Michie Patricia T, Innes-Brown Hamish, Todd Juanita, Jablensky Assen V
Centre for Clinical Research in Neuropsychiatry, University of Western Australia, Nedlands, Australia.
Biol Psychiatry. 2002 Oct 1;52(7):749-58. doi: 10.1016/s0006-3223(02)01379-3.
One of the most consistent findings in schizophrenia research over the past decade is a reduction in the amplitude of an auditory event-related brain potential known as mismatch negativity (MMN), which is generated whenever a deviant sound occurs in a background of repetitive auditory stimulation. The reduced amplitude of MMN in schizophrenia was first observed for deviant sounds that differ in duration relative to background standard sounds, and similar findings have been observed for sounds that are deviant in frequency. The aim of this study was to determine whether first-degree relatives of schizophrenia patients show a similar reduction in MMN amplitude to duration deviants.
We measured MMN to duration increments (deviants 100 msec vs. standards 50 msec) in 22 medicated patients with a diagnosis in the schizophrenia spectrum, 17 individuals who were first-degree unaffected relatives of patients, and 21 healthy control subjects.
Mismatch negativity amplitude was reduced in patients and relatives compared with control subjects. There were no significant differences between patients and relatives. In contrast, the subsequent positive component, P3a, was larger in relatives compared with patients.
These findings suggest that a reduced MMN amplitude may be an endophenotype marker of the predisposition to schizophrenia.
在过去十年的精神分裂症研究中，最一致的发现之一是一种被称为失配负波（MMN）的听觉事件相关脑电位的波幅降低，MMN是在重复性听觉刺激背景中出现异常声音时产生的。精神分裂症患者中MMN波幅降低首先在相对于背景标准声音持续时间不同的异常声音中被观察到，并且在频率异常的声音中也观察到了类似的发现。本研究的目的是确定精神分裂症患者的一级亲属是否表现出与持续时间异常声音类似的MMN波幅降低。
我们测量了22名诊断为精神分裂症谱系的服药患者、17名患者的一级未患病亲属以及21名健康对照者对持续时间增加（异常声音为100毫秒，标准声音为50毫秒）的MMN。
与对照者相比，患者和亲属的失配负波波幅降低。患者和亲属之间没有显著差异。相比之下，随后的正向成分P3a在亲属中比在患者中更大。
这些发现表明，MMN波幅降低可能是精神分裂症易感性的一种内表型标记。
