By: Aliana Gordon
Visual Center
The brain is the control center for the entire body having four lobes with varying responsibilities. This article will be focusing on the occipital lobe which lies in the back of the head. The occipital lobe is primarily responsible for interpreting visual stimuli and information that is received from the retinas of the eyes and deciphering it in the primary visual cortex, also referred to as Brodmann area 17 or V1.
Allowing you to:
- Assess distance, size, and depth
- Determining color
- Recognizing object movement
- Mapping the visual world
- Reading
Occipital Lobe Epilepsy
Epilepsy is a neurological disorder that is classified by the type and location of the seizures, so when thinking of occipital lobe epilepsy, it can be derived that the abnormal electrical activity will affect one’s vision. The seizures are characterized by focal sensory visual seizures and are subjective to each person. Focal sensory visual seizures begin in one area of the brain resulting in elementary visual hallucinations and can spread to both hemispheres. There are two additional distinctions to determine the type of seizure, whether it is idiopathic having an unknown origin or symptomatic where it is associated with known lesions. The occipital seizures are also often mistaken for migraines. A way to possibly differentiate the difference is that focal sensory visual seizures commonly last for less than 2 minutes where migraines can last anywhere from 5 to 15 minutes.
Occipital lobe epilepsy is a rarer type of epilepsy where it accounts for 5% to 10% of all epileptic seizures equally affecting all genders. It often begins early in childhood between the ages of 5 to 7 years old but can develop at any age. Occipital lobe epilepsy could be congenital that resulted from a birth defect or could be hereditary. The disorder has also been associated with celiac disease, where the person has a gluten sensitivity. Additionally, occipital seizures may be a manifestation of Lafora disease or mitochondrial disorders.
Symptoms
With seizures occurring in the visual center of the brain, they begin with visual hallucinations, such as blinking lights or rapid blinking. It can be subjected to either side of the visual field. If it affects the left side of their visual field, it is occurring on the right side of the cortex and the opposite for the right visual field.
Other symptoms include:
- Visual illusions
- Decreased vision, sometimes blindness
- Palinopsia, image repetition
- Eye pain
- Nystagmus, involuntary eye movement
- Nausea
After the seizure activity, the postictal phase may involve headaches that could last minutes to hours allowing the brain to recover.
There are further sub-types of seizures depending on the location of the cortex it occurs in. In the primary visual cortex, the seizures result in focal sensory visual seizures including bilateral loss of vision or positive or negative visual phenomena. Bilateral loss of vision may occur in the form of a black-out or white-out. If occurring in the extrastriate cortex, focal cognitive seizures are present which are associated with more complex visual hallucinations. That includes clear, lifelike pictures of people, animals, or scenery. Epileptic nystagmus may occur if the seizures are occurring at the parietal-occipital sulcus. Eye movements such as eye fluttering are common along with retained awareness, the head or trunk may also be affected. If the seizure occurs below the calcarine sulcus, focal impaired awareness seizures are produced and tend to spread to the temporal lobe. If it is above the calcarine sulcus, frontal atonic motor seizures occur of it spreads to the frontal lobes, but the seizure may spread to the parietal lobe as well.
Treatment
The development of occipital lobe epilepsy can be a result of many different instances. As mentioned, it could be congenital from a birth defect or hereditary from genetic factors. It could also be caused by brain trauma, cancer, inflammation, or infections. To confirm if a patient has occipital lobe epilepsy, various tests may be utilized, including an electroencephalogram (EEG). EEG readings and flashing lights could reveal abnormal responses to visual stimulation as a result of having occipital lobe epilepsy.
The patient will be prescribed anti-epileptic drugs (AEDs). Carbamazepine, levetiracetam, and lamotrigine are often the first AEDs that are prescribed and found effective. If the patient also has celiac disease, AEDs and a gluten-free diet would be beneficial. If the medication is not effective, neurosurgery may be considered. The doctor would remove any lesions on the brain or remove a section of the lobe that is causing the seizure activity.
Overview
The occipital lobe is responsible for processing visual input from the eyes. The symptoms of occipital lobe epilepsy involve vision, such as nystagmus, visual hallucinations, and decreased vision. There are various types of occipital lobe seizures depending on the location of the seizure activity. Often medication is found effective to control seizures, but surgery may be necessary if medication is ineffective or to remove lesions. Occipital lobe epilepsy can be associated with celiac disease and in that case medication and a gluten-free diet would be beneficial.
Resources
Focal Epilepsy. 2020, www.hopkinsmedicine.org/health/conditions-and-diseases/epilepsy/focal-epilepsy#:~:text=Occipital%20lobe%20epilepsy%20is%20the%20term%20for%20recurring,Seizures%20beginning%20in%20the%20occipital%20lobe%20are%20rare. \
University of Wisconsin Hospitals and Clinics Authority. “Occipital Lobe Epilepsy.” UW Health, 2020, www.uwhealth.org/epilepsy-seizures/occipital-lobe-epilepsy/40378.
“OCCIPITAL LOBE SEIZURE.” Epilepsydiagnosis.org, 2020, www.epilepsydiagnosis.org/seizure/occipital-overview.html.
“Occipital Lobe Epilepsy: Symptoms & Treatment | Study.com.” Study.com, 2021, study.com/academy/lesson/occipital-lobe-epilepsy-symptoms-treatment.html.
