Most people are aware that there are different types of seizures. The most common type of seizures seen in the media are dramatic, convulsive seizures in which people have sudden loss of consciousness, fall to the ground and convulse for several minutes. Obviously, these are clearly abnormal events for which families seek immediate medical attention. Staring spells, however, are more subtle and difficult to characterize. There are two main kinds of epileptic staring spells – absence seizures and complex partial seizures.
Although absence and complex partial seizures both involve staring and unresponsiveness, there are several key differences which are important to recognize as the diagnostic testing, treatment and prognosis are significantly different between the seizure types. To help differentiate between absence and complex partial seizures it is important to consider the age of onset, duration, associated movements, and after effects.
Absence seizures usually start during preschool/early elementary years and generally resolve by puberty. It is rare for absence epilepsy to persist into adulthood. Complex partial seizures may begin at any age from early infancy through adulthood. Therefore, any staring spell seizures starting during infancy or as an adult are unlikely to be absence seizures.
Another difference is that absence seizures tend to be shorter than complex partial seizures – generally lasting less than 10 seconds and very rarely persisting beyond 30 seconds. Complex partial seizures almost always last longer than 30 seconds (typically one to three minutes).
Body or facial movements during the spells may provide clues to determining the seizure type. The movements during seizures may be of the trunk/shoulder, arms, legs or other automatisms (repetitive unconscious gestures such as lip smacking, chewing, or swallowing). Interestingly, the movements are often an unusual continuance of the pre-ictal activity. For example, if a child is talking or chewing prior to the seizure there may be an unusual chewing-like movement during the seizure. It is much more common to have unusual movements with complex partial seizures.
The after effects (postictal state) are another difference between the two seizure types. After an absence seizure, the child will resume his prior (pre-ictal) activity. Most of the time with an absence seizure there is a “reset” in which there is a brief moment of confusion and then the pre-ictal activity is resumed. There is sometimes an interesting smooth “continuance” of activity where a child will complete a sentence or seamlessly “pick up where he left off” at an activity immediately after the seizure as if nothing had happened. With complex partial seizures there is usually some sort of altered mental status (confusion, difficulty speaking, sleepiness or unusual emotions) lasting anywhere from several seconds to more than a few hours after the seizure.
For an experienced neurologist, clinically characterizing the spells is the most accurate way to make a diagnosis; however, electroencephalography (EEG) may reveal abnormal electrical activity which helps clarify the diagnosis. In absence epilepsy there is often a very characteristic EEG finding which is observed throughout the entire brain (generalized epileptiform discharges). The corresponding EEG findings for complex partial seizures tend to show abnormal electrical activity localized to one area (focal epileptiform discharges).
Once the seizure type is carefully characterized, there are implications regarding further diagnostic testing, treatment and long term prognosis. For example, if there is a very typical description of absence seizures and a supporting EEG, often no further testing is necessary. However, if there is any suggestion of complex partial seizures, the American Academy of Neurology recommends neuroimaging (an MRI being the preferred imaging modality). Treatments are also considerably different between the two seizure types with some medications for complex partial seizures possibly worsening absence seizures.
It is important for parents to realize that not all staring spells are “daydreaming” or defiant/ignoring behavior. With new treatment options available, clinically characterizing staring spells, getting appropriate testing and adequate treatment from an experienced pediatric neurologist can make a tremendous difference in a child’s life.
If you have any questions or would like information about scheduling an appointment with Dr. McIntosh, contact our office at (949) 249-3780 or visit our website for more information.