A. Gaskell, R.D. Sanders, J. Sleigh

Editor—Brown and colleagues¹ have apparently misquoted our original conclusions.² We concluded that an alpha-delta dominant frontal EEG power spectrum is not sufficient to ensure unconsciousness during intended general anaesthesia.² It is hard to argue against the validity of our conclusion, given that three of the six observed volitional responses occurred during periods where the frontal EEG showed a clear alpha-delta dominant pattern. With regards to an EEG marker of phase-amplitude coupling (PmaxI), we concluded that frontal EEG parameters do not readily discriminate volitional responsiveness from unresponsiveness.