Analysis of extrinsic and intrinsic factors affecting event related desynchronization production

Abstract

Recently there has been an increase in the number of stroke patients with motor paralysis. Appropriate re-afferent sensory feedback synchronized with a voluntary motor intention would be effective for promoting neural plasticity in the stroke rehabilitation. Therefore, BCI technology is considered to be a promising approach in the neuro-rehabilitation. To estimate human motor intention, an event-related desynchronization (ERD), a feature of electroencephalogram (EEG) evoked by motor execution or motor imagery is usually used. However, there exists various factors that affect ERD production, and its neural mechanism is still an open question. As a preliminary stage, we evaluate mutual effects of intrinsic (voluntary motor imagery) and extrinsic (visual and somatosensory stimuli) factors on the ERD production. Experimental results indicate that these three factors are not always additively interacting with each other and affecting the ERD production.

Effect of instructive visual stimuli on neurofeedback training for motor imagery-based brain–computer interface

“…This result is consistent with the fact, in a number of previous studies, that observing movements automatically causes the ERD without execution of movements (e.g., Takata et al, 2012). We can confirm a significant power decrease (dark blue) in a specific frequency band during the task period under the MO session.…”

“…Third, the current study focused only on visual information, while somatic sensation is also known to evoke ERD even when limbs are moved passively by a human experimenter (Alegre et al, 2002), a robot (Formaggio et al, 2013), or by functional electrical stimulation (Müller et al, 2003). Therefore, combining visual and somatosensory stimulation for MI-based BCI training may be worth to investigate if multisensory integration is more effective, although concurrent presentation of multimodal sensory stimuli sometimes disturbs ERD production (Takata et al, 2012). Fourth, the performance of BCI systems would be higher by including frontally positioned electrodes as suggested by Leocani, Toro, Manganotti, Zhuang, and Hallett (1997).…”