Aydin K, Ucok A, Cakir S
Department of Neuroradiology, MR Research Unit, Istanbul Medical School, Istanbul University, Capa, Istanbul, Turkey.
AJNR Am J Neuroradiol. 2007 Nov-Dec;28(10):1968-74. doi: 10.3174/ajnr.A0691. Epub 2007 Sep 26.
The callosal disconnectivity theory was previously proposed to explain the pathophysiology of schizophrenia. The goal of this study was to investigate the metabolic integrity of the corpus callosum in patients with schizophrenia by proton MR spectroscopy.
Twelve first-episode and 16 chronic patients meeting the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria for schizophrenia and 28 age- and sex-matched control subjects were enrolled in the study. We measured the absolute concentrations of neurometabolites and T2 relaxation times of tissue water (T2B) in the genu of the corpus callosum by using the internal water-reference method. The severity of symptoms in patients was rated by means of psychopathology scales. Differences in neurometabolite concentrations and T2B values between the patients and control subjects were assessed. We also investigated the correlation of metabolite concentrations with the severity of symptoms.
N-acetylaspartate (NAA) concentrations were significantly lower in the first-episode as well as in chronic patients, compared with respective control subjects (P < .001). NAA concentrations in the first-episode and chronic patient groups were negatively correlated with both the Brief Psychiatry Rating Scale and the Scale for Assessment of Negative Symptoms scores (P < .001). There was a significant negative correlation between the NAA concentrations and the Scale for Assessment of Positive Symptoms scores in all patients (P = .028). T2B values were significantly higher in the patients, compared with the control subjects (P < .001).
Decreased NAA concentration in the corpus callosum correlates with psychopathology in schizophrenia. This finding, together with prolonged T2B values of the corpus callosum, supports the previously proposed callosal disconnection theory concerning the pathophysiology of schizophrenia.
胼胝体分离理论此前被提出用于解释精神分裂症的病理生理学机制。本研究的目的是通过质子磁共振波谱法研究精神分裂症患者胼胝体的代谢完整性。
本研究纳入了12例符合《精神疾病诊断与统计手册》（DSM-IV）精神分裂症诊断标准的首发患者、16例慢性患者以及28例年龄和性别匹配的对照受试者。我们采用内部水参照法测量胼胝体膝部神经代谢物的绝对浓度和组织水的T2弛豫时间（T2B）。通过精神病理学量表对患者症状的严重程度进行评分。评估患者与对照受试者之间神经代谢物浓度和T2B值的差异。我们还研究了代谢物浓度与症状严重程度之间的相关性。
与各自的对照受试者相比，首发患者和慢性患者的N-乙酰天门冬氨酸（NAA）浓度均显著降低（P <.001）。首发患者组和慢性患者组的NAA浓度与简明精神病评定量表及阴性症状评定量表得分均呈负相关（P <.00¹）。在所有患者中，NAA浓度与阳性症状评定量表得分之间存在显著负相关（P = 0.028）。与对照受试者相比，患者的T2B值显著更高（P <.001）。
胼胝体中NAA浓度降低与精神分裂症的精神病理学相关。这一发现，连同胼胝体T2B值延长，支持了先前提出的关于精神分裂症病理生理学的胼胝体分离理论。
