Department of Neuropsychiatry, Kanazawa Medical University, Ishikawa, Japan.
Department of Neuropsychiatry, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan.
Neuroimage Clin. 2017 Aug 8;16:248-256. doi: 10.1016/j.nicl.2017.08.008. eCollection 2017.
Cognitive impairments are a core feature in schizophrenia patients (SCZ) and are also observed in first-degree relatives (FR) of SCZ. However, substantial variability in the impairments exists within and among SCZ, FR and healthy controls (HC). A cluster-analytic approach can group individuals based on profiles of traits and create more homogeneous groupings than predefined categories. Here, we investigated differences in the Brief Assessment of Cognition in Schizophrenia (BACS) neuropsychological battery (six subscales) among SCZ, unaffected FR and HC. To identify three homogeneous and meaningful cognitive groups regardless of categorical diagnoses (SCZ, FR and HC), cognitive clustering was performed, and differences in the BACS subscales among the cognitive cluster groups were investigated. Finally, the effects of diagnosis and cognition on brain volumes were examined. As expected, there were significant differences in the five BACS subscales among the diagnostic groups. The cluster-analytic approach generated three meaningful subgroups: (i) neuropsychologically normal, (ii) intermediate impaired and (iii) widespread impaired. The cognitive subgroups were mainly affected by the clinical diagnosis, and significant differences in all BACS subscales among clusters were found. The effects of the diagnosis and cognitive clusters on brain volumes overlapped in the frontal, temporal and limbic regions. Frontal and temporal volumes were mainly affected by the diagnosis, whereas the anterior cingulate cortex (ACC) volumes were affected by the additive effects of diagnosis and cognition. Our findings demonstrate a cognitive continuum among SCZ, FR and HC and support the concept of cognitive impairment and the related ACC volumes as intermediate phenotypes in SCZ.
认知障碍是精神分裂症患者（SCZ）的核心特征，也存在于 SCZ 的一级亲属（FR）中。然而，SCZ、FR 和健康对照组（HC）内部和之间的损伤存在显著的可变性。聚类分析方法可以根据特征的分布对个体进行分组，并创建比预定义类别更同质的分组。在这里，我们研究了精神分裂症简要认知评估（BACS）神经心理学测试（六个分量表）在 SCZ、未受影响的 FR 和 HC 之间的差异。为了在不考虑分类诊断（SCZ、FR 和 HC）的情况下识别三个同质且有意义的认知组，我们进行了认知聚类，并研究了认知聚类组之间 BACS 分量表的差异。最后，检查了诊断和认知对脑容量的影响。正如预期的那样，五个 BACS 分量表在诊断组之间存在显著差异。聚类分析方法生成了三个有意义的亚组：（i）神经心理学正常，（ii）中度受损，（iii）广泛受损。认知亚组主要受临床诊断影响，并且在聚类之间发现了所有 BACS 分量表的显著差异。诊断和认知聚类对脑容量的影响在前额、颞叶和边缘区域重叠。额叶和颞叶体积主要受诊断影响，而前扣带皮层（ACC）体积受诊断和认知的附加效应影响。我们的研究结果表明，SCZ、FR 和 HC 之间存在认知连续性，并支持认知障碍和相关 ACC 体积作为 SCZ 中间表型的概念。
