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Human Brain Mapping Oct 2022Focal seizures originating from the temporal lobe are commonly associated with peri-ictal hypoxemia (PIH). During the course of temporal lobe seizures, epileptic...
Focal seizures originating from the temporal lobe are commonly associated with peri-ictal hypoxemia (PIH). During the course of temporal lobe seizures, epileptic discharges often not only spread within various parts of the temporal lobe but also possibly insula and frontal lobe. The link between spatial propagation of the seizure discharges and PIH is still unclear. The present study investigates the involvement of several brain structures including medial temporal structures, temporal pole, anterior insula, and frontal cortex in the occurrence of PIH. Using quantitative indices obtained during SEEG (stereoencephalography) recordings in 38 patients, we evaluated the epileptogenicity, the spatial propagation, and functional connectivity between those structures during seizures leading to PIH. Multivariate statistical analyses of SEEG quantitative indices showed that temporal lobe seizures leading to PIH are characterized by a strong involvement of amygdala and anterior insula during seizure propagation and a more widespread involvement of medial temporal lobe structures, lateral temporal lobe, temporal pole, and anterior cingulate at the end of the seizures. On the contrary, seizure-onset zone was not associated with PIH occurrence. During seizure propagation, anterior insula, temporal pole, and temporal lateral neocortex activities were correlated with intensity of PIH. Lastly, PIH occurrence was also related to a widespread increase of synchrony between those structures. Those results suggest that PIH occurrence during temporal lobe seizures may be related to the activation of a widespread network of cortical structures, among which amygdala and anterior insula are key nodes.
Topics: Electroencephalography; Epilepsy, Temporal Lobe; Humans; Hypoxia; Seizures; Temporal Lobe
PubMed: 35703584
DOI: 10.1002/hbm.25975 -
Epileptic Disorders : International... Dec 2004Frontal lobe epilepsy accounts for only 10-20% of the patients in surgical series, but the incidence in non-surgical patient cohorts seems to be much higher. The typical... (Review)
Review
Frontal lobe epilepsy accounts for only 10-20% of the patients in surgical series, but the incidence in non-surgical patient cohorts seems to be much higher. The typical clinical presentation of the seizures includes contralateral clonic movements, uni- or bilateral tonic motor activity as well as complex automatism. The yield of surface EEG may be limited due to the difficulty in detection of mesial or basal foci, and the patient may be misdiagnosed as having non-epileptic events. In addition, in patients with mesial frontal foci the epileptiform discharges may be mislateralized ("paradoxical lateralization"). Therefore, epilepsy surgery has been commonly considered as less promising in patients with frontal lobe epilepsy. However, the advent of sophisticated neuroimaging techniques, particularly MRI with epilepsy-specific sequences, has made it possible to delineate the epileptogenic lesion and detect a specific etiology, in an increasing number of patients. Thus, the success rate of epilepsy surgery in frontal lobe epilepsy is currently comparable to temporal lobe epilepsy, if the candidates are carefully selected. Patients with frontal lobe epilepsy who do not respond to anticonvulsive medication, and who are not eligible for epilepsy surgery may benefit from alternative approaches such as electrical brain stimulation.
Topics: Anticonvulsants; Brain Mapping; Diagnosis, Differential; Electroencephalography; Epilepsy, Frontal Lobe; Evoked Potentials; Frontal Lobe; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Prognosis; Psychosurgery; Treatment Outcome
PubMed: 15634619
DOI: No ID Found -
International Journal of Surgery... Dec 2016Mesial temporal lobe epilepsy is one of the commonest indications for epilepsy surgery. Presurgical evaluation for drug resistant epilepsy and identification of... (Review)
Review
Mesial temporal lobe epilepsy is one of the commonest indications for epilepsy surgery. Presurgical evaluation for drug resistant epilepsy and identification of appropriate candidates for surgery is essential for optimal seizure freedom. The anatomy of mesial temporal lobe is complex and needs to be understood in the context of the advanced imaging, ictal and interictal Video_EEG monitoring, neuropsychology and psychiatric considerations. The completeness of disconnection of epileptogenic neural networks is paramount and is correlated with the extent of resection of the mesial temporal structures. In the Indian subcontinent, a standard but extended anterior temporal lobectomy is a viable option in view of the diverse socioeconomic, cultural and pathological considerations. The maximum utilization of epilepsy surgery services in this region is also a challenge. There is a need for regional comprehensive epilepsy care teams in a tertiary care academic hospital to form centers of excellence catering to a large population.
