The main symptom of a petit mal or absence seizure in adults is the victim stares off into space for about 15 seconds, says Johns Hopkins Medicine. When he comes out of the seizure, he may not remember what happened. This is a simple absence seizure.
Other symptoms of a petit mal seizure are fluttering eyelids and small hand movements, explains Mayo Clinic. The patient may also smack his lips, rub his fingers together or make chewing motions. If he is walking, he may suddenly stop but not fall. These seizures are called complex absence seizures, according to the Epilepsy Foundation. They last longer than simple absence seizures and may happen many times during the day.
Medical experts usually find no underlying condition that leads to a petit mal seizure in an adult, notes Mayo Clinic. Doctors know these seizures happen because the electrical "wiring" in the brain is abnormal.
Absence seizures are hard to diagnose because they are fleeting, and the patient is perfectly well and normal after the seizures are over, states the Epilepsy Foundation. However, the electrical abnormalities in the brain can be detected through an EEG, or electroencephalogram. The doctor might ask the patient to hyperventilate during the test, which triggers a seizure.