|Volume 7, Issue 4 April 2011
Temporal lobe epilepsy is the most common form of partial or localization related epilepsy. It accounts for approximately 60% of all patients with epilepsy. There are two types of temporal lobe epilepsy; one that involves what is known as the medial or internal structures of the temporal lobe, and then there is neocortical temporal lobe epilepsy, which involves the outer portion of the temporal lobe. The most common version of these two is medial temporal lobe epilepsy. Medial temporal lobe epilepsy often has an onset within a structure of the brain called the hippocampus. It accounts for almost 80% of all temporal lobe seizures. Medial temporal lobe epilepsy is also considered a syndrome, which means that a lot of different conditions can result in medial temporal lobe epilepsy. Individuals who have medial temporal lobe epilepsy have seizures by definition of temporal lobe origin. There are a lot of different names for the seizures that occur in temporal lobe epilepsy, including,“psychomotor seizures”, “limbic seizures”, and “temporal lobe seizures”.
While medial temporal lobe epilepsy is a very common form of epilepsy type, it is also one that is most frequently related to being resistant to medications and associated with a particular finding on an MRI. This finding is called hippocampal sclerosis and it makes this a challenge to treat both medically and oftentimes surgical therapy is the best option for these individuals (See arrow in figure)
The overall prognosis for patients with drug resistant medial temporal lobe epilepsy includes a higher risk for memory and mood difficulties. This in turn leads to impairments in quality of life and an increased risk for death, as observed in patients who have frequent seizures failing to respond to treatment.
The presentation of medial temporal lobe epilepsy is fairly consistent from individual to individual. For the most part, the birth, labor, and delivery and development of individuals with medial temporal lobe epilepsy is normal. However, there are some risk factors that suggest that an early injury in childhood for patients may end up developing medial temporal lobe epilepsy. Many individuals will have a history of at least one seizure having occurred in early childhood with the majority experiencing some type of febrile seizures. Others conditions often associated with temporal lobe epilepsy are head trauma that has resulted in loss of consciousness, injuries during early childhood and birth, brain malformations, infections such as encephalitis or meningitis, and even some tumors within the temporal lobe
The most common risk factor associated with this condition is the presence of having had a seizure associated with fever. Approximately two-thirds of patients with temporal lobe epilepsy have had a febrile seizure without an infection prior to the onset of complex partial seizures. Nearly 75% of these febrile seizures were considered to be either prolonged or have complex aspects to their presentation, which allows them to distinguish it from the typical seizure associated with fever. Some aspects of febrile seizures associated with epilepsy later on are those that last for a period of time of 15 minutes or longer or have a very clear neurological abnormality, such as weakness in an arm or a funny posturing that suggests an abnormality in the brain.
Despite the fact that febrile seizures are a common risk factor for people from medial temporal lobe epilepsy, it is important to understand that simply having had a seizure during a fever does not increase the risk of epilepsy above that of the general population. There is still an unclear understanding between the cause and effect between febrile seizures and development of epilepsy later on in life. Clearly, there are some individuals that have a genetic factor that seems to predispose them to develop epilepsy in later life, but nothing that can easily be predicted early in life.
The onset of medial temporal lobe epilepsy occurs at the end of a first or second decade in most people, following either a seizure with fever or an early injury to the brain. In women, hormonal influences during their menstrual cycle and ovulation may lead to reports of increased seizures during their menstrual cycle.
Seizures that often occur in temporal lobe epilepsy include what is known as simple partial seizures, such as auras, and focal seizures with complex impairment in consciousness, otherwise known as complex partial seizures. Auras associated with medial temporal lobe epilepsy can begin in isolation early on and late in life. The most common manifestation of auras typically is that of a déjà-vu experience or some gastrointestinal upset. Feelings of fear, panic, anxiety or a feeling of a rising epigastric sensation or butterflies with nausea are also other ways in which auras present in medial temporal lobe epilepsy. Some people also report a sense of unusual smell that can raise a possibility of a hippocampal abnormality or a tumor in that area.
Other seizure types that occur are complex partial seizures. Seizures often present in their teenage years. However, epilepsy can occur in all age groups. Sometimes seizures can be associated with a fixed stare, impaired consciousness, in fumbling with their fingers or lip-smacking movements that last 30 to 60 seconds. There can be a posture change in an arm that also can help to delineate the location of these seizures. Some people also note problems where they speak gibberish or lose their ability to speak in a sensible manner. Some individuals report difficulty with the language, particularly if the seizures are coming from the dominant temporal lobe. Some people may have a generalized tonoclonic jerking and this can lead to weakness after the seizure has stopped. Some individuals can also have prolonged seizures and in some rare individuals, status epilepticus may occur.
