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At least 19 recordsLinked to original sources
PubMed2006

Reactivation of medial temporal lobe and occipital lobe during the retrieval of color information: A positron emission tomography study.

It is widely accepted that memory traces of an event include various types of information about the content of the event and about the circumstances in which the individual experienced it. However, how these various types of information are stored and later retrieved is poorly understood. One hypothesis postulates that the retrieval of specific event information reactivates regions that were active during the encoding of this information, with the aid of binding functions of the medial temporal lobe (MTL) structures. We used positron emission tomography to identify the brain regions related to the encoding and retrieval of color information. Specifically, we assessed whether overlapping activity was found in both the MTL structures and color-related cortical regions during the encoding and retrieval of color information attached with meaningless shapes. During the study, subjects were asked to encode colored (red or green) and achromatic random shapes. At subsequent testing, subjects were presented with only achromatic shapes, which had been presented with or without colors during encoding, and were engaged in retrieval tasks of shapes and colors. Overlapping activity was found in the MTL and occipital lobe (the lingual and inferior occipital gyri) in the right hemisphere during the encoding and retrieval of meaningless shapes with color information compared with those without color information. Although there are some limitations to be considered, the present findings seem to support the view that the retrieval of specific event information is associated with reactivation of both the MTL structures and the regions involved during encoding of the information.

Adult↗
PubMed1997

[An operated case of intractable occipital lobe epilepsy associated with calcification in the occipital lobe].

We reported a 20-year-old female of intractable occipital lobe epilepsy associated with calcification in the left occipital lobe. She developed seizures since 2 years old and electroencephalography showed paroxysmal activities on the left occipital area. At 8 years old, partial resection of the lesion and interictal spike focus under intraoperative corticography guidance was performed, but the favorable seizure outcome was not obtained. At the age of 20 years old, the frequency of her seizures has increased and admitted to our department. Preoperative evaluation with chronic invasive subdural recording showed that the ictal zone was located in the inferior (tentorial) surface and convexity of the left occipital lobe. Functional mapping involving cortical stimulation and cortical recording of pattern-reversal visual evoked potentials demonstrated that the ictal onset zone was not in the visual area. Following cortical resection of the ictal onset zone and multiple subpial transection on the surrounding cortex, she had good relief with less than one minor seizure per 1-3 months. Histological findings of the resected specimen were consistent with those of Sturge-Weber syndrome. Thus chronic invasive subdural recording may improve seizure outcome in patients whose epileptogenic area was located near the visual field.

Adult↗
PubMedDate not supplied

Occipital lobe epilepsy: a chronic condition related to transient occipital lobe involvement in eclampsia.

Eleven hours and 6 days, respectively, after childbirth 2 women exhibited hypertension and paroxysmal visual disturbances followed by tonic-clonic seizures and no other preeclamptic signs. Both developed partial epilepsy with occipital lobe seizures with no other neurologic defects. Neuroimaging showed no lesion during either the acute episode or 3-5 year follow-up. Selective vulnerability of the occipital lobes during eclamptic hypertensive encephalopathy was the probable pathophysiologic mechanism. Aggressive antihypertensive treatment during the acute phase may have exacerbated the risk of permanent cerebral damage.

Adult↗
PubMed1998

Symptomatic occipital lobe epilepsy.

Symptomatic occipital lobe epilepsy is increasingly recognized among patients with partial-onset seizures. Although traditional clinical and electroencephalographic criteria had defined occipital lobe epilepsy in the past, new neuroimaging techniques and the recognition of specific syndromes associated with occipital lobe epilepsy have improved the diagnosis and management of these patients. These syndromes include, among others, lesional occipital lobe epilepsy (congenital vs. acquired), MELAS, and epilepsy with bilateral occipital calcifications. The diagnosis of symptomatic occipital lobe epilepsy is improving as functional and structural neuroimaging techniques enable the detection of subtle abnormalities in such patients. This has had a direct impact on the correct classification of patients with benign occipital lobe epilepsy, basilar migraine, and symptomatic occipital lobe epilepsy. The common clinical symptoms, EEG patterns, and neuroimaging findings of these patients are discussed.

