Characterization of somatosensory EEG correlates for enhancement of tactile encoding

The sense of touch represents an important aspect in our daily lives, playing a crucial role in interacting with the environment and enabling effective motor control, especially in tasks involving manipulation. In cases of upper limb amputation, the loss of fingertip touch sensation and the absence of sensory feedback in prosthetic devices underscore the importance of understanding tactile processing. This study aimed to investigate somatosensory correlates using electroencephalography (EEG) monitoring during modality-matched stimulations applied to fingertips. A customized experimental protocol was employed to deliver tactile stimulation to three fingertips. In the conducted experiment, five able-bodied participants underwent a combination of two force levels and three vibration types delivered through a haptic feedback device named TouchDIVER. Recorded EEG data were analyzed in the time domain to investigate somatosensory evoked potentials in response to various tactile stimuli and in the frequency domain to explore the modulation of brain rhythms. The results highlighted the potential of EEG recording in discerning tactile sensations, particularly emphasizing the potential involvement of deflection P50 in discriminating among sensations and of N200 and P300 in distinguishing stimulation intensities.