Temporal lobe epilepsy

Temporal lobe epilepsy is a form of epilepsy, a chronic neurological condition characterized by recurrent seizures.

Causes

Temporal lobe epilepies are a group of medical disorders in which humans and animals experience recurrent epileptic seizures arising from one or both temporal lobes of the brain. Two main types are internationally recognized. Medial temporal lobe epilepsy (MTLE) arises in the hippocampus, parahippocampal gyrus and amygdala which are located in the inner aspect of the temporal lobe. Lateral temporal lobe epilepsy (LTLE) arises in the neocortex on the outer surface of the temporal lobe of the brain. Because of strong interconnections, seizures beginning in either the medial or lateral areas often involve neighboring areas of the brain. The causes or etiology of different temporal lobe epilepsies vary. MTLE is often associated with generalized tonic-clonic (convulsive) seizures occuring in children under age 5 during fevers (febrile seizures). When MTLE begins in childhood, atrophy of the hippocampus can often be seen on magnetic resonance imaging (MRI) of the brain. When MTLE begins in adulthood, MRIs often reveal no visible abnormalities. Rarely, MTLE can be hereditary or related to brain tumors, 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.

Symptoms

The symptoms felt by the patient with TLE and the signs observable by others during seizures depend upon the specific areas of the temporal lobes and neighboring brain areas affected by the seizure. The 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 Seizures (SPS) involve small areas of the temporal lobe and do not affect consciousness. These are seizures which primarily cause sensations. These sensations may be mnestic such as deja vu (a feeling of familiarity), jamais vu (a feeling of unfamilarity), a specific single or set of memories, or amnesia. The sensations may be auditory such as a sound or tune, or gustatory such as a taste, or olfactory such as a smell that is not truly present. Sensations can also be visual or involve feelings on the skin or in the internal organs. The latter feelings may seem to move over the body. 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 sometimes called "auras" by lay persons, and are sometimes thought to just be a prelude to an acutal seizure. The latter is incorrect. SPS are seizures. Complex Partial Seizures (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 others. They usually begin with an SPS, but then the seizure spread to a large portion of the temporal lobe and impairs consciousness. Signs may include motionless staring, automatic movements of the hands or mouth, inability to respond to others, unusual speech, or unusual behaviors. Because judgement is impaired, persons experiencing CPS may not legally drive vehicles for periods of time which are set by local governments worldwide. 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 in either a flexed or extended position. After this coarse jerking of the limbs and trunk occur.

Treatments

There are oral medications available for management of epileptic seizures, but with incompletely understood mechanisms of action. Anti-seizure drugs and sedatives may normalize neurological function and soothe the affected individual but may stifle the pronounced creativity and communication demonstrated by some with TLE. Surgery, if applicable, may also be a viable alternative. Some patients experience depression and disengagement from self and environment upon normalization of a once intensely inspirational, profoundly stimulating acuity. Monitoring of treatment is done using EEGs, CT scans, MRI imaging, oral interviews, and coordination tests.

Temporal Lobe Epilepsy and the Arts

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. Artists known (with varying degrees of certainty) to have had TLE include Charles Dodgson (a.k.a. Lewis Carroll), Edgar Allen Poe, Dostoevsky (whose novel The Idiot features an epileptic protagonist, Prince Myshkin), Vincent Van Gogh, Gustave Flaubert, Soren Kierkegaard and Sylvia Plath. The contemporary author Thom Jones has temporal lobe epilepsy. The left temporal lobe affects comprehension, naming, verbal memory and other language functions.

Temporal Lobe Epilepsy, Neurotheology and Paranormal Experience

UFO Researcher Albert Budden and cognitive neuroscience researcher Michael Persinger assert that increases in local electromagnetism, triggering the temporal lobe can stimulate TLE and trigger hallucinations of apparent paranormal phenomena, for example ghosts and UFO's. Persinger has even gone as far as to create a "God helmet" to apparently demonstrate how stimulation of the parietal and temporal lobe can evoke altered states of consciousness. Quite possibly, as neurotheologians have speculated, then, individuals with temporal lobe epilepsy, who have a natural aptitude for "religious" states of consciousness (such as euphoria or samadhi) have functioned in human history as religious figures or as shamans. Persinger's theories, however, remain controversial.

Syndrome of TLE

Classical syndrome of TLE begins when there is a very early insult to the left or right hippocampus. We come to be aware of that insult in very young babies in the neonatial period. The babies may develop an infection resulting in a fever. Young babies have an immature thermoregulation system, and the fever causes the babies core body temperature to increase. The raised body temperature in infants causes febrile convulsions. Febrile convulsions are usually quite normal in babies, lasting only a few minutes, but in a few cases this febrile convulsions can last for an hour. This is a sign that the infant is in a high risk of having TLE.

Resources

Additional information on face-blindness may be obtained from http://www.faceblind.org/ , a site sponsored by Harvard University in conjunction with University College London.

A book by Bill Choisser, who is face-blind from birth, may be downloaded free of charge from http://www.choisser.com/faceblind/

Implications of face-blindness in daily functioning and some coping mechanisms is aptly described by Cecilia Berman on her site at http://www.prosopagnosia.com/main/stones/index.asp

Face-blindness as a result of temporal lobe injury is described by Dr. Daniel Amen in his book - Healing ADD - along with case histories.

Many finer points of the degree of temporal lobe impairment, the site of the source of face-blindness, are covered on the website eMedicine at http://www.emedicine.com/NEURO/topic365.htm

Media Depictions

Film Deceiver, 1997, directed by Jonas and Josh Pate, starring Tim Roth, Michael Rooker, Chris Penn and Renée Zellweger
Film Happy Accidents, 2001, directed by Brad Anderson, starring Marisa Tomei and Vincent D'Onofrio
Television show "Law and Order: Criminal Intent," episode "The Gift," 2003, guest-starring Jane Adams
Television show "Medium," 2005-, starring Patricia Arquette
Television show "Firefly," 2002, film Serenity, 2005, both created by Joss Whedon, feature character River Tam, affected with symptoms of TLE after alteration of amygdala, brain component related to TLE

References

Temporal Lobe Epilepsy eMedicine.

Neurology

Causes

Symptoms

Treatments

Temporal Lobe Epilepsy and the Arts

Temporal Lobe Epilepsy, Neurotheology and Paranormal Experience

Syndrome of TLE

Resources

See also

Media Depictions

Further reading

References

Gourt Home::Gourt :: Temporal lobe epilepsy

Causes

Symptoms

Treatments

Temporal Lobe Epilepsy and the Arts

Temporal Lobe Epilepsy, Neurotheology and Paranormal Experience

Syndrome of TLE

Resources

See also

Media Depictions

Further reading

References