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PubMed1995

Case of simple partial status epilepticus in occipital lobe epilepsy misdiagnosed as migraine: clinical, electrophysiological, and magnetic resonance imaging characteristics.

An 31-year-old man had a unique form of occipital lobe epilepsy. Since age 13 years, he has had episodes of simple partial status epilepticus (SE) occurring twice a month. These typically consisted of elementary visual hallucinations of flashing lights obscuring his left visual field for a period of 2 days, associated with a severe frontal headache initially diagnosed as migraine. These episodes of simple partial SE then evolved to a complex partial seizure (CPS) or secondarily generalized seizure. There were unique EEG features, including: (a) the perception of a flash of light in the left visual field with a single sharp/slow wave discharge over the right occipital lobe, (b) right occipital lobe epileptiform activity during the prolonged aura, and (c) an abnormal response to photic stimulation, with occipital lobe discharges during low rates of stimulation (3-5 Hz), time-locked to the stimulus. High-resolution magnetic resonance imaging (MRI) with quantitative morphometry demonstrated that the right hemisphere and right caudate nucleus were smaller than those on the left. An abnormal gyral pattern was also noted over the right parietal region. Occasionally, distinguishing occipital lobe epilepsy from migraine may be difficult.

Adult↗
PubMed1977

The pigment architecture of the human occipital lobe.

With the aid of steromicroscopical examination of pigment preparations uo to 1,000 micronm thick the various areas of the occipital lobe of the human brain are described. In the occipital lobe there are three main cortical types, forming the striate, the parastriate area, and the peristriate zone. The parastriate area is a horseshoe-shaped fringe area adjacent to the primary visual field. It is conspicuously marked by a relatively dark stripe of pigmented granule cells dividing the fourth layer into a light upper, a pigmented middle, and a light lower zone, a unique feature of the parastriate area, which is not to be found in any other isocortical area. This three-fold layer disappears abruptly as one passes from the parastriate to a peristriate area, permitting the definitive determination of this boundary. The peristriate zone is quite large in the inferior and the lateral parts of the occipital lobe and comparatively small in the superior parts. Its peripheral boundaries do not coincide with the limits of the occipital lobe. Parts of the cuneus on the one side are covered by parietal and temporal areas, whereas peristriate areas on the other side penetrate widely into the temporal lobe along the medial occipitotemporal and to a lesser extent the parahippocampal gyrus. As regards pigment architecture, the peristriate zone is divisble into ten areas. A relatively simply organized area accompaines the parastriate area. The structure of the cortex changes gradually until one reaches the various fringe areas adjacent to the parietal and temporal areas. The limit adjoining the temporal areas is sharply traceable, since the lower of two light cortical stripes vanishes abruptly when passing from a peristriate to a temporal area. The most highly developed field, the area peristriata magnopyramidalis, occupies part of the inferolateral margin of the occipital lobe. It displays a wealth of large pyramids in the lower reaches of the third layer, which contain tightly packed and densely stained pigment granules forming large rounded aggregates in the basal cytoplasm. Pyramids of this type give the field a close resemblance to association fields such as the posterior speech area, where they are commonly encountered as the predominant neurons of the third layer.

Aged↗
PubMedDate not supplied

Distribution of the occipital branches of the posterior cerebral artery. Correlation with occipital lobe infarcts.

The occipital branches of the posterior cerebral artery were examined in 31 human brains. The authors determined the origin, course, and region of supply of each occipital branch: the parieto-occipital, calcarine, posterior temporal, and common temporal arteries, as well as the lingual gyrus artery. These vessels were found in all the brains examined except the lingual gyrus artery, which was present in only 8.3%. The occipital branches were noted to supply variable cortical regions. In addition, they sometimes took part in irrigation of deep forebrain structures. It was concluded that occlusion of a certain occipital artery may cause varying clinical signs and symptoms in different patients. The neurologic deficits that may occur following the isolated occlusion of individual occipital branches of the posterior cerebral artery are discussed.

Adult↗
PubMed1999

Functional magnetic resonance imaging identifies abnormal visual cortical function in patients with occipital lobe epilepsy.

