Flash visual evoked potentials in patients with periventricular leucomalacia in children less than 1 year of age

BACKGROUND AND AIM: Children with periventricular leucomalacia (PVL) are known to have visual impairment of various forms starting from reduced vision, field defects, congnitive problems, and problems with hand eye coordination. There is very scant data/literature on the visual evoked potentials (VEPs) at an early age in children with PVL. We did a study to evaluate the flash visual evoked potentials (fVEPs) in children with PVL less than 1 year of age. MATERIALS AND METHODS: A total of nine children diagnosed as having PVL on magnetic resonance imaging were included in the study. The mean age was 9.7± 3.5 months. All children underwent handheld fVEPs under sedation at two different flash frequencies 1.4 and 8 Hz. RESULTS: The mean latency of N1 and P1 on stimulation with 1.4 Hz was 47.9± 15.2 and 77.7± 26.0 ms, respectively. However, on stimulation with 8 Hz the mean latency of N1 and P1 was 189.8± 25.6 and 238.4± 33.6 ms, respectively. The mean amplitude with 1.4 Hz and 8 stimulation frequency was 5.6± 4.5 and 5.59± 3 mV, respectively. CONCLUSION: We have found for the first time that there is a change in the latency and the delay occurs at 8 Hz frequency but not at 1.4 Hz. We also conclude that amplitudes by fVEPs may be normal even in presence of periventricular changes. The amplitudes of fVEPs are not reliable in children with PVL.