Objective: To investigate the normal data of pain-related evoked potentials (PREP) elicited with a concentric surface electrode among normal, healthy adults and the relationship between PREP and pain intensity.
Methods: Sixty healthy volunteers (22 men and 38 women; aged 36.4±10.7 years; height, 165.4±7.8 cm) were enrolled. Routine nerve conduction study (NCS) was done to measure PREP following electrical stimulation of hands (C7 dermatome) and feet (L5 dermatome). Negative peak (N), positive peak (P) latencies, peak to peak (NP) amplitudes, conduction velocity (CV), and verbal rating scale (VRS) score were obtained. Linear regression analysis tested for significant relevance between variables of PREP and VRS score.
Results: Normal NCS results were obtained in all subjects. N latency of hand PREP was 163.8 ±40.0 ms (right) and 161.0±39.9 ms (left). N latency of foot PREP was 178.0±43.9 ms (right), 180.4±43.4 ms (left). NP amplitude of hands was 20.6±10.6 µV (right) and 21.9±11.6 µV (left). NP amplitude of feet was 18.8±8.3 µV (right) and 19.0±8.4 µV (left). The calculated CV was 13.2±4.7 m/s and VRS score was 3.8±1.0. A highly significant positive correlation was evident between VRS score and NP amplitude (y=0.1069x+1.781, r=0.877, n=60, p<0.0001).
Conclusion: PREP among normal, healthy adults revealed a statistically significant correlation between PREP amplitude and VRS score.
Keywords: Electrodes; Evoked potentials; Nociceptive pain; Pain measurement.