Sea snail toxins for chronic pain

Snails offer hope for pain sufferers

The humble but lethal sea snail may hold the key to a better life for thousands of chronic pain sufferers.

Researchers from the University of Queensland believe conotoxins contained in potentially deadly sea snail venom could be used to create a treatment to replace conventional pain relief drugs such as morphine.

Dr Jenny Ekberg said her research had shown the conotoxin could produce pain relief without side effects in animals.

However, the conotoxin is yet to be tested on humans and Dr Ekberg said it could be several years before the treatment was able to be produced in marketable quantities.

"It's working beautifully at the moment, we just have to learn to synthesize it properly so that we can get enough amounts to start chemical trials on humans," she said.

Dr Ekberg said the lack of side effects meant the conotoxin had the potential to completely revolutionise pain treatment for cancer patients and chronic and neuropathic pain sufferers.

"Unlike other anaesthetics, it's very specific against the pain and doesn't cause any side effects - it's the first time anyone has discovered anything like this," she said.

Conventional medicines such as morphine can cause a range of unpleasant side effects, including nausea, vision and movement defects and drowsiness.

These symptoms often rendered sufferers unable to work and could lead to depression and, in some cases, suicide, Dr Ekberg said.

"I've met people with this, it's really horrible ... neuropathic pain, which is caused by damaged nerves, not tissue, you have to live with forever," she said.

If the research proves successful Dr Ekberg hopes the treatment will allow sufferers to live normal lives and continue working.

She believed the treatment would initially be administered through hospitals but hoped patients would eventually be able to inject it themselves at home.

© 2006 AAP

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What this is all about

Welcome to my pain for philosophers blog. Here's a bit about what you're looking at:

I'm a philosopher working on issues involving pain. That requires knowing quite a bit about what pains are. I thus try to keep up with the pain science literature, and created this blog to collect excerpts of articles relevant to philosophy of mind, philosophical psychology, cognitive science, value-theory, and applied ethics. I'm particularly keen on studies concerning the relationships between gender and pain; the role of depression, anxiety, and other affective disorders in pain; and the ways caregivers' attitudes influence their patients' pain and recovery.

After I started the site, I noticed that many of you find your way here from Google searches on pain and palliative medicine. And several websites geared toward pain patients and their families occasionally link here. Thus I've expanded my focus to include information about advances in pain care and in the understanding of common chronic pain conditions.

I hope you'll find this material helpful, if a bit technical. Please email me if you see something you'd like translated into English. Of course, I'm neither a doctor nor a lawyer, so I'm not offering anything here as medical or legal advice.

I'd greatly appreciate your bringing anything pain-related you may happen across to my attention. Also, if there is some topic or issue which especially interests you, please let me know. I'll try to do some digging.

You can email me at doloric@gmail.com

--Adam

*You'll notice that posting here comes in fits and starts. I try to survey the journals at least once a month, but that unfortunately doesn't happen in extremely busy months. You might therefore find it useful to subscribe to the XML feed to be updated when I post.

Back to the site.

Fear and anxiety's effects on pain-thresholds

Fear and anxiety: divergent effects on human pain thresholds
Rhudy, et. al.
Abstract
Animal studies suggest that fear inhibits pain whereas anxiety enhances it; however it is unclear whether these effects generalize to
humans. The present study examined the effects of experimentally induced fear and anxiety on radiant heat pain thresholds. Sixty male and
female human subjects were randomly assigned to 1 of 3 emotion induction conditions: (1) fear, induced by exposure to three brief shocks;
(2) anxiety, elicited by the threat of shock; (3) neutral, with no intervention. Pain thresholds were tested before and after emotion induction.
Results suggest that ®ndings from animal studies extend to humans: fear resulted in decreased pain reactivity, while anxiety led to increased
reactivity. Pain rating data indicated that participants used consistent subjective criteria to indicate pain thresholds. Both subjective and
physiological indicators (skin conductance level, heart rate) con®rmed that the treatment conditions produced the targeted emotional states.
These results support the view that emotional states modulate human pain reactivity. q2000 International Association for the Study of Pain.
Published by Elsevier Science B.V.
Pain 84 (2000) 65-72
PII: S0304-3959(99)00183-9
Categories: Fear,, Anxiety,, Stress-analgesia, Pain-threshold

Capsaicin undermines the effectiveness of vaginal self-stimulation

Following on the present theme of the analgesic effects of vaginal selt-stimulation:

Inverse relationship between intensity of vaginal self-stimulation-produced analgesia and level of chronic intake of a dietary source of capsaicin
Beverly Whipple, Margarita Martinez-Gomez, Laura Oliva-Zarate, Pablo Pacheco, and Barry R. Komisaruk
Abstract: Women who chronically ingest a diet rich in capsaicin, the pungent ingredient in hot chili peppers, showed a significantly lower magnitude of analgesia in response to vaginal self-stimulation than women with relatively low or medium levels of ingestion. Vaginal self-stimulation-produced analgesia was quantified by measuring (on the hand) pain detection thresholds, pain tolerance thresholds and tactile thresholds. Whereas vaginal self-stimulation produced a 32.6–43.8% increase in pain detection and pain tolerance thresholds in the low chili diet group, it produced only a 2.3–7.3% increase in these measures in the high chili diet group. The medium chili diet group showed an intermediate effect on the pain thresholds. Tactile thresholds were not increased by the vaginal self-stimulation. Baseline (no stimulation) pain thresholds did not differ significantly among the three groups. These findings are consistent with earlier studies in laboratory rats, in which capsaicin administered neonatally abolished vaginal stimulation-produced analgesia, but did not affect baseline pain thresholds to mechanostimulation.

LInk

Categories: Analgesia, Gender, Sex_pain, Vaginal_stimulation

Analgesia produced by copulation in rats

Momentary analgesia produced by copulation in female rats
P. Gómoraa, C. Beyera, G. González-Mariscala and B. R. Komisarukb

Abstract
To assess possible changes in nociception during copulation in estrous rats, electric shocks that were 20% suprathreshold for eliciting vocalization in response to tail shock (STS), were applied to thetail before the initiation of copulation and, thereafter coincident with the onset of mounting bouts by the male (Experiment 1). Females vocalized significantly less during non-intromittive mounts (M; P 0.001), intromissions (I; P < 0.001), and ejaculation (E; P < 0.01) than before the initiation of copulation. In order to assess the importance of vaginal stimulation (VS) by penile insertion during mating, in Experiment 2 30% STS were applied 300–400 ms after the initiation of mounting to ensure that the stimulation fell within the period of penile insertion ocurring during I and E. M failed to significantly inhibit vocalizations to 30% STS. By contrast, both I and E markedly inhibited vocalizations in response to STS. This effect was transitory since subjects (Ss) vocalized to nearly all 30% STS when delivered 15 s after I or E. Copulatory analgesia (CA) was abolished by the bilateral transection of the pelvic and hypogastric nerves but not by the transection of the pudendal nerve (Experiment 3). The magnitude of CA was calibrated by determining the doses of morphine sulfate (MS) required to produce similar decrements in vocalization to STS. The analgesic effects of I and E were equivalent to more than 10 mg/kg and 15 mg/kg, respectively, of MS (Experiment 4). Pelvic-hypogastric neurectomy, but not pudendal neurectomy, also significantly reduced the effect of VS on facilitating lordosis, inducing immobilization and hind leg extension, and blocking the withdrawal reflex to foot pinch (Experiment 5). Pelvic-hypogastric neurectomy also significantly reduced sexual receptivity, as indicated by a reduction in the number of I that the females in this group received.

