Of 363 infants with infantile spasms (IS) admitted into our hospital during an 18-year period, 286 were closely followed for at least 6 years and form the basis of this report. These patients were divided into symptomatic (165 cases) or cryptogenic (121 cases) groups. The cryptogenic group consisted of patients exhibiting no etiological clues and in whom development until the onset of the disorder was normal, even if some had mild impurities in their previous biography. We did not use the "doubtful subgroup" proposed by others for infants with no known etiology but with definite previous psychomotor delay. Close monitoring of ictal phenomena confirmed the latter variability and strengthened the view that IS should not be classified as a distinct seizure pattern. No statistically significant clues for etiology or prognosis were offered by the analysis of prevailing seizure patterns or frequency. Etiologies in the symptomatic group were subsumed within pre-, peri-, and post-natal periods. Asphyctic events predominated in this series. Dysgenetic, infectious, metabolic, and hemorrhagic factors were almost equally represented, except for the first, which was found somewhat more frequently. That postimmunization reactions may be one cause of IS was not considered sufficiently documented. A gender predominance ( 8 : 0 = 2: 1 ) occurred within the symptomatic group only. No significant genetic trends could be revealed after excluding those disorders that themselves carry clear genetic implications. Age of onset was earlier than in most reports because we corrected for true conceptional age. When this was done, onset of IS below 3 months carried a more unfavorable prognosis (p < 0.001). As expected, the presence of preceding neurological impairment resulted in worse outcome. Infants who had typical hypsarrhythmic EEG at the onset of IS fared better than those with atypical EEG (p < 0.02). While bacterial infections usually aggravated the condition, viral ones seemed to temporarily ameliorate it. On a short-term follow-up (10 months from onset treatment), the hypsarrhythmic pattern may disappear in both groups regardless of therapies, but on a long-term basis (6 years), the EEG evolution showed no statistically clear correlations with early therapies. The evolution into other seizure patterns also appeared independent of therapies. In our series less than a quarter eventually developed the Lennox-Gastaut syndrome. Controlled therapeutic protocols were adopted in an effort to resolve ongoing controversy about optimal treatment. Both groups were maintained, 135 136 C . T. LOMBROSO thoughout the therapeutic trial, on either antiepileptic drugs, on oral steroids alone, or on nonsynthetic ACTH alone, the latter followed in one subgroup by oral steroids also. Dosages were based on body surface or weight. Whenever cross-over or a change in the initial therapeutic regimen became necessary, the case was eliminated from the study. Clinical and laboratory tests were obtained at prefixed periods of time. For the short-term assessment ...

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We showed that hypoxia is acutely epileptogenic in immature but not in adult rats. In the present study, we evaluated whether hypoxia results in an increase in long-term seizure susceptibility to flurothyl and whether this is associated with impaired performance on behavioral tests. We also determined whether these long-term outcomes are dependent on age at time of O2 deprivation. Long Evans hooded rats were rendered hypoxic on either postnatal day (P)5, P10, or P60. Sixty to 75 days after hypoxia, rats were tested for performance in water maze, open field, and handling tests and for seizure susceptibility to flurothyl. Hypoxia at P10 significantly increased seizure susceptibility to flurothyl, whereas hypoxia at P5 and P60 induced no long-term changes in seizure threshold. At P10, greater seizure severity during hypoxia and more prolonged exposure to hypoxia significantly increased long-term seizure susceptibility. This long-term change in seizure susceptibility appeared to be dissociated from any long-term neurobehavioral consequences, because only animals rendered hypoxic as adults (P60) had impaired behavioral performance. The results suggest that hypoxia-induced seizures can alter long-term seizure susceptibility and that this long-term effect is dependent on age and on severity of seizure activity at the time of previous hypoxia.

Summary:Purpose: To describe the evolution of interictal findings in serial EEGs from patients with primary generalized epilepsy.Methods: A cohort of 89 subjects with various primary generalized epilepsies were reviewed. Thirty-one did not meet a priori criteria. Of the 58 patients analyzed, 12 had only absence seizures, 28 had absence seizures followed by one or more generalized tonic-clonic seizures, 9 had generalized tonicclonic seizures followed by absence and/or myoclonic seizures, and 9 had juvenile myoclonic epilepsy. Patients were followed for a mean of 16 years. An average of 39 EEGs were obtained on each patient.Results: Thirty-two patients (56%) had focal features present in up to 65% of the EEGs in each of the patients. Accepted focalities were only those that were consistent in lateralization, location and, often, morphology across the span of the study. Focal findings were most often temporal or frontal.Conclusions: Patients with typical primary generalized epilepsies show a high incidence of focal EEG features that cannot be explainea on the basis of structural lesions, coincidental factors, or to artifacts of the selection criteria. Although the data do not allow a definitive explanation, possible mechanisms include associated focal cortical pathology such as microdysgenesis, and development over time of localized, self-sustaining hyperexcitability in low-threshold cortical structures subjected to repeated generalized spike-wave activity. Either hypothesis implies the participation and interaction of genetic, ontogenic, and environmental factors. Key Words: Focal electroencephalograms-Idiopathic generalized epilepsy-Longterm follow-up.The classification of epilepsies and epileptic syndromes proposed in 1989 (1) defines the idiopathic (primary) generalized epilepsies (ICE) as those whose seizure phenotypes indicate the involvement of -both hemispheres from the onset, both clinically and electrographically. By definition, the IGE show no evidence of structural brain lesions, in contrast to the secondarily generalized group of epilepsies, and no known or suspected etiology other than the contributions of polygenic factors. Their EEG expression (ictally or interictally) consists of initially generalized, bilaterally symmetrical discharges, whereas the background patterns are normal for age.Despite many efforts made in the past half century by both clinicians and neuroscientists, the pathophysiology of IGE remains unsettled. Among still-controversial issues are the predicated complete lack of structural brain lesions and the precise role played by the cortex.A long-term follow-up in a population of subjects with ICE shows that their EEGs often contain focal abnormalities that are persistent and consistent in location-an