Auditory verbal hallucination can be evoked by prefrontal epileptic seizure

Auditory verbal hallucinations (AVHs) have been reported in neocortical temporal epileptic seizures and have been considered highly associated with implication of auditory cortex by epileptic discharges or electrical stimulation. Herein, we report two rare frontal epilepsy cases in which AVHs featured the habitual seizures. The epileptogenic zones of these two patients were localized in the dorsal and orbitomedial prefrontal cortex, respectively by stereoelectroencephalography (SEEG) monitoring. Comparing with the AVHs in schizophrenia, we postulated that the phenomenological similarities between the two sets of AVHs imply homology in mechanisms. Ictal SEEG confirmed that the wide involvement of prefrontal-cingulate-auditory cortical network by low-voltage fast activity corresponded the occurrence with AVHs during frontal epileptic seizures. Electrical stimulation study of one of the two cases highlighted the causal role of prefrontal-cingulate cortex in the emergence of AVHs. Based on our clinical observation, SEEG findings, and electrical cortical stimulation, we supposed that wide implication of prefrontal-cingulate-auditory cortical network during epileptic seizure underlie the emergence of AVHs, and further hypothesized that AVHs could be yielded by transient deficit of self-monitoring for inner speech in focal epileptic seizures.