PURPOSE: To determine whether functional magnetic resonance imaging (fMRI) can reliably identify lateralized cortical dysfunction in patients with suspected occipital lobe epilepsy. METHODS: We compared visual cortical function of 10 patients with intractable occipital lobe epilepsy with nine control subjects' fMRI. Visual stimulation by using an alternating checkerboard pattern results in transient increases in the intensity of the proton magnetic resonance signal of water in the occipital lobes during echo-planar imaging. We used these stimulus-dependent changes in signal intensity to construct functional activation maps, which we registered onto anatomic images. RESULTS: After full-field stimulation, none of the patients with occipital lobe epilepsy had normal activation patterns, whereas eight of the nine control subjects had normal patterns (p = 0.001). Abnormalities consisted of either a markedly asymmetric activation pattern in six of 10 patients (p = 0.04), or a complete absence of activation in four of 10 patients (p = 0.05). The abnormal side of activation was concordant with the side of seizure onset in all six patients with asymmetric activation maps. Half-field stimulation produced less reliable results. Although more patients had abnormal activation maps than did controls with half-field stimulation (p = 0.04), the abnormal side was discordant with the side of seizure onset in three of the five patients who had markedly asymmetric activation patterns. CONCLUSIONS: These results suggest that fMRI with full-field stimulation is a reliable, noninvasive method for identifying areas of abnormal visual cortical function ipsilateral to the epileptogenic region in patients with occipital lobe epilepsy.

Adolescent↗
PubMed2003

Early prediction of seizure remission in children with occipital lobe epilepsy.

The purpose of this study was to identify early predictors of seizure remission in occipital lobe epilepsy irrespective of syndrome classification i.e. idiopathic or symptomatic occipital lobe epilepsy. Forty-three children with occipital lobe epilepsy had taken part in an earlier study of seizure semiology, neurological deficits, psychomotor/cognitive status, electroencephalography (EEG) and neuroimaging. On the basis of the results of a questionnaire on the state of their epilepsy in 2000, two groups were composed. One group (n=17) consisted of the children with a complete seizure remission of 5 years or more, and the other (n=26) comprised children whose last seizure occurred less than 5 years ago. Our findings indicate that neurological deficit and EEG characteristics can predict 5 year outcome of occipital lobe epilepsy. Neuroradiological abnormality, psychomotor/cognitive status and seizure semiology appear to be of more limited value.

Child↗
PubMed1981

Inhibitory effect of central vision on occipital lobe seizures.

We studied four young patients with occipital lobe seizures (elementary visual hallucinations, blindness, and tonic deviation of the eyes) and electroencephalographic (EEG) abnormalities of occipital spike and slow-wave activity, which occurred continuously as long as the eyes were closed. The EEG abnormalities were inhibited by opened eyes in an illuminated room and returned immediately in darkness. Opening and closing the eyes in darkness did not alter the continuously occurring spike and slow-wave activity. The retention of central vision in darkness, caused by looking at a red spot of light, inhibited these abnormalities. Therefore, some occipital lobe seizures may not be "spontaneous" but may be elicited by "loss" of central vision, particularly when they occur in darkness or sleep.

Adolescent↗
PubMed1997

Occipital lobe developmental malformations and epilepsy: clinical spectrum, treatment, and outcome.

PURPOSE: Cortical developmental malformations (CDM) are increasingly recognized in association with epilepsy. We describe 10 patients (age range 14-35 years) with symptomatic occipital lobe epilepsy and CDM. METHODS: Neurologic, neuroophthalmologic and electrophysiologic studies were performed. Patients had MRI, SPECT, and in some cases intracranial EEG investigators. RESULTS: Mean age of seizure onset was 8 years. We noted strong correlations between the presence of visual auras, the scalp EEG pattern, and the subtype of underlying pathology. Magnetic resonance imaging (MRI) showed CDM in all patients, with polymicrogyria and focal dysplasia being the most frequent malformations. Despite the presence of occipital lobe structural malformations in all patients, visual field deficits were present in only 2. Those who underwent cortical resections were seizure-free or showed major improvement at a mean follow-up of 3.5 years. CONCLUSIONS: Intracranial stimulation studies and the low frequency of pre- and postoperative deficits suggest that some degree of cortical visual reorganization may occur in patients with occipital lobe malformations. Occipital lobe CDM should be sought as a cause of symptomatic occipital lobe epilepsy even though they may become symptomatic after childhood.

Adolescent↗
PubMed2001

Dementia with Lewy bodies and AD are not associated with occipital lobe atrophy on MRI.

Dementia with Lewy bodies (DLB) is associated with occipital changes in blood flow and metabolism, but structural changes in this region have not previously been assessed. The authors performed volumetric MRI measurement of the occipital lobe blind to the diagnosis in 23 subjects with DLB, 25 with AD, and 24 age-matched control subjects. There were no significant differences between groups in occipital lobe volume. The authors conclude gross structural changes in the occipital lobe do not occur in patients with mild to moderate DLB or AD.

Aged↗
PubMed1990

Detection of isolated occipital lobe anomalies during early childhood.

The authors report two children with isolated occipital lobe anomalies detected by visual evoked potentials (VEPs) and confirmed by MRI and CT scanning. Both had a markedly asymmetrical occipital distribution of flash and pattern VEPs. One child had acuity reduced to 6/36, and testing on confrontation suggested an homonymous hemianopia. The second child was visually inattentive to one side during infancy. Neither child had band atrophy of the optic disc or an afferent pupillary defect. Isolated abnormalities of the occipital lobes are difficult to detect by clinical examination during infancy and early childhood. Recording VEPs from a horizontal array of occipital electrodes can be helpful in detecting subtle occipital lobe abnormalities.

