Crisis epilépticas visuales. Semiología e implicaciones clínicas

Abstract

Visual phenomena can be symptoms of epileptic seizures, although with an uncertain clinical meaning and relationship with the epileptogenic focus. To describe the clinical implications of visual epileptic seizures according to their signs and symptoms in adults. Data were collected consecutively over a period of one year from patients who reported visual signs and symptoms as the main manifestation of their seizures, and the visual symptoms are classified according to the characteristics of the description. The sample consisted of 78 patients, with a mean age of 43.5 years. Focal epilepsy accounted for 97% of the cases. Of the 63% that were symptomatic epilepsies, 57% were vascular. The visual seizures were, in 81.9% of cases, the aura prior to the seizure, and 17.9% were isolated visual seizures. The coexistence of visual seizures and other types of seizure was associated to pharmacoresistance (p = 0.021). The visual symptoms reported were as follows: simple hallucinations (55.1%), illusions (23.1%), complex hallucinations (15.4%) and loss of vision (6.4%). The lobar localisation of the lesions was occipital (24.4%), temporoparietooccipital (21.8%), temporal (9%), parietal (3.8%) and frontal (1.3%). Occipital lesions were associated with simple visual hallucinations (p < 0.001), and visual illusions and complex visual hallucinations, with lesions affecting the temporoparietooccipital junction (p < 0.05). Of the 55.1% of patients with a unilateral lesion in the magnetic resonance scan, 33% reported symptoms in the contralateral visual hemifield. Visual seizures mainly present as epileptic auras. Simple hallucinations are related with an occipital origin, whereas complex hallucinations are associated with more anterior regions of the brain. The appearance of lateralised visual phenomena suggests an origin located in the contralateral hemisphere.