Biology 202
2002 Third Paper
On Serendip

"Ouch!!" Ordinarily, that word elicits a predictable response. However, is that response one that is unilaterally perceived? The topic of pain endurance is one that is often discussed. It is understood that the feeling of discomfort is something abhorrent to all people, and is intrinsic at birth. While most people assume that the level of torment is comparable in all people, scientists have recently begun exploring the possibility that pain tolerance may be greatly dissimilar among individuals.

Recently, in class, we have wondered how anyone could be sure that pain is felt to the same degree in all people. It is a fact that all humans feel pain due to the presence of pain receptors. When confronted with a stimulus, the nerves send signals to the brain, which interprets the signals as discomfort. We know that others feel pain because we are able to communicate with one another. If something hurts a person, that individual is able to say, "Ouch, that hurts."

While the majority of humans are able to express their discomfort, there is one group that does not have that luxury. Because babies are unable to speak, and subsequently communicate their feelings, we automatically assume they feel no pain. Because of this situation, there has long been a debate concerning babies and their threshold of pain. People recognize that babies signal their pain in a variety of ways, including crying and contorted facial gestures. Although scientists might deem these reactions as mere reflexes because they have no definitive measure of the infant's pain threshold, most doctors believe that a newborn feels pain. This tenet is due to the existence of a completed nervous system. If people are at the mercy of their systems, and this is why they feel pain, it would make sense that an infant, with a complete nervous system, would feel the same way.

Nevertheless, until ten years ago, it was not acknowledged that premature, or even, unborn children feel pain because people believed that their nervous systems were too immature to function properly (2). Because of this, it was acceptable practice in the past for doctors to operate on premature babies without anesthesia because they thought that, even if the babies felt pain, they would not suffer any long-term damage (1). However, now studies have shown that not only do unborn, premature, and newborn infants feel pain, their sensitivity to pain is likely to be much greater and more prolonged than that of a regular adult (2).

Babies have unique sensory systems, which contain pain-signaling mechanisms that disappear with age. This special wiring causes the newborns to not only feel pain sooner, but also to experience more detrimental physiological effects due to the painful stimuli. We would like to think that every individual feels pain in the same manner. However, the conclusions reached through research indicate that infants can experience pain differently than adults even when the same stimulus is present. Furthermore, the perception of pain can be different between regular newborns and premature infants. In premature children, the mechanism that comes with age, allowing older individuals to dampen down the pain, does not function properly (3). This means that babies who are born prematurely end up feeling pain like newborns when they are adults: the pain is at a greater magnitude than normal.

When a baby is born prematurely, its nervous system may or may not be developed fully. However, the tools needed to feel pain do function because the spino-thalamic system, the network that coveys pain in humans, is connected by the 20th week of gestation (5). However, the mechanism needed to reduce the pain naturally is not. In newborns, nerve pathways that carry pain-inhibiting messages from the brain stem to the spinal cord mature later than other parts of the system. The nerve fibers start to grow from the brain stem down the spinal cord early during the fetus's life, but they do not extend into the branches of the nervous system and do not begin to function until after a normal birth (3).

As a result of this loss of ability to reduce the feeling of pain, the effects of pain last a lifetime for premature children. Not only does this special system function improperly, but also painful stimuli cause a child's developing nervous system to grow more of the nerve cells that carry pain sensations to the brain. Scientists have found more nerve endings that transmit pain signals in animals that had been born prematurely. Later in life, these same animals appear more sensitive and exhibit greater responses to pain that their normal counterparts (4).

One of the reasons why I am so fascinated by these findings is because I was born two months prematurely. Growing up, I questioned whether everyone felt pain in the same way, because I firmly believed that somehow I felt it differently than the rest of my family. Like most premature babies, when I was born I was faced with operations, blood transfusions and countless needle injections to check my blood levels. Every two hours, the search for a viable vein began. Because my mother was too ill to visit me in the hospital, it became something my dad endured. My mom recalls my dad coming back from visiting me in the ICU one evening, more distraught than usual. Although it had become a common occurrence for the doctor to stick a needle into my paper thin skin forty or fifty times, this day was different. Ordinarily, I would cry as the prodding took place. One this particular evening, I showed no emotion as I was stuck 46 times in my head, toes, heels, and fingers. My parents feared I had succumbed to autism, because even though I had reacted to the pain at first, I now seemed indifferent to it. They were concerned that, because the pain had become so unbearable, I had gone into a private place within myself.