Brain Diseases↗
PubMed1992

Occipital lobe epilepsy: electroclinical manifestations, electrocorticography, cortical stimulation and outcome in 42 patients treated between 1930 and 1991. Surgery of occipital lobe epilepsy.

Our study documents the clinical and electrographic findings in 42 patients with medically refractory occipital lobe epilepsy, who underwent surgery at the Montreal Neurological Institute between 1930 and 1991, and the evolving manner in which those patients were studied by successive generations of investigators. In more than two-thirds of the patients the clinical manifestations indicated the occipital onset of the seizures. Seventy-three percent experienced visual aurae, of which elementary hallucinations were the most common and 12 also had ictal blindness. Other occipital manifestations included: contralateral eye deviation, blinking, a sensation of eye movement and nystagmoid eye movements. Intra-operative cortical stimulation elicited a habitual aura in 37% of 29 patients. Lateralizing clinical features were seen in almost two-thirds of patients: contralateral head deviation occurred in half, 59% had visual field defects contralateral to the epileptogenic area and 64% had abnormal imaging studies ipsilateral to the side of surgery. More than one-third of patients exhibited more than one seizure type, suggesting ictal spread to temporal or frontal lobe: 50% had typical temporal lobe automatisms, and 38% exhibited focal motor seizure activity. Surface electroencephalogram (EEG) recordings showed posterior temporal-occipital epileptiform discharges in 46% of patients. Only 18% had electronegative spiking limited to 01 or 02. Large epileptogenic areas were often found on intracranial recording with depth electrodes and on electrocorticography. Pre-excision electrocorticography spiking was restricted to the occipital lobe in only 13 out of 34 patients. More often spiking also involved the posterior temporal and posterior parietal regions. Twenty-three patients underwent only occipital resections; five had only temporal resections, so as to preserve the visual fields, and the remaining 14 patients had extensive resections, which included the posterior temporal or posterior parietal regions. A follow-up period of 1 to 46 yrs (mean 17 yrs) was available for 37 patients. Forty-six percent became seizure free and 21% had a significant reduction in seizure frequency. A better outcome was observed in those patients in whom there was no post-resection electrocorticographic or surface EEG epileptiform discharge, or who exhibited an occipital lobe lesion.

Adolescent↗
PubMed2006

The BOLD effect of interictal spike activity in childhood occipital lobe epilepsy.

PURPOSE: Occipital lobe epilepsy (OLE) presents in childhood with different manifestations, age of onset and EEG features that form distinct syndromes. The ictal clinical symptoms are difficult to correlate with onset in particular areas in the occipital lobes, and the EEG recordings have not been able to overcome this limitation. The mapping of epileptogenic cortical regions in OLE remains therefore an important goal in our understanding of these syndromes. METHODS: In this work, three patients with two types of idiopathic childhood OLE were studied with EEG source analysis and also with mapping of the BOLD effect associated with spikes in simultaneous EEG/fMRI recordings. RESULTS: Two patients with late onset OLE provided EEG source localizations in the lateral parietal cortex and in the medial occipital areas. The BOLD activations were more consistent and restricted to the medial parietal-occipital cortex in both cases. One patient with photosensitive idiopathic OLE presented with dipole sources in the medial parietal cortex, but the BOLD activations were widespread over inferior and bilateral occipital areas and also posterior temporal ones. There was little spatial overlap between the EEG and BOLD results, but the localizations suggested by the latter are more consistent with the ictal clinical manifestations of each type of epileptic syndrome. CONCLUSIONS: Overall, the BOLD effect associated with interictal spikes maps epileptogenic areas to different localizations than the ones suggested by EEG source analysis. These maps are similar in two patients with late onset idiopathic OLE, but different from a case of photosensitive idiopathic OLE.

Adolescent↗
PubMed1988

Transient cortical blindness with occipital lobe epilepsy.

