Somatosensory Evoked Potential N20 as a Prognostic Tool for Upper Limb Function in Stroke Patients: A Focus on Basal Ganglia and Thalamus

Objective: This study is aimed at elucidating the prognostic utility of somatosensory evoked potentials (SEPs) N20 in the recovery of upper limb functionality among stroke patients with varying cerebral lesions. Methods: A cohort of 60 stroke patients enrolled in this study and stratified into two groups: 30 patients with strokes affecting the basal ganglia and 30 with thalamic involvement. Each patient underwent an SEP test after admission and participated in rehabilitation training for 3 months. Assessments were carried out using the Fugl–Meyer Assessment for Upper Extremity (FMA‐UE), the Modified Ashworth Scale (MAS), and the Modified Barthel Index (MBI) at admission and 3 months after treatment to analyze the correlation between SEP‐N20 indices and the function assessment scales in the two groups. Results: (1) SEP in stroke patients revealed notable abnormalities, in which a more pronounced reduction of the amplitude ratio of the N20 (SEPAR‐N20) wave between the affected and unaffected sides was observed in the thalamus group ( p < 0.05). (2) After 3 months, a significant positive correlation was established between the improvement rate of FMA‐UE scores and SEPAR‐N20 in the basal ganglia group ( r = 0.696, p < 0.0001). Conversely, this correlation was not evident within the thalamus group ( r = −0.157, p > 0.05). (3) There was no significant correlation between MAS or MBI scores and SEPAR‐N20 in either group ( p > 0.05). Conclusion: The extent of SEP abnormality poststroke is associated with the location of the lesion. Strokes involving the thalamus exhibited more pronounced changes in the N20 component. SEPAR‐N20 might serve as a valuable predictor for the recovery of upper limb functionality, particularly in cases of basal ganglia strokes. Trial Registration: Chinese Clinical Trial Registry: ChiCTR2300075570