DOI

Categories: Gender, Pain_and_sex, Analgesia, Stress_analgesia

Vaginal stimulation and pain threshold

Elevation of pain threshold by vaginal stimulation in women.
Whipple B, Komisaruk BR.

Abstract
In 2 studies with 10 women each, vaginal self-stimulation significantly increased the threshold to detect and tolerate painful finger compression, but did not significantly affect the threshold to detect innocuous tactile stimulation. The vaginal self-stimulation was applied with a specially designed pressure transducer assembly to produce a report of pressure or pleasure. In the first study, 6 of the women perceived the vaginal stimulation as producing pleasure. During that condition, the pain tolerance threshold increased significantly by 36.8% and the pain detection threshold increased significantly by 53%. A second study utilized other types of stimuli. Vaginal self-stimulation perceived as pressure significantly increased the pain tolerance threshold by 40.3% and the pain detection threshold by 47.4%. In the second study, when the vaginal stimulation was self-applied in a manner that produced orgasm, the pain tolerance threshold and pain detection threshold increased significantly by 74.6% and 106.7% respectively, while the tactile threshold remained unaffected. A variety of control conditions, including various types of distraction, did not significantly elevate pain or tactile thresholds. We conclude that in women, vaginal self-stimulation decreases pain sensitivity, but does not affect tactile sensitivity. This effect is apparently not due to painful or non-painful distraction.

Pain. 1985 Apr;21(4):357-67
Categories: Gender, Pain_sex, Pain_threshold

Breeding season affects stress-induced analgesia in mice

Sex differences in the expression and antagonism of swim stress-induced analgesia in deer mice vary with the breeding season
Kavaliers and Galea

Summary (you might want to skip to the underlined part)
Swim stress-induced analgesia (SSIA) was examined in photoperiodically induced 'breeding'
(reproductive) and 'non-breeding' (non-reproductive) adult male and female deer mice, Perornyscus maniculatus.
Nociceptive responses (50°C, hot-plate) of breeding and non-breeding deer mice were determined after either a 1-
or 3-min swim in 20°C water. The 1-min swim induced an immediate and relatively short-lasting naloxone (1.0
mg/kg) insensitive 'non-opioid'-mediated SSIA that was antagonized by the N-methyl-D-aspartate (NMDA)
antagonist, MK-801 (0.10 mg/kg) in all of the groups of mice except the breeding (reproductive) females. Breeding
females displayed a non-opioid analgesia that was insensitive to MK-801. The 3-min swim induced a relatively more
prolonged mixed opioid and 'non-opioid' SSIA of which the initial portion was sensitive to antagonism by MK-801
in all groups of the mice except the breeding females, while the latter portion (15 min after swim) was reduced by
naloxone in all of the groups of mice. Overall, the breeding males displayed greater levels of SSIA than the breeding
females, with no consistent sex differences in the non-breeding mice. Within sexes, the breeding males displayed
greater levels of opioid and non-opioid SSIA than the non-breeding males, while the non-breeding females
displayed greater levels of SSIA than the breeding females. These results show that both sex and reproductive status
affect the expression and neurochemical mediation of non-opioid SSIA. These findings also suggest that reproductive
females may have an unique or novel hormonally (estrogen) dependent mechanism associated with the
expression of SSIA
(c) 1995 Elsevier Science

Pain 65 (1995) 327-334
Categories: Pain_and_gender, Stress-induced_analgesia

Vaginal pain during sex

Vestibular tactile and pain thresholds in pain with vulvar vestibulitis syndrome
Pukall, et al.

Abstract
Vulvar vestibulitis syndrome (VVS) is a common cause of dyspareunia** in pre-menopausal women. Little is known about sensory function
in the vulvar vestibule*, despite Kinsey's assertion that it is important for sexual sensation. We examined punctate tactile and pain thresholds
to modified von Frey filaments in the genital region of women with VVS and age- and contraceptive-matched pain-free controls. Women
with VVS had lower tactile and pain thresholds around the vulvar vestibule and on the labium minus than controls, and these results were
reliable over time. Women with VVS also had lower tactile, punctate pain, and pressure-pain tolerance over the deltoid muscle on the upper
arm, suggesting that generalized systemic hypersensitivity may contribute to VVS in some women. In testing tactile thresholds, 20% of trials
were blank, and there was no group difference in the false positive rate, indicating that response bias cannot account for the lower thresholds.
Women with VVS reported significantly more catastrophizing thoughts related to intercourse pain, but there was no difference between
groups in catastrophizing for unrelated pains. Pain intensity ratings for stimuli above the pain threshold increased in a parallel fashion with
log stimulus intensity in both groups, but the ratings of distress were substantially greater in the VVS group than in controls at equivalent
levels of pain intensity. The data imply that VVS may reflect a specific pathological process in the vestibular region, superimposed on
systemic hypersensitivity to tactile and pain stimuli.
(c) 2002 International Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved

Pain 96 (2002) 163-175
PII: S0304-3959(01)00442-0

* The vulvar vestibule is located posterior to the glans clitoris between the labia minora, and contains the vaginal and urethral openings
and the ducts of the Bartholin’s glands.

**Dyspareunia: Painful sexual intercourse.

Categories: Pain_and_sex
.

Sexual headaches

My new favorite word of the day:

Coital Cephalalgia (headache during or after sex)

Of course, since sex has been shown to reduce regular headaches in normal people, pre-coital cephalalgia is not as serious a condition...

The cerebral hemodynamics of headache associated with sexual activity
Evers, et al.

Abstract
Headache associated with sexual activity is an idiopathic headache disorder and regarded to be a vascular headache but no pathophysiological
studies have been performed to date to elucidate the underlying mechanisms. We investigated 12 patients with the explosive type of
sexual headache according to the criteria of the International Headache Society during a headache-free state by means of acetazolamide test
and of stress Doppler sonography. Twelve age-matched migraine patients and 14 healthy subjects served as control groups. Changes of blood
pressure, cerebral blood flow velocity (CBFV), and pulsatility index (PI) were evaluated. Patients with sexual headache showed a significantly
higher increase of blood pressure during standardized physical exercise as compared to healthy subjects and migraine patients.
Changes of CBFV by physical exercise were not different between the three examination groups. After 1 g acetazolamide, CBFV showed a
significantly higher increase in patients with sexual headache (plus 66% ^ 16%) than in healthy subjects (plus 46% ^ 18%), and PI showed a
significantly lower decrease as compared to healthy subjects and migraine patients. These data suggest that in patients with sexual headache
the metabolic rather than the myogenic component of the cerebral vasoneuronal coupling is impaired.
q 2002 International Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved

Pain 102 (2003) 73-78
DOI
Categories: Headache, Pain_and_sex

Pain and cocaine

Blockade of tolerance to morphine analgesia by cocaine
Misra, et al.