Child↗
PubMed2002

Occipital lobe morphological anatomy: anatomical and surgical aspects.

BACKGROUND: The occipital lobe is an important region of the central nervous system and site of a wide variety of lesions. Different from others regions of the brain, whose anatomy has been already meticulously detailed, controversies about occipital lobe morphology can occasionally hinder the surgical approaches to it. METHOD: Twenty-six hemispheres were dissected, examining the distances of the medial structures of the posterior interhemispheric fissure region; identifying the sulci and gyri more frequently found in the lateral surface; and detailing the anatomy of the occipital horn of the lateral ventricle. Also, anatomical details of structures such as the calcarine sulcus and preoccipital notch were evaluated. RESULTS: Twenty-four hemispheres (92%) showed sulci with evident transverse trajectories in the lateral surface, and it was possible to identify marked longitudinal sulci in 16 (61%). All of the specimen presented a transverse sulcus in the inferior third of the lobe - labeled in this paper as Inferior Transverse Occipital - and 69% of the cases showed a transverse sulcus in the superior third - labeled as Superior Transverse Occipital. The occipital horn was present in 53% of the cases at level of the anterior boundary of the lobe. It was a half moon shaped cavity, whose the medial wall was formed by the calcar avis and the lateral wall, roof and floor formed by fibers of the tapetum. CONCLUSION: The occipital lobe presents parameters that are often recognized in most of the dissected brain and can be useful for the planning and performance of surgery in this area of the brain.

Adult↗
PubMed1995

Photoreactive flow changes in the posterior cerebral artery in control subjects and patients with occipital lobe infarction.

BACKGROUND AND PURPOSE: Photoreactive flow changes of the posterior cerebral artery (PCA) in control subjects and patients with unilateral occipital lobe infarction were investigated to study the hypothesis that occipital lobe infarction of varying extent leads to a reduced visually activated flow increase in the ipsilateral PCA. METHODS: Maximum mean flow velocity (MFV) of the PCA was investigated by transcranial Doppler sonography after photic stimulation of the retina. RESULTS: In 25 control subjects MFV was increased by 30.6 +/- 9.7%. In 13 patients with unilateral occipital lobe infarction the ipsilateral MFV increase was significantly lower than in control subjects. Nine patients with homonymous hemianopsia showed an ipsilateral MFV increase of 3.4 +/- 4.1% (P < .001) and four patients with incomplete occipital lobe infarction and homonymous quadrantanopsia had an MFV increase of 16.0 +/- 12.8% (P < .05). CONCLUSIONS: We conclude that photoreactive flow changes of the PCA represent a noninvasive and reliable measure of functional impairment due to occipital infarction.

Blood Flow Velocity↗
PubMed1997

Ictal single photon emission computed tomography in occipital lobe seizures.

PURPOSE: Ictal single photon emission computed tomography (SPECT) has been evaluated as an adjunctive localizing technique in temporal lobe epilepsies and, to a lesser degree, in some extratemporal epilepsies. The purpose of this study was to determine whether occipital lobe seizures are associated with distinctive ictal cerebral blood perfusion (rCP) patterns. METHODS: SPECT was used with the tracer 99mTc HMPAO to image ictal rCP in 6 patients in whom clinical, EEG, and imaging data indicated occipital lobe seizures. RESULTS: Two patterns of rCP were seen. Four patients had hyperperfusion that was restricted to the occipital lobe, and two patients had hyperperfusion of the occipital lobe and the ipsilateral mesial temporal lobe, with hypoperfusion of the lateral temporal lobe. The latter 2 patients had clinical and surface EEG evidence of temporal lobe involvement in the seizure discharge. CONCLUSIONS: Ictal rCP patterns in occipital lobe seizures are distinct from those in temporal lobe seizures and may vary according to whether or not ipsilateral temporal lobe structures are involved in the ictal discharge.

Adolescent↗
PubMed2000

Bilateral occipital lobe stroke with inferior altitudinal defects.

