The Prognostic Utility of Electroencephalography in Stroke Recovery: A Systematic Review and Meta-Analysis.

Publication bias may inflate how good EEG looks here, because studies that found nothing are less likely to be published; the authors acknowledge the prognostic value found in the review may be overstated. Most studies were exploratory rather than testing a pre-chosen EEG measure, and many reported results for several variables, outcomes and time points, so some positive findings are likely to be chance. Reporting was often incomplete. The average quality score was 11 out of 16, and 7 of the 75 studies were rated poor, mostly for missing variance estimates or no adjustment for confounders such as age and initial clinical score. No study directly compared ischemic with hemorrhagic stroke, so the review cannot say whether EEG predicts recovery differently for the two types. Only papers published in English were included. Samples were small: the median study had 34 participants. The review used stricter criteria than the original authors, counting some results as negative that the papers themselves called positive, so the studies may look weaker here than in their own reports.

The authors declare no conflicts of interest. No funder is named in the declaration.

Do not read this as a tool for predicting an individual patient's recovery. The pooled numbers come mostly from exploratory studies of mixed quality, with a median of 34 participants each, and the authors say no consensus exists yet on which EEG measure to use.