Three youths with occipital seizures and intermittent visual loss are presented. All three had occipital epileptiform discharges. Visual loss occurred during seizures and improved with anticonvulsant medication. In the absence of an underlying structural lesion of the occipital lobe, occipital seizures in children often respond to antiepileptic medication and may spontaneously resolve. As occipital seizures are often associated with headaches and sometimes with vomiting, differentiating them from basilar migraine may be difficult. The possibility of ongoing seizure activity should be considered in a patient who presents with acute visual loss without an obvious cause.

Adult↗
PubMed1998

Surgical outcome in occipital lobe epilepsy: implications for pathophysiology.

Medically refractory occipital lobe epilepsies are increasingly treated with surgery, but outcome and its relationship to etiology, pathological substrate, occipital lobe location, surgical approach, and electroclinical features have not been systematically investigated in a substantial group of patients. Thirty-five patients who underwent surgery for intractable occipital lobe seizures were retrospectively evaluated. Outcome and occipital lobe location were analyzed with respect to surgical procedure, pathology, clinical seizure characteristics, seizure onset and termination locations, and localization of interictal spikes. Most patients had developmental abnormalities (14) or tumors (13, all gliomas). Developmental abnormalities consisted of focal cortical dysplasia (5), heterotopia (2), hamartoma (3), cortical duplication (1), polymicrogyria (1), Sturge-Weber syndrome (1), and tuberous sclerosis (1). There was 1 patient with a vascular abnormality, 1 with chronic inflammatory changes, 4 with gliosis, 1 with cerebral ossification, and 1 with normal pathology. Developmental abnormalities had significantly worse outcome (45% excellent/good) than tumors (85% excellent/good). In the developmental group, low-grade focal cortical dysplasias had better outcome than heterotopia and hamartoma regardless of type of surgical procedure. Pathological groups did not significantly differ with respect to location within the occipital lobe (overall medial [50%] or lateral [38%]); clinical seizure characteristics referable to specific lobe (occipital [14%], temporal [34%], frontal [23%], more than one type [29%]); electroencephalographic localization (to occipital [17%], temporal [27%], or other/multifocal locations [56%]); or intracranial ictal onset or termination location. Electroclinical variables were also unrelated to the occipital lobe location of abnormality. Surgical outcome was not predicted by surgical approach (lesion excision with margins or lobectomy). The main pathological substrates of uncontrolled occipital lobe epilepsy are gliomas and developmental abnormalities. Whereas resection of occipital lobe tumors associated with chronic epilepsy produces nearly uniform seizure control, outcome after resection of occipital lobe developmental abnormalities is less uniform.

Adolescent↗
PubMed1986

Occipital lobe infarction caused by tentorial herniation.

Occipital lobe infarction caused by tentorial herniation was described based on computed tomography findings in nine patients. The whole area of the occipital lobe was involved in five patients; some areas were spared in the others. Infarction other than the ipsilateral occipital lobe was seen in four areas of nine patients: the ispsilateral posterior limb of the internal capsule, contralateral Ammon's horn, and two contralateral occipital lobes. Hemorrhagic infarction was seen in two patients.

Adolescent↗
PubMed2001

[An operated case of bitemporal lobe epilepsy associated with old infarction in the left occipital lobe].

A 15-year-old female, who presented with bitemporal lobe epilepsy associated with old infarction in the left occipital lobe, was reported. MRI with fluid attenuated inversion recovery sequence demonstrates cortical atrophy with hyperintensity of the white matter in the left occipital lobe as well as volume loss and hyperintensity of the left hippocampus. Interictal positron emission tomography with [18F]fluorodeoxy glucose (FDG-PET) and single photon emission computed tomography with technetium-99m-ethyl-cysteinate dimer indicate hypometabolism and hypoperfusion in the left occipital lobe and the left temporal lobe, respectively. Scalp recorded EEG did not lateralize the side of the epileptogenic zone. Chronic subdural electrode recording demonstrated that the ictal onset zones were located in the bilateral side of the temporal lobe. Eighty-nine percent of 19 spontaneous seizures were left sided onset. The anterior temporal lobectomy with hippocampectomy was performed for the left side. Although temporal lobe epilepsy is sometimes a bilateral disease, unilateral lobectomy for a strong predominant side, based on the MRI and FDG-PET findings, is effective for some patients.

