Design of all eligible studies on the relationship between onchocerciasis and epilepsy by use of a comparison group.

aAssessment of Epilepsy: ITW = interview; MD = medical doctor; NE = neurologic examination; SITW = standardized interview;bAssessment of Onchocerciasis: Nod q = examination for presence of nodule(s); Nod Q = assessment of number of nodules; mf q = microscopic examination for presence of microfilariae in skin biopsies (no count); mf Q = assessment of skin microfilarial density; Nod+mf q = assessment of presence of nodules OR of mf; PCR = detection of parasite DNA in skin biopsy by using polymerase chain reaction.cControl for confounding factors: IoE = Intensity of exposure (residence); ToE = Time of exposure (age/duration of residence).dThe article by Kabore et al. [33] reports data from only 5 of the 12 villages for which data are given in reference [34] and [35].ePatients without skin microfilariae but having experienced a reaction to ivermectin treatment within 1 year were also considered infected.fResults of eye examinations were reported in this study but are not considered in the present analysis.