Advanced Analysis of Pharmaco-EEG Data in Humans

Pharmaco-electroencephalography (EEG) is a non-invasive method used to assess the effects of pharmacological compounds on the central nervous system by processing the EEG signals which directly reveal the spontaneous synchronised postsynaptic neuronal activity of the cortex with high temporal resolution. The International Pharmaco-Encephalography Society (IPEG) has recently published guidelines, which were produced by a global panel of EEG experts, with the goal to increase the standardisation of pharmaco-EEG studies in human subjects and facilitate the comparability of data across laboratories, thus enabling data-pooling and meta-analyses. The recommended standard experimental procedure is to measure EEG activity under vigilance-controlled and resting conditions. The IPEG guidelines thoroughly present the technical details and therefore constitute a robust reference. The complementary aim of the present paper is to focus on practical aspects, pitfalls and precautions to be considered when processing pharmaco-EEG data by covering the following topics: (1) investigate the stability and reliability of 5-min EEG recordings under both vigilance-controlled and resting conditions; (2) assess the spontaneous time-dependent changes in spectral activity over time, and (3) apply the data-processing strategies suggested in the pharmaco-EEG guidelines and designed to optimally capture drug effects. For this purpose, the EEG data from a randomised, double-blind, crossover trial aimed at comparing the effect of diazepam (10 mg) and placebo in 16 healthy male volunteers is used to illustrate the discussion of the processing techniques and difficulties commonly faced when analysing pharmaco-EEG data.