Pinprick Evoked Potentials—Reliable Acquisition in Healthy Human Volunteers

Abstract

Objective Pinprick evoked potentials (PEPs) represent a novel tool to assess the functional integrity of mechano-nociceptive pathways with a potential toward objectifying sensory deficits and gain seen in neurological disorders. The aim of the present study was to evaluate the feasibility and reliability of PEPs with respect to age, stimulation site, and skin type. Methods Electroencephalographic responses evoked by two pinprick stimulation intensities (128 mN and 256 mN) applied at three sites (hand dorsum, palmar digit II, and foot dorsum) were recorded in 30 healthy individuals. Test–retest reliability was performed for the vertex negative–positive complex amplitudes, N-latencies, and pain ratings evoked by the 256mN stimulation intensity. Results Feasibility of PEP acquisition was demonstrated across age groups, with higher proportions of evoked potentials (>85%) for the 256mN stimulation intensity. Reliability analyses, that is, Bland-Altman and intraclass correlation coefficients, revealed poor to excellent reliability upon retest depending on the stimulation sites. Conclusions This study highlights the reliability of PEP acquisition from cervical and lumbar segments across clinically representative age groups. Future methodological improvements might further strengthen PEP reliability in order to complement clinical neurophysiology of sensory nerve fibers by a more specific assessment of mechano-nociceptive pathways. Beyond looking at sensory deficits, PEPs may also become applicable to revealing signs of central sensitization, complementing the clinical assessment of mechanical hyperalgesia.

Pain‐autonomic interaction: A surrogate marker of central sensitization

“…To this end, pinprick evoked potentials (PEPs) represent a reliable tool to examine the functional integrity of mechano-nociceptive A-delta fibres (Iannetti, Baumgärtner, Tracey, Treede, & Magerl, 2013;Rosner, Scheuren, Stalder, Curt, & Hubli, 2019). Apart from capturing sensory deficits, it might be able to reveal sensitization of mechano-nociceptive pathways as PEPs were enhanced in the area of secondary hyperalgesia (van den Broeke, Lambert, Huang, & Mouraux, 2016;Broeke et al, 2015;Broeke, de Vries, Lambert, Torta, & Mouraux, 2017;Iannetti et al, 2013).…”

Reliability of Upper Limb Pin-Prick Stimulation With Electroencephalography: Evoked Potentials, Spectra and Source Localization

“…One possible reason for this is the thickness of pin-prick filament. Recently, Rosner et al (2020), identified that 256 mN stimulation intensity led to higher reliable values than the 128 mN which was used in our study (Rosner et al, 2020). The main reason for choosing a smaller force was to minimize pain through the lateral spinothalamic tract but also to explore the response to crude touch and pressure from pinprick stimulation through the anterior spinothalamic tract.…”

“…Pin-prick evoked potentials (PPEP) have been shown to consist of a biphasic negative-positive (N-P) wave with average peak latencies of 111 and 245 ms and average amplitudes of 3.5 and 11.1 μV in young healthy adults ( Iannetti et al, 2013 ). Recently, Rosner et al (2020) explored the reliability of PPEP measurement. They identified a poor reliability (ICC = 0.27) of N-P amplitude measurement at dermatome C6 but higher reliability of N2-latency (ICC = 0.63) in healthy younger and older adults.…”

Revisiting the Examination of Sharp/Dull Discrimination as Clinical Measure of Spinothalamic Tract Integrity

“…By evaluating the interrater reliability of sharp/dull discrimination in a cohort of both individuals with SCI and non-disabled participants, we found conclusive reliability of this fundamental part of the pin-prick examination for testing the integrity of spinothalamic tract function/pain perception (36,37). This is further emphasized by consistently narrow confidence intervals of the reliability coefficients (31).…”