Intra-individual changes to peak alpha frequency map to pain perception following high frequency sensitisation of central nociceptive pathways: A test-retest reliability study

Resting-state EEG can capture cortical dynamics relevant to sensitised pain states in the absence of ongoing nociceptive engagement. However, whilst the slowing of global oscillations is evident within various chronic pain conditions, the mechanistic specificity of PAF and α-band power remains uncertain. Therefore, the present study assessed these features across two identical test-retest sessions in which HFS was applied to induce the development of SHA as characterised through 128 mN MPS. Crucially, changes in α-band features post-HFS were investigated. Blind source separation was also applied to identify independent sensorimotor components relevant to nociception and assess their test-retest reliability. Results demonstrated good test-retest reliability for sensor-level data at baseline, with inter-individual changes in global PAF reflecting MPS post-HFS. However, no specific regional driver of this signal was evident. Alternatively, components identified through sensorimotor template matching revealed a significant influence of α-band power on MPS both at baseline and post-HFS. However, only a small number of these components genuinely localised to pre- or post-central gyri, and test-retest reliability of α-band power was poor. Together, these findings indicate that resting-state EEG may be useful for tracking changes in cortical α-band oscillations alongside the development of pain sensitivity. However, methods of sensorimotor component identification evidenced limited agreement and global PAF slowing could not be linked to a specific electrode grouping.