Hi Bruins.

I sort of stumbled on this forum and would like to help you with this the report you have posted. I am not an epileptologist, but I work closely with them. I do various kinds of testing and monitoring for seizures at a well-known hospital. I know that when I have tried to research my own and family's medical issues I have always appreciated getting a response from someone who actually works in that field and can give me accurate information.

Anyway - the terms used in your report would be difficult for patients to make sense of. That's where I can help.

1. Frontally dominant beta: Beta is the name of one of four basic frequencies. Frequency means how many times it cycles in one second. Beta is the fastest frequency. It doesn't *have* to show up on a normal EEG, but if it does, it is normal when it is limited to the frontal areas of the brain. It often increases during drowsiness and early sleep. It *might* be abnormal if it is coming from all areas of the brain, but is not abnormal if the patient is taking certain kinds of common medication. That primarily includes AED's, benzos and some antidepressants.

2. The Photic Stimulation procedure: The photic lamp *can* cause abnormal discharges in a very few seizure types - mostly Juvenile Myoclonic Epilepsy. The reason a bunch of different frequencies are used is that most people that will have abnormal discharges only have them on certain frequencies. If the test is otherwise normal, it can be helpful to see the discharges to guide diagnosis. The ACNS guidelines that govern our practice tell us that if we see abnormal discharges during a certain frequency, that frequency is repeated to determine if it was actually provoked by the light. If a patient starts having clinical seizures during photic stimulation, we stop the light to prevent the patient from going into status and notify the reading epileptologist immediately. A clinical seizure is one that has abnormal EEG accompanied by body movements that are consistent with seizures. Photic Driving: This is a phenomenon that some, but not all, people have. Light is processed by the back area of the brain. The electrodes on those spots can show frequencies that are coordinated with the light. For example, if the light flashes at a frequency of 15, then photic driving means there is a rhythm coming from the leads on the back of the brain (called O1 and O2) that is at 15 cycles per second, exactly like the light, and it is "time-locked". In other words it starts when the 15-frequency light starts flashing, and ends when it stops. It is not abnormal. Your report says that there were no abnormal clinical or electrographic responses. Clinical response would be abnormal body movements and electrographic would be brain responses showing up on the EEG. The symptoms you reported taking place during photic stimulation were apparently not considered abnormal by the reading physician. Sometimes the flashing light can make people feel anxious, and sometimes the rooms are cold, so maybe that contributed to your symptoms?

3. Hyperventilation is another "activation procedure" that can be diagnostic for Absence Epilepsy. It should be done on every EEG exam unless the patient has contraindications, such as very bad asthma, heart conditions, COPD, stroke, sickle cell, and a few others. The report says you had "modest symmetric build-up of slow activity." That means that you had a moderate "build up" of a normal response to hyperventilation for children and even young adults. It is characterized by moderate to high amplitude waves that are slower than 'normal' - usually about 4 hz (four cycles per second). Symmetrical means it was showing up the same on both sides of your brain. If it was only showing up on one side it could indicate a tumor - so it being symmetric is what you want. The reason they make a big deal of it on the report is because if you were not hyperventilating and those wave forms showed up, it would be an abnormality. The reason it shows up has to do with hyperventilation changing the balance between oxygen and carbon dioxide. And this particular activation procedure is nearly 100% diagnostic for Absence seizures...meaning that if hyperventilation is done adequately by the patient, it would be rare for it to not provoke a seizure.

4. Sleep deprivation: This is actually considered another "activation procedure." Being sleep deprived can provoke seizures or at least abnormal discharges in people with certain epilepsy types. The main purpose, however, is to make sure the patient can sleep. A person with epilepsy can have an absolutely normal EEG while they are awake. BUT WHEN THEY GET DROWSY AND START FALLING ASLEEP - THE EEG CAN COME ALIVE WITH ABNORMAL ACTIVITY THAT WE OTHERWISE WOULD NOT SEE! I made that in all caps to make it stand out. Falling asleep during an EEG is one of the most important parts of the exam, and at my hospital we ask outpatients to come back most of the time if they did not sleep during the exam. Sleep is that important. We also run outpatient routine EEG's up to an hour in an attempt to capture sleep. 20 min. EEG's go against ACNS guidelines that require a 20 min. background on top of activation procedures and sleep. We not only send out an information packet to patients before the exam explaining sleep deprivation, but we also call them the day before to remind them to get no more than 4 - 6 hours of sleep that night in order to take a nap during the test. If you have another EEG, now you know. I would also ask that they not perform photic until the end of the exam. I do hyperventilation first, because it can also help them fall asleep and I do photic last to avoid making patients anxious or overly stimulated before sleepy-time So.. if you continue to have symptoms concerning for seizures, you may want to ask for another EEG that includes sleep.

I hope I've provided some useful information. I am not a physician and do not diagnose people or give medical advise, but I get great satisfaction when I can help someone understand a complicated and sometimes scary testing procedure.


Crescent Moon