Temporal lobe epilepsy
Encyclopedia
Temporal lobe epilepsy a.k.a. Psychomotor epilepsy, is a form of focal
epilepsy
, a chronic
neurological
condition characterized by recurrent seizure
s. Over 40 types of epilepsies are known. They fall into two main categories: partial-onset (focal or localization-related) epilepsies and generalized-onset epilepsies. Partial-onset epilepsies account for about 60% of all adult epilepsy cases, and temporal lobe epilepsy (TLE) is the most common single form causing refractory epilepsy.
Temporal lobe epilepsies are a group of medical disorders in which humans and animals experience recurrent epileptic seizures arising from one or both temporal lobe
s of the brain. Two main types are internationally recognized according to the International League Against Epilepsy.
Because of strong interconnections, seizures beginning in either the medial or lateral temporal areas often spread to involve both areas and also to neighboring areas on the same side of the brain as well as the temporal lobe on the opposite side of the brain. The causes or etiology
of different temporal lobe epilepsies vary and are discussed below.
that causes neuron death. Infants may develop lung or skin infections resulting in a fever. Babies have an immature thermoregulation system, and the fever causes the baby's core body temperature to increase more drastically than in adults. In some children, elevated body temperature can cause febrile seizures. Febrile seizures are relatively normal as they occur in 2-5% of children under age 5 years. They typically last only a few minutes or even a matter of seconds, but are neither severe motor convulsions nor followed by weakness on one side of the body. In a small number of babies, these convulsions can last for over an hour and involve repeated convulsive episodes. These are known as complex febrile seizures and may be causatively associated with TLE. As discussed below in the section on causes, it remains controversial whether complex febrile seizures actually cause TLE, or whether they are simply the earliest manifestation of the TLE condition.
s (seizures coinciding with episodes of fever in young children) and subsequent temporal lobe epilepsy has been suggested, but the exact role remains unclear.
Some studies have shown abnormalities of the hippocampus
on magnetic resonance imaging
(MRI) in status epilepticus
, which supports the theory that prolonged seizures damage the brain.
Interestingly, some cases of MTLE present without the typical changes of mesial temporal sclerosis
or other abnormalities on MRI scans. This has been termed paradoxical mesial temporal lobe epilepsy. The epilepsy in these patients tends to occur at a later age, which might suggest that an early event leads to hippocampal damage causing MTLE.
Although this theory needs confirmation, some studies have pointed to human herpesvirus 6 (HHV-6) as a possible link between febrile convulsions and later MTLE. Some studies suggest that HHV-6 infection happens prior to the occurrence of febrile seizures. However, only a minority of primary HHV-6 infections may be associated with febrile seizures. Secondly, other studies found HHV-6 DNA in brain tissue removed during surgery for MTLE.
Rarely, MTLE can be hereditary or related to brain tumor
s, spinal meningitis, encephalitis, head injury or blood vessel malformations. MTLE can occur in association with other brain malformations. Most often, a cause cannot be determined with certainty.
LTLE is less common. It can be hereditary, as in Autosomal Dominant Lateral Temporal Lobe Epilepsy (ADLTLE) with auditory or visual features, but can also be associated with tumors, meningitis, encephalitis, trauma, vascular malformations or congenital brain malformations. Again, in many affected persons it is common that no cause can be identified.
Dispersion of granule cell layer in the hippocampal dentate gyrus
is occasionally seen in temporal lobe epilepsy and has been linked to the downregulation of reelin
, a protein that normally keeps the layer compact by containing the neuronal migration. It is unknown whether changes in reelin expression play a role in epilepsy.
Following each of these seizures, there is some period of recovery in which neurological function is altered. This is called the postictal state
. The degree and length of the impairment directly correlates with the severity of the 3 seizure types listed above. SPS often last less than 60 seconds, CPS often last less than 2 minutes, and SGTCS usually last less than 3 minutes. The postictal state in the case of CPS and GTCS often lasts much longer than the seizure ictus
itself. Because a major function of the temporal lobe is short-term memory, CPS and GTCS cause amnesia for the seizure. As a result, many persons with temporal lobe CPS and GTCS will not remember having had a seizure.
Local and national laws exist regarding the operation of vehicles, aircraft and vessels by patients with epilepsy. Most licensing departments do not allow driving of vehicles by persons with CPS or GTCS until they have been seizure-free for a specified period of time. The laws are complex and varied; affected persons must check with the appropriate licensing authority. In a few locations, health care providers are legally-required to report patients with epilepsy (and other medical conditions which cause episodes of altered consciousness) to their local department of motor vehicles.
s available for the management of epileptic seizures. They were previously called anticonvulsants however this term is misleading because most seizures are not convulsions. The modern term is antiepileptic drugs (AEDs). In TLE, the most commonly used older AEDs are phenytoin
, carbamazepine
, primidone
, valproate and phenobarbital
. Newer drugs, such as gabapentin
, topiramate
, levetiracetam, lamotrigine
, pregabalin
, tiagabine
, lacosamide
, and zonisamide
promise similar effectiveness, possibly with fewer side-effects
. Felbamate
and vigabatrin
are newer AEDs, but can have serious adverse effects so they are not considered first-line AEDs. Nearly all AEDs function by decreasing the excitation of neurons (e.g., by blocking fast or slow sodium channels or modulating calcium channels) or by enhancing the inhibition of neurons (e.g., by potentiating the effects of inhibitory neurotransmitters like GABA
). Unfortunately, many patients with medial temporal lobe epilepsy (up to one-third) will not experience adequate seizure control with medication.
