Trading baseline with forelimbs somatosensory evoked potential for longitudinal analysis in thoracic transection spinal cord injury

Patients who suffered from spinal cord injury (SCI) that come to healthcare professionals for diagnosis and treatment do not have electrophysiology baseline of somatosensory evoked potential (SSEP). The SSEP has always been used in research for data comparison to detect onset and severity of the SCI as well as for assessing its progress, endogenous and therapeutic recovery. This unmet need has motivated us to develop a new tool to substitute the baseline data with forelimb SSEP data of the same day. In this study, we report the development and investigation of three distinctive thoracic transection (right T10 hemi-transection (Rxl), left T8 and right T10 double hemi-transection (Dxl) and T8 complete transection (Cxl)) spinal cord injuries in an adult rat model. We used our well-established monitoring methods to obtain SSEP baselines as well as post-injury signals from days 4, 7, 14 and 21. We observed that spectral coherences obtained from non-injured spinal cord pathways are always above 0.8. The spectral coherence is dimensionless measure with values between 0 and 1 and measures the correlation between two time signals in the frequency domain. Analysis of variance (ANOVA) results also showed that there is a significant difference between the spectral coherence componanet means before and after injury with reachingp = 0.05 for Rxl, p = 0.02 for DxI, and p = 0.00 for CxI. Our signal processing enables us to replicate comparable detection of the natural history of injuries longitudinally without the implication of baseline SSEP signals, highlighting the potential of this analysis method for clinical studies.