To describe the relationship between the age of onset and duration of epilepsy, and the neuropsychological and developmental performance, in patients with refractory epilepsy (RE), admitted to the Epilepsy Monitoring Unit (EMU) of the Costa Rica National Children's Hospital.

Cognitive impairment has been described in patients that debut with a high burden of seizures. In patients with severe epileptic syndromes, an age of onset of epilepsy before the first year of life, is associated with a worse cognitive and motor prognosis. 

We evaluated the medical records of 347 patients admitted to our EMU for RE between November 2000 and May 2014. All of these patients underwent baseline neuropsychological and developmental evaluations.

The median age of onset of epilepsy was 2 years and the median age of enrollment in this study was 10 years. Only 58 patients (16.7%) reported normal scores in the developmental scales used. We found an association between having a later epilepsy debut and scoring a normal value for developmental performance, with an OR of 1.21 per year of onset of diagnosis (95%CI 1.1-1.3, p=<0.001). Furthermore, an increased duration of epilepsy correlated with a lower odd of showing a normal development (OR 0.92; 95%CI 0.9-1.0, p=0.032). In the patients evaluated with the Wechsler Intelligence Scale for Children

(WISC), moderate and statistically significant correlations were found between an increasing age of onset of epilepsy and each of the subcategories of this scale.

This is the first study evaluating neuropsychological and developmental performance in a cohort of RE pediatric patients from Costa Rica. Our data suggests that an earlier age of epilepsy onset as well as an increased duration of the disease correlates with an abnormal neuropsychological and developmental performance in pediatric patients with RE.