What is a "tonic-clonic" seizure?

What is a "tonic-clonic" seizure?

Charles Ribak, Ph.D. (Professor of Anatomy and Neurobiology, UC Irvine School of Medicine) gives expert video advice on: What is a "photosensitivity" seizure trigger?; What is an "automatism"? and more...

With epilepsy, a tonic-closure seizure involves a lot of the activity or behavior of the body during a large seizure. One of these generalized epileptic seizures usually starts out with a tonic movement, and then it progresses into the clonic movement. So, there's first this extension with a lot of shaking and trembling, and then the clonic movement starts in, where the flexor activity occurs.