TEMPORAL INTERMITTENT RHYTHMIC DELTA-ACTIVITY IN ELECTROENCEPHALOGRAMS

Temporal intermittent rhythmic delta activity (TIRDA) has been reporte d to be highly specific for diagnosing complex partial epilepsy. Of 12 ,198 electroencephalographic (EEG) recordings performed at the Mayo Cl inic between May 1, 1990 and May 1, 1991, 33 records from 27 patients (18 women and nine men; mean age, 41.5 years; range, 13-82 years) show ed TIRDA. Clinical seizures were diagnosed in all patients, and comple x partial epilepsy was well documented in 23. In a control group of 10 0 patients without TIRDA and matched for age and sex, generalized seiz ures were diagnosed in 25 and partial seizures in 15. Differences betw een TIRDA and control groups were highly statistically significant. Fo cal temporal sharp waves or spikes occurred in 23 patients with EEG re cordings that contained TIRDA; three of these patients also exhibited generalized atypical spike-and-wave discharges. Four patients had TIRD A but no other epileptiform activity, although earlier EEGs of three o f these patients contained spikes or sharp waves. These findings confi rm earlier work, and we conclude that TIRDA represents an important ep ileptogenic abnormality.