Impaired illness awareness (Imp-IA) in schizophrenia is associated with interhemispheric imbalance, resulting in left hemisphere dominance, primarily within the posterior parietal area (PPA). This may represent an interhemispheric "disconnection syndrome" between PPAs. To test this hypothesis, we aimed to determine if diffusion-based measures of white matter integrity were disrupted in the corpus callosal tracts linking PPAs (i.e., splenium) in patients with Imp-IA in schizophrenia. T1-weighted and diffusion-weighted scans were acquired on a 1.5T GE scanner for 100 participants with a DSM-IV-TR diagnosis of schizophrenia and 134 healthy controls aged 18 to 79 years. The corpus callosal white matter tracts were compared among patients with Imp-IA (n = 40), intact illness awareness (n = 60), and healthy controls. White matter disruption was measured with fractional anisotropy (FA) and mean diffusivity (MD). Group differences in FA were found in the splenium, with patients with Imp-IA having the lowest FA, which remained significant after controlling for sex, age, global cognition, and premorbid intelligence. No group differences in MD were observed. Splenial white matter tracts of the corpus callosum appear compromised in patients with Imp-IA. Transcallosal interhemispheric PPA white matter disruption may represent a "disconnection syndrome", manifesting as Imp-IA in schizophrenia. Future studies are required to investigate the effects of noninvasive brain stimulation interventions, such as transcranial direct current or magnetic stimulation, on Imp-IA in association with white matter changes in patients with schizophrenia.

中文翻译：

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精神分裂症和后体white体白质束完整性的疾病意识受损。

精神分裂症的疾病意识（Imp-IA）受损与半球间不平衡相关，导致左半球占优势，主要在后顶叶区（PPA）内。这可能代表了PPA之间的半球间“断开综合症”。为了检验该假设，我们旨在确定在患有精神分裂症的Im-IA患者中，基于扩散的白质完整性度量是否在连接PPA（即脾）的the体道中被破坏。在1.5T GE扫描仪上对100名参与者进行了T1加权和弥散加权扫描，这些患者被诊断为精神分裂症的DSM-IV-TR和134位年龄在18至79岁的健康对照。比较Imp-IA（n = 40），完整疾病意识（n = 60）和健康对照患者的call体白质道。用分数各向异性（FA）和平均扩散率（MD）测量白质破坏。在脾脏中发现了FA组的差异，Im-IA患者的FA最低，在控制性别，年龄，整体认知和病前智力后，FA仍显着。在MD上未观察到组差异。Imp-IA患者的call体脾白质束似乎受损。经call间半球间PPA白质破坏可能代表“分离综合征”，表现为精神分裂症中的Imp-IA。需要进一步的研究来研究无创性脑刺激干预措施（例如经颅直流电或磁刺激）对Imp-IA与精神分裂症患者白质变化的影响。