The Relationship between Generalized Paroxysmal E.e.g. Discharges and Various Test Situations in Two Epileptic Patients.

This investigation was carried out on two patients suffering from so-called primary subcortical epilepsy. Serial studies were made both of variations in the amount of paroxysmal electrical activity recorded from the brain during the performance of psychological tests and of changes in test performance in the presence of paroxysmal discharges. There is no doubt that changes in the alpha rhythm can be shown to accompany alterations in behaviour in all subjects. The paroxysmal E.E.G. discharges recorded from epileptics have rarely been studied from this point of view. It is, however, widely held that petit mal attacks do not occur randomly with respect to mental state. Lennox and Lennox (1960), who tended to equate the electro-encephalographic dysrhythmia with the clinical ictus, considered that petit mal attacks occur less often when the patient is kept occupied. According to Pond (1961), petit mal attacks may be precipitated by emotional disturbance. In the present investigation a series of E.E.G. examinations and of psychological tests was carried out pari passu in order to determine whether there were systematic differences in the amount of paroxysmal activity recorded in different test situations. Such differences as were found were then further explored in an attempt to discover the factors responsible for them. Autonomic function seemed to be one variable of possible significance, and respiration and pulse rate were therefore recorded throughout. The investigation was also planned to permit the study of changes in test performance during the occurrence of generalized paroxysmal discharges. Patients were selected whose E.E.G. records contained brief generalized wave-spike discharges, without clinical accompaniments. A distinction is often drawn (Kiloh and Osselton, 1961) between such 'inter-seizure' discharges and the electrical disturbance associated with petit mal attacks. However, brief discharges do not differ qualitatively in their E.E.G. parameters from bursts of longer duration and might be expected to have behavioural correlates which could be measured by a more refined method than clinical observation. A number of studies have been made of responses to psychological tests during brief discharges but the findings are conflicting. Schwab (1941) and Cornil, Gastaut, and Corriol (1951) stated that reaction times are delayed, but Prechtl, Boeke, and Schut (1961) found no impairment in the rate of performance on a serial reaction test, and Milstein and Stevens (1961) found no impairment in auditory learning and avoidance conditioning during brief generalized discharges. Kooi and Hovey (1957) recorded spontaneous paroxysmal discharges in epileptics during intelligence testing. …