Occipital intermittent rhythmical delta activity in a schoolgirl with microcephaly

Abstract

The clinical significance of occipital intermittent rhythmic delta activity (OIRDA) on the electroencephalogram (EEG) has not been fully established. Over the years, it has been suggested that the interpretation of the OIRDA electroencephalographic pattern may be related to metabolic problems, structural lesions, infections and epilepsy. Recent studies suggested that this pattern occurs almost exclusively in children and is probably of epileptic origin in most case. It has been associated with primary generalized epilepsy syndromes, such as childhood absence. An 8-year-old schoolgirl, attending the 3^rd grade, with easy distractibility, inattention, low school performance,and microcephaly is described. EEG was performed awake during hyperventilation revealed occipital intermittent rhythmic delta with a frequency of 3 Hz, bilateral and synchronous, with 2^nd and 4^th sec of duration. Antiepileptic therapy with valproic acid was begun. After being treated for 8 months, no OIRDA was detected on follow up EEG. The presence of OIRDA activity on EEG in a child should alert us to the presence of absence epilepsy.

Keywords

Occipital rhythmic - absences - electroencephalogram - epilepsy - delta activity