Late EEG findings and clinical status after organic mercury poisoning

The EEGs of four siblings with organic mercury poisoning were recorded. The series of EEGs spanned two to eight years. Additional EEGs were obtained from an asymptomatic family member (the mother) who initially had elevated mercury levels. Various types of abnormalities were noted in the tracings of the siblings, including epileptiform features and disturbances of background rhythms. The mother's EEGs were normal. The degree of EEG change reflected the clinical state. In the two cases in which seizures were present, epileptiform activity was seen. Both clinical severity and EEG abnormalities may correlate with age.