Wellcome Centre for Human Neuroimaging, University College London, UK.
Institute of Cognitive Neuroscience, University College London, UK.
Brain. 2019 Jan 1;142(1):15-22. doi: 10.1093/brain/awy302.
The proportional recovery rule asserts that most stroke survivors recover a fixed proportion of lost function. To the extent that this is true, recovery from stroke can be predicted accurately from baseline measures of acute post-stroke impairment alone. Reports that baseline scores explain more than 80%, and sometimes more than 90%, of the variance in the patients' recoveries, are rapidly accumulating. Here, we show that these headline effect sizes are likely inflated. The key effects in this literature are typically expressed as, or reducible to, correlation coefficients between baseline scores and recovery (outcome scores minus baseline scores). Using formal analyses and simulations, we show that these correlations will be extreme when outcomes are significantly less variable than baselines, which they often will be in practice regardless of the real relationship between outcomes and baselines. We show that these effect sizes are likely to be over-optimistic in every empirical study that we found that reported enough information for us to make the judgement, and argue that the same is likely to be true in other studies as well. The implication is that recovery after stroke may not be as proportional as recent studies suggest.
比例恢复规则断言，大多数中风幸存者会恢复失去功能的固定比例。在一定程度上，如果这是真的，那么仅从急性中风后基线测量就可以准确预测中风后的恢复情况。有报道称，基线分数可以解释超过 80%，有时甚至超过 90%的患者恢复的差异，这种报道正在迅速增加。在这里，我们表明这些头条效应大小可能被夸大了。该文献中的关键效应通常表示为（或可简化为）基线分数与恢复（结果分数减去基线分数）之间的相关系数。我们使用正式分析和模拟表明，当结果的变化明显小于基线时，这些相关性将非常极端，而无论结果与基线之间的实际关系如何，这种情况在实践中通常都会发生。我们表明，在我们发现并报告了足够信息以使我们能够做出判断的每个经验研究中，这些效果大小都可能过于乐观，并认为在其他研究中也可能如此。这意味着中风后的恢复情况可能并不像最近的研究表明的那样成比例。
