Non-invasive insular stimulation for peripheral neuropathic pain: Influence of target or symptom? - 12/03/22

Doi : 10.1016/j.neucli.2022.02.001

Pedro Henrique Martins da Cunha ^a, Liu Dongyang ^a, Ana Mércia Fernandes ^a, Raíssa Benocci Thibes ^b, João Sato ^b, Harki Tanaka ^c, Camila Dale ^a, Jorge Dornellys da Silva Lapa ^a, Adriano Donizeth Silva de Morais ^a, Felipe Henriques Carvalho Soares ^a, Valquíria Aparecida da Silva ^a, Thomas Graven-Nielsen ^d, Manoel Jacobsen Teixeira ^a, Daniel Ciampi de Andrade ^a,^d,^{^{1
Present address: Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Fredrik Bajers Vej 7D-3, 9220 Aalborg E, Denmark.},}^⁎
^a LIM-62, Pain Center, Department of Neurology, University of São Paulo, São Paulo, Brazil
^b Center for Computing Mathematics and Cognition of the Federal University of ABC, Santo André, Brazil
^c Center for Engineering, Modeling and Applied Social Sciences at the Federal University of ABC, Santo André, Brazil
^d Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark

^⁎Corresponding author at: LIM-62, Pain Center, Department of Neurology, University of São Paulo, São Paulo, Brazil.LIM-62, Pain CenterDepartment of NeurologyUniversity of São PauloSão PauloBrazil

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Abstract

Objectives

The posterior-superior insula (PSI) has been shown to be a safe and potentially effective target for neuromodulation in peripheral neuropathic pain (PNP) in humans and animal models. However, it remains unknown whether there is a measurable responder profile to PSI stimulation. Two factors were hypothesized to influence the response of repetitive transcranial magnetic stimulation (rTMS) of the PSI: differences in rTMS target (discrete subregions of the PSI) or PNP phenotype.

Methods

This is a secondary analysis from a randomized, double-blind, sham-controlled, cross-over trial assessing PSI-rTMS in PNP (N = 31, 5 days rTMS) (10.1016/j.neucli.2021.06.003). Active PSI-rTMS true responders (>50% pain reduction from baseline after active but not after sham series of treatment) were compared with not true responders, to determine whether they differed with respect to 1) rTMS neuro-navigational target coordinates, and/or 2) specific neuropathic pain symptom inventory (NPSI) clusters (pinpointed pain, evoked pain, and deep pain) at baseline.

Results

Mean rTMS target coordinates did not differ between true (n = 45.1%) and not true responders (p = 0.436 for X, p = 0.120 for Y, and p = 0.116 for Z). The Euclidian distance between true and not true responders was 4.04 mm. When comparing differences in responders between NPSI clusters, no participant within the evoked pain cluster was a true responder (p = 0.024).