Do negative expectations increase high-frequency electrical stimulation-induced secondary mechanical hypersensitivity? A replication study

• DOI: 10.31219/osf.io/5psq9
• Publication Date: 2024-11-11T21:42:30Z
• Authors: Ketan Prafull Jal...; Diana Torta; Martina D'Agostini; Lies De Voeght; Margot Kinnart; Emanuel van den B...
• Keywords: Health Psychology; Cognitive Psychology; Psychology; Social and Behavioral Sciences

Increased mechanical sensitivity of uninjured skin surrounding a cutaneous tissue injury, is considered a manifestation of central sensitization and can be induced in healthy volunteers using high frequency electrical stimulation (HFS). Little evidence exists on the effect of negative expectations on the development of mechanical hypersensitivity. Here, we aimed to replicate and extend the findings of the only study which found that negative expectations increased the extent of mechanical hypersensitivity after HFS. Sixty participants were randomised to a control or nocebo group and underwent HFS on one forearm. We measured the increase in pinprick sensitivity and the spread of this increase. Additionally, we recorded resting and pinprick evoked pupil dilation to examine tonic arousal and pinprick-evoked phasic locus coeruleus activity. More participants in the nocebo group expected increased skin sensitivity, but the difference was not statistically significant. There was no group difference in the increase of pinprick sensitivity, its spread, or pupil dilation. These data do not replicate previous behavioural findings showing that negative expectations lead to more mechanical hypersensitivity after HFS. However, we observed that participants in the control group also expected an increase in pinprick sensitivity, potentially reducing the difference between the two groups and explaining our results.