For patients with medial TLE whose seizures remain uncontrolled after trials of several AEDs (intractable), resective surgery
should be considered. Epilepsy surgery has been performed since the 1860s and physicians and surgeons had observed for decades that it was highly effective in producing seizure freedom. However, it was not until 2001 that a scientifically sound study was performed on the effectiveness of temporal lobectomy. This study proved that after the failure of several AEDs to control seizures in TLE temporal lobe surgery is far more effective in producing seizure freedom than is additional medication trials. The unanswered question that remains is how many medications a person must fail before considering surgery. A United States sponsored research study called ERSET was begun to answer the question of whether surgery can successfully be performed early in the course of TLE. Although the study ended earlier than anticipated, limited results are expected soon.
In preparation for these surgeries, patients are monitored by various methods to determine the focus of their seizures (that is, the region of the brain where seizures tend to arise before spreading). This can be done with video-EEG monitoring, intracranial EEG
(where electrodes are placed beneath the skull, either within or resting just outside the brain), or SPECT imaging. MRI studies may additionally be used to seek evidence of hippocampal sclerosis. Once the epileptic focus has been determined, it can be excised, which usually involves removing part of the hippocampus
and often the amygdala
. To avoid removing areas of the brain responsible for speech (so-called "eloquent" areas), the surgical team will conduct a Wada test
pre-operatively, wherein amobarbital
is injected in the left or right carotid artery
to temporarily quiet one half of the brain. If the patient performs poorly on neuropsychological testing during the intracarotid amobarbital (Wada) test, the surgical team may advise the patient against surgery or may offer a more limited operation.
If a person is not an optimal candidate for epilepsy surgery, then AEDs not previously tried, the vagus nerve stimulator, or AEDs in clinical research trials might be alternative treatments. For children, the ketogenic diet
may also be tried. Other possible future therapies such as brain cortex responsive neural stimulators, deep brain stimulation
, and stereotactic radiosurgery (such as gamma knife) are undergoing research studies for treatment of TLE and other forms of epilepsy.
. They include Vincent Van Gogh
, Charles Dodgson (a.k.a. Lewis Carroll), Edgar Allan Poe
, Fyodor Dostoevsky
(whose novel The Idiot
features a protagonist with epilepsy, Prince Myshkin), Gustave Flaubert
, Philip K. Dick
, Sylvia Plath
and contemporary author
Thom Jones
. Peter O'Leary has also discussed this in relation to work of poet Philip Jenks in his "Gnostic Contagion: Robert Duncan and the Poetry of Illness". Sadi Ranson-Polizzotti
has discussed the significance of Lewis Carroll's epilepsy online and in a forthcoming book on the subject.
, who noted a constellation of symptoms, including hypergraphia
, hyperreligiosity, fainting spells
, and pedantism, often collectively ascribed to a condition known as Geschwind syndrome
.
Vilayanur S. Ramachandran
explored the neural basis of the hyperreligiosity seen in TLE using galvanic skin response
(which correlates with emotional arousal) to determine whether the hyperreligiosity seen in TLE was due to an overall heightened emotional state or was specific to religious stimuli (Ramachandran and Blakeslee, 1998). By presenting subjects with neutral, sexually arousing and religious words while measuring GSR, Ramachandran was able to show that patients with TLE showed enhanced emotional responses to the religious words, diminished responses to the sexually charged words, and normal responses to the neutral words. These results suggest that the medial temporal lobe is specifically involved in generating some of the emotional reactions associated with religious words, images and symbols.
Cognitive neuroscience
researcher Michael Persinger
asserts that stimulating the temporal lobe electromagnetically
can cause TLE and trigger hallucination
s of apparent paranormal phenomena such as ghost
s and UFOs. Persinger has even created a "God helmet
" which purportedly can evoke altered states of consciousness through stimulation of the parietal
and temporal lobes. Neurotheologians
speculate that individuals with temporal lobe epilepsy, having a natural tendency to experience states of consciousness such as euphoria
or samādhi
, have functioned in human history as religious figures or shamans.
is pro-epileptic and progesterone
is anti-epileptic. These counterbalancing effects may account for "catamenial epilepsy
" i.e. epilepsy preceding or made more severe prior to menstruation
or during peri-ovulation. Gender may differentially influence neocortical pathologies in patients with refractory temporal lobe epilepsy.
Focal seizures
Partial seizures are seizures which affect only a part of the brain at onset. The brain is divided into two hemispheres, each consisting of four lobes - the frontal, temporal, parietal and occipital lobes...
epilepsy
Epilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
, a chronic
Chronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...
neurological
Neurology
Neurology is a medical specialty dealing with disorders of the nervous system. Specifically, it deals with the diagnosis and treatment of all categories of disease involving the central, peripheral, and autonomic nervous systems, including their coverings, blood vessels, and all effector tissue,...
condition characterized by recurrent seizure
Seizure
An epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...
s. Over 40 types of epilepsies are known. They fall into two main categories: partial-onset (focal or localization-related) epilepsies and generalized-onset epilepsies. Partial-onset epilepsies account for about 60% of all adult epilepsy cases, and temporal lobe epilepsy (TLE) is the most common single form causing refractory epilepsy.
Temporal lobe epilepsies are a group of medical disorders in which humans and animals experience recurrent epileptic seizures arising from one or both temporal lobe
Temporal lobe
The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....
s of the brain. Two main types are internationally recognized according to the International League Against Epilepsy.
- Mesial temporal lobe epilepsy (MTLE) arises in the hippocampusHippocampusThe hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
, parahippocampal gyrusParahippocampal gyrusThe parahippocampal gyrus is a grey matter cortical region of the brain that surrounds the hippocampus. This region plays an important role in memory encoding and retrieval....
and amygdalaAmygdalaThe ' are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.-...
which are located in the inner aspect of the temporal lobe. - Lateral temporal lobe epilepsy (LTLE) arises in the neocortexNeocortexThe neocortex , also called the neopallium and isocortex , is a part of the brain of mammals. It is the outer layer of the cerebral hemispheres, and made up of six layers, labelled I to VI...
on the outer surface of the temporal lobe of the brain.
