Speech intelligibility is best predicted by intensity, not cochlea-scaled entropy

Cochlea-scaled entropy (CSE) is a measure of spectro-temporal change that has been reported to predict the contribution of speech segments to overall intelligibility. This paper confirms that CSE is highly correlated with intensity, making it impossible to determine empirically whether it is CSE or simply intensity that determines speech importance. A more perceptually relevant version of CSE that uses dB-scaled differences, rather than differences in linear amplitude, failed to predict speech intelligibility. Overall, a parsimonious account of the available data is that the importance of speech segments to overall intelligibility is best predicted by their relative intensity, not by CSE.