Fisher Derek J, Campbell Debra J, Abriel Shelagh C, Ells Emma M L, Rudolph Erica D, Tibbo Philip G
1 Department of Psychology, Mount Saint Vincent University, Halifax, Nova Scotia, Canada.
2 Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada.
Clin EEG Neurosci. 2018 Jul;49(4):238-247. doi: 10.1177/1550059418761459. Epub 2018 Mar 4.
The mismatch negativity (MMN) is an EEG-derived event-related potential (ERP) elicited by any violation of a predicted auditory "rule," regardless of whether one is attending to the stimuli and is thought to reflect updating of the stimulus context. Redirection of attention toward a rare, distracting stimulus event, however, can be measured by the subsequent P3a component of the P300. Chronic schizophrenia patients exhibit robust MMN deficits, as well as reductions in P3a amplitude. While, the substantial literature on the MMN in first-episode and early phase schizophrenia in this population reports reduced amplitudes, there also exist several contradictory studies. Conversely, P3a reduction in this population is relatively consistent, although the literature investigating this is small. The primary goal of this study was to contribute to our understanding of whether auditory change detection mechanisms are altered in early phase schizophrenia and, if so, under what conditions. Event-related potentials elicited by duration, frequency, gap, intensity, and location deviants (as elicited by the "optimal" multi-feature paradigm) were recorded in 14 early phase schizophrenia (EP) patients and 17 healthy controls (HCs). Electrical activity was recorded from 15 scalp electrodes. MMN/P3a amplitudes and latencies for each deviant were compared between groups and were correlated with clinical measures in EPs. There were no significant group differences for MMN amplitudes or latencies, though EPs did exhibit reduced P3a amplitudes to gap and duration deviants. Furthermore, PANSS (Positive and Negative Syndrome Scale) positive symptom scores were correlated with intensity MMN latencies and duration P3a amplitudes in EPs. These findings suggest that MMNs may not be as robustly reduced in early phase schizophrenia (relative to chronic illness), but that alterations may be more likely in patients with increased positive symptomatology. Furthermore, these findings offer further support to previous work suggesting that the understudied P3a may have good complementary utility as a marker of early cortical dysfunction in psychosis.
失匹配负波（MMN）是一种从脑电图得出的事件相关电位（ERP），由任何违反预测听觉“规则”的情况引发，无论个体是否关注刺激，并且被认为反映了刺激情境的更新。然而，将注意力重新导向一个罕见的、分散注意力的刺激事件，可以通过P300的后续P3a成分来测量。慢性精神分裂症患者表现出明显的MMN缺陷，以及P3a波幅降低。虽然，关于该人群首发和早期精神分裂症患者MMN的大量文献报道波幅降低，但也存在一些相互矛盾的研究。相反，该人群中P3a降低相对一致，尽管对此进行研究的文献较少。本研究的主要目的是帮助我们了解早期精神分裂症患者的听觉变化检测机制是否改变，如果改变，是在什么情况下。在14名早期精神分裂症（EP）患者和17名健康对照者（HC）中记录了由持续时间、频率、间隙、强度和位置偏差（由“最佳”多特征范式引发）所诱发的事件相关电位。从15个头皮电极记录电活动。比较了两组之间每种偏差的MMN/P3a波幅和潜伏期，并将其与EP患者的临床指标进行关联。MMN波幅或潜伏期在两组之间没有显著差异，尽管EP患者对间隙和持续时间偏差的P3a波幅确实降低。此外，阳性和阴性症状评定量表（PANSS）的阳性症状评分与EP患者的强度MMN潜伏期和持续时间P3a波幅相关。这些发现表明，早期精神分裂症（相对于慢性疾病）患者的MMN可能不会像那样显著降低，但阳性症状增加的患者可能更易出现改变。此外，这些发现为之前的研究提供了进一步支持，表明研究较少的P3a作为精神病早期皮质功能障碍的标志物可能具有良好的互补效用。
