Lag Time An interesting observation was the lag time we found (up to 48 hours) in some infants between the time of injury and admission to the ER. This was common with younger infants when parents at first underestimated the apparently minor head injury (fall from less than 1 m). These infants were eventually brought to the ER, however, because of some deterioration or unusual behavior. Another lag time was observed between admission to the ER and operation. This lag time was probably attributable to the good neurologic condition of some infants on admission. Less than half of the infants were operated on immediately on arrival or within 1 hour of presentation to the ER. This may suggest a rather subacute presentation of EDH in infants compared with children and adults. It can be explained either by better compliance of the infant cranium and brain, which delayed the appearance of severe symptoms, or by underestimation of the injury by the parents and the doctor as well.