Assessing potential neurophysiological signatures of chronic corneal pain and its modulation through non-invasive brain stimulation: A commentary
Chronic corneal pain (CCP) is a highly disabling condition and its diagnosis is typically made based on patients’ self-report. Recent advances in the understanding of the pathophysiology of chronic pain syndromes have led to the hypothesis that sensitization of both peripheral (i.e. trigeminal) and central (i.e. thalamocortical) pathways may be involved, resulting in pathological alterations of brain activity. However, no objective neurophysiological biomarker associated with symptom presence or severity has been identified to date. Moreover, the lack of effective therapeutic options for medically-refractory cases further complicates the management of CCP. In recent years, several techniques such as electroencephalography (EEG) and transcranial magnetic stimulation (TMS) have been used to investigate the neurophysiological signatures of several chronic pain conditions. Additionally, transcranial direct current stimulation (tDCS) has emerged as a promising alternative for the treatment of chronic medically-refractory pain. In this commentary, we discuss the interest of EEG and TMS as potential clinically relevant tools to identify biomarkers of chronic corneal pain reflecting disrupted cortical and/or thalamocortical processing. Furthermore, these techniques could be used to guide the development and application of alternative therapeutic options such as tDCS to reduce the symptoms associated with this condition.