Please cite this article in press as: Casanova I, et al. Motor excitability measurements: The inﬂuence of gender, body mass index, age and temperature in healthy controls. Neurophysiologie Clinique/Clinical Neurophysiology (2014), http://dx.doi.org/10.1016/j.neucli.2014.03.002 ARTICLE IN PRESS +Model NEUCLI-2433; No. of Pages 6 Neurophysiologie Clinique/Clinical Neurophysiology (2014) xxx, xxx—xxx Disponible en ligne sur ScienceDirect www.sciencedirect.com ORIGINAL ARTICLE/ARTICLE ORIGINAL Motor excitability measurements: The inﬂuence of gender, body mass index, age and temperature in healthy controls Mesures d’excitabilité des ﬁbres motrices : inﬂuences du sexe, de l’indice de masse corporelle, de l’âge et de la température chez les sujets sains I. Casanova , A. Diaz , S. Pinto , M. de Carvalho * Clinical and translational physiology unit, physiology institute, faculty of medicine, Instituto de Medicina Molecular, university of Lisbon, avenue Professor Egas Moniz, 1649-028 Lisbon, Portugal Received 29 June 2013; accepted 6 March 2014 KEYWORDS Age; Body mass index; Nerve excitability; Gender; Temperature Summary Study aims. — The technique of threshold tracking to test axonal excitability gives information about nodal and internodal ion channel function. We aimed to investigate variability of the motor excitability measurements in healthy controls, taking into account age, gender, body mass index (BMI) and small changes in skin temperature. Materials and methods. — We examined the left median nerve of 47 healthy controls using the automated threshold-tacking program, QTRAC. Statistical multiple regression analysis was applied to test relationship between nerve excitability measurements and subject variables. Results. — Comparisons between genders did not ﬁnd any signiﬁcant difference (P > 0.2 for all comparisons). Multiple regression analysis showed that motor amplitude decreases with age and temperature, stimulus-response slope decreases with age and BMI, and that accommodation half-time decrease with age and temperature. Conclusion. — The changes related to demographic features on TRONDE protocol parameters are small and less important than in conventional nerve conduction studies. Nonetheless, our results underscore the relevance of careful temperature control, and indicate that interpretation of stimulus-response slope and accommodation half-time should take into account age and BMI. In contrast, gender is not of major relevance to axonal threshold ﬁndings in motor nerves. © 2014 Elsevier Masson SAS. All rights reserved. ∗ Corresponding author. E-mail addresses: mamedemg@mail.telepac.pt, mamedemg@netcabo.pt (M. de Carvalho). http://dx.doi.org/10.1016/j.neucli.2014.03.002 0987-7053/© 2014 Elsevier Masson SAS. All rights reserved.