Minati Ludovico, Visani Elisa, Dowell Nick G, Medford Nick, Critchley Hugo D
Department of Psychiatry, Brighton & Sussex Medical School (BSMS), Falmer, UK.
J Med Eng Technol. 2011 Aug-Oct;35(6-7):370-6. doi: 10.3109/03091902.2011.595533. Epub 2011 Jul 23.
Brain near-infrared spectroscopy (NIRS) is emerging as a potential alternative to functional magnetic resonance imaging (fMRI). To date, no study has explicitly compared the two techniques in terms of measurement variability, a key parameter dictating attainable statistical power. Here, NIRS and fMRI were simultaneously recorded during event-related visual stimulation. Inter-subject coefficients of variation (CVs) for peak response amplitude were considerably larger for NIRS than fMRI, but inter-subject CVs for response latency and intra-subject CVs for response amplitude were overall comparable. Our results may represent an optimistic estimate of the CVs of NIRS measurements, as optode positioning was guided by structural MRI, which is normally unavailable. We concluded that fMRI may be preferable to NIRS for group comparisons, but NIRS is equally powerful when comparing conditions within participants. The discrepancy between inter- and intra-subject CVs is likely related to variability in head anatomy and tissue properties, which may be better accounted for by emerging NIRS technology.
脑近红外光谱技术（NIRS）正逐渐成为功能磁共振成像（fMRI）的一种潜在替代方法。迄今为止，尚无研究在测量变异性方面对这两种技术进行明确比较，而测量变异性是决定可达到的统计功效的关键参数。在此，在事件相关视觉刺激期间同时记录了NIRS和fMRI。NIRS的峰值反应幅度的受试者间变异系数（CVs）比fMRI大得多，但反应潜伏期的受试者间CVs和反应幅度的受试者内CVs总体上相当。由于光极定位是由通常无法获得的结构MRI引导的，我们的结果可能是对NIRS测量CVs的乐观估计。我们得出结论，在进行组间比较时，fMRI可能比NIRS更可取，但在比较参与者内部的条件时，NIRS同样有效。受试者间和受试者内CVs之间的差异可能与头部解剖结构和组织特性的变异性有关，新兴的NIRS技术可能能更好地解释这一点。