Because of strong interconnections, seizures beginning in either the medial or lateral temporal areas often spread to involve both areas and also to neighboring areas on the same side of the brain as well as the temporal lobe on the opposite side of the brain. The causes or etiology
Etiology
Etiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
of different temporal lobe epilepsies vary and are discussed below.
Syndrome of Temporal Lobe Epilepsy (TLE)
The classical syndrome of TLE may begin when there is a very early insult to the left or right hippocampusHippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
that causes neuron death. Infants may develop lung or skin infections resulting in a fever. Babies have an immature thermoregulation system, and the fever causes the baby's core body temperature to increase more drastically than in adults. In some children, elevated body temperature can cause febrile seizures. Febrile seizures are relatively normal as they occur in 2-5% of children under age 5 years. They typically last only a few minutes or even a matter of seconds, but are neither severe motor convulsions nor followed by weakness on one side of the body. In a small number of babies, these convulsions can last for over an hour and involve repeated convulsive episodes. These are known as complex febrile seizures and may be causatively associated with TLE. As discussed below in the section on causes, it remains controversial whether complex febrile seizures actually cause TLE, or whether they are simply the earliest manifestation of the TLE condition.
Causes
A link between febrile seizureFebrile seizure
A febrile seizure, also known as a fever fit or febrile convulsion, is a convulsion associated with a significant rise in body temperature...
s (seizures coinciding with episodes of fever in young children) and subsequent temporal lobe epilepsy has been suggested, but the exact role remains unclear.
Some studies have shown abnormalities of the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
on magnetic resonance imaging
Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
(MRI) in status epilepticus
Status epilepticus
Status epilepticus is a life-threatening condition in which the brain is in a state of persistent seizure. Definitions vary, but traditionally it is defined as one continuous unremitting seizure lasting longer than 5 minutes, or recurrent seizures without regaining consciousness between seizures...
, which supports the theory that prolonged seizures damage the brain.
Interestingly, some cases of MTLE present without the typical changes of mesial temporal sclerosis
Mesial temporal sclerosis
Mesial temporal sclerosis is a specific pattern of hippocampal neuron cell loss . There are 3 specific patterns of cell loss; Cell loss might involve sectors CA1 and CA4, CA4 alone, or CA1 to CA4 . Associated hippocampal atrophy and gliosis is common...
or other abnormalities on MRI scans. This has been termed paradoxical mesial temporal lobe epilepsy. The epilepsy in these patients tends to occur at a later age, which might suggest that an early event leads to hippocampal damage causing MTLE.
Although this theory needs confirmation, some studies have pointed to human herpesvirus 6 (HHV-6) as a possible link between febrile convulsions and later MTLE. Some studies suggest that HHV-6 infection happens prior to the occurrence of febrile seizures. However, only a minority of primary HHV-6 infections may be associated with febrile seizures. Secondly, other studies found HHV-6 DNA in brain tissue removed during surgery for MTLE.
Rarely, MTLE can be hereditary or related to brain tumor
Brain tumor
A brain tumor is an intracranial solid neoplasm, a tumor within the brain or the central spinal canal.Brain tumors include all tumors inside the cranium or in the central spinal canal...
s, spinal meningitis, encephalitis, head injury or blood vessel malformations. MTLE can occur in association with other brain malformations. Most often, a cause cannot be determined with certainty.
LTLE is less common. It can be hereditary, as in Autosomal Dominant Lateral Temporal Lobe Epilepsy (ADLTLE) with auditory or visual features, but can also be associated with tumors, meningitis, encephalitis, trauma, vascular malformations or congenital brain malformations. Again, in many affected persons it is common that no cause can be identified.
Dispersion of granule cell layer in the hippocampal dentate gyrus
Dentate gyrus
The dentate gyrus is part of the hippocampal formation. It is thought to contribute to new memories as well as other functional roles. It is notable as being one of a select few brain structures currently known to have high rates of neurogenesis in adult rats, .The dentate gyrus cells receive...
is occasionally seen in temporal lobe epilepsy and has been linked to the downregulation of reelin
Reelin
Reelin is a large secreted extracellular matrix protein that helps regulate processes of neuronal migration and positioning in the developing brain by controlling cell–cell interactions. Besides this important role in early development, reelin continues to work in the adult brain. It modulates the...
, a protein that normally keeps the layer compact by containing the neuronal migration. It is unknown whether changes in reelin expression play a role in epilepsy.
Symptoms
The symptoms felt by the person, and the signs observable by others, during seizures which begin in the temporal lobe depend upon the specific regions of the temporal lobe and neighboring brain areas affected by the seizure. The International Classification of Epileptic Seizures published in 1981 by the International League Against Epilepsy (ILAE) recognizes three types of seizures which persons with TLE may experience.- Simple Partial SeizuresSimple partial seizureSimple partial seizures are seizures which affect only a small region of the brain, often the temporal lobes and/or hippocampi. People who have simple partial seizures retain consciousness...
(SPS) involve small areas of the temporal lobe such as the amygdala or the hippocampus. The term "simple" means that consciousness is not altered. In temporal lobe epilepsy SPS usually only cause sensations. These sensations may be mnestic such as déjà vuDéjà vuDéjà vu is the experience of feeling sure that one has already witnessed or experienced a current situation, even though the exact circumstances of the prior encounter are uncertain and were perhaps imagined...
(a feeling of familiarity), jamais vuJamais vuIn psychology, jamais vu is the phenomenon of experiencing a situation that one recognises but that nonetheless seems very unfamiliar.-Linguistics:...
(a feeling of unfamiliarity), a specific single or set of memories, or amnesiaAmnesiaAmnesia is a condition in which one's memory is lost. The causes of amnesia have traditionally been divided into categories. Memory appears to be stored in several parts of the limbic system of the brain, and any condition that interferes with the function of this system can cause amnesia...
