Edit concept Question Editor Create issue ticket

Temporal Lobe Epilepsy

Temporal Lobe Epilepsy Syndrome

Temporal lobe epilepsy is considered to be one of the most common types of epilepsy. Structures that constitute the mesial temporal lobe, primarily hippocampus, are hypothesized to be the origin of excitatory signals. Cognition, memory and functional ability are all impaired as a result of seizure activity. Imaging studies and EEG confirm the diagnosis, whereas treatment is primarily surgical, as this form of epilepsy is resistant to antiepileptics.


Presentation

The clinical presentation of patients suffering from TLE starts with partial seizures and the appearance of an aura. Epigastric sensations, fear, deja vu or olfactory hallucinations are forms of aura that are encountered in these patients and are quite common [9]. In neonates and infants, however, these auras may be difficult to attain and recognize [9]. Seizures are characterized by arrest of motor behavior, blank stare, and automatisms [5]. At some point, symptoms that indicate memory loss, executive function, language deficits and various other impairments [11]. Both autobiographical and working memory loss has been observed [11], whereas significant disability may be seen as a result of slowed mental processing speed, mood and personality disorders, as well as extensive changes in emotional responses [5] [11]. Namely, failure to recognize fear, sadness and disgust have been observed, which may be used as indicative signs of temporal lobe involvement [12]. Interictal (the period between seizures) depression is diagnosed in up to one third of patients [5], suggesting that this condition carries a significant psychological burden.

