Detection of auditory hallucinations from electroencephalographic brain–computer interface signals

Schizophrenia is a chronic psychiatric disorder that is highly debilitating. One of the most frequent symptoms is the presence of auditory hallucinations (AH), which could be related to alterations in brain electrical activity measurable with electroencephalography (EEG). Although many previous works have recorded EEG signals of schizophrenia patients with medical EEG devices, the study of AH has never been developed by means of portable EEG measuring instruments. Therefore, the aim of this study is to detect AH in schizophrenia patients with a wireless EEG device. For that purpose, the spectral power from EEG recordings of periods with and without AH has been evaluated in a group of nine schizophrenia patients. Results reported that the main activation during hallucinations was found in right frontal locations, whereas the left hemisphere presented a stronger activation in hallucination-free periods. Furthermore, a generalized decrease of spectral power in hallucination with respect to hallucination-free episodes has been observed. Hence, this work demonstrates the possibility of detecting AH episodes with a wearable EEG device. In addition, the results obtained were compatible with the default model network, reporting a greater activation during no hallucination periods compared to hallucination moments.