Abstracts

Rationale: Rationale: Auto-antibodies have been implicated as causing acute and chronic seizures. The routine EEG and longer term recordings are utilized to in the evaluation and management of people with suspected and confirmed seizures. The utility of routine and long term EEG of these patients with such an uncommon condition is uncertain. Methods: Methods: We reviewed the Mayo Clinic Arizona/Florida EMU data bases for patients who had EEGs and confirmed auto-antibodies. A total of 20 consecutive patients over the last 5 years with clinically diagnosed seizures have positive antibody screens (one or more) were analyzed. History, seizure type, antibody type and EEG findings were reviewed. EEG results were interpreted by five CNP board certified neurologists. Results: Results: Voltage-gated potassium channel (VGKC) (8) Thyroperoxidase (TPO)- (7), GAD-65-(4), ANNA-1 (1), NMO (1), Striated muscle AB- (4), ENA +ANA+SSA-(1) AH-R Antibodies (1). 13 of 20 Cases had two or more antibodies identified (12 cases w/ 2, one w/ three). Eighteen of 20 inter-ictal EEGs of patients were all interpreted as abnormal, with 14/18 showing non-specific frontal or temporal slowing and 4/18 showing focal epileptiform activity. When a seizure was recorded, 8/13showed rhythmic ictal focal theta or delta activity and 5/13 showed evolving temporal or frontal focal sharp waves or spikes. Six patients were recorded during status epilepticus, with 4/6 showing evolving focal rhythmic theta or diffuse slowing with 2/6 showing independent evolving bi-temporal sharp waves. Specific antibody types were not associated with specific EEG patterns. Conclusions: Conclusion: In our series, focal EEG abnormalities predominate in both inter-ictal and ictal EEGs with the majority showing focal slowing (frontal and temporal). The majority of our patients have multiple auto-antibodies that do not correlate with specific EEG abnormalities. The majority of patients with auto antibodies where seizures are recorded did not show traditional sharp or spike and wave patterns. Only 1/6 patients presenting in clinical status epilepticus showed multifocal sharp waves with most showing non-specific focal slowing. Traditional sharp or spike and wave abnormalities are seen in only a minority of seizure patients with presumed autoantibody etiology. EEG readers should be aware of these findings in patients presenting with auto antibodies and clinical seizures.