Another consideration is that low spatial sampling (i.e., less than 30 channels) may provide as accurate or even better surface Laplacian estimates than those obtained from dense electrode arrays (128 or more channels) in the presence of high spatial frequency noise (Babiloni et al., 1995). Under these conditions, low spatial density as well as reduced spline flexibility will effectively counteract EEG recording noise and other variations in signal quality, including topographical distortions caused by electrode placements or electrolyte bridging (e.g., Tenke and Kayser, 2001; Alschuler et al., 2014), and render more reliable CSD estimates (cf. Tenke and Kayser, 2012). While this may come at the costs of being less precise (cf. Fig. 7), these estimates are nevertheless more useful for the overall research purpose.
