Waking and sleep EEGs were recorded in 67 siblings of 52 patients with febrile seizures (FS) at the Epilepsy Centre Bethel, Bielefeld, F.R.G. Epileptic activity was recorded in at least one sibling of 54% of patients. Epileptic discharges were noted in 50% of the 67 siblings; only in waking in 3%, in waking and sleep in 31% and in sleep only in 15%. The greatest number of epileptic discharges were noted in the waking state during hyperventilation (33%) and during sleep stage C (39%). Of nine patients with complicated febrile seizures 56% had at least one sibling with seizure discharges and of 43 patients with simple febrile seizures 54% had a sibling with seizure discharges. Of nine patients with later onset epileptic seizures, 44% had seizure discharges in the EEG. Siblings age six to ten years had the highest rates of activation (67%). Epileptic discharges occurred in 83% of siblings with seizures, but in only 46% of those without seizures. Epileptic activity in patients and in siblings was significantly greater in those who had occipital slow wave activity in the EEG. A multifactorial inheritance of EEG abnormalities was suggested and the genetic factor was important in patients with both simple or complicated FS. Exogenous brain damage may act as an accidental event or catalytic effect leading to the activation of FS, mental retardation, neurologic deficits, behavior disturbances, focal FS, and/or a higher rate of later epileptic seizures. 
COMMENT. The importance of sleep EEGs and other activating procedures in the prediction of prognosis in patients with febrile seizures is demonstrated by this study. Reports minimizing the value of the EEG in prognosis and later occurrence of epilepsy are often based on EEGs in the waking state only, and without sleep recordings.
A case control study of risk factors for febrile seizures in the People’s Republic of China is reported from the Neurological Institute, Sun Yat-Sen University of Medical Sciences, Guangzhou, Beijing Neurosurgical Institute, Beijing, China; National Institutes of Health, Bethesda, MD; and the World Health Organization, Geneva, Switzerland. Information was gathered by door-to-door survey in six major cities in the People’s Republic of China . Family history of febrile seizures, birth and postnatal factors were assessed in 182 subjects and in an equal number of matched controls. The odds ratio for risk of FS in children with a family history of FS in a first-degree relative was 10. Apart from maternal acute respiratory infection during the first trimester of pregnancy none of the other examined factors was associated with an increased risk. Birth asphyxia was not a significant risk factor.