Nonconvulsive status epilepticus of frontal origin

Objectives: To determine the electroclinical characteristics and causative factors of nonconvulsive status epilepticus (NCSE) of frontal origin. Metho ds: The authors conducted a 5-year prospective study. Results: Ten patients were studied (seven men, three women; mean age, 56.4 years). Six patients did not have previous epilepsy. The mean diagnostic delay was 48 hours (ran ge, 3 to 96 hours). Two types of frontal NCSE were identified. Tn type 1 (n = 7), mood disturbances with affective disinhibition or affective indiffer ence were associated with subtle impairment of cognitive functions without overt confusion. EEG showed a unilateral frontal ictal pattern and normal b ackground activity. In type 2 (n = 3), impaired consciousness was associate d with bilateral. asymmetric frontal EEG discharges occurring on an abnorma l background. Ictal and postictal Tc-99m hexamethyl propylene amine oxime ( HMPAO) SPECT was performed in five patients and showed unilateral or bilate ral frontal HMPAO uptake that aided localization, especially in type 2 NCSE of frontal origin. Etiologies included a focal frontal lesion in six patie nts (three of which were tumors, neurosyphilis, and nonketotic hyperglycemi a. Eight patients did not respond to initial IV benzodiazepine (BZ), but IV phenytoin controlled six patients successfully. The immediate outcome was favorable in all patients. There was no long-term recurrence of SE in seven patients. Conclusions: NCSE of frontal origin is a heterogeneous syndrome. Some cases are best described as simple partial NCSE, others as complex pa rtial SE, and there are forms that overlap with absence SE. Emergency EEG a nd neuropsychological assessment are diagnostic, and SPECT may be useful. M any patients may not respond to IV BZ.