Abstract
Tolerance to morphine was induced in male Sprague-Dawley rats by s.c. implantation of a morphine base pellet (75 mg) on the first and second day and determining the magnitude of tolerance 72 h after the first implant by s.c. injection of a test dose of morphine (5 mg/kg). Implantation of a cocaine hydrochloride pellet (25 mg), concurrently with morphine pellets or of a cocaine hydrochloride (50 mg) pellet after the development of tolerance, blocked both the development and expression of morphine analgesic tolerance. In morphine-pelleted animals pretreatment for 3 days with desipramine or zimelidine or phenoxybenzamine but not haloperidol produced no significant morphine tolerance. Pretreatment with a combination of desipramine and zimelidine, however, was as effective as cocaine in blocking morphine tolerance. ?-Methyl-p-tyrosine methyl ester counteracted the effect of cocaine in blocking morphine tolerance and potentiated the tolerance development. Blockade of morphine tolerance by cocaine was reinforced and facilitated by pretreatment with fenfluramine or p-chlorophenylalanine ethyl ester and to a lesser extent by clonidine and haloperidol. Acute administration of fenfluramine or zimelidine or a combination of desipramine and zimelidine or ?-methyl-p-tyrosine methyl ester or p-chlorophenylalanine ethyl ester did not significantly affect morphine analgesia. The study suggests an important role of the concomitant depletion of both central noradrenaline and serotonin in the blockade of morphine tolerance by cocaine and stresses the importance of the counter-balancing functional relationship between these two neurotransmitters in the central nervous system.
(c) 1989 Elsevier Science

DOI
Categories: Morphine, Analgesia, Pain_and_cocaine

Exercise-induced stress analgesia?

Exercise-induced analgesia: fact or artifact?
Padawer and Levine

Abstract
This study critically examines the reported exercise-induced previous termanalgesianext term effect in view of the potential previous termstressnext term-induced previous termanalgesianext term of pain testing itself. Two designs were used to test whether previous findings of previous termanalgesianext term were induced by the exercise procedures or by the previous termstressnext term of the pain testing procedures themselves used in such experiments. In the first design, post-test cold pressor pain ratings were obtained from college students following exercise (bicycle ergometry) and two control tasks (minimal exercise and non-exercise). No significant differences between these groups were found. In the second design, exercise and non-exercise groups pre-exposed to cold pressor pain testing were compared to groups that were not pre-exposed to pain testing. There were no significant effects for exercise; however, significant previous termanalgesianext term effects for pain test pre-exposure were demonstrated. Therefore previous research claiming exercise-induced previous termanalgesianext term may have confounded the effects of exercise with the effects of pre-exposure to pain testing itself.
(c)1992 Elsevier Science

Pain 48 (2) 1992, 131-135
http://dx.doi.org/10.1016/0304-3959(92)90048-G
Categories: Stress-analgesia,, Pain_and_exercise

Age differences in endogenous analgesia

Age-related differences in the endogenous analgesic response to repeated cold water immersion in human volunteers
Washington, et al.

Abstract
Recent animal studies using stress-induced analgesia have suggested a general age-related decline in endogenous pain inhibitory systems.
The aim of the current study was to examine age-related differences in the magnitude of endogenous analgesia in human volunteers, using
psychophysical measures of neuroselective electrical, and thermal CO2 laser induced pain thresholds, before, immediately after and 1 h after
repeated cold water immersion of the hand. Sensory detection thresholds did not differ between age groups indicating that the functional
integrity of primary afferent sensory ®bres appears to be intact in older people. Consistent with many previous studies, older adults required a
higher intensity of noxious stimulation in order to ®rst report the presence of pain. The cold water immersion task was effective in eliciting a
powerful analgesic response, regardless of age; pain thresholds were shown to increase by up to 100% immediately after the cold pressor test.
This effect was relatively transient with thresholds returning to baseline within 1 h. The magnitude of analgesic response, however, was found
to be signi®cantly less in older people. Age differences in the ef®cacy of endogenous analgesic systems may be expected to reduce the ability
of older adults to cope with severe persistent pain states and may help explain some of the variation in the literature on pain report.
(c) 2000 International Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved.

Pain 89 (2000) 89-96
PII: S0304-3959(00)00352-3
Categories: Pain_and_age,, Endogenous_analgesia,, Pain_threshold

Negative affect and pain

Negative affect: effects on an evaluative measure of human pain
Rhudy, et al.

Prior work indicates that exposure to fear-inducing shock inhibits finger-withdrawal to radiant heat in humans (hypoalgesia), whereas
anxiety induced by threat of shock enhances reactivity (hyperalgesia; Pain 84 (2000) 65–75). Although finger-withdrawal latencies are
thought to reflect changes in pain sensitivity, additional measures of pain are needed to determine whether pain perception is altered. The
present study examined the impact of negative affect on visual analog scale (VAS) ratings of fixed duration thermal stimuli. One hundred
twenty-seven male and female human subjects were randomly assigned to one of three emotion-induction conditions: (1) negative affect
induced by exposure to three brief shocks; (2) negative affect elicited by the threat of shock without presentation; and (3) neutral affect, with
no intervention. VAS ratings were tested before and after emotion-induction. Results suggest that both negative affect manipulations reduced
pain. Manipulation checks indicated that the emotion-induction treatments induced similar levels of fear but with different arousal levels.
Potential mechanisms for affect induced changes in pain are discussed.
(c) 2003 International Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved.

Pain 104 (2003) 617-626
doi:10.1016/S0304-3959(03)00119-2

Categories: Fear,, Anxiety,, Stress-induced_analgesia,, Pain-modulation

Stress-induced analgesia

Cigarette smoking, stress-induced analgesia and pain perception in men and women
Girdler, et al.

Abstract
This study examined gender differences in smoking-related analgesia and stress-induced analgesia (SIA), as a function of pain modality. Forty men (20 smokers, 20 nonsmokers) and 37 women (17 smokers) were tested twice for pain sensitivity to tourniquet ischemia, thermal heat, and cold pressor tests; once following mental stress and once following rest control, counterbalancing order. Cardiovascular and neuroendocrine responses to mental stress were also examined. While expected gender differences in pain sensitivity were observed, women smokers had greater threshold and tolerance times to ischemic pain than women nonsmokers (P!0.05) when pain testing followed rest. Male smokers had greater threshold and tolerance to cold pressor pain than male nonsmokers (P!0.05) after both rest and stress Only women showed evidence for SIA, since women nonsmokers demonstrated greater ischemic pain threshold and tolerance following mental stress versus rest (P!0.05), and all women reported lower thermal heat pain unpleasantness after stress versus rest (PZ0.05). Only nonsmokers showed expected inverse relationships between sympathetic and hypothalamic–pituitary–adrenal (HPA) axis reactivity measures and sensitivity to pain. Smokers showed evidence for blunted HPA-axis function at rest and stress. These results indicate that analgesia related to both being a smoker and stress is influenced by gender and pain modality. The reduced pain perception in smokers and absence of relationships between endogenous pain regulatory mechanisms and pain sensitivity may reflect a maladaptive response to chronic smoking.
(c) 2005 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Pain 114(2005) 372-385
doi:10.1016/j.pain.2004.12.035

Categories: Stress-induced, analgesia

More on NSAID and cox-2 dangers

Old, 'safe' painkillers found to cause same heart ills as new

ANDRÉ PICARD

From Wednesday's Globe and Mail

Some older, "safe" painkillers appear to cause the same heart problems as the much-scrutinized and discredited painkiller Vioxx, according to new research, which raises new concerns about the safety of treatments for chronic painful conditions such as arthritis.

At the same time, Vioxx itself appears to have even more side effects than previously believed, according to research published on-line yesterday by the Journal of the American Medical Association.

Three articles in JAMA feature some striking conclusions, including:

Older painkillers such as diclofenac sharply increase the risk of heart attacks in regular users.

Other traditional painkillers including meloxicam, indomethacin and perhaps even over-the-counter products such as ibuprofen may also increase the risk of heart disease.

