White matter abnormalities associated with auditory hallucinations in schizophrenia: A combined study of voxel-based analyses of diffusion tensor imaging and structural magnetic resonance imaging

한글 요약

조현병의 대표 증상인 환청이 백질의 어떤 이상과 관련되는지를 살핀 연구입니다. 연구팀은 환청이 있는 환자, 환청이 없는 환자, 정상 대조군을 대상으로 확산텐서영상(DTI)에서 얻은 분할 비등방도(FA)와 구조 MRI에서 얻은 백질 밀도를 복셀 단위로 함께 비교했습니다. 두 환자군 모두에서 좌측 상종속 다발의 FA가 감소하고 좌측 하종속 다발의 백질 밀도는 증가해 있었으며, 환청 환자군에서는 좌측 상종속 다발 전두엽 부분의 FA가 환청의 심각도와 관련을 보였습니다. 백질 변화가 주로 전두엽과 측두엽에서 나타났다는 점에서 좌측 전두-측두 영역의 연결 단절이 조현병의 병태생리에 기여하며, 이 영역의 백질 병변이 환청 발생의 중요한 단계일 수 있음을 시사합니다.

White matter (WM) abnormalities in schizophrenia may offer important clues to a better understanding of the disconnectivity associated with the disorder. The aim of this study was to elucidate a WM basis of auditory hallucinations in schizophrenia through the simultaneous investigation of WM tract integrity and WM density. Diffusion tensor images (DTIs) and structural T1 magnetic resonance images (MRIs) were taken from 15 hallucinating schizophrenic patients, 15 non-hallucinating schizophrenic patients and 22 normal controls. Voxel-based analyses and post-hoc region of interest analyses were obtained to compare the three groups on fractional anisotropy (FA) derived from DTI as well as WM density derived from structural MRIs. In both the hallucinating and non-hallucinating groups, FA of the WM regions was significantly decreased in the left superior longitudinal fasciculus (SLF), whereas WM density was significantly increased in the left inferior longitudinal fasciculus (ILF). The mean FA value of the left frontal part of the SLF was positively correlated with the severity score of auditory hallucinations in the hallucinating patient group. Our findings show that WM changes were mainly observed in the frontal and temporal areas, suggesting that disconnectivity in the left fronto-temporal area may contribute to the pathophysiology of schizophrenia. In addition, pathologic WM changes in this region may be an important step in the development of auditory hallucinations in schizophrenia.