A 20-year-old man suffered a significant closed head injury after a diving accident. He is left with minor memory impairment but makes a full recovery. A few months later, he has a witnessed loss of consciousness with some arm and leg twitching. After the event, he is disoriented for 2 hours and then gradually returns to baseline. There was no incontinence or tongue biting, and his examination is normal. Which of the following is the most likely diagnosis?
syncope generalized seizure focal seizure cardiac arrhythmia