Rofecobix (brand name Vioxx) -- already pulled from the market because it increased the risk of heart attacks and stroke -- may also cause kidney damage and heart arrhythmia (abnormal heart rhythm).

Celecoxib (brand name Celebrex) -- which is still available -- may cause heart problems, but only when taken at relatively high doses of 200 milligrams or more daily.

The painkiller naproxen does not reduce the risk of cardiovascular problems, as previous research has suggested, but it does not cause additional risk, either.

More than 30 million people worldwide take these medications, known as non-steroidal anti-inflammatory drugs, for the daily treatment of pain and inflammation. So, the potential repercussions of the findings are widespread.

NSAIDs are already known to cause gastrointestinal problems, and adding heart problems to the mix could deter patients from their use.

"It's important not to get too alarmed by these findings," said David Juurlink, a scientist at the Toronto-based Institute for Clinical Evaluative Sciences.

He said the news that taking diclofenac can increase risk by 40 per cent may alarm some users, but that they need to bear in mind that individual risk depends on dose and cardiovascular risk factors.

"All drugs have risks and benefits and data like this force us to scrutinize our behaviour," Dr. Juurlink said.

One study, led by Jingjung Zhang of Harvard Medical School in Boston, looked at the safety of cyclooxygenase 2 (cox-2) inhibitors such as Vioxx, Celebrex and valdecoxib (brand name Bextra, it has also been withdrawn from the market). The researchers combined the findings of 114 studies involving more than 115,000 patients and found that those taking Vioxx had markedly higher rates of kidney problems and arrhythmia.

Patients taking the other drugs did not have the same problems, leading Dr. Zhang to conclude that there is "no cox-2 inhibitor class effect."

The second study, led by Patricia McGettigan of the University of Newcastle in New South Wales, Australia, examined the cardiovascular risks associated with a broad range of painkillers, new and old. The review of 17 studies included more than 75,000 patients taking cox-2 inhibitors and 375,000 taking traditional NSAIDs.

Patients taking Vioxx saw their risk of heart attack double, while those taking diclofenac saw their risk increase 40 per cent. Ibuprofen increased risk by 7 per cent, a virtually negligible effect.

David Graham of the U.S. Food and Drug Administration (but who has clashed publicly with his employer about its policies), said in an editorial published by JAMA that, for patients with arthritis and other chronic conditions that require pain relief "naproxen appears to be the safest NSAID choice."

He said that while the data on Celebrex look relatively good, it is no better than traditional NSAIDs, so its use is not justified.
© Copyright 2006 Bell Globemedia Publishing Inc.

Link

The effect of dread on pain preferences

Straight from the neuroeconomists to you:

Research Shows Anticipating Pain Hurts
By LAURAN NEERGAARD AP Medical Writer

May 04,2006 | WASHINGTON -- Anyone who's ever taken a preschooler to the doctor knows they often cry more before the shot than afterward. Now researchers using brain scans to unravel the biology of dread have an explanation: For some people, anticipating pain is truly as bad as experiencing it.

How bad? Among people who volunteered to receive electric shocks, almost a third opted for a stronger zap if they could just get it over with, instead of having to wait.

More importantly, the research found that how much attention the brain pays to expected pain determines whether someone is an "extreme dreader" -- suggesting that simple diversions could alleviate the misery.

[....]

Standard economic theory says that people should postpone bad outcomes for as long as possible, because something might happen in the interim to change improve the outlook.

In real life, the "just get it over with" reaction is more likely, said Berns, a professor of psychiatry and behavioral sciences. He offers a personal example: He usually pays credit card bills as soon as they arrive instead of waiting until they're due, even though "it doesn't make any sense economically."

So Berns designed a study to trace dread inside the brain. He put 32 volunteers into an MRI machine while giving them a series of 96 electric shocks to the foot. The shocks varied in intensity, from barely detectable to the pain of a needle jab.

Participants were told one was coming, how strong it would be, and how long the wait for it would be, from 1 to 27 seconds.

Later, participants were given choices: Would they prefer a medium jolt in 5 seconds or 27 seconds? What about a mild jolt in 20 seconds vs. a sharp one in 3 seconds?

When the voltage was identical, the volunteers almost always chose the shortest wait. But those Berns dubbed "extreme dreaders" picked the worst shock if it meant not having to wait as long.

The MRI scans showed that a brain network that governs how much pain people feel became active even before they were shocked, particularly the parts of this "pain matrix" that are linked to attention -- but not brain regions involving fear and anxiety. The more dread bothered someone, the more attention the pain-sensing parts of the brain were paying to the wait.

In other words, the mere information that you're about to feel pain "seems to be a source of misery," George Lowenstein, a specialist in economics and psychology at Carnegie Mellon University, wrote in an accompanying review of the work.

"These findings support the idea that the decision to delay or expedite an outcome depends critically on how a person feels while waiting," Lowenstein added.

© 2006 The Associated Press.
Link

Categories: Attention, Anticipation

Milimeter wave therapy

A Soviet technology developed during the Cold War to keep short-range military communications secure may someday provide relief from hard-to-treat conditions such as nerve pain, intense itching, and nausea caused by chemotherapy. And, with the support of a $4 million grant from the National Institutes of Health, Temple University School of Medicine scientists are the only group in the United States now investigating this alternative therapy.
[....]
Millimeter wave therapy, which directs a low-intensity electromagnetic beam to the skin, has been used for more than 25 years in Eastern Europe, where it is credited with alleviating more than 50 different conditions, ranging from heart disease to skin wounds and even cancer. Doctors there believe that the waves boost the immune system, act as an anti-inflammatory, and provide sedation and pain relief, all with virtually no side effects.

While the therapy remains largely unknown in the West, Marvin Ziskin, M.D., professor of radiology and medical physics at Temple, first encountered it in the early 1990s on a trip to the former Soviet Union.
[....]
"We found that millimeter waves reduce pain in laboratory animals, stimulate the immune system and slow the progression of skin melanomas, without damage to the skin or other harmful side effects. It's a painless, non-invasive, easily tolerated therapy," said Ziskin.
[....]
Eastern European doctors directly apply millimeter waves to skin lesions and acupuncture points. It's also common to beam them onto a diseased organ or a troublesome joint.

Absorbed very rapidly by the skin, millimeter waves appear to initiate a response in peripheral nerve endings. Ziskin's working hypothesis is that as waves reach these nerve endings, a signal is conveyed to the nervous system to modulate neural activity, in the process activating various biological effects. In one possible scenario, millimeter waves trigger the release of opioids that are known to be involved in sedation, pain relief and modulation of the immune system.

"Applying the waves to points on the skin with the highest density of nerves appears to work best. Using this approach, under strict double-blind conditions, we've produced evidence of pain relief in experimental animal models as well as in a small group of human volunteers," said Ziskin.
LInk

Categories: Analgesics, Chronic_pain

Obese people more sensitive to pain?

COLUMBUS , Ohio – Obese people may be more sensitive to pain than people who aren't obese, a new study suggests.

All of the older adults who completed the study had osteoarthritis of the knee, a disease that causes inflammation and extreme pain in the knees.

Participants were given a mild electrical stimulation on their left ankle to measure their pain reflex. The stimulus was given before and after the participants took part in a 45-minute coping skills training session that included a progressive muscle relaxation exercise.

The obese patients showed a greater physical response to the electrical stimulation than did the non-obese people, both before and after the training session. This indicates they had a lower tolerance for the painful stimulation despite reporting, in questionnaires, that they felt no more pain than non-obese people.

