fMRI: Is it possible to prove pain?

6. July 2015

Pain can be simulated well when the need arises. Even doctors with a lot of experience sporadically fall for it. Conversely, patients in court often have it tough proving chronic pain. In the US, the first diagnostics companies using fMRI are finding success.

There are sometimes considerable sums paid out for experiencing pain. It’s not always the case that a plaintiff’s court testimonies about pain and suffering seem to be credible. In contrast: a small accidental injury in some instances can lead to severe pain that lasts a lifetime and is only partially compensated with money. How much easier it would be for a court to act if pain were documented not only on a subjective scale, but on the basis of objective measured data. Especially where the cause of chronic pain already dates back many years, evidence is often shaky. And women have even fewer opportunities for adequate compensation, because psychological impacts are deemed to be worth less than pain following physical injury.

Yet it’s not only in court that a judgement made regarding indefinable, pain-based experiences will depend on the personality and the persuasiveness of the client. “Hysterical” female patients also have more difficulty at the doctor’s office in getting access to medications or other appropriate therapies. No wonder reviewers ever more urgently wish for an easy-to-read machine-generated scale dealing with the intensity of pain.

“Pain pictures” via magnetic resonance

Researchers have now already come so far with their work that pain is being made visible both on the screen in the form of functional magnetic resonance (fMRI) and EEG. Mostly. For every pain is different – and not only in terms of location and quality. Signals from activated brain regions also depend on the environment and the situation in which the subject is located. Nevertheless, neurologists such as Tor Wager from the University of Colorado in Boulder show in smaller studies that in spite of all the variables there exist enough similarities for identifying the pain of patients with more than 90 percent accuracy.

Vania Apkarian from Chicago examined back pain patients shortly after a triggering event. The 50 percent of patients whose acute pain then became chronic pain showed altered MRI images. Whereas at first the nerve centres in the insula were active, the focus point shifted many months later to the prefrontal cortex and the amygdala, ie. the cognitive emotion centres. Often it’s chronic pain in particular which is associated with a strong psychological component. Depression is often associated with chronic pain and both elements promote one other. It’s thus no wonder that chronic pain sometimes reacts well to antidepressants.

Market niche for specialised diagnostics companies

In the US – the context being one of a health system that is confronted with large claims in court processes – a market opportunity has opened in recent years for innovative diagnostics companies which therefore specialise in the supply of evidence in such processes. Using various fMRI analysis systems, they are trying to help chronic pain patients in dealing with their rights. So says a spokesperson from Millenium Magnetic Technologies in Birmingham, Alabama, that thanks to the data from the scans there have been more than ten extra-judicial settlements in damages processes. With 92-percent accuracy in predicting chronic pain, touts the Californian company “Chronic Pain Diagnostics”. The cost of such scans is around 4,000 to 6,000 dollars. University-based institutes such as Columbia University’s Institute for FMI Research in New York are also participating in the seemingly lucrative business.

Does it need to be so accurate?

None of the methods used so far are scientifically validated. The analyses do indeed work quite well in the research laboratory, however in the real world of legal disputes there is a lack of certainty that the procedure is not responding to fake pain, and that it is independent of the interests of the diagnostician. The other question is: is 90 percent accuracy enough? Furthermore, only relatively inaccurate information on the strength of the pain has so far been able to be gathered. Proponents argue that scientific accuracy in the courtroom is not at all necessary if the data only contributes to finding the truth and to answering the question as to whether the person is suffering from pain or not. Graphics and data that have been created with complicated technology, argue court observers, can impress those such as jury members more than any eloquent lawyer can.

Apart from in the United States, the scans have achieved very little dissemination so far in the legal field, a similar situation to the lie detector based on magnetic resonance, which until now has not asserted its presence.

Objective metrics for clinical trials

A second major area, where the brain scan for pain measurement may perhaps be coming more into routine use, is in pharmacological research. This is particularly the case in the development of analgesics: studies in which recording the participants’ subjective pain is replaced by measurement of data, as much as possible unaffected by current emotional states and other influences on the psyche, which would be desired not only for manufacturers. One example of how such things could work out was delivered in a report [Paywall] by Eugene Duff in February this year in Science Translational Medicine. She and her colleagues from Oxford, Cambridge and Cardiff took up the data from previous studies on CNS drugs involving fMRI analysis with the intention of constructing a new study protocol – one which also proved itself in practice in a first test.

However, if one considers that analgesics affect not only the sensation of pain, but also mood, decision-making processes in the brain and even the feelings related to one’s personality, one can imagine how complicated the matter is. Especially in this area there are lots of completely different substances which have a very similar effect, and vice versa.

Good, but not perfect

More and more the line between different pains are blurred, between those for example resulting from an injury and psychosomatic pain – lines which have been studied inadequately using the appropriate imaging. Pain being brought about by mental trauma does not however mean that the subject only imagines the pain. On the other hand, the absence of fMRI signal is not proof that the pain which the patient feels does not exist. However, because in the reverse situation the desired signals can be produced in the scanner through neurofeedback training, pain measurement using data from the brain is still far from being routine clinical practice, and not only for economic reasons. Large lawsuits, which due to fake evidence lead to miscarriages of justice, would lay a huge stone in the path here going from the research lab to use in the field.

When it really matters and the high expenses are covered, data derived from a variety of technical and subjective measurement methods would probably still be most likely to come to a credible result and arrive at the relevant findings. The desire for and equally so the need for objective data in the extremely complex area of “pain” is constantly growing. Are we however ready in obtaining these desired outcomes to take into account inaccuracies and false-positive results?


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Medicine, Neurology, Psychiatry

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