The following is a summary of “Studying the effect of expectations on high-frequency electrical stimulation-induced pain and pinprick hypersensitivity,” published in the September 2024 issue of Pain by Gousset et al.

Negative expectations have been linked to increased pain perception, suggesting the contribution to the development of central sensitization.

Researchers conducted a study to investigate whether verbal suggestions inducing expectations of increased pain from high-frequency electrical stimulation (HFS) could influence pain ratings and induce pinprick hypersensitivity in healthy volunteers.

They randomly assigned 50 healthy volunteers to a control group (N=25) and a nocebo group (N=25) and received a patch containing water on the right forearm, but the nocebo group was informed about capsaicin, which would sensitize their skin. Pain ratings were assessed using single electrical stimuli before and after patch attachment. After patch removal, participants rated their expected pain and fear before receiving HFS, followed by an assessment of pinprick sensitivity.

The results showed that the nocebo group reported higher perceived intensity for the single electrical stimulus after patch removal compared to the control group, confirming the effectiveness of the manipulation. However, this did not translate into differences in expected pain for HFS or pain intensity ratings during HFS.

They concluded that HFS increased pinprick sensitivity with no group differences.

Source: jpain.org/article/S1526-5900(24)00644-8/abstract