The diagnosis of medial temporal lobe epilepsy is still by listening to a person describe their seizures or talking over the symptoms of the seizures with a witness. An MRI of the brain is considered the standard radiology procedure on these individuals in order to see the characteristic abnormalities associated with medial temporal lobe epilepsy. An EEG is also an essential aspect of the management of patients with medial temporal lobe epilepsy and they often present with anterior temporal spike or sharp waves, which can invariably occur in both wakefulness and/or sleep. Sometimes recording seizures is essential in a video EEG monitoring unit. This is often done in order to localize seizures in preparation for surgery so that a decision can be made, whether surgery can be offered, and whether this may be helpful to stop the seizures in this situation.
With regards to treatment, most patients with focal seizures will respond to medical treatment with appropriate anti-epileptic drugs. However, almost a third of patients may not respond to therapy and they may report problems, such as worsening short term memory, difficulty with socialization, and a fear of leaving their home. They may restrict their activities of daily life, which in turn leads to a decrease in quality of life. It is important to let your physician and/or healthcare professional know about this so that things can be done in order to help individuals. If seizures fail to respond to medication, then surgical approaches are an appropriate option. In individuals where the MRI has a clear lesion demonstrating hippocampal sclerosis in the medial temporal lobe, as well as EEGs that show abnormality in that particular temporal lobe, may be able to be cured by surgery and in some cases, up to 70% of people can be rendered seizure-free with minimal problems afterwards.
It is important to understand and recognize the features of medial temporal lobe epilepsy given how common it is and how responsive treatments such as surgery and medications can be for this condition. It is important to consider the presenting aspects of how these seizures manifest in order to make the right diagnosis.
How can Epilepsy Therapy Project help?
The Epilepsy Therapy Project is involved in the funding and development of new therapies for all types of epilepsy. Epilepsy.com is the educational web site for the Epilepsy Therapy Project and has a considerable amount of information regarding surgical treatment and on medial temporal lobe epilepsy specifically with regards to outcome and treatment. Moreover, My Seizure Diary is a useful tool to record seizures and note if medications are helpful in stopping these events from occurring.
Important Tips about Temporal Lobe Epilepsy
- Most common form of focal or partial epilepsy
- Surgery may be an option for individuals who fail to respond to medications.
- MRI and EEG are important tests in the diagnosis of this condition.
- Individuals may report worsening short term memory and quality of life if seizures are not controlled.
MARK YOUR CALENDAR!
Upcoming grant cycles, epilepsy-related Hallway Conversations, conferences, symposia, and events include:
Meet ETP in Miami!
April 27-29, 2011
Antiepileptic Drug and Device Trials XI Conference
Turnberry Isle Resort
For almost two decades a group of individuals have been meeting on a biannual basis to discuss ways in which the process of bringing new therapies to patients can be expedited. Participants include individuals from academia, from interested government agencies such as the Food and Drug administration/EMEA and the National Institutes of Health, as well as representatives from the pharmaceutical and device industries. The purpose of these meetings has been the exchange of ideas, discussion of roadblocks to therapeutic development, dialogue about regulatory strategies, and sharing of successful approaches.
AED2 XI Conference is Sponsored by: The Epilepsy Study Consortium in collaboration with the University of Pennsylvania Epilepsy Center and the Epilepsy Therapy Project
Hallway Conversations a series of audio podcasts in which Dr. Joseph Sirven, Editor-in-Chief of epilepsy.com, has the pleasure of having a brief conversation with thought leaders and newsmakers in the field of epilepsy on a range of seizure related topics. The series is intended as a second opinion to help clinicians understand the latest research as explained by the investigator or perhaps focus on a clinical issue with the help of a leading epilepsy authority on the topic. The purpose is to frame the latest epilepsy news in the right context so as to better manage patients with seizures and improve quality of life. We hope that you find the series informative and helpful and that you join me in listening on a regular basis.
Listen to the latest podcasts in the Hallway Conversations series from:
Wednesday, March 23, 2011
Gregory Krauss, MD
Professor of Neurology
Comprehensive Epilepsy Center
Johns Hopkins Medical School
Johns Hopkins University
Topic: Perampanel: A New Antiepileptic Drug
Wednesday, March 2, 2011
Steven Lomazow, MD
Author of FDR's Deadly Secret
Topic: Franklin Roosevelt and his epilepsy
April 2011 Shows
Wednesday, 4/20/11 5:00pm EST
Steven Karceski, MD
Director of Clinical Trials at the Cornell Comprehensive Epilepsy Center
Topic: Mood and Epilepsy
Interested In Participating?
If you are interested in participating in a Hallway Conversation interview, please contact ETP at: email@example.com