Introduction: It is an observation that Visual Evoked Potential (VEP) amplitude and latency may be altered in Occipital-lobe-epilepsy (OLE). Other factors can also influence amplitude and latency of VEP. Objectives: We aimed to do a comparative study of VEP in childhood epilepsy with occipital paroxysms (CEOP) and symptomatic occipital epilepsy (SOE). Our secondary objectives were to ascertain the factors that determine the VEP latency and amplitude and to study the electroclinical features of OLE. Methods: A cross sectional study was done in consecutive children above four-years-of age with occipital-lobe-epilepsy (SOE and CEOP). The family was interviewed to assess the electro clinical features. Results: We recruited 120 children (n=70;CEOP and n=50;SOE). Female preponderance was seen (SOE-58%, CEOP-65.7%). Mean amplitude of VEP in the CEOP group (14.77±6.23µvolt) was significantly higher than in the SOE group (9.02±7.07 µvolt;p<0.001). Mean latency of VEP in the SOE group (124.81±30.83 milliseconds) was prolonged compared to the CEOP group (108.53±26.88 milliseconds;(p=0.003). Developmental delay influenced the mean latency in both groups (p<0.05). Polytherapy had a negative correlation with the amplitude in SOE (r = -0.522). Ulegyria was the most common MRI finding in SOE (26%). Vomiting and tonic eye deviation was the commonest semiology noted in both groups. Focal slowing and sleep activated epileptiform discharges was higher in children with SOE (p<0.05). Conclusion: If a child with occipital-lobe-epilepsy has high VEP amplitude one could possibly take it as an indicator of CEOP and a prolonged VEP should make one suspicious that the diagnosis is SOE.

Azmi Habeeb
Government Medical College Trivandrum
India

Mary Iype
Government Medical College Trivandrum
India

Shahanaz Ahamed
Government Medical College Trivandrum
India

Bineej Jayan
Government Medical College Trivandrum
India

Geetha Saradakutty
Government Medical College Trivandrum
India

Mini Sreedharan
Government Medical College
India

Anchu Cherian
Government Medical College Trivandrum
India