Central cardio-autonomic disorganization in interictal states of epilepsy detected by phase space analysis

Faustmann PM and Ganz RE (1994) Central cardio-autonomic disorganization in interictal states of epilepsy detected by phase space analysis. Int J Neurosci 78:1-2 43–7.

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Abstract: In a study of central autonomic organization in interictal states of idiopathic generalized epilepsy, we measured the spontaneous oscillations of the heart rate in 8 young epileptics with normal interictal electroencaphalograms (EEGs), 6 young epileptics with epileptiform discharges in the interictal EEGs and 8 healthy controls. The temporal structure of the heart rate (HR) dynamics was operationalized through the estimation of the largest Lyapunov exponent (LLE). For all patients and controls, the LLEs of the HR dynamics were positive, indicating chaotic oscillations. The patients with interictal epileptiform discharges showed significantly lower LLEs of the HR dynamics than the epileptics with normal EEGs and the healthy controls. By comparison, the values of the epileptics with normal EEGs und those of the healthy controls did not differ significantly. This finding suggests a more rigid and thus less adaptable central cardio-autonomic organization in epileptics with epileptiform discharges in the interictal EEG.

Keywords: Autonomic regulation, heart rate, epilepsy, chaos theory, Lyapunov exponent

Context

• Study of autonomic function in 14 patients with idiopathic epilepsy, 8 with normal interictal EEG and 6 with epileptiform activity on interictal EEG, as well as in 8 healthy controls. The maximal Lyapunov exponent for heart rate dynamics, an index of the rate of divergence of trajectories in phase space, was positive in all cases, consistent with chaotic behavior. However the MLE was lower in the patients with abnormal interictal EEG, consistent with reduced variability.