This paper proposes an alternative measure for estimating the amplitude modulation (AM) of newborn EEG that can control the frequency content of the AM function. The EEG amplitude estimation method is based on the envelope (AM) fitting procedure defined in the sifting process of the empirical mode decomposition (EMD). The ability to control the frequency content of the AM function is implemented by modifying the EMD envelope fitting procedure to reject extrema that lie too closely together. This method is shown to offer superior performance when using EEG amplitude to segment trace alternant (TA) and detect sleep state (SS), in newborn EEG, compared to conventional measures of amplitude.