"The relaxation procedure helped both groups cope with pain," said Charles Emery, the study's lead author and a professor of psychology at Ohio State University. "Additionally, our tests showed both groups had higher physical pain thresholds after the relaxation session. But the obese participants still had a lower threshold for tolerating the pain."

"This is important because if an obese person begins an exercise program, he may not cognitively experience pain when in fact it is hurting the body on some level," Emery said. "That could lead to severe pain down the road."
[....]
But they were particularly interested in seeing how the obese group responded to pain; according to Emery, a small number of studies have looked at pain sensitivity in obese people, but many of these studies report conflicting results.

"Some studies say that obese people are more tolerant of pain, while other studies say they are less tolerant," Emery said.

About a third of the study's 62 participants were obese. Researchers determined who was obese based on participants' body mass index (BMI) scores, which relates height to weight. Obese patients in this study had a BMI greater than 30 but less than 35. (Scores higher than 35 are considered morbidly obese.)

The participants underwent two rounds of electrical stimulation – once before, and once after a 45-minute training session where they learned different ways of coping with pain, including instruction in progressive muscle relaxation therapy.
Link

Categories: Pain_tolerance

Another acetaminophen warning

Wow. Acetaminophen overdose causes 40-50% of acute liver failure cases.

Medical News Today
Expert Warns Of Overuse Of Over-the-Counter Pain Medication
13 Mar 2006

Acetaminophen is generally a safe and effective medication, one that is used by millions of people every day to treat minor aches and pains and to diminish fevers. It might surprise many people, then, that overdoses of Tylenol and other products containing acetaminophen account for a staggering 40 percent to 50 percent of all acute liver failure cases each year in the United States.

Of those cases, nearly half are unintentional overdoses, a recent finding that many experts say is alarming. That's why people need to take extra care not to take even a little more of the medication than the recommended dose during any 24-hour period.

“My overall recommendation for people using Tylenol is that it is a safe drug,” says Robert J. Fontana, M.D., associate professor of internal medicine at the University of Michigan Medical School, member of the Gastroenterology Division and medical director of liver transplantation. “However, like most other things in life, too much of a good thing can be bad for you.”

For instance, an adult should not take more than eight Tylenol Extra Strength pills, which contains 500 milligrams per tablet, in a 24-hour period (i.e. the maximum daily dose is 4,000 milligrams per day). Exceeding that dosage, could lead to inadvertent liver or kidney damage in some people, Fontana says.

Fontana notes that damage occurs acutely rather than chronically - in other words, it isn't the dosage of the medicine a person takes over several weeks that is the problem, it is the daily dose that may lead to liver toxicity.

Here's how the problem occurs: Whenever you take a medication, your liver typically is involved with metabolizing, or eliminating, the drug from your system. When you take too much acetaminophen, you overwhelm your body's ability to eliminate the medication safely. High levels of the medication can build up in the blood, and that can damage liver cells that are trying to metabolize the drug, which can lead to liver injury, Fontana says.

A multicenter study that the U-M Health System recently participated in indicated that about half of acetaminophen overdoses that resulted in liver failure were unintentional, something the researchers refer to as “therapeutic misadventures.”

“What I mean by that is that individuals were taking acetaminophen for some type of medical problem - such as a headache, back pain or the flu - inadvertently took too much and subsequently developed liver failure,” Fontana says. “If you go to a drug store, as many as 150 products that consumers can buy without a prescription have acetaminophen in them.”

It doesn't take much for someone to consume a toxic dose of acetaminophen. For instance, consider someone who is taking an over-the-counter product that helps stop sneezing or coughing that contains 350 to 500 milligrams of acetaminophen per dose, with one or two doses every four hours. If that person also has a headache or muscle aches, he or she may take some acetaminophen and quickly go into the potentially toxic range.

In addition to the possible overuse of acetaminophen when taking non-prescription medications, another potential hazard occurs among people who take Tylenol or a similar medication in addition to a prescription pain reliever that also contains acetaminophen, such as Vicodin or Darvocet.

“We're particularly concerned that health care providers may not be aware of this, and when they prescribe these potent pain medicines, there needs to be greater education of our patients of the total dose it is safe for them to take,” Fontana says. “In addition, patients with severe or chronic pain may take increasing doses of prescription narcotics and not be aware that they contain 500 to 750 milligrams of acetaminophen in each tablet.”

This is a concern not only for adults, but also for children because there's been a shift toward using acetaminophen products for babies and children. “As parents,” Fontana says, “we need to be aware of this so that we avoid inadvertent toxicity in trying to treat our children at home when they have high fevers.”

Other factors can compound a person's likelihood of developing liver damage from overuse of acetaminophen. Information increasingly suggests that if you drink alcohol daily or on a chronic basis, that may predispose you to liver damage from acetaminophen, Fontana says. That may occur due to development of nutritional deficiencies or a reduction in the level of the detoxifying enzymes in your liver as a result of drinking, he notes.

The U-M Health System and other institutions are involved with ongoing studies of acute liver failure and drug-induced liver injury. In addition to exploring and identifying the causes and natural history of acute liver failure, researchers also are doing exploratory work on a potential genetic predisposition to acute liver failure.

A recent study also described a new blood test to help identify patients with acetaminophen liver toxicity so that treatment can be started rapidly. “This new blood test holds great promise for identifying patients early on prior to the development of life-threatening liver failure,” Fontana says.

Facts about acetaminophen and liver damage:

-- Before taking acetaminophen, experts recommend that you tell your doctor if you have ever had liver disease or if you drink alcohol daily or on a chronic basis.

-- One way to prevent acetaminophen-related liver toxicity is to carefully read the labels on all medications so you are aware of their acetaminophen content (both prescription and over-the-counter).

-- Acetaminophen is found in Tylenol-brand products, but it also is found in numerous other brand-name medications, including some varieties of Excedrin, FeverAll, Genapap, Percocet and more. It also is included in combination products, such as Midol Teen Menstrual Formula Caplets containing Acetaminophen and Pamabrom. Many prescription pain relievers also contain acetaminophen, such as Lorcet Plus, Darvocet and Vicodin.

-- In case of an overdose, call your local poison control center at 1-800-222-1222. If the victim is not breathing, call 911.

-- Remember to keep medications locked up or out of reach of children.

-- Do not take the full day's dose of acetaminophen at one time; space it out over the course of the day.

Written by Katie Gazella
Link

Categories: acetaminophen

Fentanyl

Another entry in my occasional series: Meet your analgesics (and anesthetics in this case)

Fentanyl



What it is:

First synthesized in Belgium in the late 1950s, fentanyl, with an analgesic potency of about 80 times that of morphine, was introduced into medical practice in the 1960s as an intravenous anesthetic under the trade name of Sublimaze®. Thereafter; two other fentanyl analogues were introduced; alfentanil (Alfenta®), an ultra-short (5-10 minutes) acting analgesic, and sufentanil (Sufenta®), an exceptionally potent analgesic (5 to 10 times more potent than fentanyl) for use in heart surgery. Today, fentanyls are extensively used for anesthesia and analgesia. Duragesic®, for example, is a fentanyl transdermal patch used in chronic pain management, and Actiq® is a solid formulation of fentanyl citrate on a stick that dissolves slowly in the mouth for transmucosal absorption. Actiq® is intended for opiate-tolerant individuals and is effective in treating breakthrough pain in cancer patients. Carfentanil (Wildnil®) is an analogue of fentanyl with an analgesic potency 10,000 times that of morphine and is used in veterinary practice to immobilize certain large animals. Link

Wikipedia entry

Its use in chemical warfare:
Center for Nonproliferation Studies
The Moscow Theatre Seige

Categories: Fentanyl, Analgesics

Pain measurement

Some of the various tools for measuring pain:

The McGill Pain Questionnaire (the granddaddy of them all)
The Short-Form McGill Pain Questionnaire (the nice-uncle of them all)

The Brief Pain Inventory (long-form) (short-form)

A literature review (geared toward end-of-life issues)

A list from City of Hope with links

Categories: Pain_assessment, McGill_Pain_Questionnaire

Self-indulgence

In case you've been riveted to your seats these past few months, waiting to see if I get a job, the search is over.