. The sensations may be auditory such as a sound or tune, gustatory such as a taste, or olfactory such as a smell that is not physically present. Sensations can also be visual, involve feelings on the skin or in the internal organs. The latter feelings may seem to move over the body. Psychic sensations can occur such as an out-of-body feeling. Dysphoric or euphoric feelings, fear, anger, and other sensations can also occur during SPS. Often, it is hard for persons with SPS of TLE to describe the feeling. SPS are often called "auras" by lay persons who mistake them for a warning sign of a subsequent seizure. In fact, they are indeed seizures. Persons experiencing only SPS may not recognize what they are or seek medical advice about them. SPS may or may not progress to the seizure types listed below. - Complex Partial SeizuresComplex partial seizureA complex partial seizure is an epileptic seizure that is associated with bilateral cerebral hemisphere involvement and causes impairment of awareness or responsiveness, i.e. loss of consciousness.-Presentation:...
(CPS) by definition are seizures which impair consciousness to some extent. This is to say that they alter the person's ability to interact with his or her environment. They usually begin with an SPS, but then the seizure spreads to a larger portion of the temporal lobe resulting in impaired consciousness. Signs may include motionless staring, automatic movements of the hands or mouth, altered ability to respond to others, unusual speech, or unusual behaviors. - Seizures which begin in the temporal lobe but then spread to the whole brain are known as Secondarily Generalized Tonic-Clonic Seizures (SGTCS). These begin with an SPS or CPS phase initially, but then the arms, trunk and legs stiffen (tonic) in either a flexed or extended position and then clonic jerking of the limbs often occurs. GTCS are often known in the vernacular as convulsions or "grand mal" (originally a French term) seizures.
Following each of these seizures, there is some period of recovery in which neurological function is altered. This is called the postictal state
Postictal state
The postictal state is the altered state of consciousness that a person enters after experiencing a seizure. It usually lasts between 5 and 30 minutes, but sometimes longer in the case of larger or more severe seizures and is characterized by drowsiness, confusion, nausea, hypertension, headache or...
. The degree and length of the impairment directly correlates with the severity of the 3 seizure types listed above. SPS often last less than 60 seconds, CPS often last less than 2 minutes, and SGTCS usually last less than 3 minutes. The postictal state in the case of CPS and GTCS often lasts much longer than the seizure ictus
Ictus
-Medicine:*ictus, a sudden event such as a stroke, seizure, collapse, or faint-Music and poetry:*ictus, in music and conducting, the instant when a beat occurs*ictus, in poetry, a way of indicating a stressed syllable...
itself. Because a major function of the temporal lobe is short-term memory, CPS and GTCS cause amnesia for the seizure. As a result, many persons with temporal lobe CPS and GTCS will not remember having had a seizure.
Local and national laws exist regarding the operation of vehicles, aircraft and vessels by patients with epilepsy. Most licensing departments do not allow driving of vehicles by persons with CPS or GTCS until they have been seizure-free for a specified period of time. The laws are complex and varied; affected persons must check with the appropriate licensing authority. In a few locations, health care providers are legally-required to report patients with epilepsy (and other medical conditions which cause episodes of altered consciousness) to their local department of motor vehicles.
Treatments
There are many oral medicationMedication
A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
s available for the management of epileptic seizures. They were previously called anticonvulsants however this term is misleading because most seizures are not convulsions. The modern term is antiepileptic drugs (AEDs). In TLE, the most commonly used older AEDs are phenytoin
Phenytoin
Phenytoin sodium is a commonly used antiepileptic. Phenytoin acts to suppress the abnormal brain activity seen in seizure by reducing electrical conductance among brain cells by stabilizing the inactive state of voltage-gated sodium channels...
, carbamazepine
Carbamazepine
Carbamazepine is an anticonvulsant and mood-stabilizing drug used primarily in the treatment of epilepsy and bipolar disorder, as well as trigeminal neuralgia...
, primidone
Primidone
Primidone is an anticonvulsant of the pyrimidinedione class, the active metabolites of which, phenobarbital and phenylethylmalonamide , are also anticonvulsants...
, valproate and phenobarbital
Phenobarbital
Phenobarbital or phenobarbitone is a barbiturate, first marketed as Luminal by Friedr. Bayer et comp. It is the most widely used anticonvulsant worldwide, and the oldest still commonly used. It also has sedative and hypnotic properties but, as with other barbiturates, has been superseded by the...
. Newer drugs, such as gabapentin
Gabapentin
Gabapentin is a pharmaceutical drug, specifically a GABA analogue. It was originally developed for the treatment of epilepsy, and currently is also used to relieve neuropathic pain...
, topiramate
Topiramate
Topiramate is an anticonvulsant drug. It was originally produced by Ortho-McNeil Neurologics and Noramco, Inc., both divisions of the Johnson & Johnson Corporation. This medication was discovered in 1979 by Bruce E. Maryanoff and Joseph F. Gardocki during their research work at McNeil...
, levetiracetam, lamotrigine
Lamotrigine
Lamotrigine, marketed in the US and most of Europe as Lamictal by GlaxoSmithKline, is an anticonvulsant drug used in the treatment of epilepsy and bipolar disorder. It is also used as an adjunct in treating depression, though this is considered off-label usage...
, pregabalin
Pregabalin
Pregabalin is an anticonvulsant drug used for neuropathic pain and as an adjunct therapy for partial seizures with or without secondary generalization in adults. It has also been found effective for generalized anxiety disorder and is approved for this use in the European Union. It was designed...
, tiagabine
Tiagabine
Tiagabine -Indications:Tiagabine is approved by U.S. Food and Drug Administration as an adjunctive treatment for partial seizures in ages 12 and up. It may also be prescribed to treat anxiety disorders and neuropathic pain . For anxiety and neuropathic pain, tiagabine is used primarily to augment...
, lacosamide
Lacosamide
Lacosamide is a medication developed by UCB for the adjunctive treatment of partial-onset seizures and diabetic neuropathic pain marketed under the trade name Vimpat....