BACKGROUND: Cerebrovascular disease is the most common cause of neurological disability in Western countries. Patients who survive cerebrovascular accidents exclusive to the occipital lobe often have no significant neurological deficits other than visual-field loss. Visual-field defects from occipital lobe stroke typically include congruous homonymous hemianopsias or quadranopsias, with or without macular sparing. CASE REPORT: A 61-year-old white man came to us with symptoms of sudden loss of vision and difficulty reading. Visual-field testing revealed a bilateral inferior altitudinal defect with normal optic nerve and fundus appearance in both eyes. On radiological examination, he was found to have had a bioccipital lobe cerebrovascular accident secondary to complete occlusion of the left vertebral artery. An embolic event causing the artery occlusion, in combination with bilaterally compromised cerebellar and posterior cerebral arteries, presumably caused the bilateral stroke. After appropriate medical and neurological consultation, optometric management consisted of maximizing the patient's remaining vision with a prismatic spectacle correction. DISCUSSION/CONCLUSION: Patients with infarction exclusive to the occipital lobe typically have no other neurological deficits except visual-field loss and are often easier to manage than patients with infarctions to other areas of the cerebral cortex or multiple infarctions. Visual-field loss from occipital lobe damage can be successfully managed with optical systems and/or visual rehabilitation. Factors related to management include location and extent of visual-field damage, functional visual needs, and both personal and health concerns of the patient. A discussion is presented on cerebrovascular disease, occipital lobe infarction, imaging techniques, and visual rehabilitation.

Diagnosis, Differential↗
PubMed2002

[A boy with occipital lobe epilepsy showing prolonged QTc in the ictal ECG].

We report a 9-year-old boy with occipital lobe epilepsy who showed a prolonged QTc on the ictal electrocardiogram (ECG). He complained of sudden onset of blindness accompanied with vomiting and headache. Since ECG revealed a prolonged QTc, he was transferred to our pediatric emergency center. Occipital spike and slow wave complexes on the electroencephalogram (EEG) suggested the diagnosis of occipital lobe epilepsy. Administration of carbamazepine (190 mg) resulted in the disappearance of the blindness and abnormal waves on EEG. This is the first report to describe the occurrence of prolonged QTc during seizures of occipital lobe epilepsy. Because of the high risk of life-threatening ventricular arrhythmia induced by prolongation of QTc such as torsades de pointes, attention should be paid to the ECG findings in patients with occipital lobe epilepsy.

Anticonvulsants↗
PubMed1995

Reduced frontal and occipital lobe asymmetry on the CT-scans of schizophrenic patients. Its specificity and clinical significance.

Frontal and occipital lobe width were determined in the computed tomographic (= CT) scans of 135 schizophrenic patients, 158 neuropsychiatrically healthy and 102 psychiatric control subjects, including patients with affective psychosis, neurosis and schizoaffective psychosis. Most healthy right handed subjects demonstrate a relative enlargement of the right frontal as well as left occipital lobe compared to the opposite hemisphere. These normal frontal and occipital lobe asymmetries were selectively reduced in schizophrenics (f.: 5%, p < .0005; o.: 3%, p < .05), irrespective of the psychopathological subgroup. Schizophrenic neuroleptic non-responders revealed a significant reduction of frontal lobe asymmetry (3%, p < .05), while no correlation between BPRS-subscores and disturbed cerebral laterality could be detected. In sum the present study demonstrates disturbed cerebral lateralisation in schizophrenic patients supporting the hypothesis of interrupted early brain development in schizophrenia.

Adult↗
PubMed2003

Direction of flow in posterior communicating artery on magnetic resonance angiography in patients with occipital lobe infarcts.

BACKGROUND AND PURPOSE: In some people the blood supply to the posterior cerebral artery occurs partly or even exclusively via the carotid system. This anatomic configuration may influence the risk of occipital lobe infarction. We studied the presence and direction of flow in the posterior communicating artery (PCoA) in patients with an occipital lobe infarct and in healthy controls. METHODS: Forty-seven patients with an occipital lobe infarct were studied by MR angiography, as well as 50 young healthy controls. Special attention was paid to the presence of a PCoA and, if present, to the direction of flow. RESULTS: Significantly fewer patients than controls had an exclusive blood supply to the posterior cerebral artery via the carotid system, in both the affected (4% versus 17%; 95% CI of difference, 4% to 22%) and unaffected hemispheres (5% versus 17%; 95% CI of difference, 3% to 22%). Patients also less often had a patent PCoA with anteroposterior flow than controls (affected hemisphere, 8% versus 22%; unaffected hemisphere, 12% versus 22%; 95% CI of differences, 3% to 25% and -2% to 23%, respectively). With analysis at the level of individuals, significantly more patients showed no anteroposterior flow through the PCoA in either hemisphere than controls (79% versus 42%; 95% CI of difference, 19% to 55%). CONCLUSIONS: Supply of the posterior cerebral artery by the carotid system occurs less often in patients with an occipital lobe infarct than in healthy controls. The same was true for the unaffected hemisphere of patients, which suggests that the anatomic difference represents a causal factor (fewer collateral pathways after occlusion of the posterior cerebral artery or its branches) rather than a consequence (redistribution of blood flow after occipital infarction).

Adult↗