Introduction

Early and accurate prediction of post-stroke recovery potential, ideally during the first week, is needed to assist selection of treatment approaches and inform patient selection in clinical trials1. A range of models to predict upper limb motor outcome have been published2,3,4,5,6. At the simplest level, measurable grip strength at 1 month5 or presence of shoulder abduction or finger extension at 3-days post stroke7 are suggested as plausible predictors for upper limb recovery. The more complex models propose various neurophysiological and neuroimaging techniques combined with clinical assessments8,9,10.

There are, however, significant barriers to the clinical implementation of existing prediction algorithms. For example, use of more comprehensive scales, such as Fugl-Meyer Assessment, within days of stroke is a challenge in acute settings, particularly in patients with complex needs. The requirement to take repeated measurements within the first weeks11 can also be problematic when typical length of stay within a stroke unit is less than 2-weeks12,13. Further, the need to draw upon neurophysiological and neuroimaging techniques to determine the corticospinal integrity are costly and not accessible to most clinical practices1,14. Prediction models using easily accessible clinical data i.e. simple clinical tests with routinely available equipment early after stroke5,6,15 would be a more realistic solution for developing clinically usable prognostic algorithms.

Prediction models only including clinical assessments have shown to be inferior compared to the models combining clinical and neurophysiological or neuroimaging techniques9,16,17. This seem to be particularly valid for patients with initial poor motor function9,16,17. Recently, a prediction algorithm only including clinical bedside assessment reported an overall accuracy of 61% at predicting upper limb activity capacity at 3 months post stroke, although the sensitivity and specificity varied across the four outcome categories17. An external validation of a prediction model for upper limb activity capacity at six months post stroke, discriminating poor outcome (Action Research Arm Test < 10) and using shoulder abduction and finger extension as clinical predictor variables, showed high sensitivity (> 0.80) but lower specificity (0.40–0.70)18. For discrimination of a higher outcome level (Action Research Arm Test > 32), likewise, the sensitivity was high (> 0.92) but specificity was lower (0.28–0.60)18. These studies confirm that prediction models only using clinical assessments can provide clinically useful information, perform better than a chance alone and could therefore be considered as alternatives for more complex models17. Based on previous literature, to reach clinical relevance, a prediction algorithm only including clinical assessments should be expected reach an accuracy, sensitivity and specificity at least between 60 and 70%.

To target this clinical need we aimed to identify a set of clinical assessments feasible in routine practice early after stroke that can provide an accurate and differentiated prediction of upper limb activity capacity at 3-months post-stroke.