Testing coming up negative Is it still seizures and possible epilepsy?

[Boozer]

I'm a little confused? I started seeing the doc about 3 months ago and was told that I was having seizures. But so far the only thing that has come up with anything is a CT scan showing a hypodensity on the left frontal lobe. My EEG came up negative even though during the photosensitivity portion I had a seizure and then my MRI came back normal. I go to see a neurologist next. I am so confused. I don't see how they can't catch what is going on with me and am afraid this is going to take forever for a diagnosis. I have read a lot about what others are experiencing with their seizures and have no doubt that it is the same thing. It seems like simple partial or complex partial seizures. Has anyone else had this happen to them or someone they love? I am looking for answers and all I want from the docs is help so I can feel better. If it's not seizures what else could it be anyone have an idea? Thanks ahead of time from anyone who is willing to lend me a hand. Erin

 

[Nick88]

Nothing shows on my EEGs but on my MRIs and CTs it does. But if your having seizures then your having seizures no matter what the scans show. Sorry I couldn't be more help.

 

[BrandiBrat]

Hi Erin, if you had a seizure during any portion of your EEG then your test would have given your neurologist a positive reading. Either during the photosensitivity or the hyperventilation section. I'm not sure why you had a seizure during your EEG, but were told it was a negative EEG.

 

[Boozer]

I'm hoping that the neurologist will have more answers for me. I read somewhere online that the EEG only tests the surface electrical impulses of the brain and that if the seizure is deeper in the tissue it may not be picked up. Has anyone else heard of this? Just looking for answers.

 

[chmmr]

I'm hoping that the neurologist will have more answers for me. I read somewhere online that the EEG only tests the surface electrical impulses of the brain and that if the seizure is deeper in the tissue it may not be picked up. Has anyone else heard of this? Just looking for answers.

I have heard this too. I heard that frontal lobe seizures are particularly hard to pick up so given your MRI results that could certainly be the case.

http://www.cnsspectrums.com/aspx/articledetail.aspx?articleid=1973

Frontal Lobe Seizures

Seizures of frontal lobe origin are relatively common, but difficult to recognize. Approximately 20% of patients admitted to an epilepsy program will have seizures of frontal lobe origin.1 Until ~30 years ago, we thought that most seizures were of temporal lobe origin. Not many of us knew about frontal lobe seizure, parietal seizure, or occipital seizure. We talked about temporal lobe seizure because that was what we thought it was all about. But that is not correct. We have now learned a lot more about it.

How do seizures of frontal lobe origin present? They can present with a wide variety of clinical manifestations, and that is why it is difficult to diagnose them. They can mimic other disorders, in particular psychiatric ones, or vice versa. They can pose a real challenge for neurologists and psychiatrists. Factors that limit the study of the frontal lobe include its anatomic size, its extensive networking, and its limited access to the scalp during EEG recording.

The frontal lobe is heavily interconnected with the limbic system. The orbital mesiofrontal region are connected with the cingulate, the hippocampus, and amygdala. Seizures arising in this area may be expressed as complex partial seizures of different origin.2 Clinical symptoms of frontal lobe origin can, at times, be confused with temporal lobe epilepsy or generalized epilepsy or nonepileptic event or psychiatric disorders.

In the patient mentioned earlier, with episodes of fear, the meningioma was localized in the orbital region; however, the clinical manifestations (fear and irritability) were suggestive of a temporal lobe, amygdala focus because immediately there is a spread through the temporal lobe. She only later had an magnetic resonance imaging (MRI), at which point she was diagnosed to have a meningioma in the orbital frontal region. It was removed, and she is perfectly fine.

To compound this issue, much of the frontal lobe is inaccessible to standard scalp EEG. When you perform an EEG the electrodes are placed on the frontal area, then anterior temporal, and posterior temporal region. If you have a focus on the dorsolateral area, it is easier to pick up paroxsymal discharges; however, discharges from the mesial (interhemisheric) cortex, the orbitofrontal region, and the cingulum often shows no surface EEG correlate during ictal activity as they can be volume conducted over a wide region bifrontally, sometimes with a controlateral maximum. They might spread at a wide angle so that it spreads all over the scalp so that it might not be picked up on the EEG. When it is picked up, it looks like generalized discharges and the fact that they had a frontal lobe discharge can be missed. A large portion of the prefrontal region give us no symptoms on electrical stimulation.

If we have a patient in our office with stereotypic events ,that patient is sent to get an EEG. When it comes back normal we believe that the patient did not have a seizure. That is not correct because an initial outpatient standard EEG in detects abnormalities in 29% to 55% of patients. If you perform an ictal EEG, several series have reported no ictal EEG changes in 33% to 36% of patients. Some series have reported that only 14% to 15% of patients with frontal lobe seizures have localized frontal lobe discharges.2,3

If a patient has an episode during the EEG it might not be picked it up because if there is a lesion right in the orbital frontal area or mesial area, it can really spread by wide angle and will not be picked it up. Some series have shown that only 40% to 50% of patients with frontal lobe seizures have actually localized frontal lobe discharges.

What are the features that help us in our office to make a decision? Again, stereotypicity. They are always the same because the focus is always in one area of the brain and the spread is normally the same (ie, it does not change from one episode to another). The duration is normally the same (brief), unless it generalizes. Get a detailed history: What is the first thing that comes to your mind? What is it that you remember? Seizures are normally brief and nonspecific, which makes it difficult to diagnose. They can also occur in clusters and they can be nocturnal. Repetitive motor activity is one clue that should direct you toward the diagnosis of frontal lobe epilepsy in patients. Postictal confusion is not a major issue. We asked patients with seizure if they were confused afterward. If they were not confused, we might think it was not a seizure. However, people with epilepsy of frontal lobe origin have little postictal confusion, if at all.

If a patient has focal motor activity, it might be easier to make a diagnosis of frontal lobe seizure. But seizure of frontal lobe origin can also present with motor automatism, which can be simple or complex. Presentation depends on the area of the frontal lobe involved and whether or not you have a quick spread or not. My patient looked like she had a temporal lobe seizure, which was misdiagnosed to have panic attacks for different reasons. At the end, she had a meningioma in the orbital frontal region.

There are different types of automatism that you can have in frontal lobe seizures, including tapping (eg, people who just go tap their fingers as part of their seizure); kicking; rubbing; pelvic thrusting; thrashing; picking; genital manipulations; scratching; and rearranging on the clothes. There are also behavior manifestations, which can be stereotypic. There can be also speech disturbance, speech arrest, forced vocalization (ie, moaning, grunting); repetition of words; and repetitive motor activity. There can be autonomic dysfunction: dizziness and lightheadedness. Autonomic dysfunction are tough to diagnose. Pseudoabsences and olfactory hallucinations can also be present. Forced thinking is less easy to recognize. Anything that is very strange but is repetitive and occurs over and over again, should make you consider the possibility of a a seizure of frontal lobe origin. There are also can be somatosensory symtpoms, visceral symptoms, hallucinatory or illusional phenomena, and immediate generalization.4,5

 

[Boozer]

Thank you so much for the information. I have thought it was frontal lobe oriented because for the most part my auras are connected to emotional type of things like irritability and frustration for no reason at all. The things I picked up on in the article you included are very familiar to me. Most of the time I don't get confused after my seizure activity. I generally clear up and feel sometimes fine all together. I started to notice that I have a tendency to run my hand through my hair or rub my left temple before and during the seizures. I am writing all of this type thing down for the neurologist so I won't forget anything during my visit.Thanks again. Erin