, and zonisamide
Zonisamide
Zonisamide is a sulfonamide anticonvulsant approved for use as an adjunctive therapy in adults with partial-onset seizures for adults; infantile spasm, mixed seizure types of Lennox-Gastaut syndrome, myoclonic, and generalized tonic clonic seizure.-History:...
promise similar effectiveness, possibly with fewer side-effects
Adverse effect
In medicine, an adverse effect is a harmful and undesired effect resulting from a medication or other intervention such as surgery.An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. If it results from an unsuitable or incorrect dosage or...
. Felbamate
Felbamate
Felbamate is an anticonvulsant drug used in the treatment of epilepsy. It is used to treat partial seizures in adults and partial and generalized seizures associated with Lennox-Gastaut syndrome in children...
and vigabatrin
Vigabatrin
Vigabatrin is an antiepileptic drug that inhibits the catabolism of gamma-aminobutyric acid by irreversibly inhibiting GABA transaminase. It is an analog of GABA, but it is not a receptor agonist...
are newer AEDs, but can have serious adverse effects so they are not considered first-line AEDs. Nearly all AEDs function by decreasing the excitation of neurons (e.g., by blocking fast or slow sodium channels or modulating calcium channels) or by enhancing the inhibition of neurons (e.g., by potentiating the effects of inhibitory neurotransmitters like GABA
Gabâ
Gabâ or gabaa, for the people in many parts of the Philippines), is the concept of a non-human and non-divine, imminent retribution. A sort of negative karma, it is generally seen as an evil effect on a person because of their wrongdoings or transgressions...
). Unfortunately, many patients with medial temporal lobe epilepsy (up to one-third) will not experience adequate seizure control with medication.
For patients with medial TLE whose seizures remain uncontrolled after trials of several AEDs (intractable), resective surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
should be considered. Epilepsy surgery has been performed since the 1860s and physicians and surgeons had observed for decades that it was highly effective in producing seizure freedom. However, it was not until 2001 that a scientifically sound study was performed on the effectiveness of temporal lobectomy. This study proved that after the failure of several AEDs to control seizures in TLE temporal lobe surgery is far more effective in producing seizure freedom than is additional medication trials. The unanswered question that remains is how many medications a person must fail before considering surgery. A United States sponsored research study called ERSET was begun to answer the question of whether surgery can successfully be performed early in the course of TLE. Although the study ended earlier than anticipated, limited results are expected soon.
In preparation for these surgeries, patients are monitored by various methods to determine the focus of their seizures (that is, the region of the brain where seizures tend to arise before spreading). This can be done with video-EEG monitoring, intracranial EEG
EEG
EEG commonly refers to electroencephalography, a measurement of the electrical activity of the brain.EEG may also refer to:* Emperor Entertainment Group, a Hong Kong-based entertainment company...
(where electrodes are placed beneath the skull, either within or resting just outside the brain), or SPECT imaging. MRI studies may additionally be used to seek evidence of hippocampal sclerosis. Once the epileptic focus has been determined, it can be excised, which usually involves removing part of the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
and often the amygdala
Amygdala
The ' are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.-...
. To avoid removing areas of the brain responsible for speech (so-called "eloquent" areas), the surgical team will conduct a Wada test
Wada test
The Wada test, named after Canadian neurologist and epileptologist Juhn Atsushi Wada, also known as the "intracarotid sodium amobarbital procedure" , is used to establish cerebral language and memory representation of each hemisphere.-Method:...
pre-operatively, wherein amobarbital
Amobarbital
Amobarbital is a drug that is a barbiturate derivative. It has sedative-hypnotic and analgesic properties. It is a white crystalline powder with no odor and a slightly bitter taste. It was first synthesized in Germany in 1923...
is injected in the left or right carotid artery
Carotid artery
Carotid artery can refer to:* Common carotid artery* External carotid artery* Internal carotid artery...
to temporarily quiet one half of the brain. If the patient performs poorly on neuropsychological testing during the intracarotid amobarbital (Wada) test, the surgical team may advise the patient against surgery or may offer a more limited operation.
If a person is not an optimal candidate for epilepsy surgery, then AEDs not previously tried, the vagus nerve stimulator, or AEDs in clinical research trials might be alternative treatments. For children, the ketogenic diet
Ketogenic diet
The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used primarily to treat difficult-to-control epilepsy in children. The diet mimics aspects of starvation by forcing the body to burn fats rather than carbohydrates...
may also be tried. Other possible future therapies such as brain cortex responsive neural stimulators, deep brain stimulation
Deep brain stimulation
Deep brain stimulation is a surgical treatment involving the implantation of a medical device called a brain pacemaker, which sends electrical impulses to specific parts of the brain...
, and stereotactic radiosurgery (such as gamma knife) are undergoing research studies for treatment of TLE and other forms of epilepsy.
Temporal Lobe Epilepsy and the Arts
As Eve LaPlante discusses in her book, Seized, the intense emotions, sensory experience including vibrancy of colors, and particular mental state provoked by temporal lobe abnormalities may have contributed to the creation of significant works of art. A number of well-known writers and artists are known, or in many cases suspected to have had temporal lobe epilepsy, aggravated, in some cases, by alcoholismAlcoholism
Alcoholism is a broad term for problems with alcohol, and is generally used to mean compulsive and uncontrolled consumption of alcoholic beverages, usually to the detriment of the drinker's health, personal relationships, and social standing...
. They include Vincent Van Gogh
Vincent van Gogh
Vincent Willem van Gogh , and used Brabant dialect in his writing; it is therefore likely that he himself pronounced his name with a Brabant accent: , with a voiced V and palatalized G and gh. In France, where much of his work was produced, it is...
