Epileptic blindness in children: a localizing sign of various epileptic disorders

Elucidating the visual phenomena in epilepsy: A mini review

Epilepsy is one of the most recognizable neurological diseases, globally. Epilepsy may be accompanied by various complications, including vision impairments, which may severely impact one's quality of life. These visual phenomena may occur in the preictal, ictal and/or postictal periods of seizures. Examples of epilepsy associated visual phenomena include visual aura, visual hallucinations, transient visual loss and amaurosis (blindness). These ophthalmologic signs/symptoms of epilepsy may be temporary or permanent and may vary depending of the type of epilepsy and location of the seizure foci (occipital or temporal lobe). Some visual phenomena may even be utilized to diagnose the epilepsy type, although solely depending on visual symptoms for diagnosis may lead to mistreatment. Some antiseizure medications (ASMs) may also contribute to certain visual disturbances, thereby impacting its therapeutic efficiency for patients with epilepsy (PWE). Although the development of visual comorbidities has been observed diversely among PWE, there may still be a lack of understanding on their relevance and manifestation in epilepsy, which may contribute to the rate of misdiagnosis and the current scarcity in therapeutic relieve. Therefore, this mini narrative review aimed to discuss the common epilepsy associated visual phenomena, based on the available literature. This review also showcased the relationship between the type of visual complications and the site of seizure onset, as well as compared the visual phenomena between occipital lobe epilepsy and temporal lobe epilepsy. Evaluation of these findings may be crucial in reducing the risk of permanent seizure/epilepsy related vision deficits among PWE.

Favorable outcome of epileptic blindness in children

Acute blindness is a rare presentation of epileptic seizures, referring to loss of sight without loss of consciousness associated with electroencephalographic (EEG) epileptic discharges, mainly representing an ictal phase but also either pre- or postictal. We report a series of 14 children with documented epileptic blindness, describing the accompanying fits and thereafter the response to therapy to resolve the blindness and control associated seizures. All patients experienced episodes of acute complete visual obscuration lasting for 1 to 10 minutes. Seven patients hadaccompanying generalized seizures, with a photosensitive response recorded in three of them. All of these seven children were treated with valproic acid, regaining full vision, and six of them became seizure free. Three patients with acute blindness who had accompanying focal motor seizures and unilateral temporooccipital posterior epileptic discharges were treated with carbamazepine regained full vision and complete seizure control. Four additional children had the constellation of migrainous headaches, focal motor phenomena, and complete blindness, along with occipital discharges compatible with Gastaut syndrome, benign childhood epilepsy with occipital paroxysms. All four patients were started on carbamazepine and became asymptomatic. Our overall experience suggests that epileptic blindness in children is associated with a favorable outcome when promptly diagnosed and treated appropriately, resulting in complete resolution of blindness in all children and satisfactory control of seizures in most of them. We therefore recommend performing a prompt EEG in any child presenting with acute visual obscuration, even in the absence of other epileptic phenomena.

Infantile spasms as a cause of acquired perinatal visual loss

BACKGROUND

Visual abnormalities have been described in patients with infantile spasms (IS), an epileptic syndrome of early childhood.

METHODS

We report on 3 children who exhibited cortically mediated visual regression in association with the development of IS.

RESULTS

In 1 patient, loss of visual behavior was the presenting complaint. In all patients, visual behavior improved with treatment of seizures.

CONCLUSIONS

IS are a potentially treatable cause of cortically impaired vision in early childhood. Because visual behavior might improve when the seizures are treated, patients should be referred appropriately.

Localizing value of epileptic visual auras

It is difficult to differentiate between seizures of occipital or temporal lobe origin in patients with focal epileptic seizures associated with visual aura. These are often suspected to originate from the visual cortex, which causes reluctance to propose resection as treatment for the affected patient. To determine the value of localizing different types of visual auras, we report on 20 patients experiencing visual aura from a series of 878 surgically treated patients suffering from intractable focal seizures. In all of these patients, a morphological abnormality was identified on MRI (n = 18) or cranial CT (n = 2). These abnormalities were shown to represent the morphological correlate of the epileptogenic zone in each case, as demonstrated by intracranial ictal EEG recordings and/or seizure freedom after focal resective surgery. Elementary hallucinations, illusions and visual loss were reported not only by all patients with occipital lobe epilepsy, but also by patients with occipitotemporal and anteromedial temporal seizure onset. Complex hallucinations never occurred in occipital lobe seizures but were present in the two other groups. The same correlation was found for concentric changes of visual field (tunnel vision), a newly described ictal phenomenon. We conclude that elementary hallucinations, illusions and visual loss, although typical for occipital lobe epilepsy, can also occur in anteromedial temporal or occipitotemporal seizures and are therefore not a discordant feature in presurgical evaluation of patients with suspected temporal lobe epilepsy. Complex hallucinations and tunnel vision, however, should be considered concordant only with the assumption of an anteromedial temporal or occipitotemporal seizure onset.

Focal extratemporal epilepsy: clinical features, EEG patterns, and surgical approach

The objective of this review is a summary of the clinical and electrographic findings in those forms of epilepsy to which the term 'extratemporal' (ExT) can be applied. They form a group that differs in many ways from the better known temporal lobe epilepsies. Seizure foci are difficult to localize by clinical semiology alone but modern imaging now often allows a precise definition of the epileptogenic area. The most common causes of ExT epilepsy are tumors and cortical dysgenesis. The concept of 'dual pathology' implies the coexistence of two or more distinct lesions, typically mesial temporal sclerosis and cortical dysplasia. Electroencephalography (EEG) and electrocorticography (ECoG) are valuable tests in the definition of the epileptogenic area beyond the structural lesion, and surgical removal must be guided by the nature of the lesion and the extent of the epileptogenic zone.