Maurits Natasha M, Elting Jan Willem, Jager Dick K R B, van der Hoeven Johannes H, Brouwer Wiebo H
Department of Neurology, University Medical Center Groningen, Groningen, The Netherlands.
J Clin Neurophysiol. 2005 Jun;22(3):166-75.
P300 latency variability in normal subjects limits its diagnostic applicability as a test for cognitive function. One of the causes of variation is the overlap in P300 (P3A and P3B) components resulting in inaccurate latency determination. Recently, we have shown that identification of P3A and P3B components using source analysis techniques significantly reduces P300 latency variability in healthy younger subjects. Here, we included a novel paradigm to enhance sensitivity and investigated the efficiency of the source analysis technique in reducing the P300 latency variability in healthy older subjects. Data were recorded with a 128-channel EEG system in 28 healthy subjects (aged 53-82 years, 12 males). We used a standard two-tone and a novel three-tone auditory oddball paradigm and an established source analysis technique, and compared the latencies to those obtained with conventional P300 analysis. The source analysis method identified both P3A and P3B components in a substantially larger percentage of subjects (93% versus 32%) than the conventional method. Both for the standard and novel paradigm, the source analysis method yielded a later mean P3B latency (361.4 versus 344.2 milliseconds, P = 0.017, and 374.4 milliseconds versus 354.3 milliseconds, P = 0.014, respectively) with a smaller standard deviation (15.8 versus 26.2 milliseconds, P = 0.013, and 18.9 versus 30.0 milliseconds, P = 0.052, borderline significant, respectively) than the conventional P300 method, for subjects aged 50 to 70 years. When applying the source analysis technique, as in young healthy subjects, a considerable reduction of P300 latency variability was thus found in healthy older subjects aged 50 to 70 years for both paradigms. This may have important consequences for applications of clinical event-related potential research in the early diagnosis of dementia, because the first signs of this disease are mostly observed in this age category.
正常受试者的P300潜伏期变异性限制了其作为认知功能测试的诊断适用性。变异的原因之一是P300（P3A和P3B）成分的重叠，导致潜伏期测定不准确。最近，我们已经表明，使用源分析技术识别P3A和P3B成分可显著降低健康年轻受试者的P300潜伏期变异性。在此，我们采用了一种新的范式来提高敏感性，并研究了源分析技术在降低健康老年受试者P300潜伏期变异性方面的效率。使用128通道脑电图系统记录了28名健康受试者（年龄53 - 82岁，男性12名）的数据。我们使用了标准双音和新的三音听觉oddball范式以及一种既定的源分析技术，并将潜伏期与传统P300分析获得的潜伏期进行比较。与传统方法相比，源分析方法在更大比例的受试者中识别出了P3A和P3B成分（分别为93%和32%）。对于标准范式和新范式，源分析方法得出的P3B平均潜伏期均较晚（分别为毫秒361.4对344.2，P = 0.017；374.4毫秒对354.3毫秒，P = 0.014），标准差较小（分别为15.8对26.2毫秒，P = 0.013；18.9对30.0毫秒，P = 0.052，临界显著），对于年龄在50至70岁之间的受试者，与传统P300方法相比。因此，与年轻健康受试者一样，当应用源分析技术时，在年龄50至70岁的健康老年受试者中，两种范式的P300潜伏期变异性都有相当大的降低。这可能对临床事件相关电位研究在痴呆早期诊断中的应用产生重要影响，因为这种疾病的最初迹象大多在这个年龄组中观察到。
