ENHACED SENSORIMOTOR REPRESENTATIONS IN SPINAL CORD INJURY THROUGH LUMBOSACRAL NEUROMODULATION

Spinal cord injury (SCI) disrupts afferent and efferent pathways, leading to maladaptive cortical reorganization that affects sensorimotor function and motor-related cognition. Lumbosacral peripheral neuromodulation (LION) has shown promise in improving autonomic and motor outcomes after SCI, but whether it modulates cortical motor representations remains unclear. Here, we test the hypothesis that LION-based rehabilitation is associated with partially preserved cortical motor imagery representations following SCI.

We conducted a cross-sectional electroencephalography (EEG) study of lower-limb motor imagery in three cohorts: healthy controls (CTRL, n=9), individuals with SCI without neuromodulation (LM, n=7), and individuals with SCI implanted with the LION system who underwent rehabilitation sessions using the device (LML, n=10).

Cortical activity was analyzed in the mu–beta frequency range using central EEG channels (C3, Cz, C4) over sensorimotor areas. In addition to conventional spectral features, we applied a covariance-based approach capturing relationships between EEG channels, enabling characterization of the structure of motor imagery representations.

We observed a clear neurophysiological separation between groups. Cortical representations in the LM group were markedly distant from healthy controls, indicating disrupted motor imagery organization. In contrast, the LML group exhibited representations that were intermediate between LM and CTRL, consistent with partial preservation of cortical motor networks. These group differences were more pronounced when considering inter-channel relationships than when using channel-wise spectral features alone.

Together, these findings suggest that LION-based rehabilitation is associated with modulation of cortical motor representations and that relational EEG features provide valuable insight into sensorimotor network organization after SCI.