A neurological disorder characterized by recurrent seizures (fits), which may include convulsions or loss of consciousness.
彼は子どものころにてんかんと診断されたが、薬で発作はだいぶおさまった。
He was diagnosed with epilepsy as a child, but the seizures have been much reduced with medication.
発作が起きたときは慌てずに、頭を保護して横向きに寝かせ、口に物を入れないでください。
If a seizure occurs, don't panic: protect the head, place the person on their side, and do not put anything in their mouth.
てんかんは脳波検査（EEG）やMRIで原因を調べることが多い。
Epilepsy is often investigated with an EEG (electroencephalogram) or MRI to look for causes.