Objectives: This work aimed at describing EEG abnormalities in epileptic patients living in areas endemic for cysticercosis, underlining the electroclinical correlations and discussing the interest of EEG examination in this context.
Methods: During a case-control study, 250 EEGs from patients with epilepsy were recorded with a portable system. Types of seizures were assessed clinically and from information obtained through a standardised questionnaire, and along with EEG were related to the results of cysticercosis serological tests.
Results: Among the 249 EEGs, 48% were normal, 5.2% had epileptic abnormalities, 6.8% showed an association between epileptic abnormalities and slow alterations. Slow theta and delta abnormalities were found in 21.8% of cases, and isolated deterioration of basic rhythms was observed in 17.3% of cases. Most seizures were generalized, and 61% of the patients had positive serology. One EEG was uninterpretable and another showed isolated spikes. Electroclinical agreement was considered to be satisfactory in 33 patients, and was better with the epileptic than with slow abnormalities. The existence of epileptiform EEG abnormalities confirmed clinically diagnosed epilepsy, but did not allow etiological diagnosis. Electroserological agreement was good in 24 patients. A significant association (Chi2, p = 0.03) existed between slow focal abnormalities and positive cysticercosis serology. Conversely, no significant association was detected between epileptic patterns and serology results.
Conclusion: While the EEG alone clearly does not allow aetiological diagnosis, its joint use with clinical and biological results was a key element of the etiological and therapeutic discussion. When it shows focal abnormalities in a patient with epilepsy living in a high prevalence cysticercosis area, it confirms the clinical suspicion of neurocysticercosis. Morphological imagery alone can provide etiological information on the seizures by showing the nature and localization of the parenchymal lesions.