Electroencephalography in mesial temporal lobe epilepsy. The term temporal lobe epilepsy tle was included in the classification of the. The mesial part of the temporal lobe is richly connected with surrounding extra temporal cortical. Mesial temporal lobe sclerosis mts is the most common pathology associated with intractable temporal lobe epilepsy. Temporal lobe epilepsy tle is the most common cause of drug refractory epilepsy, especially in adults. Mesial temporal lobe epilepsy jama neurology jama network. Long term outcome of temporal lobe epilepsy surgery. Little is known about the epidemiology of tle, because it requires advanced neuroimaging, positive eeg, and appropriate clinical semiology to confirm the diagnosis. A magnetic resonance imaging mri follow up study of children after febrile. Temporal lobe epilepsy caused by mesial temporal sclerosis and. Aura occurs in the majority of temporal lobe seizures. A history of febrile seizures especially complex febrile seizures is common in tle and is frequently associated with mesial temporal sclerosis. The present study evaluated complete reelin signalling pathway in mtle in human tissue hippocampus and anterior temporal lobe atl.
Mesial temporal epilepsy is the best known and the most frequent bercovici et. Mesial temporal lobe epilepsy mtle affects the inner part of the temporal lobe manifesting in the hippocampus, parahippocampal gyrus and the amygdala. The mesial part of the temporal lobe is richly connected with surrounding extratemporal cortical. Surgical intervention can prevent temporal lobe seizure recurrence in patients with mtle. Benign mesial temporal lobe epilepsy bmtle, which is defined as at least 24 months of seizure freedom with or without antiepileptic medication, has probably been underrecognized because of. In young individuals, mesial temporal sclerosis is commonly recognized with temporal lobe epilepsy tle. Retrospective studies from tertiary epilepsy centres suggest that many patients with drug resistant temporal lobe epilepsy have a history of complex febrile seizures. Effects of chronic temporal lobe epilepsy on memory functions. Granule cell dispersion gcd is pathognomonic of hippocampal sclerosis seen in mesial temporal lobe epilepsy mtle.
Hermann et al 1 recently identified the neuropsychological features of the syndrome of mesial temporal lobe epilepsy mtle. Neurological and mental state usually normal prior to seizure onset. Mesial temporal sclerosis is the most common lesion found in adults with temporal lobe epilepsy. However, recent improvements in structural imaging have allowed for. Temporal lobe epilepsy with mesial temporal sclerosis usually presents between 610 years of age but can present from infancy to the 30s. Tle is most of all characterized by the repeated and unprovoked occurrence of epileptic seizures which take their origin in temporal lobe structures. Epilepsy is a disorder in which the electrical activity in the brain briefly becomes irregular. Since then the phenomenon of temporal lobe epilepsy tle has been a source of knowledge about much, if not most, of what we know about the neurocognition of. Hippocampal sclerosis is the most common cause of mesial temporal lobe epilepsy. Mesial temporal sclerosis and epilepsy health science journals. The electroencephalogram eeg of mesial tle contains interictal features often associated with anterior temporal epileptifo. Mesial temporal sclerosis and temporal lobe epilepsy. Anterior temporal polar focal cortical dysplasia is often missed on a.
Mesial temporal lobe epilepsy mtle is the most common form of partial epilepsy in adults 1, and it is estimated that it represents about 40% of all epilepsies in this age range. Periodic epileptiform discharges in mesial temporal lobe. Hippocampal onset accounts for at least 80% of all. It is seen in up to 65% of autopsy studies, although significantly less on imaging. Most auras and automatisms last a very short period seconds or 1 to 2 minutes. Simple focal seizures are the initial nonfebrile seizures followed by complex focal. Mesial temporal lobe epilepsy an overview sciencedirect. Mtle is the most common type of epilepsy and is often characterized by the sense of an aura immediately preceding the seizure. A focal seizure in the temporal lobe may spread to other areas in the brain when it may become a focal to bilateral seizure. Detection of lesions in mesial temporal lobe epilepsy by. Mesial temporal lobe epilepsy mtle, the most common epilepsy in adults, is generally intractable and is suspected to be the result of recurrent excitation or inhibition circuitry. Recurrent excitation and the development of seizures have been associated with aberrant mossy. Considerations of intractable mesial temporal lobe epilepsy.
