Zur Frage der epileptischen Aktivität des Okzipitallappens

Abstract

Our analysis of the course of illness in 14 patients, whose common electroencephalographic characteristic was epileptogenic activity in the occipital area, showed very different clinical symptoms. The first group comprised patients who presented bilateral amaurosis. In four of these cases, the occipital hypersynchronous EEG activity was merely a secondary symptom of either ischaemic hypoxia or of a degenerative process in the occipital visual cortex and was not responsible for the genesis of the actual blindness. In two further cases of monosymptomatic temporary loss of vision, it was difficult to make a differential diagnosis between ictal blindness, respectively status epilepticus amauroticus occurring in a occipital lobe epilepsy and a migraine attack involving the basilar territory. The second group comprised five patients with paroxysmal visual hallucinations respectively illusions. Three of them suffered from hallucinations of the elementary type, respectively flickering fits in the hemianopic field, symptoms which are based on discharges in the visual cortex of the occipital lobe. In a case of one patient with complex visual hallucinations as well as in a further case with visual illusions, it was not possible to find out with certainty their place of origin. A study of these cases shows that the cortical or sub-cortical functional disturbance within the visual system causing the various optical deformations and visual hallucinations, form an inhomogeneous group with different etiology. In the only patient belonging to the third group, whose seizures were i.a. characterized through motor phenomena in the field of the ocular organs and the tonic lateral turning movement of the bulbi of the eyes and of the head, an occipital epileptic crisis with spread of discharges from the occipital pole to the frontomesial surface should be assumed. The occurrence of complex partial seizures, respectively generalized tonic-clonic attacks in two patients of the fourth group who have definite epileptogenic EEG-activity in the occipital area, can be explained by a propagation of paroxysmal activity to the temporal lobe or to the motor cortex. Because of the marked tendency to propagation of the hypersynchronous activity originating in the occipital lobe, many combinations of sensory and/or motor symptoms can occur within the frame-work of occipital epileptic seizures. On the basis of one scalp EEG finding, no final localizing conclusions may be drawn here.

Visual Hallucinations in Recovery From Cortical Blindness

“…It should be stressed that cortical blindness occurred as a consequence of hypoxemia after cardiac arrest and CPR but not after the preceding generalized seizure, although both conditions have been reported to cause cortical blindness. 8,9 Similar to other patients who have been rescued from cardiac arrest, 4 our patient also showed a severe hypometabolism in the parieto-occipital visualassociation cortex. The prognosis of cortical blindness is usually favorable, if it is not caused by ischemia and no bioccipital abnormalities are present on computed tomographic scans.…”

“…Visual hallucinations occur frequently during recovery from cortical blindness. 1,4,9,10 We observed in our patient that they were associated with activations in secondary visual areas, which initially showed a severely depressed rCMRGlu, but recovered to normal values. Since in the ischemic cortex the balance between excitatory and inhibitory neurotransmission is disturbed, leading to hyperexcitability, [11][12][13] the visual hallucinations are likely to be the correlate of postlesional hyperexcitability.…”

Occipital Lobe Status Epilepticus, A Stroke Mimic with Novel Imaging Findings: A Case Report

“…Hyperperfusion of the left occipital lobe seen on perfusion CT angiography and MRI, may represent preliminary findings associated with focal status epilepticus. 7,8 This is the first report of this finding to our knowledge to be reported in the EM literature. While this finding would be more likely associated with an AVF, one was not visualized by angiography or MRI.…”

“…It is possible for propagation of the seizure to include adjacent areas of the brain to incorporate oculomotor or other motor features. 7 To our knowledge, this is the first occurrence of occipital lobe status epilepticus to be reported in the emergency medicine (EM) literature.…”

“…This association has recently gained attention in the neuroradiology literature. 6,7,8 Hyperperfusion, however, is not limited to seizure. It has been demonstrated following reperfusion of cerebral vessels as might occur with TIA or therapeutic reperfusion.…”