A 5-year experience with 562 carotid endarterectomies, using electroencephalogram (EEG) monitoring and selective shunting, was reviewed. EEG changes occurred in 102 patients (18%). The frequency of EEG changes, as related to cerebral vascular symptoms, was as follows: transient ischemic attacks, seven per cent (19/259); completed strokes, 37% (36/98); vertebral basilar insufficiency, 24% (32/135); asymptomatic, 21% (15/71). Patients with contralateral carotid occlusion exhibited EEG changes in 37% (28/76) of operations. Fifteen patients suffered perioperative strokes (2.6%). Nine of the 15 were associated with a technical problem of either thrombosis of the internal carotid artery (five) or emboli (four). Technical problems were more common when shunts were used (five per cent) than when they were not (0.9%). Patients who suffered strokes prior to surgery were more at risk to develop a perioperative stroke (three per cent) than those not suffering prior strokes (0.3%). The EEG did not change in three patients who had lacunar infarcts prior to surgery and who awoke with a worsened deficit. Our series does not clearly establish the advantages of EEG monitoring, which is expensive (+375/patient) and may not detect ischemia in all areas of the brain. However, the use of shunts may introduce a risk of stroke due to technical error that is equal or greater than the risk of stroke due to hemodynamic ischemia. Since the need for protection is unpredictable by angiographic or clinical criteria, the benefit of EEG monitoring may be in reducing the incidence of shunting in those patients whose tracing remains normal after clamping. The decision to shunt, however, when there is electrical dysfunction after carotid clamping should be based not only on the EEG but also on the clinical signs and computed tomography (CT) scan. Our data does not show a net benefit in selective shunting unless the patient has sustained a stroke prior to surgery.

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Muscimol, a gamma-aminobutyric acid (GABA) analogue that exerts potent and specific agonist effects on GABA receptors, was administered orally to 10 patients with Huntington's disease. In this double-blind study, muscimol treatment did not result in improvement in these patients' motor or cognitive functions. However, muscimol administration did ameliorate chorea in the most severely hyperkinetic patient, and it was associated with the appearance of dystonic features, electroencephalographic changes, and behavioral alterations in some patients. These latter observations support a functional relationship between GABA-ergic activity and the genesis of both systonia and EEG abnormalities in humans. The therapeutic failure of muscimol indicates that the GABA disturbances in Huntington's disease does not alone account for the clinical features of this disorder.

EEG monitoring and carotid back pressure were performed on 100 patients undergoing elective carotid endarterectomy. Shunts were inserted selectively in those patients who showed change in EEG after a trial period of carotid clamping (15%). No patient in the series awoke with a neurologic deficit. Back pressures were significantly lower in the shunted group and these pressures roughly correlated with EEG changes. Only one patient with a back pressure of greater than 40 mmHg had EEG changes and this patient had a recent mild stroke. EEG changes were most frequent in patients with contralateral carotid occlusions and in asymptomatic significant stenoses. EEG is a more discriminating indicator for shunt insertion than back pressure, although a pressure greater than 40 mmHg is safe in patients without recent stroke.

T HE PRESENT paper is based on a longterm study of 275 patients with petit mal. In this study an attempt was made to assess the incidence and character of other forms of epilepsy as they occur in patients with petit mal, to report the results of psychometric testing, and to obtain a critical insight into the problems of drug therapy and social prognosis for these patients. In addition, the genetic and other etiologic implications of the material will be discussed. Previous authors have covered some of these questions on the basis of smaller series.1-5 Their conclusions will be discussed in due course, as will also some common, but less well-documented, beliefs about petit mal. Report of CasesThe patients were drawn predominantly from the Seizure Clinic at the Columbia-Presbyterian Medical Center. The median duration of clinic attendance was eight years. More importantly, the ages to which patients were finally followed are given in Table 1, from which it is seen that the majority was followed be¬ yond the years of puberty; these years, as will be shown, are critical for the assessment of prognosis. In