Reduced percentage of neurocysticercosis cases among patients with late-onset epilepsy in the new millennium

Objective: To determine if the number of neurocysticercosis cases among patients with late-onset epilepsy has decreased over the past two decades. Design: Retrospective cohort study of 431 consecutive patients with recurrent seizures starting after the age of 20 years evaluated at our Institution from 1990 to 2009. Methods: Patients were classified according to the year in which they were first seen. Group I included 129 patients evaluated between 1990 and 1994, Group II included 108 patients evaluated between 1995 and 1999, Group III included 106 patients evaluated between 2000 and 2004, and Group IV included 88 patients evaluated between 2005 and 2009. We correlated the percentage of persons with cryptogenic and symptomatic epilepsy between the groups to determine if there was any change in the causes of late-onset epilepsy. Results: One hundred seventy-one patients had cryptogenic and 260 had symptomatic epilepsy. Common causes of symptomatic epilepsy were neurocysticercosis in 120 cases, cerebrovascular disease in 68, and brain tumors in 40. We found a reduction in the number of patients with symptomatic epilepsy (p = 0.0007) as well as a reduction in the number of neurocysticercosis cases (p = 0.0004) over the study years. There was a reduction in the weight of neurocysticercosis as an etiological factor for symptomatic late-onset epilepsy related to a drop in the number of patients with this condition evaluated between 2005 and 2009 (p = 0.0045). Conclusion: The number of neurocysticercosis cases among patients with late-onset epilepsy has changed over the years. This parasitic disease is no longer the most common cause of symptomatic late-onset epilepsy in our population.