Preserved somatosensory conduction in complete spinal cord injury: Discomplete SCI

Restoring the Sense of Touch Using a Sensorimotor Demultiplexing Neural Interface

“…This result demonstrates the ability to decode residual sensory neural activity from M1 that is below conscious perception, from functionally relevant hand dermatomes. Furthermore, this intracortical electrophysiological evidence of sensory discompleteness extends previous studies using noninvasive imaging of evoked activity (Wrigley et al, 2018;Awad et al, 2015;Ioannides et al, 2002;Sabbah et al, 2002).…”

“…Touch-regulated grip-intensity BCI control demonstrates that limb reanimation controlled by decoded afferent cortical activity is possible. Overall, these results suggest that sensory discompleteness (Wrigley et al, 2018;Awad et al, 2015;Ioannides et al, 2002;Sabbah et al, 2002) can be leveraged for multimodal restoration of touch and motor function.…”

“…Spinal cord injury (SCI) damages sensorimotor circuits leading to paralysis, an impaired sense of agency, and sensory dysfunction. Interestingly, recent evidence suggests that a severe clinically complete SCI does not entirely block ascending sensory information transmission from skin innervated below the lesion (Wrigley et al, 2018;Awad et al, 2015;Ioannides et al, 2002;Sabbah et al, 2002). These important studies demonstrate that, even years after SCI, tactile stimuli that the patients cannot feel evoke changes in cortical activity.…”

“…These important studies demonstrate that, even years after SCI, tactile stimuli that the patients cannot feel evoke changes in cortical activity. ''Discomplete'' SCIs are now being investigated-where no clinical evidence of fiber tract function is detectable, but spared fibers may affect some physiological activity (Dimitrijevic, 1987;Sherwood et al, 1992;Finnerup et al, 2004;Wrigley et al, 2018;Awad et al, 2015;Ioannides et al, 2002;Sabbah et al, 2002). It is estimated that ''sensory discomplete'' SCI occurs in a considerable proportion of patients with a clinically complete SCI ($50 %; Wrigley et al, 2018;Finnerup et al, 2004).…”

“…Unfortunately, no studies to date have reported touch-related electrophysiological activity in human M1 following severe AIS-A SCI (Wrigley et al, 2018;Awad et al, 2015;Ioannides et al, 2002;Sabbah et al, 2002). Even in uninjured humans, there is significant evidence of a separation between touch and movement representations in the cortex (Harding-Forrester and Feldman, 2018;Kaas, 2012;Goldring and Ratcheson, 1972;Roux et al, 2018;Ibá ñ ez et al, 1995;Stippich et al, 1999;Kurth et al, 1998).…”