I have, for a long time now, been reading articles, books, textbooks, and research papers by Professor Melzack. Some of these quotes are from articles, books, textbooks, but most are from research papers (or where Prof. Melzack is the first author). Professor Melzack is well known in pain research circles. But among healthcare professionals, he is one of the lesser-known pain experts, but in my opinion, he deserves a lot more attention for the pioneering of work that he did.
Professor Melzack was a Canadian psychologist and emeritus professor of psychology at McGill University. Professor Melzack was a founding member of the International Association for the Study of Pain (IASP), an honorary life member and a past president of The IASP.
Prof. Melzack was also a Member of the Canadian Medical Hall of Fame and was elected a Fellow of the Royal Society of Canada in 1982. He held two Canadian honorary degrees and was the first recipient of the E.P. Taylor Chair in Pain Studies at McGill.
Professor Melzack was a true pioneer in pain research and pain management. Most healthcare professionals will not know him by name but will recognize some of the scientific theories and frameworks he coauthored, namely the gate control theory, that was published in 1965 (1) and the pain neuromatrix, that was published in 1989 (2, 3). He also was a critical factor in the development of the McGill Pain Questionnaire. He continued to work on the pain neuromatrix. He co-authored one of the most excellent overviews in pain medicine (4) in 2013, a paper that should be essential reading for all healthcare professionals.
Professor Melzack also authored and co-authored multiple books and textbooks in the pain field, like “The challenge of Pain”, “Puzzle of Pain”, “Handbook of Pain Assessment (with Dennis C. Turk) and The “Textbook of Pain” (with Patrick D. Wall).
It is with great sadness that I found out that Professor Melzack passed away on December 22, 2019. Professor Melzack was a world-renowned authority on pain, and he published many important papers within this complex field.
You will be greatly missed Professor Melzack, but you do leave behind a goldmine of research that will continue to inform healthcare professionals for the better.
Without further ado, here are 22 something quotes from Professor Melzack PhD:
“Pain is not simply the end product of a linear sensory transmission system; it is a dynamic process that involves continuous interactions among complex ascending and descending systems. The neuromatrix theory guides us away from the Cartesian concept of pain as a sensation produced by injury, inflammation, or other tissue pathology and toward the concept of pain as a multidimensional experience produced by multiple influences.” Professor Melzack PhD
“Pain is not injury; the quality of pain experiences must not be confused with the physical event of breaking skin or bone. Warmth and cold are not ‘out there’; temperature changes occur ‘out there’, but the qualities of experience must be generated by structures in the brain. There are no external equivalents to stinging, smarting, tickling, itch; the qualities are produced by built-in neuromodules whose neuro signatures innately produce the qualities.” Professor Melzack PhD
“The nature of pain has been the subject of bitter controversy since the turn of the century (I). There are currently two opposing theories of pain: (i) specificity theory, which holds that pain is a specific modality like vision or hearing, “with its own central and peripheral apparatus” (2),and (ii) pattern theory, which maintains that the nerve impulse pattern for pain is produced by intense stimulation of nonspecific receptors since “there are no specific fibers and nonspecific endings” (3). Both theories derive from earlier concepts proposed by Von Frey (4) and Goldscheider (5) in 1894, and historically they are held to be mutually exclusive.” Professor Melzack PhD
“Consider the proposition that the skin contains “pain receptors.” To say that a receptor responds only to intense, noxious stimulation of the skin is a physiological statement of fact; it says that the receptor is specialized to respond to a particular kind of stimulus. To call a receptor a “pain receptor,” however,is a psychological assumption: it implies a direct connection from the receptor to a brain center where pain is felt (Fig. 1), so that stimulation of the receptor must always elicit pain and only the sensation of pain.” Professor Melzack PhD
“Specificity theory proposed that injury activates specific pain receptors and fibers which, in turn, project pain impulses through a spinal pain pathway to a pain center in the brain. The psychological experience of pain, therefore, was virtually equated with peripheral injury. In the 1950s, there was no room for psychological contributions to pain, such as attention, past experience, anxiety, depression, and the meaning of the situation.” Professor Melzack PhD
“There was no place in the specificity concept of the nervous system for ‘plasticity,’ in which neuronal and synaptic functions are capable of being molded or shaped so that they influence subsequent perceptual experiences. Plasticity related to pain represents persistent functional changes, or ‘somatic memories,’29–31 produced in the nervous system by injuries or other pathological events. The recognition that such changes can occur is essential to understanding chronic pain syndromes, such as low back pain and phantom limb pain that often destroy the lives of the people who suffer them.” Professor Melzack PhD
“The pathological pain states of causalgia (a overt burning pain that may moat from a partial lesion of a peripheral nerve), phantom limb pain (which may occur after amputation of a limb), and the peripheral neuralgias (which may occur after peripheral nerve infections or degenerative diseases) provide a dramatic refutation of the concept of a fixed, direct-line nervous system.” Professor Melzack PhD
“Four features of these syndromes plague patient,physician, and theorist (8, 10). 1) Surgical lesions of the peripheral and central nervous system have been singularly unsuccessful in abolishing these pains permanently, although the lesions have been made at almost every level (Fig. 2). Even after such operations,pain can often still be elicited by stimulation below the level of section and may be more severe than before the operation (8, 10).