Tachycardia
  • Ictal tachycardia was documented with EEG-EKG recording in the latter patient, prior to right anterior temporal lobectomy and amygdalohippocampectomy.[ncbi.nlm.nih.gov]
  • Autonomic phenomena (pallor, flushing, tachycardia) are common. Upper limb automatisms may be unilateral and may lateralize the seizure to the ipsilateral hemisphere.[epilepsydiagnosis.org]
  • […] called focal aware) Auras/focal aware may be classified by symptom type, as follows: Sensory – auditory, gustatory, hot-cold sensations, olfactory, somatosensory, vestibular, visual Autonomic – Heart rate Change (asytole, bradycardia, palpitations, tachycardia[emedicine.com]
Delusion
  • […] symptomatology, and include: viscerosensory aura typically from lesions of the amygdala or insular cortex psychic (experienced) aura typically from limbic structures variable including dysmnesic phenomena, cognoscitive phenomena, emotional phenomena, delusions[radiopaedia.org]
  • Arzy and Schurr concluded that the man suffered from “grandiose religious delusion of revelation and missionary zeal in the context of post-ictal psychosis (PIP).”[timesofisrael.com]
  • At the time of discharge, 28 days after her admission, the patient’s delusions, irritability, and mood lability had resolved, but she continued to have hypergraphia and hyperreligiosity. Mrs.[consultant360.com]
  • Relationships between delusions and hallucinations in brain disease. In Keup, W. (Ed.), Origin and mechanisms of hallucinations. New York : Plenum, 1970. Pp. 53 – 57. Google Scholar Crossref[oadoi.org]
Anger
  • Other symptoms may include visual agnosia (inability to visually recognize objects), loss of normal fear and anger responses, memory loss, distractibility, seizures, and dementia.[web.archive.org]
  • They can also be characterised by irritating senses of smell or taste, autonomic symptoms (flushing, sweating, changes of heart rate), emotional changes (rising fear or anxiety, anger, depression, euphoria) or memory symptoms (déjà vu or jamais vu – a[epilepsyqueensland.com.au]
  • […] tachycardia), flushing, gastrorintestinal, pallor, piloerection, respiratory Cognitive/psychic – Déjà vu or jamais vu, dissociation, depersonalization or derealization, forced thinking, aphasia/dysphasia, memory Emotional/affective - agitation, aggression, anger[emedicine.com]
  • Dysphoric or euphoric feelings, fear, anger, and other emotions may also occur.[en.wikipedia.org]
Visual Hallucination
  • In a study published this week in Medical Humanities, the authors feel that temporal lobe epilepsy is a more likely explanation as it can produce complex visual hallucinations, which are usually brief, fragmentary, and stereotyped, just like those Chopin[medicalnewstoday.com]
  • Auditory and visual hallucinations may occur, that is the patient thinks they are hearing voices or see visions. Their need for sleep is greatly reduced. In it's most severe state it is a mental health emergency and may need inpatient care.[netdoctor.co.uk]
  • These visual illusions differ from the visual hallucinations associated with occipital lobe seizure in that there is no formed visual image. Objects may appear smaller or larger than usual.[patient.info]
  • Less frequent are primitive visual hallucinations (figures, blobs of colors), speech arrest, vertigo, and smells. Seizures may be provoked by sleep.[doctorstrizhak.com]
Panic Attacks
  • BACKGROUND: Panic attack semiology as a manifestation of epileptic seizures may lead to difficulties and delay in diagnosis.[ncbi.nlm.nih.gov]
  • Given its often nonspecific neuropsychiatric manifestations and frequently negative electroencephalographic workup, TLE can be easily misdiagnosed as a psychiatric disorder, particularly panic attacks.[ncbi.nlm.nih.gov]
  • Panic attacks. Occipital lobe epilepsy: may spread to the temporal lobe and be clinically indistinguishable from a temporal lobe seizure. Psychogenic seizures: patients with psychogenic seizures may also have epileptic seizures.[patient.info]
  • Other medical conditions with similar symptoms include panic attacks, psychosis spectrum disorders, tardive dyskinesia, and occipital lobe epilepsy. Many anticonvulsant oral medications are available for the management of temporal lobe seizures.[en.wikipedia.org]
Depersonalization
  • He would appear to have been depersonalized, as it took three days for his body to be reunited with his soul.[dx.doi.org]
  • […] sensations, olfactory, somatosensory, vestibular, visual Autonomic – Heart rate Change (asytole, bradycardia, palpitations, tachycardia), flushing, gastrorintestinal, pallor, piloerection, respiratory Cognitive/psychic – Déjà vu or jamais vu, dissociation, depersonalization[emedicine.com]
Seizure
  • 60% of patients reoperated in the ipsilateral temporal lobe for persistent seizures became seizure free.[ncbi.nlm.nih.gov]
  • Instead of focal seizures, prolonged absence seizures were validated by video-EEG monitoring and she became seizure-free after a change to broad-spectrum antiepileptic drugs.[ncbi.nlm.nih.gov]
  • Seizure frequency and lateralization are 2 important clinical factors that characterize epileptic seizures.[ncbi.nlm.nih.gov]
  • Anticonvulsive medication previously controlled secondary generalized seizures over a period of years but focal seizures continued at a lower rate.[ncbi.nlm.nih.gov]
  • Infantile onset of epilepsy, family history of seizures, initial seizure frequency, antecedents, and early seizure remissions were not predictive of seizure outcome.[ncbi.nlm.nih.gov]
Aura
  • The uncommon, isolated psychic symptoms associated with it suggests that ADLTE encompasses a wider range of auras of temporal origin than hitherto reported.[ncbi.nlm.nih.gov]
  • Presentation [ 1 ] Aura occurs in the majority of temporal lobe seizures. Most auras and automatisms last a very short period - seconds or 1 to 2 minutes.[patient.info]
  • Most auras and automatisms last a very short period - seconds or 1 to 2 minutes.[web.archive.org]
  • Abstract Neocortical temporal lobe epilepsy (NTLE) comprises a heterogeneous group of epilepsies with focal seizures characterized by auditory, somatosensory, or psychic auras followed by motionless staring, early contralateral clonic activity often secondarily[ncbi.nlm.nih.gov]
  • Auras are variable in symptomatology, and include: viscerosensory aura typically from lesions of the amygdala or insular cortex psychic (experienced) aura typically from limbic structures variable including dysmnesic phenomena, cognoscitive phenomena,[radiopaedia.org]
Amnesia
  • One of the patients received the diagnosis of transient epileptic amnesia (TEA). All patients underwent a standardized clinical protocol for diagnosis including a comprehensive neuropsychological assessment.[ncbi.nlm.nih.gov]
  • Our findings demonstrate the diagnostic value of a nonvisual fMRI task to lateralize MTLE despite congenital blindness and may therefore contribute to the risk assessment for postsurgical amnesia in rare cases with refractory MTLE and accompanying congenital[ncbi.nlm.nih.gov]
  • The second patient showed a sudden fearful expression, followed by oral automatisms, staring, and amnesia for the event. Both patients had left mesial temporal lobe epilepsy.[ncbi.nlm.nih.gov]
  • Multiple habitual events were recorded for each patient, characterized by staring, oral automatisms and amnesia. In addition, partial preservation of responsiveness and speech were seen during seizures in all three patients.[ncbi.nlm.nih.gov]
  • Author information 1 School of Psychology, University of East London, Water Lane, London E15 4LZ, UK. t.mcgibbon@uel.ac.uk Abstract Accelerated long-term forgetting (ALF) refers to a slowly developing anterograde amnesia in which material is retained[ncbi.nlm.nih.gov]
Deja Vu
  • vu (a sense of familiarity) or recalled memories or emotions A sudden, intense emotion not related to anything happening at the time During the seizure, a person may experience motor disturbances, sensory symptoms, or autonomic symptoms.[webmd.com]
  • They may be followed or preceded by auras (strange sensations in the stomach, deja-vu or visual and auditory hallucinations), together with various neurological complaints.[symptoma.com]
  • Some symptoms of a temporal lobe seizure may be related to these functions, including having odd feelings — such as euphoria, deja vu or fear. Temporal lobe seizures are sometimes called focal seizures with impaired awareness.[mayoclinic.org]
  • Some symptoms of a temporal lobe seizure may be related to these functions, including having odd feelings — such as euphoria, deja vu or fear. During a temporal lobe seizure, you may remain aware of what's happening.[web.archive.org]
Jamais Vu
  • Psychic phenomena: Feeling of déjà vu (familiarity) or jamais vu (unfamiliarity). Depersonalisation (ie feeling of detachment from oneself) or derealisation (surroundings appear unreal). Fear or anxiety.[patient.info]
  • Symptoms Hallucinations: hearing of sounds, vertigo, visual hallucinations and illusions, déjà vu, jamais vu Motor seizures: hand automatisms, grimacing, clonic movements in the face, arm posturing, vocalizations, whole body rotation, speech disturbance[doctorstrizhak.com]
  • They can also be characterised by irritating senses of smell or taste, autonomic symptoms (flushing, sweating, changes of heart rate), emotional changes (rising fear or anxiety, anger, depression, euphoria) or memory symptoms (déjà vu or jamais vu – a[epilepsyqueensland.com.au]
  • […] gustatory, hot-cold sensations, olfactory, somatosensory, vestibular, visual Autonomic – Heart rate Change (asytole, bradycardia, palpitations, tachycardia), flushing, gastrorintestinal, pallor, piloerection, respiratory Cognitive/psychic – Déjà vu or jamais[emedicine.com]

