Nikolin Stevan, DʼSouza Olav, Vulovic Vedran, Alonzo Angelo, Chand Nicholas, Dong Vanessa, Martin Donel, Loo Colleen
Consultation Liaison Advanced Trainee RANZCP.
J ECT. 2019 Jun;35(2):127-132. doi: 10.1097/YCT.0000000000000537.
The dorsolateral prefrontal cortex (DLPFC) is a commonly targeted site using noninvasive brain stimulation techniques. Methods used to localize this site commonly rely on the International 10-20 electroencephalography (EEG) system, including elastic EEG caps, which stretch to accommodate varying head sizes, as well as the Beam F3 algorithm, which uses scalp measurements to calculate the location of the DLPFC. Both methods have been validated against magnetic resonance imaging-based DLPFC localization and are regularly used in research centers and clinics, but an in vivo comparison of reliability has not yet been conducted. This study examines whether Beam F3 and EEG cap methods differ in DLPFC localization, when applied by different practitioners (measurers) on a range of subjects. Further, whether measurer experience or subject head characteristics influence localization.
Measurers (n = 5) of varying levels of experience identified the location of the left DLFPC on subjects (n = 6) with varying head sizes, using both Beam F3 and EEG cap methods. An independent assessor recorded the measurers' placements along the anterior-posterior and medial-lateral planes. Values were normalized to the subjects' mean nasion-inion and tragus-tragus distances and examined using a mixed effects repeated measures analysis.
The Beam F3 method resulted in significantly more anterior placements (~11.5 mm) compared with the EEG cap. Subjects with smaller head sizes had more anterior placements, compared with medium and large heads, regardless of the method used. There was no significant difference between methods along the medial-lateral plane. Measurer experience did not significantly influence DLPFC localization.
Beam F3 and EEG cap methods resulted in similar DLPFC placements, with a small difference along the anterior-posterior plane. Measurer experience did not affect either method, suggesting that 2 weeks of training is sufficient to achieve competency. Training and reliability of DLPFC placement therefore do not represent substantial barriers to application of either method. Special care should be taken with subjects with small heads as both methods resulted in more anterior DLPFC placements.
背外侧前额叶皮层（DLPFC）是使用非侵入性脑刺激技术时常用的靶点。用于定位该部位的方法通常依赖于国际10-20脑电图（EEG）系统，包括可拉伸以适应不同头围大小的弹性EEG帽，以及使用头皮测量来计算DLPFC位置的Beam F3算法。这两种方法均已通过基于磁共振成像的DLPFC定位进行验证，并在研究中心和诊所中经常使用，但尚未进行体内可靠性比较。本研究考察了Beam F3和EEG帽方法在不同从业者（测量者）应用于一系列受试者时，在DLPFC定位上是否存在差异。此外，测量者经验或受试者头部特征是否会影响定位。
经验水平不同的测量者（n = 5）使用Beam F3和EEG帽方法，在头围大小不同的受试者（n = 6）上确定左侧DLFPC的位置。一名独立评估者记录测量者在前后和内外平面上的放置位置。将数值归一化为受试者的平均鼻根-枕骨和耳屏-耳屏距离，并使用混合效应重复测量分析进行检查。
与EEG帽相比，Beam F3方法导致的放置位置明显更靠前（约11.5毫米）。无论使用何种方法，头围较小的受试者与中等和较大头围的受试者相比，放置位置更靠前。在内外平面上，两种方法之间没有显著差异。测量者经验对DLPFC定位没有显著影响。
Beam F3和EEG帽方法导致的DLPFC放置位置相似，在前后平面上存在微小差异。测量者经验对两种方法均无影响，这表明两周的培训足以达到胜任水平。因此，DLPFC放置的培训和可靠性并不是应用这两种方法的重大障碍。对于头围较小的受试者应特别注意，因为两种方法都导致DLPFC放置位置更靠前。
