Occipital Epilepsy and Visual Phenomena - An Overview

Introduction

Epilepsy is a persistent neurological illness that results in seizures due to aberrant electrical activity in the brain. Occipital epilepsy is distinguished by visible symptoms (hallucinations or visual field abnormalities). Individual features of duration, color, form, size, position, movement, pace of growth, and advancement make clinical identification of visual seizures simple.

They differ significantly from migraine visual aura, although they frequently cause migrainous Headaches, most likely by activating trigeminovascular or brain stem pathways. Elementary visual hallucinations, blindness, or both, combined with headache and vomiting, characterize symptomatic occipital epilepsy. The progression to temporal lobe structures differs from and is consistent with symptomatic occipital lobe epilepsy. Continue reading to learn more, including its origins, symptoms, and treatment options.

What Is the Cause of Occipital Epilepsy?

• Occipital epilepsy is occipital seizures caused by an epileptic focus in the occipital lobes. Based on their clinical appearance, these epilepsies are divided into two types.

• Autonomic symptoms characterize children with Panayiotopoulos syndrome (PS), whereas visual symptoms characterize children with idiopathic childhood occipital epilepsy of Gastaut (ICOE-G).

• A tiny proportion of people with this disease cannot be classified into one of these two groups.

• The cause of benign occipital seizures is thought to be hereditary.

• While no genetic aberration has been found, the genetic basis is believed to be complicated and polygenic.

• The lateral supra calcarine region is the source of sensory and motor complaints.

• Complex posture results from medial supra calcarine spread.

What Is the Occurrence of Occipital Epilepsy?

Occipital epilepsy accounts for between five and ten percent of all epilepsies. These uncommon disorders have a shallow occurrence; nevertheless, the precise incidence is unknown. The prevalence in published demographic research is six percent, close to the five percent documented in the neurosurgical series. Occipital seizures were found in one percent of newly diagnosed epilepsy cases in population research. However, this study recognized the possibility of underdiagnosis because occipital epilepsies might mirror other epilepsy syndromes and be mistaken. Seizures frequently migrate from the occipital area to the brain's more anterior regions. In fifty percent of neurosurgery series, infra calcarine occipital foci migrated to the ipsilateral medial temporal lobe.

What Is Occipital Epilepsy and Visual Phenomena?

• Transient visual symptoms, which can be positive (flashes, phosphenes) or negative (amaurosis, hemianopia, scotoma), define visual subjective symptoms.

• Positive visual hallucinations often manifest unilaterally in the temporal visual field, opposite to the epileptogenic center.

• Between ten and thirty percent of the time, they appear in the center or an ambiguous place.

• Depending on the trajectory after their first display, they might multiply, grow in size, or alter their placements and luminance.

• The three main types of motion are rotation, translation on a two-dimensional plane, and flickering or flashing. They often have a circular shape and are multicolored.

• Other shapes are uncommon, but if the occipitotemporal cortex is involved, they grow more complex.

• Heautoscopy is a rare condition in which the patient may view their picture.

• Simple visual hallucinations can develop into more severe forms after spreading to different areas.

• There are also perceptual illusions when an object appears to be distorted. Simple perceptual illusions include distortions in illumination, color, clarity, shape (metamorphopsia), size (macropsia, micropsia), and shape (metamorphopsia).

• Macroproxiopia and microtelepsia, as well as teleopsia, are examples of complex illusions where objects appear disoriented in the distance.

• Alternatively, the patient may have permanent or recurrent palinopsia and diminished or improved stereoscopic vision. Palinopsia, sensory hallucinations of ocular movements, or blindness can also occur in individuals. Visual hallucinations may make an appearance first, followed by ictal blindness. On occasion, it might be the only sign. Ictal hemianopia (occurs less commonly) and ictal blindness (occurs in thirty-three percent of symptomatic and 67 percent of idiopathic occipital epilepsy patients, respectively) are both common.

• In nearly fifty percent of cases, headaches that resemble migraines manifest themselves. Blindness may occur with severe seizures or status epilepticus.

What Is the Significance of Occipital Epilepsy?

Visual hallucinations, ictal blindness, orbital discomfort, headache, nausea, and vomiting are all possible symptoms. Patients may experience localized sensory or motor complaints when problems move beyond the occipital lobe. Seizures are common in certain youngsters and might occur regularly if not treated.

Transient visual symptoms that might be favorable (flashes, phosphenes) or negative (amaurosis, hemianopia, scotoma) characterize visible subjective symptoms. Positive visual hallucinations most commonly manifest unilaterally in the temporal visual field contralateral to the epileptogenic center. They appear centrally or in an unknown place between ten and thirty of the time. Depending on the development, they may increase, grow in size, or change places and brightness after their first appearance.

Flickering or flashing is widespread, translation in a two-dimensional plane is less common, and rotation or movement towards or away from the camera is uncommon. They are often multicolored and round. Other forms are uncommon, but they grow more complicated when the occipitotemporal cortex is involved.

How Is the Occipital Epilepsy Diagnosed?

Temporal scalp EEG commonly exhibits aberrant findings with distinguishing features particular to underlying causes. Around the board, posterior temporal activity is the most frequent observation. Bilateral frontally predominate paroxysms and widely dispersed diffuse posterior sharp or spike activity are additional observations. An EEG may capture bilateral epileptiform discharges from each occipital lobe.

The discharges with lower voltage indicate secondary spread. It is crucial to remember that EEG results could not reveal the occipital origin of the seizure but rather the spread to the frontal, parietal, and posterior temporal regions. Children may experience quick dissemination of the seizure to the opposing occipital lobe, but adults may see delayed findings. Structural abnormalities may be found via neuroimaging.

How Is Occipital Epilepsy Treated?

• Depending on the cause and severity of occipital epilepsy, medical or surgical treatment may be utilized.

• The anti-seizure drugs carbamazepine, lamotrigine, levetiracetam, oxcarbazepine, and topiramate are advised.

• Children with idiopathic occipital epilepsies are most frequently treated with carbamazepine, which has a 90 percent clinical success rate.

• Children with idiopathic photosensitive occipital epilepsy may benefit from sodium valproate.

• Surgery is increasingly being considered for those with medically intractable occipital epilepsy, with total long-term seizure remission occurring in 65 percent of cases. A visual field deficiency is the most frequent problem.

• Since fewer patients than expected had post-surgical visual field abnormalities, there are theories that some patients have cortical reorganization.

• Before surgery, neuroimaging techniques like ictal Spectroscopy and ictal positron emission tomography (PET) may be used to confirm the resection area.

• Although it has been utilized to preserve visual integrity during intraoperative mapping using electrocortical stimulation while awake, it is currently not routinely practiced.

Conclusion

Occipital epilepsy is distinguished by visible symptoms (hallucinations or visual field abnormalities). In a temporal hemifield, supplementary visual hallucinations mainly comprised colorful and tiny circular patterns flashing or multiplying. It was uncommon to see flashing lights or non-circular patterns. Visible seizures were often common, occurring in many clusters daily or monthly. They often appeared alone, although they frequently progressed to additional occipital and extra-occipital ictal symptoms. Misdiagnosis of visual seizures as migraine aura was widespread. The use of medicine, surgery, and technology can achieve control. Many people have had success in reducing or eliminating seizures.