If Only There Were a Pain Scanner

Neuroscience has made great strides in last few decades and promises to uncover more about the mind and how it is brought into being by the brain. One day soon, for example, we may be able to hook a person up to a series of electrodes or an MRI or some other type of brain-scanning device and read what is going on in his or her mind, like whether the person is experiencing pain and to what degree. One day, so the thinking goes, we'll have an objective machine that can definitively measure pain.

I'm not so sure. First of all, brain activity during pain is extremely complex, occurring at multiple sites (in sensory, affective, memory, and higher order cortical processing centers). What would stand as criteria? Is one site or type of activity sufficient or would you need the entire package of activity? And even if scientists could agree, would the test really be definitive? Wouldn't it be possible that despite, say, anterior cingula activation (the part of the brain that accounts for pain's aversive quality, the need to turn away from it), a patient might not feel pain, or conversely, that he actually feels pain in the absence of such activity? The truth is that only the person in pain can feel his pain, not a group of neurons firing and not another person watching those neurons.

We don't yet know what it's like to be a bat, or how the pain of another person feels, and according to some scientists and philosophers, may never know or can't possibly know. Pain, like any mental state, is irreducibly subjective. There is no foolproof objective test. The closest thing to proof we have is the word of the sufferer. An observer must in a real sense take a sort of leap of faith if he or she is to believe and accept the claim.

Now this fact, which is too often glossed over, creates serious problems in a materialistic minded society like ours. Laypeople and doctors alike don't feel especially confident taking leaps of faith. They prefer an objective basis for pain - a visible bruise on the skin, a lesion on the MRI. And if there is no lesion or the lesion doesn't quite correlate with pain levels, then (in the absence of that elusive pain machine) skepticism quickly sets it. This is especially true in many cases of chronic pain where no visible injury is detected so the observer often concludes that the pain must be "in the mind" - a euphemism that the patient is either faking or mentally ill.

The outsider's tendency to remain skeptical or in some cases, to actively disbelieve, is disastrous for the person in real pain (we'll leave out for the moment cases in which a person is lying or exaggerating). It is surely one of the reasons for the chronic undertreatment of pain in medicine. Studies have estimated that 25% of cancer patients in this country die in severe, unremitting pain. And if this happens in patient populations that have plenty of objective reasons for their pain (like bone metastases and serious infections), it can only be worse for patients with fibromyalgia or back pain who may have no such reasons. The general consensus is that a large percentage of chronic pain patients don't receive adequate pain relief. Clearly the word of the patient is not always taken at face value or is undermined by other factors (e.g. misperceptions about pain medication and management by doctors as well as patients).

Aside from these treatment-related failures, the absence of outsider belief has a second disastrous consequence. It strengthens the wall that pain erects between sufferer and world. Surely when your spouse or doctor looks at you skeptically, or worse, like you're crazy, it can only make you feel more alone, and ongoing isolation, as we saw in a previous blog, can exacerbate the pain. Moreover, instead of simply focusing on the pressing need of getting relief, a sufferer now has to spend considerable time and energy making himself believed; he feels compelled to validate his pain to an outsider and when he fails, the frustration and resignation mounts.

"What do you do all day?" was a question repeatedly posed to Lous Heshusius, a patient whose persistent pain after a car accident had become so severe and incapacitating that she had to give up her job. But no matter what she said in reply, the friend or colleague asking remained puzzled. "I have given up expecting others to understand," she writes in a poignant memoir about her experience.

When and if the pain machine comes, things may be a lot easier. But until then, we must continuously acknowledge the most important criteria in assessing pain: the word of the sufferer. And we must acknowledge the consequences of ignoring or disbelieving or denying that word.

References:

A D Craig, Mapping Pain in the Brain (www.wellcome.ac.uk/en/pain/microsite/science2.html)

Lous Heshusius, Inside Chronic Pain: An intimate and Critical Account (Cornell University Press, 2009)