CORRELATION OF N30 SOMATOSENSORY EVOKED POTENTIALS WITH SPASTICITY AND NEUROLOGICAL FUNCTION AFTER STROKE: A CROSS-SECTIONAL STUDY

OBJECTIVE: To test whether the presence of N30 somatosensory evoked potentials, generated from the supplementary motor area and premotor cortex, correlate with post-stroke spasticity, motor deficits, or motor recovery stage. DESIGN: A cross-sectional study. PATIENTS: A total of 43 patients with stroke hospitalized at Maoming People’s Hospital, Maoming, China. METHODS: Forty-three stroke patients underwent neurofunctional tests, including Modified Ashworth Scale (MAS), Brunnstrom stage, manual muscle test and neurophysiological tests, including N30 somatosensory evoked potentials, N20 somatosensory evoked potentials, motor evoked potentials, H-reflex. The results were compared between groups. Correlation and regression analyses were performed as well. Results: Patients with absence of N30 somatosensory evoked potential exhibited stronger flexor carpi radialis muscle spasticity (r = –0.50, p < 0.05) and worse motor function (r = 0.57, p < 0.05) than patients with presence of N30 somatosensory evoked potential. The generalized linear model (GLM) including both N30 somatosensory evoked potentials and motor evoked potentials (Akaike Information Criterion (AIC) = 121.99) better reflected the recovery stage of the affected proximal upper limb than the models including N30 somatosensory evoked potentials (AIC = 125.06) or motor evoked potentials alone (AIC = 127.45). CONCLUSION: N30 somatosensory evoked potential status correlates with the degrees of spasticity and motor function of stroke patients. The results showed that N30 somatosensory evoked potentials hold promise as a biomarker for the development of spasticity and the recovery of proximal limbs.