Pain is probably one of the most universal perceptions that humans, or indeed any animal, can experience. From stress headaches to stubbing one's toe, we come into contact with pain on a daily basis. This is normal data about the experience of pain. However, there are several groups of people that do not feel pain in a common way. Either they don't feel enough pain to tell them that something is wrong, as in the cases of lepers and some diabetics, or they have too much pain, as in the cases of some diabetics, people with phantom limb pain, cancer victims, stroke victims, and other diseases of the brain or spinal cord (Casey, 1996).

The effects of pain on these people is in many cases debilitating; their normal lives are likely gone or, at best, on hiatus. These reasons are incentive enough for scientists trying to discover more ways to eradicate wanton pain (or the absence of pain) because there is a threat that many of us, at some point, will be subject to these same problems.

The first case of underprotective pain perception that will be discussed is that of leprosy. Leprosy is a bacterial pathogen (M. leprae) that attacks the peripherial nervous system in humans and is the leading cause of peripheral nerve disease in the world. The bacteria attack the Scwann cells that form the myelin sheath around nerve fibers. Without the protection and insulation of the myelin sheath, nerve cells fire inefficiently. The net results of this bacterial infection are skin lesions and damage to the nerves, mainly in the extremities and facial area (Henderson, 1998) .

The result of the nerve damage that is pertinant to this topic is the loss of sensation. This lack of feeling complicates normal living: the person with leprosy is not able to identify cuts or burns on his or her skin. Without the protection of normal pain responses, this person could conceivably fail to notice for quite some time that he has been injured and therefore not take further conscious protective measures such as cleaning the cut with alcohol or treating the burn with salve. The effects of this lack of protective sensation are grim: lesions and eventual deformities result from the lack of care given to the body. Although luckily the bacteria can be killed with a month-long course of several drugs, unfortunately the nerve damage is permanent (Henderson, 1998). This means that the person with leprosy will remain feeling a lack of sensation fo the rest of his life, and constant vigilance may be necessary to prevent infections and complications from something as small as a paper cut.

The next people subject to the phenomena of an underprotective pain mechanism are diabetics. Diabetes, aside from the primary problem of blood sugars as the result of renal failure, offers a host of complications ranging from diabetic retinopathy to diabetic neuropathy. The causes of peripheral neuropathy suffered by diabetics is not yet known but is characterized by pain in the legs and toes and, paradoxically, the loss of sensation in those same places (Lavery, Armstrong, Vela, Quebedeaux, & Heischlt, 1998). The general pain felt in the legs will be discussed along with overactive pain; the loss of sensation is of primary importance here.

The loss of sensation due to peripheral neuropathy manifests itself in a way similar to that of a person with leprosy; lower extremities are subject to foot ulceration and foot deformities. Ulcers on the foot are adequate avenues for infections, and when coupled with a high incidence of poor wound healing, can lead to even greater problems, namely lower extremity amputation. Foot ulcers, along with foot deformities and abnormal pressures resulting from diabetes are all major risk factors for amputation. There is also some evidence that the impaired visual acuity of the diabetic as a result of diabetic retinopathy could also be a factor in the incidence of foot ulcerations (Lavery et al, 1998).

On a practical level, the diabetic is subject to many problems. They must be vigilant about foot care which can be compromised by vision problems, all a result of their condition. The lack of a protective pain perception in these people can lead to amputations, which in turn reveals a new set of problems discussed later to which amputees are subject. In addition to this lack of protective pain perception in diabetics is the opposite side of diabetic neuropathy: neuropathy that manifests itself as unlocalized chronic pain (Tesfaye, Watt, Benbow, Pang, Miles, & MacFarlane, 1996). This may seem to be a paradox. However, nearly every patient who has chronic pain has difficulty detecting protective pain in that same area (Casey, 1996).

Pain associated with peripheral neuropathy is charaterized by lower extremity pain, night-time exacerbation of the problem, and extreme sensitivity to bedclothes leading to loss of sleep. The pain from this condition can be disabling and is chronic. Unfortunately, conventional methods of pain management for this condition is difficult; the drugs often don't work or they produce too many side effects and complications to be efficacious Tesfaye, et al, 1996).

Another type of pain occurring from a pathological pain perception, is that of the phenomena of phantom limb pain, a condition in which an amputee not only feels the prescence of the missing limb, but she experiences pain in it as well. Recent findings suggest that phantom limb pain is not a result of grief for the missing limb as was once assumed. (Fisher & Hanspal, 1998). Research continues to determine the source of this phenomena.