2) Gentle touch, vibration, and other nonnoxious stimuli (8, 10) can trigger excruciating pain, and sometimes pain occurs spontaneously for long periods without any apparent stimulus. The fact that the thresholds to these stimuli are raised rather than lowered in causalgia and the neuralgias(10), together with the fact that referred pain can often be triggered by mild stimulation of normal skin (8),makes it unlikely that the pains can be explained by postulating pathologically hypersensitive “pain receptors.”
3) The pains and new “trigger zones” may spread unpredictably to unrelated parts of the body where no pathology exists (8, 11).
4) Pain from hyperalgesic skin areas often occurs after long delays,and continues long after removal of the stimulus (10). Gentle rubbing, repeated pin pricks, or the application of a warm test tube may produce sudden,severe pain after delays as long as 35 seconds. Such delays cannot be attributed simply to conduction in slowly conducting fibers; rather, they imply a remarkable temporal and spatial summation of inputs in the production of these pain states (8. 10).” Professor Melzack PhD
“Stimulation of the skin evokes nerve impulses that are transmitted ·to three spinal cord systems (Fig. 3): the cells of the substantia gelatinosa in the dorsalhorn, the dorsal-column fibers that project toward the brain, and the first central transmission (T) cells in the dorsal horn. We propose that (i) the substantia gelatinosa functions as agate control system that modulates the afferent patterns before they influence the T cells; (ii) the afferent patternsin the dorsal column system act, in part at least, as a central control trigger which activates selective brain processes that influence the modulating properties of the gate control system;and (iii) the T cells activate neural mechanisms which comprise the action system responsible for response and perception. Our theory proposes that pain phenomena are determined by interactions among these three systems.” Professor Melzack PhD
“A gate control system modulates sensory input from the skin before it evokes pain perception and response.” Professor Melzack PhD
“The gate control theory’s most important contribution to understanding pain was its emphasis on central neural mechanisms. The theory forced the medical and biological sciences to accept the brain as an active system that filters, selects and modulates inputs.” Professor Melzack PhD
“The sensory mechanisms alone fail to account for the fact that nerve lesions do not always produce pain and that, when they do, the pain is usually not continuous. We propose that the presence or absence of pain is determined by the balance between the sensory and the central inputs to the gate control system.” Professor Melzack PhD
“The model suggests that the action system responsible for pain perception and response is triggered after the cutaneous sensory input has been modulated by both sensory feedback mechanisms and the influences of the central nervous system.” Professor Melzack PhD
“The recognition that pain is a multidimensional experience determined by psychological as well as physical factors has broadened the scope of pain therapies. Patients with chronic pain need every possible therapy to battle the pain. Chronic pain is not a symptom but a syndrome in its own right, and requires therapists from a wide range of disciplines.” Professor Melzack PhD
“Pain has many valuable functions. It often signals injury or disease, generates a wide range of adaptive behaviors, and promotes healing through rest. Despite these beneficial aspects of pain, there are negative features that challenge our understanding of the puzzle of pain, including persistent phantom limb pain after amputation or total spinal cord transection.” Professor Melzack PhD
“Despite these beneficial aspects of pain, there are negative features that challenge our understanding of the puzzle of pain. What is the benefit of chronic phantom limb pain to an amputee whose stump has healed completely? The pain, not the physical impairment, prevents them from leading a normal life. Likewise, most backaches, headaches, muscle pains, nerve pains, pelvic pains, and facial pains serve no discernible purpose, are resistant to treatment, and are a catastrophe for the people who are afflicted.” Professor Melzack PhD
“Pain is a personal, subjective experience influenced by cultural learning, the meaning of the situation, attention, and other psychological variables. Pain processes do not begin with the stimulation of receptors. Rather, injury or disease produces neural signals that enter an active nervous system that (in the adult organism) is the substrate of past experience, culture, and a host of other environmental and personal factors. These brain processes actively participate in the selection, abstraction, and synthesis of information from the total sensory input.” Professor Melzack PhD
“Melzack’s19 analysis of phantom limb phenomena, particularly the astonishing reports of a phantom body and severe phantom limb pain in people with a total thoracic spinal cord section,17 led to four conclusions which pointed to a new conceptual model of the nervous system.
