Continuing seizures (despite medication)
There are many people in whom medications have never stopped seizures
without difficult side effects. These patients need more evaluation.
Continued seizures place the person at risk for memory loss as well as
difficulties in the workplace, at school and in relationships.
Electroencephalography (EEG), or brainwave recordings, while seizures
are occurring must be conducted to make sure that the diagnosis is
correct.
Epilepsy centers that record continuing seizures find that 25% of
patients do not have seizures after all, which is why their medications
for seizures didn't work. These recordings are difficult to obtain early
in the diagnostic process due to the infrequency of seizures. When
medications fail, this evaluation is the next step.
Often patients are faced with whether or not to be concerned that they
continue to have seizures. Questionnaires have shown they often don't
report their seizures to their doctors. Some patients may be afraid of an
unpleasant diagnosis or discovering what the future may bring; others may
fear additional side effects from treatment or be concerned that no answer
can be found for their medical problem. However, continued seizures are a
serious issue. People with seizures at least monthly have more injuries,
less employment and lower self-esteem. Continued seizures are definitely
serious and should be checked out.
Treatments for epilepsy, such as phenobarbitol, introduced in 1912,
worked in about half the patients, and most people were happy with any
improvement. The question with newer medications was whether there was a
best choice. A study commissioned by the Veterans Administration examined
four epilepsy drugs. The newest drug in the 1970s, carbamazepine, appeared
to be the most effective. But after one year of treatment, only about 50%
of patients were still seizure-free, and less than 50% were seizure-free
for many of the other drugs. This discouraging result was blamed on the
nature of the study, and it took 25 years until a second large study in
the United Kingdom showed a similar result.
In fact, the second drug tried after the initial medication produced
seizure freedom in only 14%, which was similar to the VA study results.
Few if any patients in the UK study benefited from a third drug or drug
combination. Some seizures appear to resist medication treatment. These
seizures are either so strong or different that we just don't get them
to stop. Sometimes the cause of continued seizures is that the condition
being treated is not what we thought it was. A different seizure type or
some other condition resembling seizures will not respond to medications
because it wasn't the illness we thought it was. There are other tests
that can be helpful in the situation where seizures continue.
All of the following diagnostic procedures are available at the
Regional Epilepsy Center at
Aurora St. Luke's Medical Center in Milwaukee.
Video-EEG Monitoring
Seizures and their description to the doctor are often the only way the
doctor and the patient share what is happening to the patient. Sometimes
a third party, such as a family member, gives the patient information
about what happens during the seizures. This information can be
misleading or not completely helpful for the doctor. When the seizures
don't stop, the information being provided to the physician may be the
problem.
Many other illnesses have this problem. Chest pain is an example. Many
times the chest pain is not happening while the patient is with the
doctor. Heart doctors have developed tests that allow them to see the
blood flow shortages while stressing the patient on a treadmill. This
stress testing allows them to know the problems the patient has by
seeing them, as they happen, with the tools to diagnosis them. Sometimes
it turns out that the chest pain is not from the heart and the ability
to observe the patient with the diagnostic tools to measure things helps
the doctor.
Video-EEG monitoring provides the epilepsy doctor with a similar tool.
The hospitalized patient has the EEG electrodes applied to the head and
a continuous video image is recorded. A correlation of the seizure
appearance and the area of EEG abnormality detected during the recording
help the epilepsy doctor define the area responsible for the seizures or
to determine that the events are not seizures. Seizures are frequently
not common enough to do this recording without hospitalization and
because medication withdrawal is necessary to increase the frequency.
Medication withdrawal outside the hospital is unsafe and even if
seizures are frequent, the presence of the medication can sometimes mask
EEG changes. Video-EEG allows the seizure to be reviewed by the family or
friends of the patient to verify that the seizures recorded are typical
for the patient and are the ones causing the problems.
For more information about epilepsy monitoring, see
Frequently Asked Questions.
Magnetic Resonance Imaging (MRI)
One of the biggest changes in the science of the brain has been the use
of MRI. MRI produces images of the brain (or other areas of the body) by
measuring small amounts of energy released after an atom is placed in a
strong magnetic field and then the field is turned off. The pictures can
yield much information and can be modified to show different things
based on the turning on and off of the magnet.
The MRI technique is important to show abnormalities that may cause
seizures. Most MRIs are normal if taken using standard methods, but
advanced imaging approaches increase the discovery of abnormalities to
70%. Versions of MRI highlighting the presence of water show us where such
abnormalities are located. Some of the abnormalities are groups of brain
cells that are in the wrong place, called dysgenesis, and others are
damaged or sclerotic (scarred). Sclerosis or damage to the middle portion
of the brain's temporal lobe, called mesial temporal sclerosis, is an
important sign of difficult-to-stop seizures.
