Short-term and long-term predictors of balance function in stroke patients: a 6-month follow-up study

We aimed to determine early predictors of balance function (Berg Balance Scale, BBS) at 3 and 6 months after stroke using clinical, neurophysiological, and neuroimaging variables. Seventy-nine patients with hemiparesis after a stroke were included. Demographics, stroke characteristics, and clinical variables [Mini-Mental State Examination, BBS, strength in the hemiparetic hip, knee, and ankle muscles, and Fugl-Meyer Assessment Lower Extremity (FMA-LE)] were evaluated 2 weeks post-stroke, on average. Somatosensory-evoked potentials (SEP) from both tibial nerves and diffusion tensor imaging data were collected respectively within 3 weeks and 4 weeks post-onset to calculate the SEP amplitude ratio and the laterality index of fractional anisotropy of the corticospinal tract. In multiple linear regression analysis, younger age, higher FMA-LE score, and stronger hemiparetic hip extensors were independent predictors of higher BBS at 3 months post-stroke (adjusted R2  = 0.563, P  < 0.001). At 6 months post-stroke, significant predictors of higher BBS were younger age, higher FMA-LE, stronger hemiparetic hip extensors, and larger SEP amplitude ratio (adjusted R2  = 0.552, P  < 0.001), although the incremental contribution of the latter was rather small ( R2  = 0.019). We conclude that age and the initial motor impairment of the affected lower limb can inform the state of balance function at 3 and 6 months after stroke.