Regional neocortical thinning in mesial temporal lobe epilepsy. Pathological changes to the hippocampus and other medial temporal lobe structures are well documented in patients with medial temporal lobe epilepsy mtle dreifuss et al. The idea that verbal and nonverbal forms of memory are segregated in their entirety, and localized to the left and right hippocampi, is arguably the most influential concept in the neuropsychology of temporal lobe epilepsy, forming a cornerstone of presurgical decision making, and a frame for interpreting postoperative outcome. Mesial temporal lobe epilepsy texas childrens hospital. Little is known about the epidemiology of tle, because it requires advanced neuroimaging, positive eeg, and appropriate clinical semiology to confirm the. The timing of surgical intervention for mesial temporal. Fifty years have elapsed since the publication of the first seminal papers on neuropsychological outcome after surgery for the alleviation of temporal lobe seizures scoville and milner, 1957. Frontal lobe epilepsy is the term for recurring seizures beginning in the frontal lobe the area of the brain behind the forehead. Mesial temporal lobe epilepsy with hippocampal sclerosis. It can be hard for people with tle to become completely seizure free with seizure medicines alone, though medicines may lower the number of seizures. A focal seizure in the temporal lobe may spread to other areas in the. Temporal lobe epilepsy tle is a chronic disorder of the nervous system characterized by recurrent, unprovoked focal seizures that originate in the temporal lobe of the brain and last about one or two minutes. Advances in neuroimaging and neurophysiology have enabled more precise localisation of the epileptogenic zone and the eloquent.
People with drugresistant medial temporal lobe epilepsy have a higher risk for memory and mood difficulties. Left hippocampal atrophy was associated with severe verbal memory deficits and there was. Mesial temporal lobe epilepsy with temporal lobe epilepsy and history of febrile convulsions, demonstrated the presence of discrete changes in the internal structure, conformation, and volume of the hippocampus. Temporal lobe epilepsy tle is the most common form of focal partial epilepsy. Hippocampal onset accounts for at least 80% of all temporal lobe seizures. Pdf chronic deep brain stimulation in mesial temporal. The case histories, interictal eeg, seizure semiology, ictal eeg and postoperative outcome of.
The term temporal lobe epilepsy tle was included in the classification of the ilae in 1989 under the group of localization related symptomatic epilepsies characterized by seizures with sp e. Mesial temporal sclerosis radiology reference article. Mesial temporal lobe epilepsy an overview of surgical. On the other hand, it is an often unrecognized cause of cognitive decline, typically presenting with severe memory loss. Epilepsy surgery such as laser ablation or temporal lobectomy may be an option, especially when the cause of the seizures is an abnormality in the brain such as mesial temporal sclerosis. Although their neuropsychological battery was comprehensive, they neglected to adequately define certain constructs of cognition. Mesial temporal sclerosis in epilepsy pubmed central pmc. The electroencephalogram eeg of mesial tle contains interictal features often associated with anterior temporal epileptiform discharges with a maximal voltage over the basal. Mesial temporal sclerosis mts is the most common cause of medically refractory temporal lobe epilepsy tle. The epileptogenic region in mesial temporal lobe epilepsy mtle is known to extend beyond the hippocampus, to a network of cortical and subcortical structures, varying across patients. Chronic deep brain stimulation in mesial temporal lobe epilepsy. Influence of restingstate network on lateralization of.