Adolescent↗
PubMed1997

Seizure semiology of occipital lobe epilepsy in children.

PURPOSE: Occipital lobe epilepsy in children occurs as an idiopathic form, i.e., Benign Epilepsy with Occipital Paroxysms (BEOP), and a symptomatic form. This study attempted to determine whether seizure semiology could distinguish between the two forms. METHODS: Fifty children (34 boys, 16 girls) with clinical seizures and interictal EEGs presenting occipital spikes were included consecutively in the study. Seizure onset was between the ages of 2 months and 15 years. Epilepsy was considered symptomatic when psychomotor retardation and/or abnormalities at neurological and/or neuroradiological examination were found: 17 children were classified as idiopathic, and the remaining 33 children were classified as symptomatic. Seizure semiology was assessed by means of a structured interview of the children and their parents, using a detailed questionnaire. Seizure semiology was determined to comprise motor (versive or other movements of the eyes, versive movements of the head, (hemiconvulsions), visual, other signs (e.g. vomiting and headache), and impairment of consciousness. RESULTS: There were no statistically significant differences in seizure semiology between the two groups. CONCLUSIONS: Seizure semiology cannot distinguish between different forms of occipital lobe epilepsy: Further clinical examination, clinical neurophysiological investigations, and neuroimaging studies are needed for a correct classification.

Adolescent↗
PubMed1981

Neuronal firing patterns during the spread of an occipital lobe seizure to the temporal lobes in man.

Neuronal recordings from occipital cortex and hippocampus during a seizure originating in the occipital lobe of a patient with an occipito-temporal tumor demonstrated that the visual aura resulted from neuronal activation of medial peristriate and possibly other occipital lobe neurons while the psychomotor automatisms followed 10-20 sec later and were caused by recruitment of hippocampal neurons bilaterally. This confirmed that the complex seizure symptoms were caused by propagation from an occipital lobe focus. The psychomotor symptoms have not recurred for the 6 months since interruption of occipito-temporal connections; however, the spared medial occipital neurons still produce visual auras.

Astrocytoma↗
PubMed2005

Visual field preservation after curative multi-modality treatment of occipital lobe arteriovenous malformations.

OBJECTIVE: Occipital lobe arteriovenous malformations (AVMs) provide challenging management decisions because of their proximity to the visual cortex and optic radiations. Preservation of visual function throughout treatment is the mainstay of therapeutic planning. We reviewed visual field (VF) outcomes of all patients who received curative treatment for occipital AVMs at Stanford University to evaluate the efficacy of different treatment strategies. METHODS: We conducted a retrospective review of 55 patients with occipital AVMs treated at Stanford University between 1984 and 2003. Clinical presentation, AVM morphology, and treatment modality were correlated with VF function before and after therapeutic intervention. RESULTS: Of 55 patients, 48 (87.3%) underwent multimodality AVM treatment (7 patients < 3 yr from radiosurgery were excluded from final analysis). One patient died from intracerebral hemorrhage 11 months post-radiosurgery, and five patients deferred further treatment. Forty-two patients (87.5%) were cured, with no residual AVM on final angiography. Curative therapeutic modalities used included embolization alone (2 patients), microsurgery alone (6 patients), microsurgery with radiosurgery (1 patient), microsurgery with embolization (23 patients), radiosurgery with embolization (4 patients), and embolization with radiosurgery and microsurgery (6 patients). Mean follow-up was 5.8 years including treatment. VF follow-up was available in all 42 patients. Twenty-eight (66.7%) patients experienced no change in VFs, six (14.3%) patients with previously abnormal VFs improved, and eight (19.0%) patients showed worsening of VFs (although none developed a new homonymous VF deficit). Duration of treatment was related to VF outcome in patients who presented without a history of AVM-related hemorrhage. CONCLUSION: Occipital AVMs can be safely cured using multimodality strategies with minimal risk to visual function despite the proximity of these lesions to the visual cortex and associated pathways.