Workup

The initial diagnosis of epilepsy can be made based on clinical criteria, whereas a confirmation of TLE can be made through the following methods [2] [13]:

  • Imaging studies - MRI is considered as a very good first-line imaging procedure that identifies hippocampal atrophy with great specificity [2]. Additional studies include positron emission tomography (PET) and single photon emission computed tomography (SPECT), methods that are valuable in detecting extra-temporal sources of excitatory signals, especially in patients in whom MRI findings are inconclusive, or in those who already had surgery [3]. The role of SPECT is not as significant unless it is performed during an attack [3]. MRI spectroscopy has also been listed as one of the possible methods, due to its even higher specificity.
  • EEG - Evaluation of brain signaling, in combination with imaging studies, is considered as the optimal diagnostic approach in patients suffering from epilepsy of any type. Both invasive and noninvasive EEG studies may be performed, but video EEG is recommended in all patients [5]. Invasive methods include intracranial depth electrodes and subdural grids (also known as iEEG), whereas epidural, scalp and foramen ovale electrodes are non-invasive forms of EEG [3]. In addition to evaluating brain signals at the location where imaging studies have determined the presumable focus, a thorough evaluation of the entire brain should be conducted, as bilateral changes may be observed, which may substantially complicate treatment.
Epileptiform Activity
  • However, little is currently known about the modulation of these networks by epileptiform activity, such as interictal spikes and seizures.[ncbi.nlm.nih.gov]
  • Neurophysiologic findings in NTLE are typically a predominance of lateral temporal interictal epileptiform activity (IEA) and an ictal onset pattern consisting of irregular, hemispheric delta slowing.[ncbi.nlm.nih.gov]
  • Our study focused on lateralization and extent of epileptiform activity regarding postoperative seizure persistence and the effect of reoperation. METHODS: This study comprises 426 consecutive patients operated for intractable mTLE.[ncbi.nlm.nih.gov]
  • Changes in Cl- transporter expression thus contribute to human epileptiform activity, and molecules acting on these transporters may be useful antiepileptic drugs.[ncbi.nlm.nih.gov]
  • However, these methods lack the spatiotemporal resolution to allow precise localization of epileptiform activity.[ncbi.nlm.nih.gov]
Temporal Epileptiform Discharges
  • 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.[journals.lww.com]

