Correlations between brain changes and pain management after cognitive and meditative therapies: A systematic review of neuroimaging studies.

BACKGROUND: There are different ways of dealing with pain and cognitive and meditative therapies (CMT) are alternative ways to regulate the emotions associated with pain. Current studies apply neuroimaging techniques trying to elucidate the neural mechanisms of cognitive strategies for pain. This systematic review aimed to summarize the evidence on brain activity changes after CMT, which include cognitive behavioral therapy, mindfulness and/or meditation, for pain management as well as to evaluate clinical pain outcomes.

METHODS: Electronic databases - Pubmed, EMBASE, PsycINFO, Science Direct, Scopus - were searched to find randomized controlled trials (RCTs) examining neuroimaging data of CMT for chronic pain patients or healthy individuals with experimental pain. Two reviewers independently selected the relevant trials, rated for quality assessment and extracted all data using a standardized form. Primary outcome was brain activity changes (activation, deactivation or functional connectivity). Secondary outcomes were pain intensity, self-management, pain coping, quality of life, anxiety and depression.

RESULTS: Nine RCTs were included involving 280 adults (18-59 years), 139 chronic pain patients vs. 148 healthy subjects. Three main kinds of intervention were identified: cognitive-behavioral therapy (n = 4), mindfulness meditation (n = 4) and transcendental meditation technique (n = 1). Neuroimaging results revealed distinct patterns of activity, but the main findings were related to increased activation of prefrontal cortex (PFC), specially dorsolateral prefrontal cortex (dlPFC) and ventrolateral prefrontal cortex (vlPFC), orbitofrontal cortex (OBF), somatosensory cortices (SSC) and limbic system in chronic pain population; and increased activation of anterior cingulate cortex (ACC), anterior insular cortex (AI) and decreased activation of thalamus in healthy individuals following CMT.

CONCLUSION: This result means that regulation of pain by CMT can alter functioning of brain regions in an extensive network including non-nociceptive regions. CMT reduced the affective experience of pain, while reductions of pain intensity ratings were less consistent. Brain changes have been demonstrated as a result of the application of psychological measures and may represent the clinical implications of changes in brain activity or morphology.