Finding a way to manage these diverse types of pain is represented by a large volume of research and is the subject of its own journal, Pain. There are several different tracks research has taken, from studying how electricity effects nerves to techniques that are new altogether.

A technique recently researched to help treat painful peripheral neuropathy associated with diabetes is called electrical spinal-cord stimulation (ESCS). This involves placing a stimulator with a lead on the dorsal side of the spinal cord. The lead is then connected to an outside stimulator. The patient controlled the frequency of stimulation from 5 Hz to 1400 Hz and the intensity from 0 V to 10 V. Patients were instructed to adjust the frequency and amplitude of the impulses as they saw fit. Since all pain relieving drugs were halted for the study, the electrical current was the only means for reducing pain. The findings demonstrated that ESCS is an effective pain management technique for diabetics with peripheral neurpathy. ESCS is also effective for treating other people with Chronic Pain Syndrome, associated with patients suffering from stroke, multiple sclerosis, trauma, and other spinal cord disorders (Tesfaye et al 1996; Casey, 1996).

Further study on the neural level has been conducted in relation to a substance Substnce P (SP), which is released in the spinal cord as a response to painful stimuli. Receptor sites for SP were not just blocked, as in older studies, but killed altogether by the experimenters in this experiment performed on rats. This seemed to have a positive effect, however, future studies involving humans may be difficult; the conseqeunces of the permanent removal of SP receptor sites is uncertain (Mantyh, Rogers, Honore, Allen, Ghilardi, Li, Daughters, Lappi, Wiley, & Simone, 1997).

Another method of pain management which has been in use for 2,500 years in China and is just now beginning to gain acceptance in the West is acupunture. Based on the principle that there are patterns of energy flow that are disrupted by disease, acupuncture utisizes the insertion of fine needles to correct the imbalances of flow. A more scientifc explanation has been offered by Goldstein (1999). The needles are inserted and produce the analgesic effect because of the gate control theory, a system of excitatory and inhibitory cells that "open" or "close" the pain gate. The needles may activate the cells that inhibit pain. However, the real nature of acupunture is still unknown. There is much debate about it amongst the medical community in the United States. One camp tentatively believes in its uses, and the other thinks that it is the result of suggestion and could therefore be dangerous. Whteher or not this is the case, there still remains the problems of deciding when to use acupuncture, how to train for it, and how to certify the trainees (Marwick, 1997).

A more psychological approach to the problem of controlling pain is the (approved) use of nondirective suggestions. Imbedded in a neutral text, the suggestions in an experiment were introduced in order to influence pain tolerance, pain threshold, and pain intensity perception. The subjects in the experiment listend to a 20-minute tape on pain theory in which the statements that pain control was easy and that one should recall the effects of analgesic drugs were made. Pain tolerance and thresholds were measured. The group that received the suggestions had significantly prolonged pain tolerance, according to the results. The discussion section put forth the theory that this method of pain management may be effective for short lasting medical procedures but that relxation and imagery might be more efficacious for long-term amd chronic pain. Hypnosis and other forms of altered consciousness are also cited as possibly haviing an effect on pain threshholds, as well (Neumann, Kugler, Seelbach, & Kruskemper, 1997).

In the same line of work is a study about mood and pain tolerance (Weisenberg, Raz, & Hener, 1998). A desired mood is induced by means of subjects watching a either a humorous, holocaust, or neutral film in 15, 30, or 45 minute lengths. The results concluded that no matter which subject was presented, the longer movies had more effect than the shorter length film. Although the effects of watching the movies took about 30 minutes to manifest physiologically, the subjects then performed with greater pain tolerance than the original baseline. This method ties in with the above non-directive suggestion tecnique. It follows, then, that this method of pain management may not be too helpful in long-term or chronic patients, but good for shor-term procedures.

Further research is being done on gene transfer and the implantation of genetically engineered cells, as well as subtances known as noci-toxins (Caudle, 1997). With the increased availability of something as efficacious as ESCS and the other treatments described here, chronic pain caused by diabetic neuropathy, chronic pain syndrome, and other disorders may well begin to be seen as a treatable conditions and not and certain doom of pain and sleepless nights. The harder reserachers work to find answers now, the better care can be taken of these unfortunate people in the future.

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