Temporal Lobe Epilepsy

Temporal lobe epilepsy is a syndrome that results from recurrent epileptic seizures that can be traced back to the temporal lobe. In general, epilepsy is a brain disorder in which clusters of nerve cells, or neurons, in the brain sometimes signal abnormally. Neurons normally generate electrochemical impulses that act on other neurons, glands, and muscles to produce human thoughts, feelings and actions (NINDS, 2006). In temporal lobe epilepsy the normal pattern of neuronal activity becomes disturbed, causing strange sensations, changes in behaviour or emotions, muscle spasms, or convulsions and even partial seizures which originate from medial or lateral temporal lobe. During a seizure, neurons may fire as many as 500 times a second, much faster than the normal rate of about 80 times a second (NINDS, 2006). Anything that disturbs the normal pattern of neuron activity can cause epilepsy and the most common pathologies or causes of Temporal Lobe Epilepsy are: mesial sclerosis, hippocampal sclerosis, tumours, malformations, neoplasms and inflammatory scars from infection (Armstong D, 1993). Although this debilitating syndrome has caused vast human suffering, it has also given us a glimpse into the functions in which these areas of the brain subserve.

Most damage, including lesions, ongoing epileptic activity and undesired treatment effects associated to Temporal Lobe Epilepsy (TLE) is localised to the medial temporal lobe (Chelune, 1995). This area consists of the hippocampal region (CA fields, dentrate gyrus and subiculum) and the adjacent perirhinal, entorhinal and parahippocampal cortices. This system of anatomically related structures has been found to be essential for declarative memory (Squire & Clark, 2004). Declarative memory is one of the most essential human cognitive functions; it provides individuals basic biography, identity and is involved in cognitive behaviour development. One can see that the impairment of such memory functions would

References: Armstrong D, 1993 - The neuropathology of temporal lobe epilepsy. Armstrong D, PubMed:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmedo S G. J. Chelune (1995) – Hippocampal adequacy versus functional reserve: Predicting Memory functions following Temporal Lobectomy. Archives of clinical neuropsychology, Vol. 10, No. 5, pp 413-432 (1995). Squire, L.R. et al. (2004) – The medial temporal lobe. Annual review of Neuroscience, 27, 279-306. Van Hoesen GW, Hyman BT, 2003 –‘Hippocampal formation: anatomy and the patterns of pathology in Alzheimer 's disease ' Van Hoesen GW, Hyman BT, Department of Anatomy, University of Iowa College of Medicine V Weintrob, D.L., et al (2002) – Verbal memory in left temporal lobe Epilepsy: Evidence for task-related localisation. Annals of Neurology, 51, 422-447.