Quantitative movement analysis differentiates focal seizures characterized by automatisms

The analysis of epileptic seizures is typically performed by visual inspection, limited by interrater variation. Our aim was to differentiate seizures characterized by automatisms with an objective, quantitative movement analysis. In part 1 of this study we found parameters (extent and speed of movement of the wrist and trunk) separating seizures with predominant proximal (hyperkinetic, n = 10) and distal (automotor, n = 10) limb automatisms (P < 0.002). For each movement parameter we used the lowest value recorded for a hyperkinetic seizure in part 1 as the cutoff parameter in part 2 on a consecutive sample of 100 motor seizures. As in part 1, the difference between hyperkinetic and non-hyperkinetic seizures was highly significant (< 0.001). When all movement parameters were above the threshold, a hyperkinetic seizure was identified with a probability of 80.8%, but the probability for a non-hyperkinetic seizure to have all parameters above the threshold was only 0.02%.

Research Highlights
► Visual inspection of epileptic seizures may have high interrater variability.
► We investigated different epileptic automatisms by quantitative analysis.
► We found parameters that clearly separate hyperkinetic from non-hyperkinetic seizures.
► Our findings establish objective parameters to identify different seizure types.