Original article Visual evoked potentials in children with occipital epilepsies Ahmet Gokcay * , Nes ¸e Celebısoy, Figen Gokcay, O ¨ zgu ¨l Ekmekcı, Ayfer Ulku Ege University Medical School, Department of Neurology, Bornova, I ˙ zmir 35100, Turkey Received 21 June 2002; received in revised form 7 October 2002; accepted 8 November 2002 Abstract The objectives of this study are to see if any visual evoked potential (VEP) differences are present in two forms of occipital epilepsy, childhood epilepsy with occipital paroxysms (CEOP) and symptomatic occipital epilepsy (SOE) with respect to etiology, as CEOP is a benign age- and localization-related idiopathic epilepsy while SOE is a symptomatic form. Nineteen patients with CEOP and 13 patients with SOE were included in the study and P100 potential latency and amplitude values obtained from these patients were compared with the values recorded from normal controls. The amplitude values recorded from the patients with CEOP were significantly high (P ¼ 0:033). P100 potential latency values recorded in patients with SOE were significantly long (P ¼ 0:028). High amplitude VEP responses were mostly attributed to hyperexcitability of the occipital cortical structures whereas prolonged latency P100 responses were attributed to occipital structural changes. q 2002 Elsevier Science B.V. All rights reserved. Keywords: Visual evoked potentials; Childhood epilepsy with occipital paroxysms; Symptomatic occipital epilepsy 1. Introduction Occipital lobe seizures, as defined by subjective symp- toms and objective signs, can be recognized by clinical seizure characteristics in most cases. Most symptoms asso- ciated with ictal discharges arising from the occipital lobe are visual in nature and visual hallucinations are probably the most common clinical manifestation. The patients must be classified in order to be able to define the prognosis. Occipital lobe epilepsy consists of childhood epilepsy with occipital paroxysms (CEOP), idiopathic photosensitive occipital epilepsy (IPOE) and symptomatic occipital epilepsy (SOE). The causes underlying SOE are variable (e.g. hypoxic ischemic encephalopathy, cortical dysplasia, tumors, Sturge–Weber syndrome, head trauma). Neurologic examination, EEG findings and neuroimaging are the meth- ods used for differentiation in these two groups of patients. The experience of evoked potentials in epilepsy is sparse. Most of the existing studies have investigated visual evoked potentials (VEPs) especially in patients with photosensitive seizures [1–5]. The results indicate a larger variability of VEPs in epileptics with various types of seizures compared to the normal population [6,7]. We studied VEPs in two different groups of occipital lobe epilepsy, in patients with CEOP and with SOE, to find out if there are any abnormal- ities convenient for the occipital discharges and if there are any differences between the idiopathic and symptomatic groups. 2. Materials and methods Two groups of patients were taken into the study. The first group comprised the patients diagnosed as CEOP. These patients were nine cases with early onset and ten cases with late onset. In this group, eight girls and 11 boys with a mean age of 10.2 years at the time of evaluation were present. The age of onset of epilepsy ranged from 2 to 14 years. The mean age of onset of seizures was 6.5 years. In all patients the neurologic examination and MRIs were normal. Three to ten EEG recordings were obtained in each child. Occipital epileptic paroxysmal discharges were found on interictal EEGs of all patients. All the patients received antiepileptic therapy. Eighteen of them (95%) received one drug, and only one patient (5%) received two drugs. In 17 patients seizure control was achieved. However, two patients had recurrent seizures. The second group comprised patients with SOE. There were 13 patients in this group, made up of four girls and nine boys with a mean age of 10.9 years at the time of evaluation. The age of onset of epilepsy ranged from 6 months to 12 years. The mean age of onset of seizures was 42 months. In Brain & Development 25 (2003) 268–271 0387-7604/02/$ - see front matter q 2002 Elsevier Science B.V. All rights reserved. doi:10.1016/S0387-7604(02)00226-7 www.elsevier.com/locate/braindev * Corresponding author. Tel.: 190-232-38880980; fax: 190-232- 3422142. E-mail address: gokcayf@hotmail.com (A. Gokcay).