Origin coordinate influence on performance of temporally extended signal space separation in magnetoencephalography

IF 3.7 3区医学 Q1 CLINICAL NEUROLOGY Clinical Neurophysiology Pub Date : 2024-05-06 DOI:10.1016/j.clinph.2024.04.020

Yuichiro Shirota, Megumi Akita, Shotaro Tajima, Tomoyuki Mochida, Katsura Masaki, Masato Yumoto

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引用次数: 0

Abstract

Objective

Temporally extended signal space separation (tSSS) is a powerful method for artifact suppression in magnetoencephalography (MEG). Because tSSS first separates MEG signals coming from inside and outside a certain sphere, definition of the sphere origin is important. For this study, we explored the influence of origin choice on tSSS performance in spontaneous and evoked activity from epilepsy patients.

Methods

Interictal epileptiform discharges (IEDs) and somatosensory evoked fields (SEFs) were processed with two tSSSs: one with the default origin of (0, 0, 40 mm) in the head coordinate, and the other with an individual origin estimated using each patient’s anatomical magnetic resonance imaging (MRI). Equivalent current dipoles (ECDs) were calculated for the data. The ECD location and quality of estimation were compared across conditions.

Results

MEG data from 21 patients revealed marginal differences in ECD location, but the estimation quality inferred from goodness of fit (GOF) and confidence volume (CV) was better for the tSSS with individual origins. This choice affected IEDs more than it affected SEFs.

Conclusions

Individual sphere model resulted in better GOF and CV.

Significance

Application of tSSS using an individual origin would be more desirable when available. This parameter might influence spontaneous activity more strongly.

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原点坐标对脑磁图中时间扩展信号空间分离性能的影响

目的时空扩展信号空间分离（tSSS）是抑制脑磁图（MEG）伪像的一种有效方法。由于 tSSS 首先要分离来自某一球体内外的 MEG 信号，因此球体原点的定义非常重要。在这项研究中，我们探讨了原点选择对癫痫患者自发活动和诱发活动中 tSSS 性能的影响。方法用两种 tSSS 处理间歇性痫样放电 (IED) 和躯体感觉诱发电场 (SEF)：一种使用头部坐标中的默认原点 (0, 0, 40 mm)，另一种使用根据每位患者的解剖磁共振成像 (MRI) 估算的个体原点。对数据进行了等效电流偶极子（ECD）计算。结果 21 名患者的 MEG 数据显示，ECD 位置略有差异，但从拟合度（GOF）和置信区间（CV）推断，具有单独起源的 tSSS 的估计质量更好。这一选择对 IED 的影响大于对 SEF 的影响。结论个体球体模型可获得更好的 GOF 和 CV。该参数对自发活动的影响可能更大。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Clinical Neurophysiology 医学-临床神经学

CiteScore

8.70

自引率

6.40%

发文量

932

审稿时长

59 days

期刊介绍： As of January 1999, The journal Electroencephalography and Clinical Neurophysiology, and its two sections Electromyography and Motor Control and Evoked Potentials have amalgamated to become this journal - Clinical Neurophysiology. Clinical Neurophysiology is the official journal of the International Federation of Clinical Neurophysiology, the Brazilian Society of Clinical Neurophysiology, the Czech Society of Clinical Neurophysiology, the Italian Clinical Neurophysiology Society and the International Society of Intraoperative Neurophysiology.The journal is dedicated to fostering research and disseminating information on all aspects of both normal and abnormal functioning of the nervous system. The key aim of the publication is to disseminate scholarly reports on the pathophysiology underlying diseases of the central and peripheral nervous system of human patients. Clinical trials that use neurophysiological measures to document change are encouraged, as are manuscripts reporting data on integrated neuroimaging of central nervous function including, but not limited to, functional MRI, MEG, EEG, PET and other neuroimaging modalities.