A fast visual evoked potential method for functional assessment and follow-up of childhood optic gliomas

Clin Neurophysiol. 2004 Jan;115(1):217-26. doi: 10.1016/s1388-2457(03)00282-7.

Abstract

Objective: To evaluate a fast technique of visual evoked potentials (VEPs) recording, in response to steady-state luminance stimuli (SS-LVEPs), for functional assessment and follow-up of childhood optic gliomas (OGs).

Methods: Eighteen OG patients (age range: 3.5-18 years), with different degrees of optic pathway damage severity, were examined. Sixteen age-matched normal subjects served as controls. Ten of the 18 OG patients were re-tested 1-3 months after the first examination. SS-LVEPs were elicited by a sinusoidally-modulated flickering (8 Hz) uniform field, generated by a light emitting diode (LED)-array and presented monocularly in a mini-ganzfeld. Amplitude and phase of the Fourier-analyzed response fundamental (1F) and second harmonic (2F) were measured. The full VEP protocol had a median duration of 6 min (range: 4-12).

Results: When compared to normal control values, median 1F and 2F SS-LVEP amplitudes of OG patients were reduced (P<0.01), with a borderline increase in 2F phase lag (P<0.05). In 11 OG patients with asymmetric optic pathway damage in between-eye comparisons, median 1F amplitude losses were greater (P<0.01) in fellow eyes with more severe damage. No significant interocular difference was observed in control subjects. Median test-retest changes of 1F and 2F component were <20% and 30 degrees for amplitude and phase, respectively. In individual OG patients, 1F and 2F amplitudes were positively correlated (P<0.01) with visual acuity. 1F amplitude losses were correlated (P=0.01) with the severity of optic disc atrophy. Considering both 1F and 2F abnormalities, diagnostic sensitivity of SS-LVEP in detecting OG-induced optic pathways damage was 83.3%.

Conclusions: The present findings support the use of this technique, as an alternative to pattern VEPs, for functional assessment and follow-up of OG in uncooperative children.

Publication types

  • Clinical Trial

MeSH terms

  • Adolescent
  • Antineoplastic Agents / adverse effects
  • Child
  • Child, Preschool
  • Electroencephalography
  • Evoked Potentials, Visual*
  • Female
  • Follow-Up Studies
  • Fundus Oculi
  • Humans
  • Male
  • Optic Nerve Glioma / diagnosis*
  • Optic Nerve Glioma / physiopathology*
  • Optic Nerve Glioma / surgery
  • Optic Nerve Neoplasms / diagnosis*
  • Optic Nerve Neoplasms / physiopathology*
  • Optic Nerve Neoplasms / surgery
  • Retinal Diseases / chemically induced
  • Retinal Diseases / physiopathology
  • Visual Acuity / physiology
  • Visual Pathways / physiopathology

Substances

  • Antineoplastic Agents