Background: There is increasing interest in biomarkers for predicting motor outcomes after stroke.
Aims: This study examined whether lower limb (LL) motor-evoked potentials (MEPs) 1-week post-stroke predict recovery of independent walking, use of an ankle-foot orthosis (AFO), or use of walking aids 3- and 6-months post-stroke.
Methods: Participants unable to walk independently were recruited 5 days post-stroke. Transcranial magnetic stimulation (TMS) was used to determine tibialis anterior MEP status and clinical assessments (age, National Institutes of Health Stroke Scale (NIHSS), ankle dorsiflexion strength, LL motricity index and Berg Balance Test) were completed 1-week post-stroke. Functional Ambulation Category (FAC), use of AFO and walking aid were assessed 3- and 6-months post-stroke. MEP status, alone and combined with clinical measures, and walking outcomes at 3- and 6-months were analysed with Pearson Chi-Square and multivariate binary logistic regression.
Results: Ninety participants were included (median age 72y (38 – 97y)). Most participants (81%) walked independently (FAC ≥ 4), 17% used AFO, and 49% used a walking aid at 3-months post-stroke with similar findings at 6-months. Independent walking was better predicted by age, LL strength and Berg Balance Test (accuracy 92%, 95% CI 85 - 97%) than by MEP status (accuracy 73%, 95% CI 63 - 83%). AFO use was better predicted by NIHSS and MEP status (accuracy 88%, 95%CI 79 – 94) than MEP status alone (accuracy 76%, 95% CI 65 – 84%). No variables predicted use of walking aids.
Conclusion: MEP status 1-week post-stroke predicts independent walking but combining age, balance and LL strength is more accurate. MEP status and NIHSS combined are stronger predictors of AFO use than MEP status alone. LL MEP status adds little value as a biomarker for walking outcomes.