When I was young I would not let my mother brush my hair. I ran around looking like a very disheveled young lady, but it was too painful to have someone comb through the rat's nest piled on top of my head. Any type of contact with my skull caused me great anguish. I also had to keep my feet covered at all times due to their sensitivity and feeling of cold. My fingers became something that had a unique connection to my soul. They were a source of solace, artistic expression, and constant sensitivity. It was only after reading an article on premature infants that I realized why those three areas held such significance for me. They were the places were I was bombarded with needles as an infant. Although I do brush my hair now, it is still a somewhat painful experience for me. I use many special solutions and a special brush just to make the experience less painful. Trips to the hairdresser are filled with dread, knowing the affect it will have on my tender scalp. I never understood why brushing one's hair was not as painful to other people as it was to me. What made my reactions so much more extreme than that of my sister or my friends'?

I believe the recent studies support how I behaved as a young girl and furthermore how I still react today. It has been proposed that more pain, and sensory receptors form in areas where distress is experienced soon after birth. It would, therefore, make sense that due to the repeated painful stimuli to my head, heels, and fingers, I have developed more sensory receptors in these areas. If I did develop more nerve endings in addition to the ones receptive to pain, then I would feel all things, including pain, to a greater extent than someone with a normal amount of receptors. Additionally, if the system that is responsible for decreasing the pain signals does not work properly, then I would feel greater pain than the average person.

Like many preemies born around the same time, anesthesia was not used on me. Doctors thought that premature babies would not be able to handle the powerful drug as well as babies born after full term. Besides, many times preemies are born under stress and need operations immediately. It is understandable that doctors would perform operations without proper anesthesia, due to the life threatening situations that often occur. The reasoning was that the infant would have no recollection of the pain endured and, therefore, would suffer no lasting harm. However, researchers now understand that the memory of pain is not the only outcome from these past practices. These tiny bodies sustain physical alterations in response to their pain that last the child's lifetime (1).

It is reasonable to question how severe the pain really is. When I was about three years old, I went to the doctor's office to receive a shot. I kicked, I screamed, but eventually the doctor administered the shot while 4 nurses held me down. Was I scared of the shot because it was so painful or was I just frightened because of my memories of needles as a baby? If it was a phobia as the result of pain in the past, it can be dismissed because the actual experience of the pain is not that great. However, if my nervous system was permanently changed as the result of the stimuli as a baby, then the pain from the needle would be greater and it is understandable why I would be so scared.

My parents believed my pain to be perceived, rather than real. Although I always knew the distress I felt was not something I had fabricated, I can now find studies that substantiate my beliefs. When I said a mere bump hurt really badly, it was not just my perception of pain, but rather a universal one.

One of the most important aspects of scientific findings is the opportunity they give us to compare our experiences with those of others. People need to realize that everyone's sensations are unique: while something may feel merely discomforting to one person, it may be tortuous to another. If it is possible for a human's capacity for pain to be changed as a result of experiences as an infant, imagine what other mechanisms used to define one's reality can be changed as well.

Some people argue that it is possible to separate the mind's action from that of the body. I believe that the scientific findings I have detailed, lead to an even stronger argument toward the brain equaling that of behavior. People only feel and respond to pain due to the presence of nerve receptors and special mechanisms. If these mechanisms were not present, the person would not "feel" any pain even though the stimulus would be the same. A greater feeling of pain is directly correlated to the presence of more pain receptors and an improperly functioning pain reducer. Therefore, mind and body are intertwined. Our mental reality is at the mercy of our physiological reality, which is totally dependent on the functioning of our body's nervous system.

References

1)Detroit News Website, has a good article about premature infants and pain

2)The Unborn Child Does Feel Pain, great website of facts given by anti-abortion groups

3)New-Born Babies Feel Pain Quicker and Longer, another good article

4)ABC News Website, "Early Pain May Rewire Brain" good article about premature babies' sensitivity to pain and other related articles

5)Anti-Abortion Website, Abortion and the Unborn Baby: The Painful Truth, overview of how unborn and premature children feel pain

6)University of Minnesota Website, Good diagrams of developing fetus

7)AbortionFacts.com, A great website with many articles and findings on the unborn fetus, premature children, and regular newborns and pain

8)PsycPort News Website, Infant pain experience may linger. Another news report on another study on preemies that undergo painful procedures.

9)Medical Research Council, gives reliable facts on how infants can feel pain

10)NEW ENGLAND JOURNAL OF MEDICINE, Vol. 317 No 21 (19 Nov. 1987): Pages 1321-1329, Pain And Its Effects in the Human Neonate and Fetus


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