Schecklmann Martin, Ehlis Ann-Christine, Plichta Michael M, Fallgatter Andreas J
University of Wuerzburg, Psychophysiology and Functional Imaging, Department of Psychiatry, Psychosomatics and Psychotherapy, University Hospital Wuerzburg, Germany.
Neuroimage. 2008 Oct 15;43(1):147-55. doi: 10.1016/j.neuroimage.2008.06.032. Epub 2008 Jul 8.
The present study investigated the short- and long-term retest reliability of brain activity measured with functional near-infrared spectroscopy (fNIRS) during verbal fluency, the most published cognitive task within fNIRS literature. We examined 15 healthy right handed subjects in a block design task with retest intervals of three weeks and one year. Performance was constant over time. Amplitude of brain activation, as indicated by increases of oxygenated (O(2)Hb) and total (totHb) and decreases of deoxygenated haemoglobin (HHb), was reduced at session two and reversed at the third session for the fluency related region of interest (ROI). Small decreases for session two and three were found outside the ROI. These changes in amplitude may contribute to variability of reproducibility as measured with intraclass correlation coefficients (ICCs) within the ROI. Acceptable reliability for all chromophores and comparisons was reached for the mean of repeated measures at cluster level. Spatial (size and localisation), temporal and whole probe set activity was completely acceptable without exception. Retest reliability was not satisfactory at single subject and single channel level. Amplitude decreases over time outside the ROI suggest higher physiological or arousal effects for session one. Amplitude recovery in the ROI in session three argues for a psychological effect. Overall our findings indicate that fNIRS analyses at single subject and single channel level should be interpreted cautiously, while group and cluster analyses have sufficient test retest reliability.
本研究调查了在言语流畅性任务中，使用功能近红外光谱技术（fNIRS）测量的大脑活动的短期和长期重测信度，言语流畅性任务是fNIRS文献中发表最多的认知任务。我们在一项组块设计任务中对15名健康的右利手受试者进行了检查，重测间隔为三周和一年。随着时间推移，表现保持恒定。对于与流畅性相关的感兴趣区域（ROI），在第二次测试时，由氧合血红蛋白（O(2)Hb）和总血红蛋白（totHb）增加以及脱氧血红蛋白（HHb）减少所表明的大脑激活幅度降低，在第三次测试时逆转。在ROI之外，第二次和第三次测试时发现有小幅下降。这些幅度变化可能导致了用组内相关系数（ICC）在ROI内测量的可重复性的变异性。对于所有发色团和比较，在聚类水平上重复测量的平均值达到了可接受的信度。空间（大小和定位）、时间和整个探头组的活动毫无例外都是完全可接受的。在单受试者和单通道水平上，重测信度并不令人满意。ROI之外随时间的幅度下降表明第一次测试时存在更高的生理或唤醒效应。第三次测试时ROI内的幅度恢复表明存在心理效应。总体而言，我们的研究结果表明，在单受试者和单通道水平上的fNIRS分析应谨慎解释，而组分析和聚类分析具有足够的重测信度。
