In the mid 1970s,<unk>  was first classified by Bryan Jennett into early and late seizures, those occurring within the first week of injury and those occurring after a week, respectively. Though the seven-day cutoff for early seizures is used widely, it is arbitrary; seizures occurring after the first week but within the first month of injury may share characteristics with early seizures. Some studies use a 30‑day cutoff for early seizures instead. Later it became accepted to further divide seizures into immediate<unk> , seizures occurring within 24 hours of injury; early<unk> , with seizures between a day and a week after trauma; and late<unk> , seizures more than one week after trauma. Some consider late<unk>  to be synonymous with post-traumatic epilepsy. Early<unk>  occur at least once in about 4 or 5% of people hospitalized with TBI, and late<unk>  occur at some point in 5% of them. Of the seizures that occur within the first week of trauma, about half occur within the first 24 hours. In children, early seizures are more likely to occur within an hour and a day of injury than in adults. Of the seizures that occur within the first four weeks of head trauma, about 10% occur after the first week. Late seizures occur at the highest rate in the first few weeks after injury. About 40% of late seizures start within six months of injury, and 50% start within a year. Especially in children and people with severe TBI, the life-threatening condition of persistent seizure called status epilepticus is a risk in early seizures; 10 to 20% of<unk>  develop into the condition. In one study, 22% of children under 5 years old developed status seizures, while 11% of the whole TBI population studied did. Status seizures early after a TBI may heighten the chances that a person will suffer unprovoked seizures later. <!--
Post-traumatic seizure
Musicogenic seizure
Reflex seizure
Post-traumatic epilepsy
Febrile seizure
Non-epileptic seizure
Musicogenic epilepsy
Transient ischemic attack