Apparent False Lateralization of Seizure Onset by Scalp EEG in Temporal Lobe Epilepsy Associated with Cerebral Cavernous Malformation: A Case Report and Overview

False lateralization of ictal onset by scalp electroencephalogram (EEG) is an infrequent entity that has been reported in patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis (HS). In these cases, a tendency for rapid seizures that spread through the frontal-limbic system and hippocampal commissural pathways to the contralateral hemisphere has been proposed. Cerebral cavernous malformations (CCMs), which constitute a collection of abnormally configured small blood vessels with irregular structures, is a well-defined epilepsy-associated pathology. Their primary association with seizures might be explained either as a result of physiological changes affecting the cerebral cortex immediately surrounding the CCM (an epileptogenic mechanism that is relevant for both, temporal and extratemporal lesions) or as a result of promoting epileptogenicity in remote but anatomo-functionally connected brain regions, a mechanism that is particularly relevant for temporal lobe lesions. To date, there have been only two publications on falsely lateralizing ictal onsets by EEG in temporal cavernoma, but not in other regions. Here, we report a rare case of apparent false lateralization of ictal onset by scalp EEG in a patient with a left medial frontal gyrus cavernoma (supplementary motor area), and discuss some relevant pathophysiological mechanisms of false lateralization.

Decompressive craniectomy in herpes simplex encephalitis: a case report

Herpes Simplex Encephalitis is the commonest form of sporadic encephalitis. Availability of effective antiviral therapy viz Acyclovir has significantly reduced the mortality of Herpes Simplex Encephalitis. Elevated intracranial pressure resulting in herniation syndromes continues to be an important cause of mortality. Antiviral therapy and medical measures for managing raised intracranial pressure including osmotic diuretics, careful usage of steroids and controlled hyperventilation continue to be the cornerstones in management of these patients. Authors present a 38-year-old male patient with Cerebrospinal fluid Meningo-encephalitic panel positivity for herpes simplex virus 1 and bilateral temporal lobe lesions with secondary decline due to impending herniation syndrome despite osmotic diuretics and steroids with patient survival and complete recovery following decompressive hemicraniectomy.

Differential diagnosis of temporal lobe lesions with hyperintense signal on T2-weighted and FLAIR sequences: pictorial essay

Various neuropathologies produce hyperintense signals on T2-weighted or fluid-attenuated inversion recovery sequences of the temporal lobes. Recognition of the distribution pattern and associated findings may narrow the spectrum of differential diagnoses or suggest a specific disease. This pictorial essay aims to illustrate the relatively common diseases that affect the temporal lobe, such as herpes simplex encephalitis, neurosyphilis, limbic encephalitis, postictal edema, neoplasia, and multiple sclerosis, as well as those that are less common, such as myotonic dystrophy type 1, CADASIL, and CARASIL, together with the particularities of each entity.

3D ultrasound–guided resection of low-grade gliomas: principles and clinical examples

3D ultrasound (US) is a convenient tool for guiding the resection of low-grade gliomas, seemingly without deterioration in patients’ quality of life. This article offers an update of the intraoperative workflow and the general principles behind the 3D US acquisition of high-quality images.The authors also provide case examples illustrating the technique in two small mesial temporal lobe lesions and in one insular glioma. Due to the ease of acquiring new images for navigation, the operations can be guided by updated image volumes throughout the entire course of surgery. The high accuracy offered by 3D US systems, based on nearly real-time images, allows for precise and safe resections. This is especially useful when an operation is performed through very narrow transcortical corridors.

