# Alterations in frontotemporal cerebral activity specific to auditory verbal hallucination during verbal fluency task in schizophrenia: a fNIRS study

## TL;DR

This study uses fNIRS to find brain activity differences in schizophrenia patients with and without auditory verbal hallucinations during a verbal task.

## Contribution

The study identifies specific cerebral activity patterns in schizophrenia patients with auditory verbal hallucinations using fNIRS during a verbal fluency task.

## Key findings

- SZ-AVHs showed higher integral values in the left STC compared to SZ-nAVHs.
- SZ-AVHs exhibited higher centroid values in the right vlPFC compared to SZ-nAVHs.
- Findings suggest SZ-AVHs have lower activation in the left STC and slower response in the right vlPFC.

## Abstract

Patients with auditory verbal hallucination (AVH) may experience significant occupational and social functional disabilities, which bring a heavy burden to their families and society. Although neuroimaging studies have explored the brain regions associated with AVH and proposed models to explain AVH, the potential pathological mechanisms are not clear. Functional near-infrared spectroscopy (fNIRS) is a portable and suitable measurement, particularly in exploring brain activation during related tasks. Hence, our researchers aimed to explore the differences in the cerebral hemodynamic function between patients with schizophrenia with AVH (SZ-AVHs) and patients with schizophrenia without AVH (SZ-nAVHs) through fNIRS to examine neural abnormalities associated more specifically with AVH.

A 52-channel functional near-infrared spectroscopy system was used to monitor hemodynamic changes in SZ-AVHs (n = 178) and SZ-nAVHs (n = 172) during a verbal fluency task (VFT). Clinical history, and symptom severity were also noted. The original fNIRS data were analyzed using NirSpark to obtain the brain functional eigenvalues including the integral value, which represents the degree of brain activation, and the centroid value, which represents the speed of blood oxygen response.

Our results showed that the integral values of the SZ-AVHs were significantly higher than those of the SZ-nAVHs in the left STC [t = 3.16, p = 0.014] while the centroid values of the SZ-AVHs were significantly higher than those of the SZ-nAVHs in the right vlPFC [t = 2.78, p = 0.046].

Our findings indicate that SZ-AVHs exhibited lower activation in the left STC and Slower response speed in the right vlPFC than SZ-nAVHs.