Lead-field bases for electroencephalography source imaging

In recent years, significant progress has been made in the area of electroe ncephalography (EEG) source imaging. Source localization on simple spherica l models has become increasingly efficient, with consistently reported accu racy of within 5 mm. In contrast, source localization on realistic head mod els remains slow, with subcentimeter accuracy being the exception rather th an the norm. A primary reason for this discrepancy is that most source imag ing techniques are based on lead fields. While the lead field for simplifie d geometries can be easily computed analytically, an efficient method for c omputing realistic: domain lead fields has, until now, remained elusive. In this paper, we propose two efficient methods for computing realistic EEG l ead-field bases: the first is element oriented and the second is node orien ted. We compare these two bases, discuss how they can be used to apply rece nt source imaging methods to realistic models, and report timings for const ructing the bases. (C) 2000 Biomedical Engineering Society. [S0090-6964(00) 00409-4].