Treatment

Temporal lobe epilepsy is not responsive to pharmacotherapy, which shifts the focus of management to surgery. The goal is to completely excise and remove the zone in which the epileptic signal originates [3], and procedures such as anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy (SAH) are indicated [10]. With successfully resected regions, many patients become seizure-free, but a small percentage is left with some form of disability, as neurosurgery carries a minor, but significant risk of brain injury. For resection to be complete and successful, a thorough preoperative assessment guided by EEG and imaging studies is detrimental [13]. In the case of bilateral hippocampal involvement, the risks and benefits of surgery should be discussed.

Prognosis

The prognosis of patients with successful surgical therapy is very good [10], and marked reduction or even disappearance of seizure activity can be achieved. The diagnosis of TLE, however, is often delayed for a considerable amount of time, which correlates with a poorer prognosis. TLE is practically nonresponsive to pharmacological therapy and precious time is often used on attempting to find the appropriate antiepileptic regimen. In fact, studies have identified that it takes up to 9 or even 10 years for surgical therapy to be instated [6], while some reports suggest that more than 20 years elapse prior to confirming TLE [6]. The importance of choosing the optimal surgical approach also has important prognostic factors in long-term management of patients, due to the fact that neurosurgical procedures are quite sensitive and may result in further damage. For these reasons, a careful and detailed pre-operative assessment through imaging modalities and EEG is necessary.

Etiology

Although the exact cause of epilepsy in general remains incompletely understood, the principal source of aberrant signaling in the case of TLE is the hippocampus [7], which undergoes sclerosis, atrophy and neuronal loss, with similar effects seen in the amygdala and parahippocampal gyri. As a result, diffuse pathological changes are observed in the morphology and structure [8]. TLE has shown to be strongly associated with several conditions [3] [9]:

  • Cortical dysplasia, a congenital condition that is also a recognized cause of epilepsy, has shown to be present in up to 20% of patients suffering from TLE.
  • Various brain tumors, including astrocytomas, gangliomas, oligodendrogliomas and neuroepithelial tumors have been diagnosed in up to 60% of patients undergoing brain surgery.
  • Vascular changes, such as cavernous hemangiomas and arteriovenous malformation are also brought into connection with TLE, although the exact mechanism remains unknown.
  • Several forms of brain trauma are considered as potential triggers of epilepsy. Namely, trauma that results in loss of consciousness for more than 30 minutes, causes penetrating injuries or linear skull fractures, but also scarring that is visible on MRI are able to provoke excitatory signaling from the temporal lobe [3].

In addition to these conditions, a hypothesis that some previous condition in early childhood triggered the pathological sequence has been suggested as well. Febrile seizures, birth injuries and status epilepticus have shown to be present in a substantial amount of patients who developed TLE, suggesting that other factors may also play a role in etiology [8].

Epidemiology

Global estimations suggest that the prevalence of all forms of epilepsy combined reach up to 1% of the population [6], with significant variations across the world. In developed countries, prevalence rates are approximately 1 per 1000 individuals, whereas developing countries have shown rates of up to 50 per 1000 individuals [1]. In general, epilepsy is most frequently encountered in young children and the elderly [1], but early childhood and adolescence is considered to be the principal age of onset [9]. TLE is the most common form of partial seizures, which comprise almost 60% of all cases of epilepsy, with estimations that of 1,200,000 Americans who suffer from epilepsy, 400,000 are affected by TLE [5]. Exact prevalence and incidence rates of TLE, however, are unknown at this moment [1]. In addition to diseases that are mentioned as potential causes of TLE, such as cortical dysplasia, tumors and vascular malformations [3], febrile seizures during infancy and birth injuries have also been identified as potential risk factors for later development of TLE [8].