Come this summer, PFP's world headquarters will be moving back to the City of Angels after experiencing 7-years of actual winter. I've been hired by Cal State University Northridge's philosophy department

I'm extremely happy since this was the job I really wanted. And when this blogger is happy, you all get more (about) pain.

Now, back to the pain and suffering.

Primer on pain

Just came across this online primer on pain physiology and psychology. I didn't get a chance to read the whole thing and so I can't vouch for it, but it seems pretty accessable and non-technical.

Categories: Links

Solicitiousness and pain, or: your blogger tries some research

Another favorite topic:

Solicitousness and chronic pain: a critical review
Toby RO Newton-John
Abstract: This article offers a critical review of the literature examining spouse responses to the pain behaviour of
chronic pain patients. An overview is given of 27 studies that have explored patient–spouse interactions
in chronic pain, together with a summary of the various .ndings. It is concluded that the body of research
is broadly supportive of the operant behavioural paradigm on which it has developed. Patients’ coping
with chronic pain is signi.cantly influenced by the ways in which those closest to them respond to their
expressions of discomfort. However, it is argued that the behavioural model alone is insuf.cient when
accounting for the complexity of pain couples’ interactions. The impact of the spouse’s response is mediated
by a range of cognitive and affective variables that have yet to be fully recognized in the research
literature. It is also argued that the operationalization of the construct of solicitousness, which is central
to research on chronic pain couples, is flawed. A number of suggestions for future theoretical and empirical
developments in this area are made.
Pain Reviews 2002; 9; 7-27

Being the dedicated scholar I am, I recently decided to see if solicitiousness had a similar effect in the short-term by breaking my ribs. Unfotunately, I've been a bit too dedicated to my research in the past. My wife has had to sit through too much blabber about solicitiousnes and pain, and therefore knows better than to pay attention to every whine.. So while I get plenty of sympathy, I still have to fetch my own Advil.

And I'm better-off for it.

Categories: Solicitiousness

CIPA

A nice resource of work on that perennial favorite of philosophers everywhere: congenital insensitivity to pain and anhidrosis (CIPA):
http://www.geometry.net/health_conditions/congenital_pain_insensitivity_page_no_2.php

Categories: Congenital_insensitivity, Links

A non-drug bibliography for palliative care

Good stuff:

http://www.cityofhope.org/prc/pdf/Non-Drug%20Bibliography.pdf

Categories: Palliative_care, Bibliography,Links

Attention and distraction (and some hypnosis)

And now some material on attention and distraction:

Effects of attentional focusing on pain perception
Britton W. Brewer and Paul Karoly
Abstract Two experiments were conducted to examine the hypothesized differential effectiveness of two attentional focusing strategies in pain perception. In the first experiment, subjects (72 male college students) rated their levels of pain after being exposed to either low- or high-intensity pressure stimulation for 75 s. Subjects were instructed to use either an external or internal focus of attention during the pain induction. Results revealed that external focusing was more effective for coping than internal focusing across both levels of stimulus intensity. The second experiment was a replication of the first, and featured bolstered internal focusing and stimulus intensity manipulations. Results showed that high-intensity stimulation produced higher pain ratings than did low-intensity stimulation for subjects in the internal focusing conditions, but not for those in the external focusing conditions. The findings support the power of distraction strategies for dealing with short-term pain with a rapid onset. Theoretical implications are discussed.
Motivation and Emotion 13(3), 193-203 DOI: 10.1007/BF00995535

Laser-evoked potentials to noxious stimulation during hypnotic analgesia and distraction of attention suggest different brain mechanisms of pain control
Marc Friederich, Ralf H. Trippe, Mustafa özcan, Thomas Weiss, Holger Hecht and Wolfgang H.R. Miltner

Psychological accounts of hypnosis have hypothesized that hypnosis and attention might share similar mechanisms and that hypnosis simply represents an extensive state of reduced attention. This assumption implies that reports of pain and electrocortical brain responses to painful stimulation should be similarly reduced when subjects are exposed to suggestions of hypnotic analgesia (HA) or requested to distract their attention from painful stimuli (distraction of attention: DA) as compared to a control condition (CC). To test this hypothesis, we recorded event-related electrical brain potentials to noxious laser-heat stimuli and pain reports during HA, DA, and CC from subjects highly susceptible to hypnotic suggestions. Pain reports were significantly reduced during HA and DA as compared to CC. The amplitudes of the late laser-evoked brain potential (LEP) components N200 and P320 were also significantly smaller during DA than during CC. However, no significant difference of these late LEP amplitudes was obtained for HA as compared to CC. Results indicate that hypnotic analgesia and distraction of attention represent different mechanisms of pain control and involve different brain mechanisms. Psychophysiology
Volume 38 Page 768 - September 2001 doi:10.1111/1469-8986.3850768

A Comparison of Distraction Strategies for Venipuncture Distress in Children
MacLaren and Cohen
Objective To compare the effects of two pediatric venipuncture distress-management distraction strategies that differed in the degree to which they required children's interaction. Methods Eighty-eight 1- to 7-year-old children receiving venipuncture were randomly assigned to one of three treatment conditions: interactive toy distraction, passive movie distraction, or standard care. Distress was examined via parent, nurse, self-report (children over 4 years), and observational coding. Engagement in distraction was assessed via observational coding.ResultsChildren in the passive condition were more distracted and less distressed than children in the interactive condition. Although children in the interactive condition were more distracted than standard care children, there were no differences in distress between these groups. Conclusions Despite literature that suggests that interactive distraction should lower distress more than passive distraction, results indicate that a passive strategy might be most effective for children's venipuncture. It is possible that children's distress interfered with their ability to interact with the distractor.
J. Pediatr. Psychol..2005; 30: 387-396. doi:10.1093/jpepsy/jsi062

Parents' Positioning and Distracting Children During Venipuncture
Effects on Children's Pain, Fear, and Distress
Kim Cavender, Melinda D. Goff, Ellen C. Hollon, Cathie E. Guzzetta,
The purpose of this study was to determine the effectiveness of parental positioning and distraction on the pain, fear, and distress of pediatric patients undergoing venipuncture. An experimental-comparison group design was used to evaluate 43 patients (20 experimental and 23 comparison) who were 4 to 11 years old. Experimental participants used parental positioning and distraction. All participants rated their pain and fear; parents and child life specialists (CLS) rated the child's fear, and CLS rated the child's distress. Self-reported pain and fear were highly correlated (p < .001) but not significantly different between the two groups. Fear rated by CLS (p < .001) and parents (p = .003) was significantly lower in experimental participants. Although no difference was found in distress between the two groups, a significant time trend was discovered (p < .001). The parental positioning-distraction intervention has the potential to enhance positive clinical outcomes with a primary benefit of decreased fear. Further research is warranted.
Children's Medical Center of Dallas Journal of Holistic Nursing, Vol. 22, No. 1, 32-56 (2004)
DOI: 10.1177/0898010104263306
Link (full text)

