A fast visual evoked potential method for functional assessment and follow-up of childhood optic gliomas.
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.
Trisciuzzi
Maria Teresa S
MT
Institute of Ophthalmology, Catholic University, Lgo F. Vito 1, 00168 Rome, Italy.
Riccardi
Riccardo
R
Piccardi
Marco
M
Iarossi
Giancarlo
G
Buzzonetti
Luca
L
Dickmann
Anna
A
Colosimo
Cesare
C
Ruggiero
Antonio
A
Di Rocco
Concezio
C
Falsini
Benedetto
B
D000293:Adolescent; D000970:Antineoplastic Agents / Q000009:adverse effects; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D005074:Evoked Potentials, Visual; D005260:Female; D005500:Follow-Up Studies; D005654:Fundus Oculi; D006801:Humans; D008297:Male; D020339:Optic Nerve Glioma / Q000175:diagnosis* / Q000503:physiopathology* / Q000601:surgery; D019574:Optic Nerve Neoplasms / Q000175:diagnosis* / Q000503:physiopathology* / Q000601:surgery; D012164:Retinal Diseases / Q000139:chemically induced / Q000503:physiopathology; D014792:Visual Acuity / Q000502:physiology; D014795:Visual Pathways / Q000503:physiopathology
D000970:Antineoplastic Agents