, Charles Dodgson (a.k.a. Lewis Carroll), Edgar Allan Poe
Edgar Allan Poe
Edgar Allan Poe was an American author, poet, editor and literary critic, considered part of the American Romantic Movement. Best known for his tales of mystery and the macabre, Poe was one of the earliest American practitioners of the short story and is considered the inventor of the detective...
, Fyodor Dostoevsky
Fyodor Dostoevsky
Fyodor Mikhaylovich Dostoyevsky was a Russian writer of novels, short stories and essays. He is best known for his novels Crime and Punishment, The Idiot and The Brothers Karamazov....
(whose novel The Idiot
The Idiot (novel)
The Idiot is a novel written by 19th century Russian author Fyodor Dostoyevsky. It was first published serially in The Russian Messenger between 1868 and 1869. The Idiot is ranked beside some of Dostoyevsky's other works as one of the most brilliant literary achievements of the "Golden Age" of...
features a protagonist with epilepsy, Prince Myshkin), Gustave Flaubert
Gustave Flaubert
Gustave Flaubert was a French writer who is counted among the greatest Western novelists. He is known especially for his first published novel, Madame Bovary , and for his scrupulous devotion to his art and style.-Early life and education:Flaubert was born on December 12, 1821, in Rouen,...
, Philip K. Dick
Philip K. Dick
Philip Kindred Dick was an American novelist, short story writer and essayist whose published work is almost entirely in the science fiction genre. Dick explored sociological, political and metaphysical themes in novels dominated by monopolistic corporations, authoritarian governments and altered...
, Sylvia Plath
Sylvia Plath
Sylvia Plath was an American poet, novelist and short story writer. Born in Massachusetts, she studied at Smith College and Newnham College, Cambridge before receiving acclaim as a professional poet and writer...
and contemporary author
Author
An author is broadly defined as "the person who originates or gives existence to anything" and that authorship determines responsibility for what is created. Narrowly defined, an author is the originator of any written work.-Legal significance:...
Thom Jones
Thom Jones
Thom Jones is an American writer, primarily of short stories.-Biography:Jones was raised in Aurora, Illinois, and attended the University of Hawaii, where he played catcher on the baseball team...
. Peter O'Leary has also discussed this in relation to work of poet Philip Jenks in his "Gnostic Contagion: Robert Duncan and the Poetry of Illness". Sadi Ranson-Polizzotti
Sadi ranson
Sadi Ranson-Polizzotti is a British poet and author living in the United States who has published widely in the United States and in Europe. Although she has written for print publications, she is most widely known as a result of her prolific output online...
has discussed the significance of Lewis Carroll's epilepsy online and in a forthcoming book on the subject.
Temporal Lobe Epilepsy, Neurotheology and Paranormal Experience
The first researcher to note and catalog the abnormal experiences associated with TLE was neurologist Norman GeschwindNorman Geschwind
Norman Geschwind pioneered behavioral neurology in America. He is best known for his exploration of behavioral neurology through disconnection models based on lesion analysis.- Early life :...
, who noted a constellation of symptoms, including hypergraphia
Hypergraphia
Hypergraphia is an overwhelming urge to write. It is not itself a disorder, but can be associated with temporal lobe changes in epilepsy and mania in the context of bipolar disorder.-Causes:...
, hyperreligiosity, fainting spells
Syncope (medicine)
Syncope , the medical term for fainting, is precisely defined as a transient loss of consciousness and postural tone characterized by rapid onset, short duration, and spontaneous recovery due to global cerebral hypoperfusion that most often results from hypotension.Many forms of syncope are...
, and pedantism, often collectively ascribed to a condition known as Geschwind syndrome
Geschwind syndrome
Geschwind syndrome, also known as "Gastaut-Geschwind" is a characteristic personality syndrome consisting of symptoms such as circumstantiality, hypergraphia, altered sexuality , and intensified mental life , hyper-religiosity and/or hyper-morality or moral ideas that is present in some...
.
Vilayanur S. Ramachandran
Vilayanur S. Ramachandran
Vilayanur Subramanian "Rama" Ramachandran, born 1951, is a neuroscientist known for his work in the fields of behavioral neurology and visual psychophysics...
explored the neural basis of the hyperreligiosity seen in TLE using galvanic skin response
Galvanic skin response
Skin conductance, also known as galvanic skin response , electrodermal response , psychogalvanic reflex , skin conductance response or skin conductance level , is a method of measuring the electrical conductance of the skin, which varies with its moisture level...
(which correlates with emotional arousal) to determine whether the hyperreligiosity seen in TLE was due to an overall heightened emotional state or was specific to religious stimuli (Ramachandran and Blakeslee, 1998). By presenting subjects with neutral, sexually arousing and religious words while measuring GSR, Ramachandran was able to show that patients with TLE showed enhanced emotional responses to the religious words, diminished responses to the sexually charged words, and normal responses to the neutral words. These results suggest that the medial temporal lobe is specifically involved in generating some of the emotional reactions associated with religious words, images and symbols.
Cognitive neuroscience
Cognitive neuroscience
Cognitive neuroscience is an academic field concerned with the scientific study of biological substrates underlying cognition, with a specific focus on the neural substrates of mental processes. It addresses the questions of how psychological/cognitive functions are produced by the brain...
researcher Michael Persinger
Michael Persinger
Michael A. Persinger is a cognitive neuroscience researcher and university professor with over 200 peer-reviewed publications. He has worked at Laurentian University, located in Sudbury, Ontario, since 1971.-Early life:...
asserts that stimulating the temporal lobe electromagnetically
Electromagnetism
Electromagnetism is one of the four fundamental interactions in nature. The other three are the strong interaction, the weak interaction and gravitation...
can cause TLE and trigger hallucination
Hallucination
A hallucination, in the broadest sense of the word, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid,...
s of apparent paranormal phenomena such as ghost
Ghost
In traditional belief and fiction, a ghost is the soul or spirit of a deceased person or animal that can appear, in visible form or other manifestation, to the living. Descriptions of the apparition of ghosts vary widely from an invisible presence to translucent or barely visible wispy shapes, to...
s and UFOs. Persinger has even created a "God helmet
God helmet
God Helmet refers to an experimental apparatus used in neuroscience, primarily in the field of neurotheology. Originally called the "Koren helmet" after its inventor Stanley Koren, it was conceived to study creativity and the effects of subtle stimulation of the mesiobasal temporal lobes...
