[The neural substrates for voice familiarity in schizophrenic patients with auditory verbal hallucinations: an event-related functional magnetic resonance imaging study].

Objective: To study the physiologic base of voice familiarity (VF) and the mechanism of auditory verbal hallucination (AVH) in the patients with schizophrenia (SCH).

Methods: Twenty-six schizophrenic patients, 13 with and 13 without AVH, and 13 healthy control subjects were instructed to passively listen to familiar or unfamiliar voices and to give their judgment and underwent event-related functional magnetic resonance imaging (efMRI) based on blood oxygenation level-dependent (BOLD) signal efficacy. The functional images were collected by using a 1.5-T MRI and were analyzed by using statistical parametric mapping 2 (SPM2).

Results: The total score of positive symptoms of the SCH patients with AVH was (45.5 +/- 13.2), significantly higher than that of the SCH patients without AVH [(22.2 +/- 6.7), P < 0.05]. In comparison with unfamiliar voices, familiar voices elicited greater responses in the left superior temporal gyrus, right frontal lobe and limbic lobe among the SCH patients with AVH (P < 0.005, K(E) > 10). IN comparison with healthy control group, when the patients with AVH discriminated the familiar voices their left precuneus lobes were activated more significantly, and when they discriminated unfamiliar voices their right frontal lobes were activated more significantly (P < 0.005, K(E) > 10). In comparison with the SCH patients without AVH when the SCH patients with AVH discriminated the familiar voices their right frontal lobe were activated more significantly (P < 0.005, K(E) > 10), however, when they discriminated unfamiliar voices there was not significantly difference in the activation of the right frontal lobe between these groups.

Conclusion: The efMRI results of the inter-group comparison support the inner speech disorder hypothesis that the activation of inner speech in the SCH patients with AVH inhibits the activation of external voice on the corresponding cerebral areas. In addition, hallucinating patients may have significant change of VF neurocognitive model.