Source reconstruction via the spatiotemporal Kalman filter and LORETA from EEG time series with 32 or fewer electrodes

Abstract

The clinical routine of non-invasive electroencephalography (EEG) is usually performed with 8-40 electrodes, especially in long-term monitoring, infants or emergency care. There is a need in clinical and scientific brain imaging to develop inverse solution methods that can reconstruct brain sources from these low-density EEG recordings. In this proof-of-principle paper we investigate the performance of the spatiotemporal Kalman filter (STKF) in EEG source reconstruction with 9-, 19- and 32- electrodes. We used simulated EEG data of epileptic spikes generated from lateral frontal and lateral temporal brain sources using state-of-the-art neuronal population models. For validation of source reconstruction, we compared STKF results to the location of the simulated source and to the results of low-resolution brain electromagnetic tomography (LORETA) standard inverse solution. STKF consistently showed less localization bias compared to LORETA, especially when the number of electrodes was decreased. The results encourage further research into the application of the STKF in source reconstruction of brain activity from low-density EEG recordings.

Source imaging of deep-brain activity using the regional spatiotemporal Kalman filter

“…When applied to localize sources of a focal seizure from an EEG recording, STKF showed more accurate and consistent localizations of the seizure onset, compared to LORETA [27]. Addi-tionally, STKF produced more accurate source reconstructions from small numbers of electrodes (9 and 19 electrodes), compared to LORETA [30].…”

“…Since both LORETA and STKF use spatial smoothness constraints, we consider it useful to compare their performance, in order to ascertain the additional advantages of temporal smoothness in the STKF model. In previous work, the original STKF model was found to be superior to LORETA with respect to the localization of sources of alpha rhythms, epileptiform discharges, and focal seizures from EEG recordings [27][28][29][30][31][32]. When applied to localize sources of a focal seizure from an EEG recording, STKF showed more accurate and consistent localizations of the seizure onset, compared to LORETA [27].…”