Frontal intermittent rhythmic delta activity (FIRDA): is there a clinical significance in children and adolescents?

BACKGROUND: Frontal intermittent rhythmic delta activity (FIRDA) has been studied extensively in adults but published literature about its clinical correlates in children and adolescents is comparatively limited.

AIMS: This study was performed to find more evidence regarding the clinical significance of this electrographic pattern in the pediatric population.

METHODS: All electroencephalograms (EEGs) with FIRDA between 07/01/2006 and 12/31/2009 at our institution were identified. Clinical data were collected from charts of patients with FIRDA. A comparison group consisting of patients matched for age and location was assembled.

RESULTS: We identified 26 EEGs in 22 patients with this electrographic pattern from a total of 4627 EEGs. All 26 EEGs were performed because of a history of seizures or to rule out seizures. Two of the 22 patients did not have evaluable clinical data. Of the remaining, 18 had seizures. The events in 2 patients were determined to be non epileptic. Amongst the 18 patients with seizures, 10 had associated epileptiform discharges and only 2 were without epileptiform activity or localizing or lateralizing features. Two patients had brain tumor. Six patients had hydrocephalus. Three patients had encephalopathy due to anoxic, metabolic or infectious etiology. There was no statistically significant difference between the study and the comparison group for occurrence of brain tumor, hydrocephalus or encephalopathy.

CONCLUSIONS: FIRDA was uncommonly observed. It was associated with a variety of conditions and was not a specific marker of brain tumor, hydrocephalus or encephalopathy.