My Husband 55 Years Old Has Been Taking 1000mg Kepra

My husband 55 years old has been taking 1000mg Kepra daily for 5 years now. He had seizure twice in 2 years and was given this medication by a neurologist after MRI and cat scan of the brain showed a slight abnormal brain activity. That was 5 years ago. We saw a seizure specialist (he works with my husbands neurologist. He did say that there is no confirmed report of my husband having seizures so he suggested a study. It's a 3 or more days procedure and monitored at the hospital. His medication will be stopped cold turkey, won't sleep for 24 hours. Dr said no sleep triggers seizure if he really have one. Dr Luciano is affiliated with NYU Langone Medical Center in New York City. Do you have idea how safe is the procedure is?