Retention of orienting reaction habituation in patients with epileptogenic cerebral tumors.

An electrographic study on habituation of the somatic (EMG), autonomic (finger plethysmogram, galvanic skin reaction, respiration, pulse) and EEG (acoustic evoked potential and EEG-blocking reaction) components of the orienting reaction elicited by a repetitive auditory stimulus during successive (weekly) sessions was performed in 41 patients with epileptogenic cerebral tumors (ECT) and in 128 control subjects. The study evidenced significant retention disturbances of orienting reaction habituation (i.e., of learning), the "saving" of stimulations, achieved from one session to the other to obtain the habituation criterion, being lesser in ECT patients than in control subjects. The severity of habituation retention disturbances depended on the tumor site and size, as well as on the electro-clinical form and frequency of seizures. Thus, the most marked habituation retention disturbances were found in patients with temporal or predominantly temporal epileptogenic tumors, in cases with large hemispheric epileptogenic tumors (over 6 cm), in patients with generalized or generalized plus partial seizures, as well as in those with frequent (daily) seizures.