" which purportedly can evoke altered states of consciousness through stimulation of the parietal
Parietal lobe
The parietal lobe is a part of the Brain positioned above the occipital lobe and behind the frontal lobe.The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the...
and temporal lobes. Neurotheologians
Neurotheology
Neurotheology, also known as spiritual neuroscience, is the study of correlations of neural phenomena with subjective experiences of spirituality and hypotheses to explain these phenomena....
speculate that individuals with temporal lobe epilepsy, having a natural tendency to experience states of consciousness such as euphoria
Euphoria (emotion)
Euphoria is medically recognized as a mental and emotional condition in which a person experiences intense feelings of well-being, elation, happiness, ecstasy, excitement and joy...
or samādhi
Samadhi
Samadhi in Hinduism, Buddhism,Jainism, Sikhism and yogic schools is a higher level of concentrated meditation, or dhyāna. In the yoga tradition, it is the eighth and final limb identified in the Yoga Sūtras of Patañjali....
, have functioned in human history as religious figures or shamans.
Temporal lobe epilepsy and hormones
Sex hormones can influence the timing and frequency of seizure activity. EstrogenEstrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
is pro-epileptic and progesterone
Progesterone
Progesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species...
is anti-epileptic. These counterbalancing effects may account for "catamenial epilepsy
Catamenial epilepsy
Catamenial epilepsy is a subtype of epilepsy, which is a chronic neurological condition characterized by recurrent seizures. Catamenial epilepsy is a subset of this population, which includes women of whom their seizure exacerbation is aligned with their menstrual cycle. Women with catamenial...
" i.e. epilepsy preceding or made more severe prior to menstruation
Menstruation
Menstruation is the shedding of the uterine lining . It occurs on a regular basis in sexually reproductive-age females of certain mammal species. This article focuses on human menstruation.-Overview:...
or during peri-ovulation. Gender may differentially influence neocortical pathologies in patients with refractory temporal lobe epilepsy.
See also
- AmygdalaAmygdalaThe ' are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.-...
- AurasAura (symptom)An aura is a perceptual disturbance experienced by some migraine sufferers before a migraine headache, and the telltale sensation experienced by some people with epilepsy before a seizure. It often manifests as the perception of a strange light, an unpleasant smell or confusing thoughts or...
- Bipolar DisorderBipolar disorderBipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or...
- Déjà vuDéjà vuDéjà vu is the experience of feeling sure that one has already witnessed or experienced a current situation, even though the exact circumstances of the prior encounter are uncertain and were perhaps imagined...
- EuphoriaEuphoriaEuphoria is an emotional and mental state defined as a sense of great elation and well being.Euphoria may also refer to:* Euphoria , a genus of scarab beetles* Euphoria, a genus name previously used for the longan and other trees...
- Geschwind syndromeGeschwind syndromeGeschwind syndrome, also known as "Gastaut-Geschwind" is a characteristic personality syndrome consisting of symptoms such as circumstantiality, hypergraphia, altered sexuality , and intensified mental life , hyper-religiosity and/or hyper-morality or moral ideas that is present in some...
- God helmetGod helmetGod Helmet refers to an experimental apparatus used in neuroscience, primarily in the field of neurotheology. Originally called the "Koren helmet" after its inventor Stanley Koren, it was conceived to study creativity and the effects of subtle stimulation of the mesiobasal temporal lobes...
- Hippocampal sclerosisHippocampal sclerosisAmmon's horn sclerosis is the most common type of neuropathological damage seen in individuals with temporal lobe epilepsy . This type of neuron cell loss, primarily in the hippocampus, can be observed in approximately 65% of people suffering from this form of epilepsy.Histopathological hallmarks...
- Intermittent explosive disorderIntermittent explosive disorderIntermittent explosive disorder is a behavioral disorder characterized by extreme expressions of anger, often to the point of violence, that are disproportionate to the situation at hand. It is currently categorized in the Diagnostic and Statistical Manual of Mental Disorders as an impulse...
- List of people with epilepsy
- MediumsMediumshipMediumship is described as a form of communication with spirits. It is a practice in religious beliefs such as Spiritualism, Spiritism, Espiritismo, Candomblé, Voodoo and Umbanda.- Concept :...
- NeurotheologyNeurotheologyNeurotheology, also known as spiritual neuroscience, is the study of correlations of neural phenomena with subjective experiences of spirituality and hypotheses to explain these phenomena....
- Post-traumatic epilepsyPost-traumatic epilepsyPost-traumatic epilepsy is a form of epilepsy that results from brain damage caused by physical trauma to the brain . A person with PTE suffers repeated post-traumatic seizures more than a week after the initial injury...
- ProsopagnosiaProsopagnosiaProsopagnosia is a disorder of face perception where the ability to recognize faces is impaired, while the ability to recognize other objects may be relatively intact...
(face blindness) - Religious ecstasyReligious ecstasyReligious ecstasy is an altered state of consciousness characterized by greatly reduced external awareness and expanded interior mental and spiritual awareness which is frequently accompanied by visions and emotional/intuitive euphoria...
- Temporal lobeTemporal lobeThe temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....
Media Depictions
- Film The Exorcism of Emily RoseThe Exorcism of Emily RoseThe Exorcism of Emily Rose is a 2005 American courtroom drama horror film directed by Scott Derrickson. The film is loosely based on the story of Anneliese Michel and follows a self-proclaimed agnostic defense lawyer representing a parish priest who is accused by the state of negligent homicide...
