oversimplified due to the limited knowledge at that time, the basic premise has been supported through studies over the years and still stands that transmission of pain stimulus is modulated from the peripheral nerves through the spinal cord to the CNS by intrinsic neurons and stimulus from the brain (Dickinson, 2002).
6. Pragmatic Adequacy:
One important strength of the Gate Control Theory of Pain is that it helps providers and patients better understand the nature of pain and different modalities to treat it. In fact, in their concluding paragraphs, Melzack and Wall explain a few circumstances when their model may be applied to clinical situations. For example in a patient with peripheral nerve damage, bathing his or her extremity in moving water and then massaging it can relieve pain as a result of the input to the large, rapid conducting nerve fibers and closing of the pain gate (Melzack & Wall, 1965). Special education and training about pain management modalities such as this one would enhance provider’s treatment of pain and application of this theory. With education the modalities would be well within the legal scope of practice of advanced practice nurses to diagnose and treat disease and would likely lead to favorable outcomes (Maryland Office of the Secretary of State, n.d.). The actions of the nurse would be compatible with the expectations of general nursing practice, which include “alleviation of suffering through the diagnosis and treatment of human response” (ANA, 2015b). Implementing clinical protocols based on the theory may be challenging, however, as the theory stresses the multifactorial nature of pain. Pain can be influenced by past pain experiences or current emotional states (Melzack & Wall, 1965). Thus it is important for providers to adopt a patient-centered approach in treating patients in pain.
Rationale for Using this Theory
We have chosen The Gate Control Pain Theory to guide our problem-solving process because of the comprehensive approach it potentially offers our patients experiencing pain in the setting of former or current substance abuse. The four authors of this site currently work in healthcare settings serving the urban poor in East Baltimore. Our experiences as Registered Nurses in infectious disease and in community public health remind us daily that pain affects every aspect of one’s livelihood- physical, psychosocial and spiritual. The challenge to control pain in East Baltimore is confounded by unprecedented rates of substance abuse including heroin, cocaine, and narcotic pain medications (Artigiani & Wish, 2013).
According to the National Institutes of Health (NIH) an estimated 100 million Americans were affected by pain in 2014 (NIDAb, 2014). In the last 20 years the frequency of opioid prescriptions has increased more than 300% and the number of deaths due to opioids is greater than the number of deaths from heroin and cocaine combined (NIDAb, 2014b). Long-term opioid use leads to decreased effectiveness of opioids to treat pain. As Dr. Nora Volkov, of the National Institute on Drug Abuse explains in this video, opioids can be an effective pain treatment, but pose sufficient risk of abuse, diversion and addiction (NIDAb, 2014):
According to the National Institutes of Health (NIH) an estimated 100 million Americans were affected by pain in 2014 (NIDAb, 2014). In the last 20 years the frequency of opioid prescriptions has increased more than 300% and the number of deaths due to opioids is greater than the number of deaths from heroin and cocaine combined (NIDAb, 2014b). Long-term opioid use leads to decreased effectiveness of opioids to treat pain. As Dr. Nora Volkov, of the National Institute on Drug Abuse explains in this video, opioids can be an effective pain treatment, but pose sufficient risk of abuse, diversion and addiction (NIDAb, 2014):
The Gate Control Theory proposes safer, more sustainable pain treatment modalities to inhibit ascending pain impulses as discussed above (massage, TENS, etc). In a setting like Baltimore City, these modalities may be ideal treatment options for patients with pain as well as former or current substance abuse. As future prescribers in an underserved community, we are committed to addressing the multifaceted causes of pain. Therefore, we chose the Gate Control Theory of Pain and its proposed modalities to assist all of our patients, regardless of substance abuse history, to manage their pain safely and sustainably.