Temporal lobe epilepsy

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

Contents

Causes

Temporal lobe epilepsies 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.

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 occurring 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.

  1. 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 déjà vu (a feeling of familiarity), jamais vu (a feeling of unfamiliarity), 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 actual seizure. The latter is incorrect. SPS are seizures.
  2. 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 spreads 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.
  3. 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.

Syndrome of Temporal Lobe Epilepsy (TLE)

The classical syndrome of TLE begins when there is a very early insult to the left or right hippocampus. Newborn babies may develop an infection resulting in a fever. Young babies have an immature thermoregulation system, and the fever causes the baby's core body temperature to increase. The raised body temperature can cause febrile convulsions. These are quite normal in babies, usually lasting only a few minutes, but in a few cases the convulsions can last for an hour. This is a sign that the infant is at a high risk of developing TLE.

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 individuals with TLE. The medications may also have extremely harsh side effects, including, but are not limited to, overall weakness (sometimes requiring support devices such as canes), tremors, slurred speech, and loss of fine motor control. Some epileptics would rather have seizures while taking less medication than have their seizures be totally controlled and suffer the debilitating effects of these medications. Surgery, if applicable, may also be a viable alternative. Some patients experience depression and disengagement from self and environment upon normalization of the sometimes intensely inspirational, profoundly stimulating experiences that accompany TLE. Monitoring of treatment is done using EEGs, CT scans, MRI imaging, oral interviews, and coordination tests.


Further reading

  • Book "Seized: Temporal Lobe Epilepsy as Medical, Historical and Artistic Phenomenon," by Eve LaPlante, 1993, reprinted 2000, discusses link between TLE and artistic creativity
  • Transcript of Horizon documentary "God on the Brain" - http://www.bbc.co.uk/science/horizon/2003/godonbraintrans.shtml
  • See "Theological Aspects of Temporal Lobe Function," by paraclete, http://www.everything2.com/index.pl?node_id=1747573, including bibliography:
  • Bard P, 1934, "On emotional expression after decortication with some remarks on certain theoretical views", Psych. Reviews; 41:309-329
  • Blumer D, 2002, "The illness of Vincent van Gogh", Am J Psychiatry; 159:519-526
  • Broca P, 1878, "Anatomie comparé de circonvolutions cérébrales. Le grand lobe limbique et la scissure limbige dans la série des mammiféres", Revue d'Anthropologie; 1:385-498
  • Cannon WB, 1927, "The James-Lange theory of emotion", Am J. Psychology; 39:106-124
  • Dewhurt K, Beard AW, 1970, "Sudden religious conversions in temporal lobe epilepsy", Br. J. Psychiatry; 117:497-507
  • Hohmann GW, 1966, "Some effects of spinal cord lesions on experienced emotional feelings", Psychophysiology; 3(2):143-56
  • James W, 1884, "What is an emotion?", Mind; 9:188-205
  • Kingsley RE, 2000, "Concise Text of Neuroscience", 2nd edition, Lippincott Williams and Wilkins, 884-888
  • Lange CG, 1887, "Uber Gemuthsbewegungen", Liepzig: T Thomas
  • Lowe J, Carroll D, 1985, "The effects of spinal injury on the intensity of emotional experience", Br J Clin Psychol.; 24(2):135-6
  • MacLean PD, 1955, "The limbic system ("visceral brain") and emotional behaviour", Arch. Neurology and Psychiatry; 73:130-134
  • Ogata A, Miyakawa T, 1998, "Religious experiences in epileptic patients with a focus on ictus-realted episodes", Psychiatry and Clinical Neuroscience; 52:321-325
  • Papez JW, 1937, "A proposed mechanism of emotion", Arch. Neurology and Psychiatry; 38:725-743
  • Peake Anthony, "Is There Life After Death" 2006 (Chartwell Books in USA & Arcturus in Europe)
  • Persinger MA, 1983, "Religious and mystical experiences as artefacts of temporal lobe function: a general hypothesis", Percept Mot Skills; 57(3):1255-62
  • Ramachandran VS and Blakeslee, 1998, "Phantoms in the Brain", 1st edition, Fourth Estate, Chapter 9
  • Thompson JG, 1988, "The Psychobiology of Emotion", 1st edition, New York: Plenum Press

References

Http://www.wikipedia.org

External links

  • [1]Anthony Peake's website (see 'Further Reading' above).
  • [2]Site featuring a number of articles about TLE / Complex Partial Seizures).
  • [3]What is a seizure - animation on Epilepsy.com.
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