Predictors of manual dexterity at 3 and 6 months after stroke: integration of clinical, neurophysiological, and neuroimaging factors

Abstract

This retrospective study aimed to predict dexterity at 3 and 6 months post-stroke by integrating clinical, neurophysiological, and neuroimaging factors. We included 126 patients with first-ever, unilateral, and supratentorial stroke. Demographic, stroke characteristics, and initial clinical assessment variables [Mini-mental state examination and Fugl–Meyer Assessment Upper Extremity (FMA-UE)] were evaluated 2 weeks after stroke. Dexterity, measured using the Manual Function Test (MFT) hand subscore, was the primary outcome. The neurophysiological variables, upper limb somatosensory evoked potential (SEP) and motor evoked potential (MEP), were assessed 2 weeks post-stroke. The neuroimaging variable, fractional anisotropy (FA) of the corticospinal tract (CST), was assessed 3 weeks post-stroke. Multiple regression analysis revealed significant predictors for improved dexterity at 3 and 6 months post-stroke, including younger age, higher FMA-UE score, presence of waveforms in the SEP and MEP, and higher FA values in the CST (adjusted R2 = 0.776, P < 0.001 at 3 months; adjusted R2 = 0.668, P < 0.001 at 6 months; where MEP, SEP, and FA accounted together for an additional 0.079 and 0.166 of variance beyond age and FMA-UE, respectively). Subgroup analysis was conducted by categorizing the participants based on their initial hand function: those with no hand function (MFT hand subscore = 0) (N = 60) and those with a score >0 (N = 51). Initial FMA-UE was a primary predictive factor regardless of the time point or initial severity, whereas the presence of MEP was a significant predictor only in the group with no initial hand dexterity.