, 2005. - Film DeceiverDeceiver (film)Deceiver, also known as Liar, or Reisser, or even BSer , is a 1997 murder mystery film. It won Best Cinematography and Best Screenplay at the 1997 Stockholm Film Festival, and the Special Jury Prize at the 1998 Cognac Police Film Festival.-Plot:Textile company heir James Wayland is accused of...
, 1997. - Film Happy AccidentsHappy AccidentsHappy Accidents is a 2000 American film starring Marisa Tomei and Vincent D'Onofrio. The movie revolves around Ruby Weaver, a New York woman with a string of failed relationships, and Sam Deed, a man who claims to be from the year 2470...
, 2001. - Law and Order: Criminal Intent episode "The Gift," 2003.
- Television show "Veronica MarsVeronica MarsVeronica Mars is an American television series created by Rob Thomas. The series premiered on September 22, 2004, during television network UPN's final two years, and ended on May 22, 2007, after a season on UPN's successor, The CW Television Network. Veronica Mars was produced by Warner Bros...
," 2004-2007, main character Veronica Mars suspected her ex-boyfriend Duncan KaneDuncan KaneDuncan Kane is a fictional character on UPN/The CW television series Veronica Mars, which debuted during the fall 2004 season on UPN. He was a series regular during seasons one and two. He is portrayed by Teddy Dunn. He is Veronica's ex-boyfriend, and the brother to her dead best friend, Lilly...
of murdering his sister and her best friend, Lilly Kane, after discovering he had been treated for TLE symptoms. (Wrongly described on the show as "Type Four Epilepsy.") - Television show "MediumMedium (TV series)Medium is an American television drama series that premiered on NBC on January 3, 2005, and ended on CBS on January 21, 2011. Themed on supernatural gifts, its lead character, Allison DuBois , is a medium employed as a consultant for the Phoenix, Arizona district attorney's office...
," 2005-, starring Patricia ArquettePatricia ArquettePatricia T. Arquette is an American actress and director. She played the lead character in the supernatural drama series Medium for which she won the Primetime Emmy Award for Outstanding Lead Actress in a Drama Series.... - Television show "FireflyFirefly (TV series)Firefly is an American space western television series created by writer and director Joss Whedon, under his Mutant Enemy Productions label. Whedon served as executive producer, along with Tim Minear....
," 2002, film Serenity, 2005, both created by Joss WhedonJoss WhedonJoseph Hill "Joss" Whedon is an American screenwriter, executive producer, director, comic book writer, occasional composer and actor, founder of Mutant Enemy Productions and co-creator of Bellwether Pictures...
, feature character River Tam, affected with symptoms of TLE after alteration of amygdala, brain component related to TLE - A current story line on the CBS daytime drama, The Young and the RestlessThe Young and the RestlessThe Young and the Restless is an American television soap opera created by William J. Bell and Lee Phillip Bell for CBS. The show is set in a fictional Wisconsin town called Genoa City, which is unlike and unrelated to the real life village of the same name, Genoa City, Wisconsin...
, features character Victor NewmanVictor NewmanVictor Newman is a fictional character on the CBS soap opera The Young and the Restless played by actor Eric Braeden from February 1980 through November 2, 2009 and again from January 15, 2010 to present. The character briefly appeared on The Bold and the Beautiful in 1999...
being diagnosed with TLE. - Television Show "ERER (TV series)ER is an American medical drama television series created by novelist Michael Crichton that aired on NBC from September 19, 1994 to April 2, 2009. It was produced by Constant c Productions and Amblin Entertainment, in association with Warner Bros. Television...
" 2007, episode "Crisis of Consciousness", patient predicts engine will fall on his head if he is not moved. - Television Show "Day BreakDay BreakDay Break is a television program for which one 13-episode season was produced. The series starred Taye Diggs as Detective Brett Hopper, who is framed for the murder of Assistant District Attorney Alberto Garza. Due to a time loop, Hopper lives the same day over and over...
" on ABC, Jared is said to have TLE. - Television show "Eli StoneEli StoneEli Stone is an American TV series, and also the name of the title character.San Francisco lawyer Eli Stone begins to see things, which leads him to discover a brain aneurysm...
," 2008, title character (Johnny Lee Miller) loosens life and changes priorities after neurological condition prompts auditory/extrasensory hallucinations, premonitions and dawning spiritual enlightenment. - Book, The Terminal ManThe Terminal ManThe Terminal Man is a novel by Michael Crichton about the dangers of mind control. Published in 1972, it was later made into a film of the same name.-Plot summary:...
by Michael CrichtonMichael CrichtonJohn Michael Crichton , best known as Michael Crichton, was an American best-selling author, producer, director, and screenwriter, best known for his work in the science fiction, medical fiction, and thriller genres. His books have sold over 200 million copies worldwide, and many have been adapted... - Book, "The Spiral Staircase" by Karen ArmstrongKaren ArmstrongKaren Armstrong FRSL , is a British author and commentator who is the author of twelve books on comparative religion. A former Roman Catholic nun, she went from a conservative to a more liberal and mystical faith...
, an autobiography including descriptions of her long undiagnosed Temporal lobe epilepsy. - The music video for "Epilepsy is Dancing" from the album The Crying LightThe Crying LightThe Crying Light is Antony and the Johnsons' third studio album and the follow-up to the band's widely-acclaimed second LP, I Am a Bird Now...
by Antony and the JohnsonsAntony and the JohnsonsAntony and the Johnsons is a music group presenting the work of Antony Hegarty and his collaborators.-Career:British experimental musician David Tibet of Current 93 heard a demo and offered to release Antony's music through his Durtro label. The debut album, Antony and the Johnsons, was released...
Further reading
Discusses link between TLE and artistic creativity., including bibliography- Lange CG, 1887, "Uber Gemuthsbewegungen", Liepzig: T Thomas