Abnormal electrical current in two brain regions might underlie the phenomenon of auditory verbal hallucinations in patients with schizophrenia.
An electroencephalographic study of patients with schizophrenia determined that their hallucination severity correlated negatively with amplitude in the frontal currents. Their negative symptom severity correlated negatively with the temporal current amplitude, according to research conducted by Dr. Jérôme Graux and his colleagues (Schizophr. Res. 2014 April 1 [doi.org/10.1016/j.schres.2014.03.007]).
Dr. Graux and his coauthors examined brainwave responses to a single spoken "A" in 13 patients with schizophrenia-related auditory hallucinations, 13 nonhallucinating patients, and 13 healthy controls. The researchers focused on waves associated with auditory processes in the frontal region (P1, N1, and P2), and current in the temporal sinks.
The overall response patterns were similar between groups, with P1 peaking first, followed by N1 and P2. But hallucinating patients showed lower-amplitude responses in the frontocentral regions. Current at the left and right temporal sinks also was reduced, reported Dr. Graux of UMR 930 Imagerie et Cerveau, INSERM, Université François Rabelais de Tours, France.
The amplitudes of both frontal and temporal current negatively correlated with symptom scores. The higher the severity of hallucinations, the smaller the amplitude of the frontal currents; the higher the PANSS (Positive and Negative Syndrome Scale) negative symptom score, the smaller the amplitude of the temporal currents, wrote Dr. Graux, who also is affiliated with CHRU de Tours Hospital, France.
"The small amplitude of the frontal current in the present study suggests the involvement of a deep source in the frontal lobe, which might correspond to the involvement of the anterior cingulate cortex in the perception of human speech," the authors wrote.
The study was supported by several French private foundations. None of the authors disclosed had any financial disclosures.
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