ELECTROENCEPHALOGRAPHIC FINDINGS IN HASHIMOTOS ENCEPHALOPATHY

Hashimoto's encephalopathy (HE) is a steroid-responsive relapsing diso rder that frequently presents with seizures and diffuse EEG abnormalit ies. We report the EEG findings in seven patients with encephalopathy, seizures, or both, associated with elevated antithyroid antibodies. T here were several combinations of findings within the same patient and between patients. The EEGs of five patients had generalized slowing o r frontal rhythmic slowing; two also had triphasic waves and one had p eriodic sharp waves. Three had focal left temporal slowing. HE is hete rogeneous clinically and electrographically. A high level of suspicion is necessary to establish the diagnosis.