Knowing someone has mesial temporal sclerosis can encourage a more
watchful approach to seizure management. Newer techniques in MRI called
fMRI involve studying the function of the brain. The components in the
images, or their spectrum in a technique called magnetic resonance
spectroscopy, can help distinguish damaged areas from tumors. The surest
way to get value from an MRI is to have it performed in a place
specializing in epilepsy and bring the pictures to your doctor to review.
Neuropsychological testing
The brain has specific areas that perform specific tasks such as
memory, talking, feeling and moving. Neuropsychologists measure these
abilities with a collection of tests that many people have taken in the
past. They can tell when someone is not able to perform like others their
age and can say where this difficulty comes from in the brain.
Seizures often come from such damaged areas and the loss of certain
abilities can point to an area similar to the MRI and video-EEG. The
overlap of abnormalities helps confirm the correctness of the results.
Neuropsychological tests include picture-naming, reading, memory for words
and stories and memory for pictures and faces. Tests take into account age
and amount of education and also help predict who is at risk for
additional functional losses from continued seizures. Continuing loss of
memory from continued seizures is often overlooked as a possible side
effect of medications.
Wada testing (intracarotid amytal test)
The Wada test (named for neurologist Juhn A. Wada) consists of
behavioral testing after the injection of an anesthetic (such as sodium
amobarbital) into the right or left internal carotid artery of the neck.
Depending on how the injection is made (and the quantity of anesthetic),
we have a certain amount of time during which the activities of one of the
cerebral hemispheres are suspended, so the neuropsychologist can test the
abilities of the brain's other hemisphere.
Typical uses of the test include the lateralization of language
abilities (the surgeon wants to know if the hemisphere being operated on
is the speech hemisphere or not), and a determination that the person will
not be amnesic after surgery. Since epilepsy surgery is usually carried
out for a non-life-threatening condition, this is an important
consideration.
Vagus nerve stimulation and epilepsy surgery are available at the
Regional Epilepsy Center at
Aurora St. Luke's Medical Center in Milwaukee.
Vagus Nerve Stimulation (VNS)
VNS is a neuromodulating treatment for refractory partial seizures. The
vagus nerve is one of the cranial nerves and provides access into the
central nervous system without interfering with outgoing messages from the
brain to the body. Early studies in the 1930s showed the EEG in cats could
be changed by vagus nerve stimulation. By the 1950s it was known that
epilepsy brain waves could be altered with VNS. It wasn't until the 1980s
that a Temple University researcher found that stimulating the vagus nerve
could interrupt a seizure. Work at Southern Illinois University
documented a sustained anti-seizure effect in the 1990s, and the
potential for a completely new treatment was born.
The technique of vagus nerve stimulation for epilepsy was generated
from researchers previously working with heart pacemakers. The treatment
consists of a disk-shaped electrical generator implanted in the chest wall
that stimulates a coiled electrode encircling the left vagus nerve in the
neck. Small current stimulations cause a diffuse change in the activity of
the brain, affecting areas prone to support seizures. Studies have proven
the ability of these stimulations to reduce seizures when medications have
failed.
Current FDA-labeled use is for refractory partial seizures. Further
studies indicate that medication-refractory generalized seizures are
potentially responsive as well. Clinical studies have shown the treatment
to be without the traditional sedative qualities of medications. However,
stimulation-related voice changes from the recurrent laryngeal nerve are
noted by many patients. These changes are intensity-dependent and diminish
over time. No safety issues exist. Surgical complications are few in
experienced surgical hands.
Epilepsy surgery
The seizures most likely not to stop with medications are the partial
seizures. They begin in a small area and spread to involve other parts
of the brain. Partial seizures can be stopped if the area they start in
can be surgically removed. Fortunately, the brain can allow such
removals because it has several areas involved in the same activity and
removing one area does not reduce the person's ability to do things.
For instance, memory is stored in the temporal lobes on both sides.
Removing the temporal lobe that is causing continued seizures will result
in the remaining temporal lobe doing the memory activity. The brain has
many of these duplicate or redundant functions. Surgically removing the
epilepsy area can allow many people to have seizure-free lives and many
can reduce or discontinue their medicines. Rates of seizure freedom vary
from 50-70% by location of the seizure's starting area. Complications such
as reduced functioning ability, bleeding or infection occur in 1-4% of
patients, according to several research articles.
For more information about epilepsy surgery, see
Frequently Asked Questions.
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