Relative and absolute reliability of somatosensory evoked potentials in response to non-noxious electrical stimulation of the paraspinal muscles in healthy participants at an interval of 3-months.

BACKGROUND

Somatosensory evoked potentials (SEPs) are used extensively to quantify cortical activity in response to noxious and/or non-noxious sensory stimuli. However, data demonstrating the reliability of SEP measures in response to non-noxious stimulation over time are scarce.

AIM

We investigated the relative and absolute reliability, and the smallest detectable change at 95% confidence (SDC) for SEPs evoked by non-noxious electrical stimulation of the paraspinal muscles in thirty-nine healthy participants at a 3-month interval.

METHODS

SEPs were evoked at an intensity three-times that of each participant's perceptual threshold and recorded from a single electrode placed over the primary somatosensory cortex (S1).

RESULTS

Our analyses reveal that i) latency, as a measure of activity onset, has poor relative reliability but good absolute reliability; ii) area, as a measure of cortical activity, has good relative and absolute reliability (except for the N component) and iii) perceptual threshold and stimulation intensity was not reliable over time.

CONCLUSION

These findings suggest that the area of the N and P SEP components, and the area of the N-N-P SEP complex, can be utilised in future studies as reliable markers of cortical activity.