Brief Cognitive Interventions for Burn Pain
Jennifer A. Haythornthwaite, John W. Lawrence, James A. Fauerbach
This study tested the efficacy of 2 brief cognitive interventions in supplementing regular medical treatment for pain during burn dressing change. Forty-two burn inpatients were randomly assigned to 3 groups: sensory focusing, music distraction, and usual care. Patients reported pain, pain relief, satisfaction with pain control, and pain coping strategies. The sensory focusing group reported greater pain relief compared to the music distraction group and a reduction in remembered pain compared to the usual care group, although group differences were not observed on serial pain ratings. In addition, after controlling for burn size and relevant covariates, regression analyses indicated that catastrophizing predicted pain, memory for pain, and satisfaction with pain control. Refinement of the sensory focusing intervention is warranted to reduce catastrophic thinking and improve pain relief.
Annals of Behavioral Medicine, 2001, Vol. 23, No. 1, Pages 42-49
(doi: 10.1207/S15324796ABM2301_7)

Categories: Attention, Distraction, Hypnosis

Virtual-reality-palooza

I've written here before about the use of virtual reality in treating pain during medical procedures. Here's a collection of abstracts that I've come across recently:

Use of Virtual Reality as a Distractor for Painful Procedures in a Patient with Pediatric Cancer: A Case Study
Jonathan Gershon, Elana Zimand, Rosemarie Lemos, Barbara Olasov Rothbaum, Larry Hodges
Virtual reality (VR) has been demonstrated as an effective tool to help people overcome a variety of anxiety disorders. In this case study, the use of VR as a distractor to alleviate pain and anxiety associated with an invasive medical procedure for a pediatric cancer patient was explored. An A-B-C-A design during four consecutive medical appointments in an outpatient oncology clinic compared no distraction (A), non-VR distraction on a computer screen (B), and VR distraction with a head set (C). Behavioral observations of distress by the researcher and reports of pain and anxiety by the patient, parent, and nurse were taken before and during the procedure. The child's pulse was monitored throughout the procedure. The findings from this case study suggest benefit from using VR distraction, as indicated by lower pain and anxiety ratings, reduced pulse, and fewer observed behavioral indices of distress. The need for larger scale studies and application of VR with younger children is discussed in the context of confirming effectiveness of this technique and providing more generalizable information about efficacy. CyberPsychology & Behavior. Dec 2003, Vol. 6, No. 6: 657-661

Effects of Distraction Using Virtual Reality Glasses During Lumbar Punctures in Adolescents With Cancer
Suzanne Sander Wint, RN, BSN, CPON, Debra Eshelman, RN, MSN, CPNP, Jill Steele, RN, MSN, and Cathie E. Guzzetta, RN, PhD, HNC, FAAN

Purpose/Objectives: To determine the effects of virtual reality (VR) glasses on adolescents with cancer undergoing lumbar punctures (LPs).

Design: Pilot study using an experimental, control group design.

Setting: In-hospital oncology clinic.

Sample: 30 adolescents with cancer (17 in the VR and 13 in the control group) undergoing frequent LPs.

Methods: Subjects were randomly assigned to groups. Both groups received standard intervention during the LP, but the experimental group also wore VR glasses and watched a video. Following the LP, both groups rated their pain using a visual analog scale (VAS) and were interviewed to evaluate their experience.

Main Research Variables: Pain, subjective evaluation of experience.

Findings: Although VAS pain scores were not statistically different between the two groups (p = 0.77), VAS scores tended to be lower in the VR group (median VAS of 7.0, range 0-48) than in the control group (median VAS of 9.0, range 0-59). 77% of subjects in the experimental group said the VR glasses helped to distract them from the LP.

Conclusions: VR glasses are a feasible, age-appropriate, nonpharmacologic adjunct to conventional care in managing the pain associated with LPs in adolescents.

Implications for Practice: The clinical application of various age-appropriate distracters to reduce pain in adolescents undergoing painful procedures should be explored.
Link

Immersive Virtual Reality for Reducing Experimental Ischemic Pain
Hunter G. Hoffman, Azucena Garcia-Palacios, Veronica Kapa, Jennifer Beecher, Sam R. Sharar
This study explored the novel use of immersive virtual environments as a nonpharmacologic pain control technique and whether it works for both men and women. Fourteen female and 8 male students underwent pain induced via a blood pressure cuff ischemia lasting 10 min or less. Pain ratings increased significantly every 2 min during the no distraction phase (0 to 8 min) and dropped dramatically during the last 2 min period when participants were in the virtual environment (a 59% drop for women and a 41% drop for men). Five visual analog pain scores for each treatment condition served as the primary dependent variables. All 22 participants reported a drop in pain in the virtual environment, and the magnitude of pain reduction from the virtual environment was large (a 52% drop) and statistically significant. This is the first study to show immersive virtual environment distraction is also effective for women. The results show that virtual environments can function as a strong nonpharmacologic pain reduction technique, showing the same pattern of results obtained from recent clinical studies using virtual environments with burn patients during physical therapy. Practical applications of virtual environment pain reduction, and the value of a multidisciplinary approach to studying pain are discussed. International Journal of Human-Computer Interaction, 2003, Vol. 15, No. 3, Pages 469-486 (doi: 10.1207/S15327590IJHC1503_10)
Link

Effects of distraction using virtual reality glasses during lumbar punctures in adolescents with cancer Suzanne Sander and Jill Steele
Key points:
*Virtual reality glasses are a feasible, age-appropriate, nonpharmacologic adjunct to converntional care in managing pain associated with lumbar punctures in adolescents with cancer.
*visual analogue pain scores tended to be lower in the VR group
*The majority of adolescents who received the VR glasses felt the glasses distracted them from the lumbar puncture and wanted to use them again.
*More research is needed to explore novel distraction techniques for managing pediatric pain associated with procedures
Link (full text)

Virtual Reality Pain Distraction
Hunter Hoffman, PhD, and David Patterson, PhD ABPP ABPH
Introduction
Patients commonly report experiencing excessive pain during medical procedures (Melzack, 1990), especially during severe burn wound care (Carrougher et al., 2003). Although opioid analgesics are currently essential for pain control during burn wound care, dosage amounts are limited by side effects (e.g., nausea, constipation, interference with appetite, sleep cycles) and other concerns associated with this class of medications (Cherny et al., 2001). Pain control is particularly challenging for patients with severe burn injuries. Patients treated for this form of trauma typically undergo daily wound care to clean, prevent infection, monitor the healing progress, and bandage again. Most burn patients report severe to excruciating pain during these medical procedures (Carrougher et al., 2003). APS Bulletin SPRING 2005 • VOLUME 15, NUMBER 2
Link (full text)

The effectiveness of virtual reality based pain control with multiple treatments.
Hoffman, H.G., Patterson, D.R., Carrougher, G.J., & Sharar, S. (2001).
Objective: The present study explored whether immersive virtual reality continues to reduce pain (via distraction) with repeated use.

Setting: Burn care unit at a regional trauma center.

Patients: Seven patients aged 9-32 years, mean age = 21.9 years (average of 23.7% total body surface area burned, range TBSA = 3% to 60%), performed range of motion exercises of their injured extremity under an occupational therapist’s direction on at least three separate days each.

Intervention: For each physical therapy session, each patient spent equal amounts of time in VR and in the control condition (no distraction). The mean duration of physical therapy in VR was 3.5, 4.9 and 6.4 minutes for the first, second and third session, respectively. Condition order was randomized and counterbalanced.

