When “slam dunk” EEG evidence is missingPosted: 12/25/2011
My daughter played video games to deliberately provoke photosensitive seizures during extended, inpatient EEG monitoring. She had plenty of seizures, but they weren’t detected by the EEG sensors on her scalp. Although she was exhausted and cognitively slow from all the seizure events, the clinicians said–based entirely on the EEG data–that they saw no sign of seizures. We’ve tried this at several hospitals, always leaving with this frustrating result.
Many patients with inconclusive EEGs are dismissed by neurologists and told there’s no evidence of seizures. This is probably even more frequently the case with visually induced seizures, since most neurologists know little about them. In their training they were taught that photosensitivity is extremely rare and that photosensitive seizures are big, generalized (grand mal) episodes.
Typically, neurologists are very conservative about issuing a diagnosis of epileptic seizures (although this was not always the case). If there’s an unmistakable seizure pattern on the EEG, they feel comfortable stating that you have seizures. Without clear EEG evidence, many neurologists may not feel a seizure diagnosis is justified. If this has happened to you, you’re not alone. Although clinicians are supposed to diagnose epilepsy based on the patient’s history as well as EEG and other tests, most often EEG results are considered more indicative than all other data–even though EEG is extremely imprecise. The result is that it can take years before a patient is properly diagnosed.
Here is a sampling from various reports we received on my daughter’s video game-induced seizures and the EEG recordings done during the events:
- “It is interesting that they almost always occur when she is alone.” [when she can concentrate fully on the game and more easily lose contact with her surroundings]
- “Most photosensitive seizures are primary generalized with bursts of spike waves, polyspike waves, or polyspikes. It is possible for some types of visual stimuli to bring on a partial seizure. These are more rare. Even in those instances, usually there is some sort of epileptic discharge.” [Oh.]
- “It is true that with surface EEG, we could miss partial seizures. At the same time, there are also many clinical signs that make a seizure unlikely…MRI has been normal and our clinical suspicions are quite low.” [Don’t seek and you shall not find.]
- “The EEGs have never shown epileptiform activity, nor has there been a photosensitive response.” [See my post on testing for photosensitivity using photic stimulation]
- “Due to the normal EEG and the precipitation of events with only limited stimuli, we feel it is unlikely that these events represent seizures.” [In other words, if only video games precipitate seizures, these can’t really be seizures.]
- “The patient was playing a video game and then stopped…There was no obvious change in the patient’s observed behavior in that she was sitting on a stool in front of a monitor playing a game…The EEG also did not show significant change…[She stopped playing the game—isn’t this a change in behavior?]
- “The two…events that were recorded…failed to reveal an identified behavioral change that would appear to be convulsive in nature.” [Since when are all seizures convulsive?]
- “The patient had a few jerks of her limbs during photic stimulation, but there was no electrographic correlate.” [Hmmmmm.]
- “There is a generalized irregular slow wave burst…at which time the patient is swaying her head to and fro while watching a video. This activity is not epileptic and most likely related to movement.” [An unsupported guess with no effort to gather more evidence. Ask the family if swaying the head to and fro is typical behavior. Or ask the patient if she recalls swaying while playing.]
Sound familiar? Anyone else want to share similar results?