Neurophysiological Correlates Of Chronic Pain: A Systematic Review

Abstract

Chronic pain is a multifaceted condition that persists beyond normal healing time and affects nearly one-fifth of the global population. Neurophysiological studies have revealed that chronic pain is associated with maladaptive changes in central and peripheral nervous system networks, including alterations in cortical excitability, thalamocortical dysrhythmia, abnormal oscillatory activity, and impaired descending inhibitory control. This systematic review synthesizes evidence from clinical neurophysiological studies, including electroencephalography (EEG), magnetoencephalography (MEG), transcranial magnetic stimulation (TMS), and functional near-infrared spectroscopy (fNIRS), as well as invasive electrophysiology, to characterize the neural correlates of chronic pain. Findings indicate consistent alterations in alpha and gamma oscillatory activity, reduced cortical inhibition, hyperexcitability of pain-related circuits, and disrupted functional connectivity within default mode and salience networks. These markers may not only advance mechanistic understanding but also serve as biomarkers for prognosis and treatment response in chronic pain syndromes. Nonetheless, heterogeneity in methodology, small sample sizes, and limited longitudinal studies constrain current knowledge. Future directions include integrating multimodal neurophysiological assessments with neuroimaging and precision medicine approaches.