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

Abstract

Objective This 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. Methods We 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 72 years and were divided into six groups by age. Results At 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. Conclusions Trigeminal 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. Significance Standardization of age‐related changes in trigeminal and hand LEPs is possible and should improve their reliability in the objective assessment of pain pathways.

Effect of Non-invasive Vagus Nerve Stimulation on Resting-State Electroencephalography and Laser-Evoked Potentials in Migraine Patients: Mechanistic Insights

“…The pain threshold was the lowest intensity that enabled at least 50% of the stimuli to be perceived as a painful pinprick. The laser intensity was two 0.5-W steps over the Pth, in accordance with previous studies ( Treede et al, 2003 ; de Tommaso et al, 2017 ). We asked all patients to rate the laser pain on a visual analog scale after each trial of stimulation.…”

“…Considering the importance of habituation in migraine pathophysiology, we also evaluated the habituation pattern. For its computation, the sequence of potentials was divided into three blocks, and we considered the average of at least three artifact-free consecutive potentials for each block ( de Tommaso et al, 2017 , 2005c ). Habituation was computed for the N2-P2 complex given that N1 is small in amplitude and recognizable only if a consistent number of potentials is averaged.…”

Pain Processing and Vegetative Dysfunction in Fibromyalgia: A Study by Sympathetic Skin Response and Laser Evoked Potentials

“…The P2 latency increase is somewhat unexpected, but confirmatory of the phenotypic complexity of patients with FM. Given the close correlation between increased latency and amplitude of the P2 component for all stimulation locations, already observed in normal samples [35], even this finding is attributable to a larger cortical activation and therefore a slower and cumbersome cortical elaboration under painful stimulation. The increase of P2 latency and amplitude observed in the FM group is in evident contradiction with our previous results [12], confirming that the LEP variability is characteristic of the disease.…”

“…Patients with prevalent peripheral sufferance presented with complete absence of LEPs or SSR, as discussed below. A tendency for an increased laser pain perception in FM group, which was significant at the lower limb, confirmed the diffuse hyperalgesia characterizing this complex syndrome [7–10], though the lack of correlation with LEP amplitude further defined that different mechanisms underlay subjective pain and pain-related cortical responses [4, 35]. Coming to the main topic of our study, that is, the SSR, this study confirms what is generally described in patients with FM, an increased latency of sympathetic skin response in all the recording sites.…”

“…Considering the age-related changes of LEPs [35], all the statistical comparisons were corrected for the age. The Person test was employed to evaluate the correlations among the neurophysiological variables and to detect the relationships with the clinical features.…”