INTERICTAL CHANGE IN CARDIAC AUTONOMIC FUNCTION-ASSOCIATED WITH EEG ABNORMALITIES AND CLINICAL SYMPTOMS - A LONGITUDINAL-STUDY FOLLOWING ACUTE DETERIORATION IN 2 PATIENTS WITH TEMPORAL-LOBE EPILEPSY

The purpose of the present study was to investigate the ictal and inte rictal changes in cardiac autonomic function (CAF), and the relationsh ip between the interictal change in CAF to the electroencephalogram (E EG) and clinical findings. In two patients with temporal lobe epilepsy (TLE) showing acute deterioration, a quantitative evaluation of their interictal CAF based on heart rate variability and their EEG using sp ectral analysis was conducted, and the findings compared with repeated clinical evaluations during the recovery period. The ictal heart rate changes and their temporal relationship to ictal discharge were inves tigated using simultaneous EEG/electrocardiogram (ECG) monitoring in o ne of the patients. Interictal parasympathetic function was decreased during the period of acute deterioration, but was increased in associa tion with improvements in the EEG and clinical findings. In contrast, the sympathetic function showed no specific changes. The ictal dischar ges were preceded by a brief bradycardia, with a long delay of up to 4 0 s. The results demonstrated that this decrease in parasympathetic fu nction was closely related to the interictal changes in central nervou s system function. On the other hand, the ictal discharges in one of t he patients were thought to have caused a transient elevation of paras ympathetic function. It is strongly suggested that patients with TLE h ave interictal as well as ictal changes in CAF that are mediated mainl y through the parasympathetic nervous system.