Abstracts

This study examines photoparoxysmal responses (PPRs) and their relationship to epileptic seizures in the pediatric population.
A retrospective analysis of abnormal EEG reports in children (from birth to 18 years) was performed. EEG requisitions and reports over a ten-year interval (1991-2000) were reviewed for the presence of a PPR (self-limited and self-sustained). Data was abstracted from the EEG requisitions, reports, and clinical records. Study variables included: age, sex, and type of PPR. Abnormalities of the background rhythm, morphology and location of spontaneous epileptiform discharges (SEDs) were also documented. Using seizure descriptions, epilepsy syndromes were characterized.
Seventy-eight children (208 records) met study criteria. The mean age for PPRs was 10.18 years (95% CI: 9.49 [ndash] 10.87). The majority (81.58%) of children with a PPR fell between ages 6 and 16 years (range: ages 0.67-17.25 years) with a peak between 8 and 12 years. The modal rate of photic stimulation at which PPRs occurred was 18 Hz. SEDs were associated with a PPR in 93 (81.58%) records and the majority (70.97%) had epileptiform discharges that were generalized in distribution. The remaining epileptiform discharges were either focal or mixed in distribution. Fifty-five (70.51%) had generalized seizures, while 19 patients (24.36%) had partial seizures. Idiopathic generalized epilepsy was the most frequently encountered syndromic diagnosis, while other symptomatic focal and generalized epilepsy syndromes were also recognized.
Photoparoxysmal responses are associated with both focal as well as generalized SEDs. Although these responses are most frequently encountered in the idiopathic generalized epilepsies, their association with a wider variety of seizures and epilepsy syndromes should be recognized by pediatric neurologists and electroencephalographers.
[Supported by: Children[rsquo]s Hospital Foundation of Manitoba]