Yeap Sherlyn, Kelly Simon P, Sehatpour Pejman, Magno Elena, Garavan Hugh, Thakore Jogin H, Foxe John J
The Cognitive Neurophysiology Laboratory, St. Vincent's Hospital, Richmond Road, Fairview, Dublin 3, Ireland.
Eur Arch Psychiatry Clin Neurosci. 2008 Aug;258(5):305-16. doi: 10.1007/s00406-008-0802-2. Epub 2008 May 26.
Visual Evoked Potential (VEP) abnormalities have been a fairly consistent finding in patients with schizophrenia, and it has been suggested that electrophysiological markers of early sensory processing may be useful as trait markers for the illness, and for development as potential diagnostic measures.
Clear amplitude reductions in the occipital P1 component of the VEP (approximately 100 ms), have been repeatedly demonstrated in patients with schizophrenia. Here, we investigated whether the extent of this deficit was related to age, clinical symptoms, medication status and length of illness, in a large cohort of ethnically homogenous patients.
DESIGN, SETTING AND PARTICIPANTS: VEP responses to simple isolated-check stimuli were examined in 52 DSM-IV diagnosed patients with schizophrenia, and compared with responses from 26 healthy age-matched control subjects. Using high-density electrical scalp recordings, we assessed the integrity of the visual P1 component across the two groups. This study was conducted at St.Vincent's Psychiatric Hospital in Fairview, Dublin, Ireland.
Substantially reduced P1 amplitude was demonstrated in the patient group compared to controls. The deficit was not linked to age, length of illness or medication status. A small positive correlation, accounting for about 11% of the variance, was found between P1 amplitude and clinical symptoms scales (BPRS and SANS). In addition, we found that a slightly later (~110 ms) fronto-central component was relatively increased in the patient group, and was inversely correlated with the occipital P1 amplitude in the patients, but not in the healthy control subjects.
Our findings clearly demonstrate a deficit in early visual processing in patients with schizophrenia (with a large effect size; Cohen's d = 0.7) that is unrelated to chronicity. The results are consistent with recent findings showing that the P1 deficit is endophenotypic of the disorder and related to genetic risk factors rather than the disease process itself.
视觉诱发电位（VEP）异常在精神分裂症患者中是一个相当一致的发现，并且有人提出早期感觉处理的电生理标记物可能作为该疾病的特质标记物以及作为潜在诊断措施的发展方向。
精神分裂症患者枕叶P1成分（约100毫秒）的波幅明显降低已被反复证实。在此，我们在一大群种族同质的患者中研究了这种缺陷的程度是否与年龄、临床症状、用药情况和病程有关。
设计、地点和参与者：对52名符合DSM-IV诊断标准的精神分裂症患者进行了VEP对简单孤立检查刺激的反应检测，并与26名年龄匹配的健康对照者的反应进行比较。使用高密度头皮电记录，我们评估了两组之间视觉P1成分的完整性。这项研究在爱尔兰都柏林美景镇的圣文森特精神病院进行。
与对照组相比，患者组的P1波幅显著降低。这种缺陷与年龄、病程或用药情况无关。在P1波幅与临床症状量表（BPRS和SANS）之间发现了一个小的正相关，约占方差的11%。此外，我们发现患者组中一个稍晚（约110毫秒）的额中央成分相对增加，并且与患者枕叶P1波幅呈负相关，但在健康对照者中并非如此。
我们的研究结果清楚地表明，精神分裂症患者存在早期视觉处理缺陷（效应量较大；Cohen's d = 0.7），且与病程无关。这些结果与最近的研究结果一致，即P1缺陷是该疾病的内表型，与遗传风险因素有关，而不是与疾病过程本身有关。
