Age-related changes in laser-evoked potentials following trigeminal and hand stimulation in healthy subjects

ObjectiveThis study aimed to evaluate age-related changes in laser-evoked potential (LEP) features, including habituation, via trigeminal and hand stimulation in a large group of healthy volunteers. MethodsWe recorded the LEPs by right-hand stimulation in 237 healthy subjects and by stimulation of the right supraorbital zone in 170 cases. The subjects ranged in age from 7 to 72years and were divided into six groups by age. ResultsAt the trigeminal level, the N2 and P2 latencies were significantly shorter and the N2-P2 amplitude was significantly larger in the 7-17 age group than in the other groups. The N2-P2 amplitude of the responses evoked by hand stimulation was significantly larger in the 7-40 age range than in the older subjects. The N1 amplitude and latency were not significantly different among the groups. The N2-P2 habituation increased with age, but no significant changes among groups were revealed by the Bonferroni test. ConclusionsTrigeminal vertex LEPs have greater amplitudes and appear earlier in children, while a progressive age-related amplitude decrease characterizes the N2-P2 waves associated with hand stimulation. The N2-P2 habituation increases in older people. The N1 latency and amplitude seem to remain stable during ageing and are therefore potentially reliable and useful patterns for nociceptive system examination. SignificanceStandardization of age-related changes in trigeminal and hand LEPs is possible and should improve their reliability in the objective assessment of pain pathways.