• A recent study on EEG responses to transcranial magnetic stimulation by Casali et al [1] has shown high correlation between conscious level of brain and logarithmic complexity in electrophysiological signals. This theory-driven approach suggested a substantial decrease in the complexity of spatiotemporal pattern of triggered cortical activations with loss of consciousness.• Another study by Schartner et al [2] studied the variations in the time-series complexity of spontaneous EEG and proposed an overall decrease in complexity of EEG signals in distinct brain regions and frequency bands.• Here we investigate Lempel-Ziv complexity for three levels of consciousness (Awake, Mild Sedation and Moderate Sedation) with high-density spontaneous EEG data of seven subjects. The dataset was analysed earlier by Chennu et al [3] and is freely available online. Our objective is to find significant combinations of brain areas and frequency bands which demonstrate a static variation pattern of normalized complexity.