Sex distribution
Age distribution

Pathophysiology

The most common and most important pathological finding in patients with TLE is atrophy and sclerosis of the hippocampus [2], one of the constitutive parts of the mesial temporal lobe, together with the amygdala, uncus, parahippocampal and dentate gyri. Presumably, hippocampal sclerosis and atrophy are a result of neuronal loss that occurs in the temporal lobe and cause disruption of signaling, causing enhanced excitation and hypersynchronnous discharge of neurons in that area that eventually lead to epilepsy [7]. In addition, various pathophysiological processes have been described - loss of interneurons, impaired neurogenesis and mossy fiber sprouting (branching of additional neurons) [8]. The exact mechanism of epilepsy, however, is still not completely understood.

Prevention

Current prevention strategies do not exist, as the exact pathophysiological mechanism of TLE remains unknown. Given the fact that recent evidence about the involvement of inflammatory changes in seizures have been published, anti-inflammatory drugs, but also growth hormone secretagogues have been proposed as potentially preventing agents [8]. Further studies, however, need to be conducted in order to determine the exact role of inflammation and other pathophysiological events in the development of TLE.

Summary

Partial-onset seizures comprise almost 60% of all epilepsies and temporal lobe epilepsy (TLE) is the most common form of partial seizures worldwide [1]. Of approximately 1,200,000 people suffering from partial seizures in the United States, TLE is the cause in more than 400,000, indicating its importance in clinical practice [2]. Theories regarding its etiology are numerous, but various studies have established that in up to a third of patients, some preexisting condition is thought to be the trigger for abnormal excitatory signaling in the mesial temporal lobe [3] [4]. Tumors, cortical dysplasia, vascular malformations, head trauma and encephalomalacia have all been discovered in a significant amount of patients who developed TLS [3]. Hence, these conditions present as significant risk factors for its appearance, but the exact pathophysiological mechanisms remain to be fully disclosed. The principal pathological findings are hippocampal sclerosis, neuronal damage and atrophy, which leaves a detrimental effect on various processes, including memory, cognition and motor function [2]. Additional structures that constitute the mesial temporal lobe - the amygdala, uncus, dentate gyrus and parahippocampal gyrus, have all shown similar pathological degradation and are also considered as potential sources of epileptic signaling [2]. The clinical presentation somewhat varies across different age groups (partly due to a varying etiology between the pediatric, adolescent and adult population), but universally includes partial seizures and the presence of auras (olfactory, epigastric or gustatory sensations). Memory and attention impairments, as well as reduced speed of mental function, mood changes and emotional abnormalities appear at some point and can be severely debilitating [5]. The initial diagnosis of epilepsy is made based on clinical findings, but imaging and electroencephalographic (EEG) studies are necessary to identify the exact origin of aberrant signals. Magnetic resonance imaging (MRI) is an effective diagnostic method, whereas single photon emission computed tomography (SPECT) and positron emission tomography (PET) may be considered when MRI findings are inconclusive [3]. Both invasive and noninvasive EEG studies, including video EEG are equally necessary as imaging studies and the combination of findings is imperative in determining the exact site of epileptic signals [4]. Because TLE is resistant to antiepileptic drugs (AEDs) in virtually all cases, a surgical approach as early as possible is advocated to assure a good quality of life and reduce functional impairment [6]. With either complete resection or removal of the structures in the mesial temporal lobe, much better outcomes have been encountered [6], which is why a prompt definite diagnosis by using all available tools and surgery can significantly reduce the burden of this condition in daily life.

