Lioi G, et al. - Researchers developed as well as tested an index that quantifies the strength and direction of information flow in electroencephalographic signals collected across the scalp. They evaluated its performance with respect to the ability to discriminate ‘wakefulness’ from ‘anaesthesia’, and compared it with estimated bispectral index and the auditory middle latency response. In 10 patients, a step-wise slow induction of anaesthesia was used and graded changes in electroencephalographic directional connectivity at propofol effect-site concentrations of 2 μg.ml⁻¹, 3 μg.ml⁻¹ and 4 μg.ml⁻¹, were evaluated. They estimated connectivity from multichannel electroencephalograms using directed coherence, as well as middle latency response and estimated bispectral index, for each stable effect-site concentration. Findings revealed 95% accuracy of directed coherence, which showed the best performance, in discriminating wakefulness from anaesthesia. This finding shows the potential of this new method (on its own or combined with others) for monitoring adequacy of anaesthesia.