RESEARCH considered in emergency department seizure patients of His- panic descent since nearly 1 in 10 were affected, a figure that was even higher in certain areas. From 1988 through 1990, 7.2% of neurocysticercosis cases reported to the Los Angeles Department of Health Services were locally acquired (25). The rate of domestic acquisition has been even higher (17% to 26%) in some studies of pediat- ric neurocysticercosis (6,8). These rates of domestic acquisi- tion appear to have increased from earlier studies in the late 1970s and early 1980s, when the rates were in the range of 2% to 3%. Because years can pass before symptoms develop, the incidence of domestically acquired cases will likely continue to rise. The apparent increase in the prevalence of neurocysticer- cosis carries a substantial economic impact. Nearly half of the seizure patients in our study were admitted to the hospital. The average cost of hospitalization for seizures in one study was $1,615 per patient, not including physician charges (26). The economic toll extends beyond such direct costs. Compared with the general population, seizure patients are seen in the emergency departments 2½ times more frequently, admitted to the hospital 3 times more frequently, and treated by specialists 3 times more frequently; they also receive psychological coun- seling 7 times more frequently (27) These figures still underes- timate the true economic impact of neurocysticercosis because up to 30% of patients who visit an emergency room do not have seizures but rather a variety of other neurologic symp- toms such as headache, visual changes, ataxia, and confusion. Hydrocephalus may develop in a substantial number if patients, requiring neurosurgical intervention. Any study of neurocysticercosis is limited by the difficulty in clearly establishing the diagnosis. The only true measure for the diagnosis of neurocysticercosis is brain biopsy, which is clearly impractical. This study therefore implemented a case definition that incorporates the classification scheme proposed by Del Brutto (17) but is therefore limited by the predictive value of CT scan and serology. Serology has previously been demonstrated to be sensitive in cases with multiple cysts (94%) but less sensitive with single cysts or calcified lesions (28%) (28). Specimen storage and periodic bulk mailing may have further affected intrinsic test performance. We found a considerable discrepancy between patients who were diagnosed with neurocysticercosis by their physi- cians and patients who met our case definition. Because we did not specifically ask the treating physicians how they arrived at their diagnosis, the exact reasons for this discrep- ancy are unclear. However, emergency room physicians appear to rely considerably on epidemiologic information when diagnosing neurocysticercosis. Of patients diagnosed by their physicians, 98% were Hispanic (compared with our 76%) and 80% were immigrants (compared with our 50%). Ten per- cent of the patients with physician-diagnosed neurocysticerco- sis had normal CT scans. Additional limitations to the study include the fact that the participating network sites are university-affiliated emergency departments. This fact may limit the generalizability of our results to other patient populations. Ideally, serologic testing would have been performed on all patients, but laboratory test- ing is not routinely performed for all seizure patients seen in emergency departments. Patients who did undergo serologic testing were, however, not statistically different from those who did not, on the basis of the demographic information col- lected. In summary, while neurocysticercosis accounts for a small proportion (2.1%) of all seizures in university-affiliated, U.S. emergency department patients, its geographic distribution appears diverse; the highest concentration is in the Southwest and in Hispanics. Our observations are consistent with current immigration trends that suggest the growing importance of neurocysticercosis in the United States. Continued surveil- lance and further studies of screening and treatment strategies appear warranted. Acknowledgments The authors acknowledge the residents and staff at the participat- ing emergency departments as well as the following study coordina- tors: Jane Dascalos, Emilio Larrier, Constance Parramore, Karen Pfaff, Marlow Price, Yvonne Sanchez, Christine Shields, Nancy Strat- ton, Jonah Tan, Amy E. Waldren, Mary Beth Wash, and Julie T. Wilke. 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