Mesial Temporal Sclerosis Mesial temporal sclerosis, also known as hip-pocampal sclerosis, is the most common cause of temporal lobe epilepsy found at surgery. [12], Although the theory is controversial, there is a link between febrile seizures (seizures coinciding with episodes of fever in young children) and subsequent temporal lobe epilepsy, at least epidemiologically. 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. In TLE, the sprouting mossy fibres are larger than in the normal brain and their connections may be aberrant. TLE is initially managed medically with anti-epileptic agents. This is followed by complex partial seizures with stereotypic semiology. Dysphoric or euphoric feelings, fear, anger, and other emotions may also occur. [citation needed], The newer classification gives two types of focal onset seizures, as focal aware and focal impaired awareness.[2]. [64][65] Cognitive rehabilitation may also help. For instance, if the dendrites of granule cells reconnect, it may be in a way (through the laminar planes) that allows hyperexcitability. [70][77], Focal to bilateral seizures or generalized seizures, Granule cell dispersion in the dentate gyrus, Please review the contents of the section and, de Lanerolle N. C. and Noebels J. L. Simple focal seizures are the initial non-febrile seizures followed by Learn more from the Epilepsy Foundation. Often, the patient cannot describe the sensations. Felbamate and vigabatrin are newer, but can have serious adverse effects so they are not considered as first-line treatments. He found a constellation of symptoms that included hypergraphia, hyperreligiosity, collapse, and pedantism, now called Geschwind syndrome. However, it was not until 2001 that a scientifically sound study was carried out to examine the effectiveness of temporal lobectomy. The relationship, if any, of mesial temporal sclerosis with febrile seizures is controversial, made all the more difficult due to the relative insensitivity of imaging and the difficulty in establishing whether a particular seizure was truly febrile. Rarely MTS can be detected in children during the first decade of life, but is not commonly found until adolescence. [7], Focal seizures in the temporal lobe involve small areas of the lobe such as the amygdala and hippocampus. Mesial temporal sclerosis is the loss of neurons and scarring of the deepest portion of the temporal lobe and is associated with certain brain injuries. Histologi- & Hermann, B.P. They usually begin with a focal aware seizure, then spread to a larger portion of the temporal lobe, resulting in impaired consciousness. Rarely NITS can be detected in children during the first decade of … In animal models, neuronal loss occurs during seizures but in humans, neuronal loss predates the first seizure and does not necessarily continue with seizure activity. Olfactory hallucinations often seem indescribable to patients beyond "pleasant" or "unpleasant". Mesial temporal sclerosis is a frequent cause of epilepsy. Mesial Temporal Sclerosis (MTS) is a term used to describe scarring in deep part of the temporal lobe of the brain. ), Benson, D.F. Methods 2.1. Though they may not seem harmful, due to the fact that the individual does not normally seize, they can be extremely harmful if the individual is left alone around dangerous objects. The etiology is uncertain, although prolonged febrile seizures and limbic encephalitis have been implicated. It has been found that GABA reversal potential is depolarising[40] in the subpopulation of the pyramidal cells due to the lack of KCC2 co-transporter. [46] This structure provides a filter for the excitability of neurons. This study was presented as an abstract at a neuroscience conference and referenced in Ramachandran's book, Phantoms in the Brain,[69] but it has never been published in the peer-reviewed scientific press. The mesial temporal lobe, also known as the medial temporal lobe, is, as the name suggests, located on the medial aspect of the temporal lobe and is distinct from the rest of the lobe, which is composed of neocortex. Mesial temporal sclerosis usually results in partial (focal) epilepsy. Epub ahead of print. Up to a third of patients with established refractory temporal lobe epilepsy have a history of seizures in childhood at the time of fever . We report on 2 male patients aged 4 years with suspected TLE due to MTS who were referred for presurgical evaluation. The relationship, if any, of mesial temporal sclerosis with febrile seizures is controversial, made all the more difficult due to the relative insensitivity of imaging and the difficulty in establishing whether a particular seizure was truly febrile. Prevalence ~20% of patients with epilepsies; 65% of mesial TLE. Mesial temporal sclerosis (MTS) is a common pathologic finding in patients with temporal lobe epilepsy. They project into the hilus of the dentate gyrus and stratum lucidum in the CA3 region giving inputs to both excitatory and inhibitory neurons. The patient reported that God had sent him to the world to "bring redemption to the people of Israel". [11] People who experience only focal aware seizures may not recognize what they are, nor seek medical care. [21] The personality changes generally vary by hemisphere. See all (206) This was noted in human tissue in 1974 and in animal models in 1985. In interictal periods, conversely, perfusion is reduced . [7] The arms, trunk, and legs stiffen (the tonic phase), in either a flexed or extended position, and then jerk (the clonic phase). Most patients present with complex partial temporal lobe epilepsy. Etiology Hippocampal sclerosis. Pedley (Eds. SPECT and PET imaging are also a useful adjuncts, with both ictal and interictal scans demonstrating abnormalities: Other causes of temporal lobe epilepsy (TLE) should be considered, especially as small temporal lobe cortical tumours can have similar appearances. Newer drugs, such as gabapentin, topiramate, levetiracetam, lamotrigine, pregabalin, tiagabine, lacosamide, and zonisamide promise similar effectiveness, with possibly fewer side-effects. Mesial temporal sclerosis Etiology Controversy exists as to the causative mechanism: is mesial temporal sclerosis a result of temporal lobe epilepsy or viceversa. TLE is the most common form of epilepsy with focal seizures. The condition called mesial temporal sclerosis is closely related to temporal lobe