Patient Information

Epilepsy is considered to be a major issue in clinical practice, as estimates suggest that 1% of the world population suffers from any of the recognized forms. Temporal lobe epilepsy (TLE) one of the most common causes, with more than 400,000 people who live in the United States are presumed to suffer from TLE. This form of epilepsy is established to be one of the most severe, since it does not respond to antiepileptic drugs and requires other therapeutic modalities. The exact cause of TLE remains to be discovered, but in up to 30% of patients, an accompanying structural abnormality such as brain tumors or cortical dysplasia has been identified. Studies have observed loss of neuronal function and atrophy of the hippocampus, one of the most important parts of the brain when it comes to memory, whereas the amygdala (principally responsible for emotions such as fear) may be affected as well. TLE may appear at any age, but it's onset is primarily seen in young children. The first and most important symptom is seizures that involve only one brain hemisphere (partial seizures) and the arrest of motor activity with a blank stare during the onset of seizures. They may be followed or preceded by auras (strange sensations in the stomach, deja-vu or visual and auditory hallucinations), together with various neurological complaints. Patients with TLE may suffer from memory loss, inability to perform daily functions, language difficulties and severe cognitive disability. The diagnosis is made through the use of imaging studies such as magnetic resonance imaging (MRI) and positron emission tomography (PET scan), together with eletroencephalography (EEG). These methods are used to visualize and map the exact location where abnormal signaling occurs, which is necessary for treatment. In the case of TLE, surgery is the recommended therapeutic method. In general, removal of parts of the brain that are determined to be the source of epileptic signals is necessary and early surgery has shown drastic success in reducing or completely abolishing the appearance of seizures. Despite the advantages of surgery, the diagnosis is delayed in many patients due to attempts to handle seizures with antiepileptic drugs, which is why a detailed diagnostic workup is essential.

References

Article

  1. Téllez-Zenteno JF, Hernández-Ronquillo L. A Review of the Epidemiology of Temporal Lobe Epilepsy. Epilepsy Res Treat. 2012;2012:630853.
  2. Thom M, Mathern GW, Cross JH, Bertram EH. Mesial Temporal Lobe Epilepsy: How do we improve surgical outcome? Ann Neurol. 2010;68(4):424-434.
  3. Diehl B, Lüders HO. Temporal lobe epilepsy: when are invasive recordings needed? Epilepsia. 2000;41(3):S61-74.
  4. Ray A, Kotagal P. Temporal lobe epilepsy in children: overview of clinical semiology. Epileptic Disord. 2005;7(4):299-307.
  5. Devinsky O. Diagnosis and treatment of temporal lobe epilepsy. Rev Neurol Dis. 2004;1(1):2-9.
  6. Engel J Jr, McDermott MP, Wiebe S, Langfitt JT, Stern JM, Dewar S, et al. Early surgical therapy for drug-resistant temporal lobe epilepsy: a randomized trial. JAMA. 2012;307(9):922-930.
  7. Engel J Jr. Mesial temporal lobe epilepsy: what have we learned? Neuroscientist. 2001;7(4):340-352.
  8. Curia G, Lucchi C, Vinet J, et al. Pathophysiogenesis of Mesial Temporal Lobe Epilepsy: Is Prevention of Damage Antiepileptogenic? Curr Med Chem. 2014;21:663-688.
  9. Berg AT. The natural history of mesial temporal lobe epilepsy. Curr Opin Neurol. 2008;21(2):173-178.
  10. Josephson CB, Dykeman J, Fiest KM, Liu X, Sadler RM, Jette N, et al. Systematic review and meta-analysis of standard vs selective temporal lobe epilepsy surgery. Neurology. 2013;80(18):1669-1676.
  11. Zhao F, Kang H, You Li, Rastogi P, Venkatesh D, Chandra M. Neuropsychological deficits in temporal lobe epilepsy: A comprehensive review. Ann Indian Acad Neurol. 2014;17(4):374-382.
  12. Monti G, Meletti S. Emotion recognition in temporal lobe epilepsy: A systematic review. Neurosci Biobehav Rev. 2015;55:280-293.
  13. Aghakhani Y, Liu X, Jette N, Wiebe S. Epilepsy surgery in patients with bilateral temporal lobe seizures: a systematic review. Epilepsia. 2014;55(12):1892-1901.

Ask Question

5000 Characters left Format the text using: # Heading, **bold**, _italic_. HTML code is not allowed.
By publishing this question you agree to the TOS and Privacy policy.
• Use a precise title for your question.
• Ask a specific question and provide age, sex, symptoms, type and duration of treatment.
• Respect your own and other people's privacy, never post full names or contact information.
• Inappropriate questions will be deleted.
• In urgent cases contact a physician, visit a hospital or call an emergency service!
Last updated: 2018-06-22 01:03