Brain imaging tests for chronic pain: medical, legal and ethical issues and recommendations

Abstract

624 | OCTOBER 2017 | VOLUME 13 www.nature.com/nrneurol CONSENSUS STATEMENT © 2 0 1 7 M a c m i l l a n P u b l i s h e r s L i m i t e d , p a r t o f S p r i n g e r N a t u r e . A l l r i g h t s r e s e r v e d . NeuroethicsA field that studies the implications of neuroscience for human self-understanding, ethics, and policy. Arterial spin labellingAn MRI-based brain imaging technique that detects cerebral blood flow based on magnetic tagging of blood.Nevertheless, diverse groups -including patients, researchers, clinicians, pharmaceutical and medical device companies, insurers and the legal communityseek methods for evaluating chronic pain besides selfreporting. Patients seek objective testing to demonstrate the reality of an invisible condition that is sometimes subject to doubt, researchers seek brain imaging markers that provide scientific, diagnostic and prognostic information that cannot be provided by patient self-reporting, and legal representatives and officials seek techniques to supplement self-reporting and objectively support or challenge claims related to chronic pain. Brain imaging technologies, including functional MRI (fMRI), PET, EEG and magnetoencephalography (MEG), have the potential to provide objective measurements of patterns of brain activity that underlie perceptual experiences (BOX 1). Consequently, some people are looking to brain imaging to provide a window into the experience of chronic pain, particularly because testimony based on fMRI was deemed to be admissible as evidence of pain in a 2015 state trial court in the USA 10,11 . This case was highly publicized, although the judgement was not published so no legal precedent was set, and the grounds on which the fMRI evidence was admitted were criticized by established experts in brain imaging studies of pain 10,11 . In this context, the development of a brain imaging test for chronic pain [12][13][14] has real-world consequences, so appropriate criteria for the use of such a test must be defined. Importantly, the way in which brain imaging evidence might be implemented in legal cases strongly depends on laws that vary greatly between countries. Therefore, examination of the capability of so-called 'pain-o-meter' brain imaging tests is critical, as is consideration of the use of such technology in light of societal views, neuroethics and legal issues. Thus, the aims of this Consensus Statement are to recommend criteria for the evaluation of neuroimaging measures of chronic pain, and to discuss the technical, biological, neuroethical and legal challenges related to establishing brain-based tests for chronic pain. MethodsA presidential task force of the International Association for the Study of Pain (IASP) was established in 2015 to examine the feasibility of a brain-imaging-based diagnostic test for chronic pain. The task force had three purposes: to consider the capacity of brain imaging (in particular fMRI), on the basis of its technical and physiological constraints, to detect whether an individual has chronic pain; to place th...

Prefrontal gamma oscillations reflect ongoing pain intensity in chronic back pain patients

“…Future studies need to take potential muscle confounds into account, but might investigate the potential of prefrontal gamma activity as a marker of ongoing pain for the diagnosis and treatment of chronic pain (Davis et al, 2017), especially in the context of neurofeedback and neurostimulation treatment approaches (Jensen et al, 2014;Sitaram et al, 2017;Thut et al, 2017). Thus, they reveal a potential neurophysiological marker of ongoing pain, which could be measured relatively easily using EEG as a noninvasive and broadly available clinical tool.…”

“…They are furthermore in line with a role of emotional-evaluative circuits rather than sensory circuits in ongoing pain, emphasizing the emotional aspects of the chronic pain experience. Future studies need to take potential muscle confounds into account, but might investigate the potential of prefrontal gamma activity as a marker of ongoing pain for the diagnosis and treatment of chronic pain (Davis et al, 2017), especially in the context of neurofeedback and neurostimulation treatment approaches (Jensen et al, 2014;Sitaram et al, 2017;Thut et al, 2017).…”

Invasive Motor Cortex Stimulation Influences Intracerebral Structures in Patients With Neuropathic Pain: An Activation Likelihood Estimation Meta-Analysis of Imaging Data

“…Various studies have shown that neuroimaging can further our understanding of chronic pain and can help us to define new therapeutic options/targets (for a consensus paper, see ref. ). Insights from neuroimaging studies could also open the field of neuromodulation for other pain disorders, for example diabetic neuropathic pain.…”

Brain dysfunction in chronic pain patients assessed by resting-state electroencephalography

“…Moreover, a potential lack of specificity does not necessarily limit the clinical usefulness and validity of a brain-based marker of chronic pain (see [18] for an in-depth discussion of criteria for brain-based markers of chronic pain). In fact, many well-established laboratory, electrophysiological and imaging tests yield results which are neither disease-specific nor symptom-specific, but are clinically highly useful.…”