Adolescent↗
PubMed1992

Occipital lobe epilepsy: clinical characteristics, seizure spread patterns, and results of surgery.

Twenty-five patients with occipital lobe seizure origin were retrospectively evaluated to determine clinical seizure characteristics and electroencephalographic manifestations. Certain symptoms and signs served to identify occipital lobe origin in 22 (88%). These included elementary visual hallucinations, ictal amaurosis, eye movement sensations, early forced blinking or eyelid flutter, and visual field deficits. Eye or head deviation, or both, was observed frequently and was contralateral to the side of seizure origin in 13, but 3 patients exhibited ipsilateral deviation in some or all their seizures. After the initial signs and symptoms, clinical seizure characteristics resembled those of seizures originating elsewhere. Seizures typical of temporal lobe origin with loss of contact and various types of automatic, semipurposeful activity occurred in 11 patients. Seizures in 3 patients exhibited asymmetrical tonic or focal clonic motor patterns characteristic of frontal lobe seizures. Eleven of the 25 patients had, on two occasions, two or more distinctly different seizure types. Scalp electroencephalographic findings were seldom helpful for occipital lobe localization and were frequently misleading. Intracranial electroencephalographic recording correctly identified occipital lobe seizure origin in most, but not all, patients who had such studies. Intracranial electroencephalic recording also proved the variability in clinical seizure characteristics was related to different seizure spread patterns, medially or laterally above and below the sylvian fissure, both ipsilateral and contralateral to the occipital lobe of seizure origin. Eighteen patients had occipital lobe lesions detected with computed tomographic or magnetic resonance imaging scans or both. Resection of the lesions in 16 patients produced excellent results in 14 (88%). Five patients had temporal lobectomies, with good results in 3, but poor results in 2. Two patients with unlocalized seizures had complete section of the corpus callosum, 1 with a good result and the other with a poor result.

Adolescent↗
PubMed1985

[Flash-pattern visual evoked potentials and limited lesions of the occipital lobe].

Four patients with restricted lobe lesions and one patient with large occipital lesions were selected for VEP studies to full-field and half-field flash pattern stimuli. The abnormalities of the responses were more important with full-field stimuli. In three patients with inner side occipital lobe damage, the P100 component disappeared ipsilaterally to the lesion, but N140 remained normal on bilateral occipital leads. In one patient with outer side occipital lobe damage, P100 was normal on bilateral occipital leads, but N140 disappeared ipsilaterally to the lesion. In one patient with large occipital lesion, P100 and N140 both disappeared ipsilaterally to the lesion. It appears that the P100 component is related to the inner and that N140 is related to the outer area of the occipital lobe.

Adult↗
PubMed1994

[A case of occipital lobe epilepsy following cerebral infarction].

We report a rare case of occipital lobe epilepsy following cerebral infarction in bilateral occipital lobes. The patient is a seventeen-year-old female, who had cerebral infarction in bilateral occipital regions a few days after an open-heart surgery at 15 years of age. Thereafter she sometimes complained of visual field defects and ictal amaurosis. Seventeen months later, she developed a tonic seizure with ictal amaurosis, visual field defects and head deviation. On admission, results of the neurological examinations were all normal with the exception of peripheral visual field defects. Scalp electroencephalographic (EEG) findings showed paroxysmal discharges that were more prominent in the frontal to parietal leads than in the occipital leads. Sometimes the laterality of paroxysmal discharges changed. Her visual defects were diagnosed as psychogenic activity by the ophthalmological visual fields test. Simultaneous recordings of pattern reversal visual evoked potential (VEP) and electroretinograms (ERG) showed normal in 15 minute checks, but prolongation of bilateral P100 latency in 30 minute checks. These findings suggested that peripheral visual fields were disturbed. In this case, EEG findings and the initial symptoms of amaurosis and visual fields defect suggested occipital epilepsy following cerebral infarction in bilateral occipital lobes. We wish to emphasize that simultaneous VEP and ERG recording is a useful diagnostic tool for estimating visual functions.

Adolescent↗