Topics: Adult; Drug Resistant Epilepsy; Electroencephalography; Epilepsy, Temporal Lobe; Female; Hippocampus; Humans; Magnetic Resonance Imaging; Male; Temporal Lobe
PubMed: 27773861
DOI: 10.1016/j.ijsu.2016.10.027 -
Frontiers in Neurology 2022Some surgical failures after temporal lobe epilepsy surgery may be due to the presence of an extratemporal epileptogenic zone. Of particular interest is the medial... (Review)
Review
Some surgical failures after temporal lobe epilepsy surgery may be due to the presence of an extratemporal epileptogenic zone. Of particular interest is the medial parietal lobe due to its robust connectivity with mesial temporal structures. Seizures in that area may be clinically silent before propagating to the symptomatogenic temporal lobe. In this paper, we present an overview of the anatomical connectivity, semiology, radiology, electroencephalography, neuropsychology, and outcomes in medial parietal lobe epilepsy. We also present two illustrative cases of seizures originating from the precuneus and the posterior cingulate cortex. We conclude that the medial parietal lobe should be strongly considered for sampling by intracranial electrodes in individuals with nonlesional temporal lobe epilepsy, especially if scrutinizing the presurgical data produces discordant findings.
PubMed: 35370889
DOI: 10.3389/fneur.2022.804128 -
Veterinary Journal (London, England :... Jan 2023In recent years there has been increased attention to the proposed entity of feline temporal lobe epilepsy (TLE). Epileptic discharges in certain parts of the temporal...
In recent years there has been increased attention to the proposed entity of feline temporal lobe epilepsy (TLE). Epileptic discharges in certain parts of the temporal lobe elicit very similar semiology, which justifies grouping these epilepsies under one name. Furthermore, feline TLE patients tend to have histopathological changes within the temporal lobe, usually in the hippocampus. The initial aetiology is likely to be different but may result in hippocampal necrosis and later hippocampal sclerosis. The aim of this article was not only to summarise the clinical features and the possible aetiology, but also being work to place TLE within the veterinary epilepsy classification. Epilepsies in cats, similar to dogs, are classified based on the aetiology into idiopathic epilepsy, structural epilepsy and unknown cause. TLE seems to be outside of this classification, as it is not an aetiologic category, but a syndrome, associated with a topographic affiliation to a certain anatomical brain structure. Magnetic resonance imaging, histopathologic aspects and current medical therapeutic considerations will be summarised, and emerging surgical options are discussed.
Topics: Animals; Cats; Cat Diseases; Epilepsy; Epilepsy, Temporal Lobe; Hippocampus; Magnetic Resonance Imaging; Temporal Lobe
PubMed: 36549606
DOI: 10.1016/j.tvjl.2022.105941 -
Biomedical Engineering Letters Nov 2018When focusing using an ultrasonic transducer array, a main lobe is formed in the focal region of an ultrasound field, but side lobes also arise around the focal region...
When focusing using an ultrasonic transducer array, a main lobe is formed in the focal region of an ultrasound field, but side lobes also arise around the focal region due to the leakage. Since the side lobes cannot be completely eliminated in the focusing process, they are responsible for subsequent ultrasound image quality degradation. To improve ultrasound image quality, a signal processing strategy to reduce side lobes is definitely in demand. To this end, quantitative determination of main and side lobes is necessary. We propose a theoretically and actually error-free method of exactly discriminating and separately computing the main lobe and side lobe parts in ultrasound image by computer simulation. We refer to images constructed using the main and side lobe signals as the main and side lobe images, respectively. Since the main and side lobe images exactly represent their main and side lobe components, respectively, they can be used to evaluate ultrasound image quality. Defining the average brightness of the main and side lobe images, the conventional to side lobe image ratio, and the main to side lobe image ratio as image quality metrics, we can evaluate image characteristics in speckle images. The proposed method is also applied in assessing the performance of side lobe suppression filtering. We show that the proposed method may greatly aid in the evaluation of medical ultrasonic images using computer simulations, albeit lacking the use of actual experimental data.