First, because the phantom limb feels so real, it is reasonable to conclude that the body we normally feel is subserved by the same neural processes in the brain as the phantom; these brain processes are normally activated and modulated by inputs from the body but they can act in the absence of any inputs.
Second, all the qualities of experience we normally feel from the body, including pain, are also felt in the absence of inputs from the body; from this we may conclude that the origins of the patterns of experience lie in neural networks in the brain; stimuli may trigger the patterns but do not produce them.
Third, the body is perceived as a unity and is identified as the ‘self’, distinct from other people and the surrounding world. The experience of a unity of such diverse feelings, including the self as the point of orientation in the surrounding environment, is produced by central neural processes and cannot derive from the peripheral nervous system or spinal cord. Fourth, the brain processes that underlie the body-self are ‘built-in’ by genetic specification, although this built-in substrate must, of course, be modified by experience, including social learning and cultural influences.” Professor Melzack PhD
“We are so accustomed to considering pain as a purely sensory phenomenon that we have ignored the obvious fact that injury does not merely produce pain; it also disrupts the brain’s homeostatic regulation systems, thereby producing ‘stress’ and initiating complex programs to reinstate homeostasis. By recognizing the role of the stress system in pain processes, we discover that the scope of the puzzle of pain is vastly expanded and new pieces of the puzzle provide valuable clues in our quest to understand chronic pain” Professor Melzack PhD
“The disruption of homeostasis by injury activates programs of neural, hormonal, and behavioral activity aimed at a return to homeostasis. The particular programs that are activated are selected from a genetically determined repertoire of programs and are influenced by the extent and severity of the injury. When injury occurs, sensory information rapidly alerts the brain and begins the complex sequence of events to re-establish homeostasis.” Professor Melzack PhD
“The neuromatrix theory of pain proposes that the neurosignature for pain experience is determined by the synaptic architecture of the neuromatrix, which is produced by genetic and sensory influences. The neurosignature pattern is also modulated by sensory inputs and by cognitive events, such as psychological stress.” Professor Melzack PhD
“The field of pain continues to develop and there are reasons to be optimistic about its future. First, imaging techniques have confirmed pain-related activity in widely distributed, highly interconnected areas of the brain. An implication of the concept is that neural programs that evolved in the brain to generate acute pain as a result of injury or disease may sometimes go awry and produce destructive chronic pain.
Future imaging research may reveal the sites of abnormally prolonged activity in chronic pain patients. Second, the detailed knowledge and technical skills developed by scientists for research on the spinal cord can be used to explore brain mechanisms in humans and animals, especially in the brainstem reticular formation, which is known to play a major role on chronic pain. Third, our knowledge of the genetic basis of pain as well as the development of the brain is growing rapidly. Genetic factors are known to contribute to a large number of chronic pain syndromes and future research will highlight their brain mechanisms.” Professor Melzack PhD
References:
1. Melzack R, Wall PD. Pain mechanisms: a new theory. Science. 1965 Nov 19;150(3699):971-9.
2. Melzack, R. (1989). Phantom limbs, the self and the brain (the D. O. Hebb Memorial Lecture). Canadian Psychology/Psychologie canadienne, 30(1), 1–16.
3. Melzack R. Pain. From the gate to the neuromatrix. 1999 Aug;Suppl 6:S121-6.
4. Melzack R., Katz J. (2013), Pain. WIREs Cogn Sci, 4: 1–15.
