Is it possible to use the nociceptive withdrawal reflex evoked by FES as feedback in a BCI system?

TABERNIG, CAROLINA; CARRERE, L. CAROLINA; BIURRUN MANRESA, JOSÉ A.; GENTILETTI, GERARDO G.; SPAICH, ERIKA G.

Toronto

Conferencia; 2019 IFESS Conference; 2019

International Functional Electrical Stimulation Society

People who suffered a stroke can perform a motor intent in response to a movement cue producing the desynchronization of sensorimotor rhythms of the electroencephalogram [3]. This physiological phenomenon, called Event Related Desynchronization (ERD), is used for the development of Brain Computer Interfaces (BCI). BCIs record the electroencephalogram, detect the ERD, and convert it into a command output for an actuator to provide sensory feedback, communication or mobility to the user [4]. BCIs constitute an emerging technology for motor recovery [5]. Functional Electrical Stimulation (FES) is one of the available feedback modalities, that can be used to evoke the Nociceptive Withdrawal Reflex (NWR) and thereby assist the production of functional movements [1]. For example, activation of the NWR can cause the flexion of the main joints of the lower limb; then, if it is performed repetitively and synergistically with the activation of the central nervous systems (detected by the ERD-based BCI), it can facilitate motor relearning and motor recovery in hemiparetic people [2]. However, the ERD happens during the voluntary motor intention and the NWR is related to the activation of the nociceptive system, and the relation between the central processing of nociceptive information and the motor intention is still unknown. In this study, the ERD produced in the first motor intent after evoking a NWR was assessed in order to evaluate if nociceptive stimulation conditions the ERD of subsequent motor intents.Eight healthy subjects were included (age: 32±9 years, 4 males) in the experimental study. The experiment consisted of using an ERD-based BCI system which provided feedback through the activation of the NWR. To evoke the NWR, the cathode was placed on the medial area of the sole of the foot and the anode was placed on the dorsum of the same foot, which resulted in dorsiflexion of the foot with minimal discomfort due to the electrical stimulus (5 pulses, pulse width: 1 ms, frequency: 200 pps, mean amplitude: 13.6±6.4 mA). The electroencephalogram from the sensorimotor cortex and the electromyogram of the tibialis anterior muscle were recorded during 30 trials. The main outcome variables were the normalized root mean square of the evoked electromyogram (reflex response), the average electroencephalogram amplitude at the maximum ERD frequency (A_fmax_ERD) and the percentage of A_fmax_ERD decrease during motor intent relative to rest (ERD%) at the first motor intent after the NWR was elicited by the BCI system.The statistical analysis did not reveal a significant difference between the size of the reflex response and both the A_fmax_ERD (p=0.663) and the ERD% (p=0.252) of the following motor intent. From these results it can be concluded that the cutaneous, proprioceptive, and visual feedback provided by FES-evoked NWR neither conditions the subsequent ERD nor the electroencephalogram from the sensorimotor cortex at fmax_ERD. Furthermore, this results suggest that it is feasible to use the FES-evoked NWR as feedback to the user in an ERD-based BCI system.[1]Andersen, O.K.; Sonnenborg, F.A. and Arendt-Nielsen, L. (1999) Withdrawal Reflexes Elicited By Electrical Stimulation of the foot sole. In: Muscle and Nerve, (November):1520-1530. [2]Spaich, E.G.; Svaneborg, N.; Jørgensen, H.R.M. and Andersen, O.K. (2014) Rehabilitation of the hemiparetic gait by nociceptive withdrawal reflex-based functional electrical therapy: A randomized, single-blinded study. In: Journal of NeuroEngineering and Rehabilitation, 11(1):1-10. https://doi.org/10.1186/1743-0003-11-81.[3]Neuper, C. and Pfurtscheller, G. (2010) Electroencephalographic characteristics during motor imagery. In: Aymeric G and Collet C (eds.) The neurophysiological foundations of mental and motor imagery. University Press Scholarship Online Oxford. https://doi.org/10.1093/acprof[4]Wolpaw, J.R. and Wolpaw, E.W. (2012) Brain-computer interfaces : principles and practice. Oxford University Press: 400 pp. [5]Tabernig, C; Lopez, C; Carrere, L; Spaich E. and Ballario, C. (2018) Neurorehabilitation therapy of patients with severe stroke based on functional electrical stimulation commanded by a brain computer interface. In: Journal of Rehabilitation and Assistive Technologies Engineering, 5: 1-12. doi: 10.1177/2055668318789280