Finger-Equipped Electrode Electrical Stimulation for Severe Upper-Limb Paresis in the Acute Phase of Stroke: A Retrospective Case Series

Aim and objective Severe upper-limb paresis during the acute phase of stroke significantly limits functional recovery. Finger-equipped electrode electrical stimulation (FEE-ES) enables therapists to synchronize electrical stimulation (ES) with the patient's motor intent, even in the absence of voluntary movement. However, evidence regarding its feasibility and preliminary therapeutic effects in the acute phase of stroke remains limited. Therefore, this study aimed to evaluate the feasibility, safety, and potential therapeutic effects of FEE-ES in patients in the acute phase of stroke who present with severe upper-limb paresis. Materials and methods We retrospectively examined six patients (mean age: 56.0 ± 15.0 years) with a first-ever stroke and severe upper-limb paresis (baseline Fugl-Meyer Assessment for Upper Extremity (FMA-UE) ≤19), without severe cognitive or attentional deficits. FEE-ES was applied for approximately one month during the acute phase as part of the rehabilitation program. Upper-limb motor function was assessed using the FMA-UE and the upper-limb items of the Stroke Impairment Assessment Set (SIAS). Spasticity and skin integrity were monitored throughout the intervention. Results The median baseline FMA-UE score was 4.0 (range: 4-6) points, which improved to 16.0 (range: 7-27) points after one month (p = 0.031, Wilcoxon signed-rank exact test; effect size r = 0.86). The Hodges-Lehmann estimator indicated a median improvement of 11 points (95% confidence interval: 3-23). Three patients exceeded the minimal clinically important difference (MCID) of 10 points. The median SIAS-Knee-Mouth and Finger Function scores increased from 0 to 1.5, and from 0.5 to 1.0, respectively. However, no increase in spasticity or skin complications was observed. Four participants had follow-up assessments at two months after stroke onset, and all exhibited continued functional gains. Conclusion This retrospective case series demonstrated that FEE-ES in the acute phase of stroke is feasible, safe, and may be associated with significant improvements in upper-limb motor function in patients with severe paresis. Notably, some individuals exhibited continued functional gains beyond the acute stage, suggesting that early synchronization of motor intent with ES may promote long-term recovery. Although preliminary, these findings support the potential of FEE-ES as an adjunct rehabilitation strategy and highlight the need for additional controlled studies to confirm efficacy and optimize protocols.