Outcome measures: For each of the three physical therapy sessions, five visual analog pain scores for each treatment condition served as the dependent variables.

Results: Pain ratings were statistically lower when patients were in VR, and the magnitude of VR pain reduction did not diminish with repeated use of VR. The results of this study may be examined in more detail at www.vrpain.com.

Conclusions: Although the small sample size limits generalizability, results provide converging preliminary evidence that virtual reality can function as a strong nonpharmacologic pain reduction technique for burn patients during physical therapy. Results suggest that virtual reality does not diminish in analgesic effectiveness with three (and possibly more) uses. Virtual reality may also have analgesic potential for other painful procedures or pain populations. Practical implications are discussed. Clinical Journal of Pain, 17, 229-235.
Link (full text)

And a link with even more resources: www.vrpain.com

Categories: Virtual_reality, Distraction, Attention, Burn_care, Palliative_care

Self-efficacy and the opioid system

Perceived Self-Efficacy and Pain Control: Opioid and Nonopioid Mechanisms
[Personality Processes and Individual Differences]

Bandura, Albert; O'Leary, Ann; Taylor, C Barr; Gauthier, Janel; Gossard, Denis

Abstract: In this experiment, we tested for opioid and nonopioid mechanisms of pain control through cognitive means and the relation of opioid involvement to perceived coping efficacy. Subjects were taught cognitive methods of pain control, were administered a placebo, or received no intervention. Their pain tolerance was then measured at periodic intervals after they were administered either a saline solution or naloxone, an opiate antagonist that blocks the effects of endogenous opiates. Training in cognitive control strengthened perceived self-efficacy both to withstand and to reduce pain; placebo medication enhanced perceived efficacy to withstand pain but not reductive efficacy; and neither form of perceived self-efficacy changed without any intervention. Regardless of condition, the stronger the perceived self-efficacy to withstand pain, the longer subjects endured mounting pain stimulation. The findings provide evidence that attenuation of the impact of pain stimulation through cognitive control is mediated by both opioid and nonopioid mechanisms. Cognitive copers administered naloxone were less able to tolerate pain stimulation than were their saline counterparts. The stronger the perceived self-efficacy to reduce pain, the greater was the opioid activation. Cognitive copers were also able to achieve some increase in pain tolerance even when opioid mechanisms were blocked by naloxone, which is in keeping with a nonopioid component in cognitive pain control. We found suggestive evidence that placebo medication may also activate some opioid involvement. Because placebos do not impart pain reduction skills, it was perceived self-efficacy to endure pain that predicted degree of opioid activation. Journal of Personality & Social Psychology. 53(3):563-571, September 1987.

Categories:
Attention
Self-efficacy

Fetal pain law

Just saw this:

Wisconsin Gov. Jim Doyle (D) on Friday vetoed a bill (SB 138) that would have required physicians to tell women seeking abortion at more than 20 weeks' gestation that fetuses can feel pain, the AP/St. Paul Pioneer Press reports (Richmond, AP/St. Paul Pioneer Press, 1/7). The state Senate and Assembly approved the bill in September and November 2005, respectively. Supporters of the bill say some research supports the claim that fetuses can feel pain, while the bill's opponents say the research has not been proven (Kaiser Daily Women's Health Policy Report, 11/10/05). Doyle said there is no definitive proof that fetuses can feel pain and added that the state Legislature, which has a Republican majority, should not be permitted to determine what constitutes scientific fact, the AP/Pioneer Press reports. Doyle in his veto message wrote, "It would be reckless to inject a requirement that doctors communicate unproven science to their patients during an already difficult and sometimes traumatic time," adding, "This bill intrudes on the doctor-patient relationship ... and contravenes the requirement that doctors provide objective and accurate information to their patients" (AP/St. Paul Pioneer Press, 1/7). Link

Here's what a pretty authoritative JAMA study concluded awhile back:

Conclusions Evidence regarding the capacity for fetal pain is limited but indicates that fetal perception of pain is unlikely before the third trimester. Little or no evidence addresses the effectiveness of direct fetal anesthetic or analgesic techniques. Similarly, limited or no data exist on the safety of such techniques for pregnant women in the context of abortion. Anesthetic techniques currently used during fetal surgery are not directly applicable to abortion procedures. Link

There are several serious philosophical problems here. One involves understanding under what conditions we should say a fetus is having pain. Nancy Hardcastle addresses this in the final chapter of her The Myth of Pain.

I'm more interested in what the normative significance of the findings. I believe, for example, that the painful sensation is a very minimally normatively significant property of pain. Other components like emotional responses and cognitive states like meanings, can be much more significant (i.e., weigh more heavily in how evil we adjudge the pain to be).

Suppose then that we find out that at n weeks fetuses have active nociceptive pathways which, when stimulated, evoke some rudimentary withdrawl response. Assuming that we want to say that the fetus experiences pain, it is a further question how normatively significant that pain is. Presumably the fetus's experience wouldn't contain the complex emotions and affect that our pains involve.

But what does this show? Does it mean that the fetus's pain would be only minimally morally significant? Or ought we assess the moral badness of pain for fetuses on a different scale from adult humans? How do we decide? If we have an account of what makes pain intrinsically bad for adult humans, should we assume that account will translate to an account for fetuses?

Categories: Fetal_pain, Legal, Abortion

Plotinus on pain

Ok. I believe some wierd* things about pain (e.g., pains are not just sensations; pains have two potentially conflicting intrinsic values; some painful sensations are not pains; pain is essentially and intrinsicaly bad in virtue of being the privation of that which is intrinsically good for a person, and many others). But Plotinus seriously one-ups me with this claim about how a person suffers pain.

13. The characteristic activities are not hindered by outer events
but merely adapt themselves, remaining always fine, and perhaps all
the finer for dealing with the actual. When he has to handle particular
cases and things, he may not be able to put his vision into act without
searching and thinking, but the one greatest principle is ever present
to him, like a part of his being- most of all present, should he be
even a victim in the much-talked-of Bull of Phalaris. No doubt, despite
all that has been said, it is idle to pretend that this is an agreeable
lodging; but what cries in the Bull is the thing that feels the torture;
in the Sage there is something else as well, The Self-Gathered which,
as long as it holds itself by main force within itself, can never
be robbed of the vision of the All-Good. Link

I wonder if Plotinus thought himself a Sage...

The Bull of Phalaris:

Perillos of Athens, a brass-founder, proposed to Phalaris, Tyrant of Agrigentum, the invention of a new means for executing criminals; accordingly, he cast a brazen bull, made totally of brass, hollow, with a door in the side. The victim was shut up in the bull and a fire was set under it, heating the metal until it became "red hot" and causing the victim inside to slowly roast to death. So that nothing unseemly might spoil his feasting, Phalaris commanded that the bull be designed in such a way that its smoke rose in spicy clouds of incense. The head of the ox was supplied by a complex system of tubes and stops so that the prisoner's screams were converted into sounds not unlike the bellowing of an infuriated ox. It is also said that when the bull was reopened, the victims' scorched bones shone like jewels and were made into bracelets.

Phalaris commended the invention, and ordered its horn sound system to be tested by Perillos himself. When Perillos entered, he was immediately locked in, and the fire was set, so that Phalaris could hear the sound of his screams.Link

* Since I'm presently on the job market, 'wierd' here means 'exciting, insightful, and challenging'
Categories: Plotinus, Torture, Wierd