Sensations and reaction times evoked by electrical sinusoidal stimulation

Autor: Gilberto Mastrocola Manzano, G. Gronich, C.A. Peres, C.J. Tierra-Criollo, João Antonio Maciel Nóbrega, Nadia Iandoli de Oliveira Braga, Lydia Maria Pereira Giuliano, Evandro Penteado Villar Felix
Rok vydání: 2009
Předmět:
Zdroj: Neurophysiologie Clinique/Clinical Neurophysiology. 39:283-290
ISSN: 0987-7053
DOI: 10.1016/j.neucli.2009.10.001
Popis: Summary Objective To determine whether 5 Hz and 2000 Hz sinusoidal electric currents evoke different sensations and to indirectly evaluate which peripheral nerve fibers are stimulated by these different frequencies. Methods One hundred and fifty subjects chose three among eight descriptors of sensations evoked by 5 Hz and 2000 Hz currents and the results were submitted to factor analysis. In 20 subjects, reaction times to 5, 250 and 2000 Hz currents were determined at 1.1x ST and reaction times to 5 Hz currents were also determined at 2x ST. Results Responses were grouped in four factors: Factor 1, which loaded mainly in descriptors related to tweezers stimulation, was higher than the other factors during 2000 Hz stimulation at 1.5x ST. Factor 2, which loaded mainly in descriptors related to needle stimulation, was higher than the other factors during 5 Hz stimulation. Factor 1 increased and Factor 2 decreased with an increase in 5 Hz intensity from 1.5 to 4x ST. Reaction times measured from the fastest responses were significantly different: 0.57 s (0.16 to 1.60), 0.34 s (0.12 to 0.71) and 0.22 s (0.08 to 0.35) for 5, 250 and 2000 Hz, respectively, and 0.22 s (0.11 to 0.34) for 5 Hz at 2x ST. Conclusions Sinusoidal electrical stimulation of 5 Hz and 2000 Hz evoke different sensations. At juxta-threshold intensities, RT measurements suggest that 2000 Hz stimulates Aβ-fibers, 250 Hz Aβ- or A∂-fibers, 5 Hz Aβ-, A∂- or C-fibers. The fiber type, which was initially stimulated by the lower frequencies, depended on inter-individual differences.
Databáze: OpenAIRE
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