epilepsy, a type of partial (focal) epilepsy in which the seizure initiation point can be identified within the temporal lobe of the brain. Furthermore, in adults 3-10% of cases of mesial temporal sclerosis demonstrate bilateral changes even though symptoms may be unilateral. Controversy exists as to the causative mechanism: is mesial temporal sclerosis a result of temporal lobe epilepsy or vice versa ? [21], The existence of a "temporal lobe epileptic personality" and of Geschwind syndrome have been disputed and research is inconclusive. Up to a third of patients with established refractory temporal lobe epilepsy have a history of seizures in childhood at the time of fever 3. [citation needed], Seizures which begin in the temporal lobe, and then spread to involve both sides of the brain are termed focal to bilateral. Psychiatric conditions with psychotic spectrum symptoms might be more plausible physical explanation of these experiences. [74] Most patients present with complex partial temporal lobe epilepsy. This is more so on the left in verbal memory loss. Mesial temporal sclerosis (MTS) is a common pathologic finding in patients with temporal lobe epilepsy. Age at onset Late childhood or adolescence. Our primary outcome is time-to-seizure recurrence. This is the postictal state. [21], The causes of TLE include mesial temporal sclerosis, traumatic brain injury, brain infections, such as encephalitis and meningitis, hypoxic brain injury, stroke, cerebral tumours, and genetic syndromes. Mesial temporal sclerosis is the loss of neurons and scarring of the deepest portion of the temporal lobe and is associated with certain brain injuries. [5], When a seizure begins in the temporal lobe, its effects depend on the precise location of its point of origin, its locus. [26][27][28], Dispersion of the 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 neuronal migration. Neurological and mental state Usually normal prior to seizure onset. It is seen in up to 65% of autopsy studies, although significantly less on imaging. [76] The purported link between TLE and religiosity has inspired work by Michael Persinger and other researchers in the field of neurotheology. [citation needed], Temporal lobe epilepsy is associated with memory disorders and loss of memory. 28-year-old male with a long-standing history of seizures localizing to the inferomedial right temporal lobe on EEG. During the peri-ictal phases, perfusion is increased, not only in the mesial temporal lobe but often in large parts of temporal lobe and hemisphere. TLE is diagnosed by taking a medical history, blood tests, and brain imaging. Ramachandran presented two subjects with neutral, sexually arousing and religious words while measuring GSR. [20], Geschwind syndrome is a set of behavioural phenomena seen in some people with TLE. They may include autonomic and psychic features present in focal aware seizures. With this type, some people do not even realize they are having a seizure and most of the time their memory from right before or after the seizure is wiped. Together with other mesial temporal structures, the amygdala is important in the epilep … These impulses modulate the brain’s circuitry. Diagnostic findings in mesial temporal sclerosis include interictal anterior temporal spikes on electroencephalography and hippocampal atrophy with increased T 2-weighted signal on magnetic resonance imaging .2, 3 Although mesial temporal sclerosis is generally unilateral, bilateral involvement is occasionally seen. [citation needed]. [12] The word grand mal comes from the French term, meaning major affliction. Most anticonvulsants function by decreasing the excitation of neurons, for example, by blocking fast or slow sodium channels or by modulating calcium channels; or by enhancing the inhibition of neurons, for example by potentiating the effects of inhibitory neurotransmitters like GABA. [39], In certain patients with temporal lobe epilepsy it has been found that the subiculum could generate epileptic activity. Neuronal loss on the right is more prominent in non-verbal (visuospatial memory loss). [43], Granule cell dispersion is a type of developmental migration and a pathological change found in the TLE brain which was first described in 1990. Automatic movements of the hands or mouth, Altered ability to respond to others, unusual speech, This page was last edited on 11 January 2021, at 00:42. The first to record and catalog the abnormal symptoms and signs of TLE was Norman Geschwind. These were previously known as grand mal seizures. When severe and long standing, additional associated findings include : Additional 3D volumetric studies can be performed, and although time consuming to post-process may be more sensitive to subtle hippocampal volume loss. [46], In TLE, granule cells are lost, the structure is no longer closely packed and there are changes in the orientation of dendrites. MR spectroscopy findings typically represent neuronal dysfunction : MR perfusion demonstrates similar changes to SPECT (see below) with blood perfusion depending on when the scan is obtained. Loss of mossy cells lowers the threshold of action potentials of the granule cells. Also, in animal models, granule cell hyper-excitability is recorded before aberrant mossy fibre sprouting has occurred.[56][57][58][59]. [6] However, as of 2017 the general classification of seizures has been revised. This seizure disorder can cause a variety of symptoms such as strange sensations, changes in behavior or emotions, muscle spasms, or convulsions.The seizures usually are localized in the brain, but they may spread to become generalized seizures, which involve the entire brain and may cause a sudden loss of awareness or consciousness. The first line of treatment is through anticonvulsants. [31](p416–431)[46][50][51][52], Aberrant mossy fibre sprouting may create excitatory feedback circuits that lead to temporal lobe seizures. [citation needed], Focal impaired awareness seizures are seizures which impair consciousness to some extent:[2] they alter the person's ability to interact normally with their environment. Clinical manifestations Pre-existing complex febrile convulsions are common. [3] Temporal lobe epilepsy (TLE) is the single most common form of focal seizure. Coronal volume and coronal high resolution T2WI/FLAIR are best to diagnose MTS. 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