Tactile Feedback Device Effects on Sensory-Motor Integration in Post-Stroke Finger Impairment: A Single-Case Experimental Multiple-Baseline Study

Background/Objectives: Post-stroke impairment (PSI) frequently causes upper limb sensorimotor deficits, including reduced ability to perceive fingertip friction, limiting dexterous movements. We evaluated the effects of a tactile sensory substitution device (“Yubi-Reco”) that delivers real-time fingertip friction information to both temporal bones via vibration and explored potential neurophysiological changes in PSI. Methods: This study used a single-case experimental multiple-baseline design. Three participants with PSI completed a 15-day AB-phase protocol. Baseline (A) consisted of daily sensorimotor tasks without Yubi-Reco, while the intervention (B) added real-time friction feedback via Yubi-Reco to the same tasks. Outcomes included electroencephalography (gamma power), the Purdue Pegboard Test, finger numbness Numerical Rating Scale (NRS), Motor Activity Log-14 (Amount of Use [AoU], Quality of Movement [QoM]), and sense of agency (SoA). Effect sizes were calculated using Tau-U. Results: Very large changes were observed in Purdue Pegboard Test performance (Tau-U = 0.80), and large changes were observed in finger numbness NRS scores (Tau-U = 0.79). Case I showed increased gamma power across frontal and central sites, Case II demonstrated relative attenuation near right frontal and parietal sites, and Case III showed bilateral central gamma reduction, suggesting neurophysiological alterations near recorded sites. AoU and SoA improved in all participants. AoU exceeded the minimal clinically important difference (0.5 points) in two cases. Conclusions: Real-time sensory substitution feedback using Yubi-Reco may improve upper-limb sensorimotor function and induce preliminary neurophysiological changes in individuals with PSI. The intervention appeared to enhance dexterous movement ability and SoA, which coincided with preliminary, exploratory neurophysiological shifts across sensorimotor networks.