MPC-14 BRAF V600E MUTANT OLIGODENDROGLIOMA-LIKE TUMORS WITH CHROMOSOMAL INSTABILITY IN ADOLESCENTS AND YOUNG ADULTS

We performed genome-wide methylation analysis on 136 pediatric low grade gliomas, identifying a unique cluster consisting of oligodendroglioma-like BRAF V600E mutant tumors with Recurrent gain of Chromosome 7 and loss of Chromosome 10 (OLIVER). Hierarchical clustering and t-stochastic neighbor embedding analyses cluster them with previously described pediatric-type low grade gliomas, separate from adult gliomas. OLIVERS exhibit distinct clinical behavior as temporal lobe lesions in adolescents and young adults, prolonged history of seizures and all are alive with no recurrence (follow-up 3.2 to 13.2 years). Morphogically, all showed oligodendroglioma-like features, including round nuclei with perinuclear halos, a chicken-wire pattern of branching capillaries and microcalcification. None showed astrocytic features or characteristics suggestive of high-grade tumors including necrosis or mitotic figures. All tumors harbored multiple chromosomal copy number abnormalities (more than 10 chromosomes per OLIVER), but none showed 1p/19q co-deletion or IDH1 mutation. Interestingly, one tumor showed a TERT promoter mutation. Although the series is small, OLIVER may represent a new category of IDH wild-type low grade gliomas which may be confused with molecular GBM. Further, they highlight the heterogeneity of IDH wild-type gliomas and the relatively indolent behavior of pediatric-type gliomas.

Spared Perception of the Structure of Scenes after Hippocampal Damage

To explore whether the hippocampus might be important for certain spatial operations in addition to its well-known role in memory, we administered two tasks in which participants judged whether objects embedded in scenes or whether scenes themselves could exist in 3-D space. Patients with damage limited to the hippocampus performed as well as controls in both tasks. A patient with large medial-temporal lobe lesions had a bias to judge objects in scenes and scenes themselves as possible, performing well with possible stimuli but poorly with impossible stimuli in both tasks. All patients were markedly impaired at remembering the tasks. The hippocampus appears not to be essential for judging the structural coherence of objects in scenes or the coherence of scenes. The findings conform to what is now a sizeable literature emphasizing the importance of the hippocampus for memory. We discuss our results in light of findings that other patients have sometimes been reported to be disadvantaged by spatial tasks like the ones studied here, despite less hippocampal damage and milder memory impairment.

Carcinoma cervix with cerebellar metastases presenting with pulmonary aspiration: a rare presentation and a rare metastatic site in a common cancer

A 52-year-old woman with cervical cancer stage IIB presented with altered sensorium and breathlessness to the emergency room 5 months after completing primary chemoradiotherapy, which was diagnosed as aspiration pneumonia. She was found to have cerebellar metastases with additional frontal, occipital, and temporal lobe lesions. She had no evidence of extracranial disease. She received supportive care and palliative whole brain radiotherapy and was asymptomatic at 6 months following radiotherapy. Median reported survival is 8–13 months.

Limbic encephalitis with relapsing polychondritis: persistent white matter lesions and brain atrophy

Relapsing polychondritis (RP) is a rare autoimmune disorder affecting cartilage. Limbic encephalitis is a rare central nervous system manifestation of RP. This current case report describes a 66-year-old Chinese male patient who complained of developing myoclonus in the left leg, ataxia and speech difficulties 3 weeks prior to hospital admission. The patient presented with cognitive impairment, sleep disorder and extrapyramidal symptoms. The patient was diagnosed with RP that affected auricular cartilage, which also manifested as limbic encephalitis. Magnetic resonance imaging showed bilateral temporal lobe lesions involving the hippocampi and basal ganglia. Signal abnormalities in the white matter persisted during the 15-month follow-up period after treatment with corticosteroids and intravenous immunoglobulin. Over the same period, the bilateral hippocampi showed significant atrophy.

Eye movements support the link between conscious memory and medial temporal lobe function

When individuals select the recently studied (and familiar) item in a multiple-choice memory test, they direct a greater proportion of viewing time toward the to-be-selected item when their choice is correct than when their choice is incorrect. Thus, for both correct and incorrect choices, individuals indicate that the chosen item is old, but viewing time nevertheless distinguishes between old and new items. What kind of memory supports this preferential viewing effect? We recorded eye movements while participants made three-alternative, forced-choice recognition memory judgments for scenes. In experiment 1 (n= 30), the magnitude of the preferential viewing effect was strongly correlated with measures of conscious, declarative memory: recognition accuracy as well as the difference in confidence ratings and in response times for correct and incorrect choices. In four analyses that minimized the contribution of declarative memory in order to detect a possible contribution from other processes, the preferential viewing effect was absent. In experiment 2, five memory-impaired patients with medial temporal lobe lesions exhibited a diminished preferential viewing effect. These patients also exhibited poor recognition accuracy and reduced differences in confidence ratings and response times for correct and incorrect choices. We propose that the preferential viewing effect is a phenomenon of conscious, declarative memory and is dependent on the medial temporal lobe. The findings support the link between medial temporal lobe function and declarative memory. When the effects of experience depend on the medial temporal lobe, the effects reflect conscious memory.