How wrong can we be? The effect of inaccurate mark-up of EEG/fMRI studies in epilepsy

Abstract

Objective: The aim of this investigation was to determine the effect of inaccurate or inconsistent marking up of events in the EEG on statistical analysis of EEG/fMRI studies of patients with epilepsy. Methods: EEGs obtained during EEG/fMRI studies conducted on 10 patients with epilepsy and six normal control subjects were reviewed. All clear epileptiform events were marked up in the patient EEGs, as were all small movement-related artefacts in the patient and control subject EEGs. We then considered the effect on the numbers of voxels above threshold in the resulting Statistical Parametric Mapping (SPM) analysis if events were omitted, mislabelled, or if event times were inconsistently mark..