Treatments of temporal lobe seizures includes medications, diet, surgery, laser, and electrical brain stimulator devices. Pdf detection of mesial temporal lobe hypoperfusion in. Mar 07, 2012 temporal lobe epilepsy with mesial temporal sclerosis usually presents between 610 years of age but can present from infancy to the 30s. Mesial temporal lobe epilepsy an overview of surgical techniques. Temporal lobe epilepsy and memory with about 70% temporal lobe epilepsy tle is the most common type of the focal symptomatic or cryptogenic epilepsies. Mts is usually a progressive disorder and seizures initially controlled with antiepileptic drugs can later become intractable in 6090% 16, 17. Pdf chronic deep brain stimulation in mesial temporal lobe. The interictal mesial temporal lobe epilepsy network. The electroencephalogram eeg of mesial tle contains interictal features often associated with anterior temporal epileptiform discharges with a maximal voltage over the basal temporal electrodes. It can be sporadic, usually with positive family history, or it can present with clear familial recurrence 2. Mesial temporal sclerosis mts, also commonly referred to as hippocampal sclerosis, is the most common association with intractable temporal lobe epilepsy tle 2,3,5. Surgical resection of the mesial temporal lobe in patients with drugresistant mesial temporal epilepsy can lead to freedom from disabling seizures in 6090% of patients. Request pdf mesial temporal lobe epilepsy temporal lobe epilepsy tle is the most common form of adult localizationrelated epilepsy. Eighty per cent of tles have onset in the hippocampus,1 and hippocampal sclerosis is a major aetiology in the adult epilepsy surgery series.
Periodic epileptiform discharges peds are an uncommon, abnormal eeg pattern seen usually in patients with acute diseases and less frequently in chronic conditions, such as mesial temporal lobe epilepsy mtle. Clinical manifestations preexisting complex febrile convulsions are common. Mesial temporal lobe epilepsy mtle is the most common and welldefined focal epilepsy syndrome, and it is also the most likely to be pharmacoresistant. Mesial peds temporal lobe epilepsy hippocampal sclerosis a b s t r a c t purpose. The complete disconnection of the epileptogenic neural networks in the mesial temporal lobe determines the success of resective surgery. Detection of mesial temporal lobe hypoperfusion in patients with temporal lobe epilepsy by use of arterial spin labeled perfusion mr imaging. Current animal studies associate gcd to deficiency of reelin, an extracellular matrix protein. Surgical considerations of intractable mesial temporal lobe. For those individuals with medically intractable mesial temporal lobe epilepsy, a selective amygdalohippocampectomy surgery can be done that. Tle is the most common form of epilepsy with focal seizures.
Auras may cause sensory, autonomic or psychic symptoms. The frequent occurrence of intractable epilepsy in the temporal lobe bears witness to the highly epileptogenic nature of the limbic structures that comprise the mesial portion of the temporal lobe. Simple focal seizures are the initial nonfebrile seizures followed by. Temporal lobe epilepsy tle is the most common form of adult localizationrelated epilepsy. Surgical considerations of intractable mesial temporal.
In temporal lobe epilepsy tle seizures could originate in the medial or lateral neocortical temporal region, and many of these patients are refractory to medical. Seizures occur suddenly and usually lasts for seconds to. Mesial temporal lobe epilepsy mtle is the most common form of epilepsy in adults. Patients with unilateral mesial temporal lobe epilepsy. The timing of surgical intervention for mesial temporal lobe. However proper patient selection is essential in order to achieve high rates of seizure freedom. Epilepsy arising in the medial temporal lobe mtle table 1 the commonest pathology underlying this type of epilepsy is hippocampal sclerosis3,4, and the entity of mesial temporal lobe epilepsy with hippocampal sclerosis mtle with hs is recognised as a distinctive constellation among the focal epilepsies5. Electroencephalography eeg has an important role in the diagnosis and classification of epilepsy. Mesial temporal lobe epilepsy mtle, one of the most common types of tle, is characterized. For many years it has been held that these lesions may be related to complicated febrile convulsions in childhood but the association is based on retrospective data and a causeandeffect relationship has not been proved. The appropriate epileptic syndrome for an rct of early surgical intervention is mesial temporal lobe epilepsy mtle, that form of temporal lobe epilepsy associated with hippocampal sclerosis. Partialonset epilepsies account for about 60% of all adult epilepsy cases, and temporal lobe epilepsy tle is the most common type of partial epilepsy referred for epilepsy surgery and often refractory to antiepileptic drugs aeds. This abnormal electrical activity results in events called seizures. Jun 05, 2015 focal epilepsy is often of temporal lobe origin but the true prevalence of tle is not known.
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