PubMed: 30603220
DOI: 10.1007/s13534-018-0079-y -
Journal of Neurology, Neurosurgery, and... Nov 1962
Topics: Agnosia; Humans; Intracranial Arteriosclerosis; Occipital Lobe; Parietal Lobe; Prosopagnosia
PubMed: 13943018
DOI: 10.1136/jnnp.25.4.336 -
Respiration; International Review of... 2012Middle lobe syndrome (MLS) is a rare but important clinical entity that has been poorly defined in the literature. It is characterized by recurrent or chronic collapse... (Review)
Review
Middle lobe syndrome (MLS) is a rare but important clinical entity that has been poorly defined in the literature. It is characterized by recurrent or chronic collapse of the middle lobe of the right lung but can also involve the lingula of the left lung. Pathophysiologically, there are two forms of MLS, namely obstructive and nonobstructive. Obstructive MLS is usually caused by endobronchial lesions or extrinsic compression of the middle lobe bronchus such as from hilar lymphadenopathy or tumors of neoplastic origin, resulting in postobstructive atelectasis and pneumonitis. In the nonobstructive type, no obstruction of the middle lobe bronchus is evident during bronchoscopy or with computerized tomography of the chest. The etiology of the nonobstructive form is not completely understood. Inefficient collateral ventilation, infection and inflammation in the middle lobe or lingula are thought to play a role, and bronchiectasis is the most common histological finding. Patients with proven endobronchial lesions or malignancy are usually offered surgical resection directly. This contrasts with nonobstructive MLS, where most patients respond to medical treatment consisting of bronchodilators, mucolytics and broad-spectrum antibiotics. However, some patients do not respond to conservative treatment and may suffer irreversible damage of the middle lobe or lingula, in addition to having recurrent symptoms of infection or inflammation. These selected patients can be offered surgical resection of the middle lobe or lingula, which is associated with a low mortality rate and favorable outcome.
Topics: Anti-Bacterial Agents; Bronchodilator Agents; Bronchoscopy; Expectorants; Female; Humans; Lung; Male; Middle Lobe Syndrome
PubMed: 22377566
DOI: 10.1159/000336238 -
Epilepsia Mar 2013Cognitive impairment is frequent in children with frontal lobe epilepsy (FLE), but its etiology is unknown. With functional magnetic resonance imaging (fMRI), we have...
PURPOSE
Cognitive impairment is frequent in children with frontal lobe epilepsy (FLE), but its etiology is unknown. With functional magnetic resonance imaging (fMRI), we have explored the relationship between brain activation, functional connectivity, and cognitive functioning in a cohort of pediatric patients with FLE and healthy controls.
METHODS
Thirty-two children aged 8-13 years with FLE of unknown cause and 41 healthy age-matched controls underwent neuropsychological assessment and structural and functional brain MRI. We investigated to which extent brain regions activated in response to a working memory task and assessed functional connectivity between distant brain regions. Data of patients were compared to controls, and patients were grouped as cognitively impaired or unimpaired.
KEY FINDINGS
Children with FLE showed a global decrease in functional brain connectivity compared to healthy controls, whereas brain activation patterns in children with FLE remained relatively intact. Children with FLE complicated by cognitive impairment typically showed a decrease in frontal lobe connectivity. This decreased frontal lobe connectivity comprised both connections within the frontal lobe as well as connections from the frontal lobe to the parietal lobe, temporal lobe, cerebellum, and basal ganglia.
SIGNIFICANCE
Decreased functional frontal lobe connectivity is associated with cognitive impairment in pediatric FLE. The importance of impairment of functional integrity within the frontal lobe network, as well as its connections to distant areas, provides new insights in the etiology of the broad-range cognitive impairments in children with FLE.
Topics: Adolescent; Child; Cognition Disorders; Cohort Studies; Epilepsy, Frontal Lobe; Female; Frontal Lobe; Humans; Male; Nerve Net; Neural Pathways; Photic Stimulation; Psychomotor Performance; Registries
PubMed: 23253092
DOI: 10.1111/epi.12044 -
Seizure Aug 1999This essay was awarded the Patient's Millennium Gowers prize of 1999 by the council of the British Branch of the International League Against Epilepsy.
This essay was awarded the Patient's Millennium Gowers prize of 1999 by the council of the British Branch of the International League Against Epilepsy.
Topics: Brain; Epilepsy, Frontal Lobe; Humans; Pituitary Neoplasms
PubMed: 10486293
DOI: 10.1053/seiz.1999.0316