Reducing the Calibration Time in Somatosensory BCI by Using Tactile ERD

Abstract

Objective: We propose a tactile-induced-oscillation approach to reduce the calibration time in somatosensory brain-computer interfaces (BCI). Methods: Based on the similarity between tactile induced event-related desynchronization (ERD) and imagined sensation induced ERD activation, we extensively evaluated BCI performance when using a conventional and a novel calibration strategy. In the conventional calibration, the tactile imagined data was used, while in the sensory calibration model sensory stimulation data was used. Subjects were required to sense the tactile stimulus when real tactile was applied to the left or right wrist and were required to perform imagined sensation tasks in the somatosensory BCI paradigm. Results: The sensory calibration led to a significantly better performance than the conventional calibration when tested on the same imagined sensation dataset (F(1,19)=10.89, P=0.0038), with an average 5.1% improvement in accuracy. Moreover, the sensory calibration was 39.3% faster in reaching a performance level of above 70% accuracy. Conclusion: The proposed approach of using tactile ERD from the sensory cortex provides an effective way of reducing the calibration time in a somatosensory BCI system. Significance: The tactile stimulation would be specifically useful before BCI usage, avoiding excessive fatigue when the mental task is difficult to perform. The tactile ERD approach may find BCI applications for patients or users with preserved afferent pathways.

Event-Related Desynchronization Induced by Tactile Imagery: an EEG Study

“…Yao and colleagues demonstrated that SAO can be reliably decoded using a BCI paradigm and used as an independent modality. They also improved SAO classification by using congruent tactile stimulation (Yao et al, 2017b(Yao et al, , 2022b and showed that the sources of sensorimotor ERD are mainly located in the somatosensory cortex (Yao et al, 2022a). Overall, these studies demonstrated similarity between neural patterns exhibited during real perceptions and TI tasks, which is consistent with the results of MI studies showing that overlapping brain regions are engaged in physical movements and motor imagery.…”

Tactile Imagery Affects Cortical Responses to Vibrotactile Stimulation of the Fingertip

“…Similarly, our results suggest that ERD-based decoding could be implemented in both TS and TI-based BCIs and perhaps ERD effects could be enhanced by BCI training. Overall, our present study aligns with the findings of Yao et al (2018Yao et al ( , 2022b, which demonstrated that BCI performance can be enhanced using tactile-induced ERD for calibration.…”

Novel electrotactile brain-computer interface with somatosensory event-related potential based control

“…Additionally, our approach is methodologically different from other tactile BCIs that utilize ERPs (mainly P300) for control, since we employed equal probability of target and distractor stimulus occurrence. This approach is different from classical oddball paradigm employed in other tactile ERP BCIs where the target (deviant, odd) stimuli is less frequent than the standard, and different from studies employing several targets of the same, smaller, probability compared to distractor stimuli (Guger et al, 2017;Spataro et al, 2018;Yao et al, 2022;Zhong et al, 2023). Guger et al (2017) and Spataro et al (2018) in one of their paradigms utilized vibrotactile stimulation on left/right wrists (targets) and distractor on the shoulder or back in order to induce P300 responses.…”