Pattern electroretinograms and visual evoked potentials in idiopathic intracranial hypertension.
A subclinical visual dysfunction can be detected by psychophysical methods in early-stage papilledema associated with idiopathic intracranial hypertension (IIH). We recorded steady-state pattern electroretinograms (PERGs) and visual evoked potentials (VEPs) to sinusoidal gratings of variable spatial frequency [0.6, 1.0, 1.4, 2.2 and 4.8 cycles/degree (cpd)] in 18 patients with IIH and early papilledema and in 21 age-matched controls. Spatial frequency selective reductions in the mean PERG (at 1-4.8 cpd) and VEP (at 4.8 cpd) amplitudes were found in patients in comparison with controls. The response functions of amplitude versus spatial frequency of patients' PERG and VEP displayed a low-pass shape, whereas in normal subjects PERG and VEP functions showed a band-pass and a high-pass shape, respectively. PERG and VEP abnormalities were found in 14 (77.7%) and 10 (55.5%) out of 18 patients, respectively. Most of these abnormalities involved only selected spatial frequencies (1.4-4.8 cpd). These results indicate spatial-frequency-dependent functional losses on both PERG and VEP in early papilledema, and suggest a potential value of these responses for detecting subtle visual abnormalities in IIH.
Falsini
B
B
Eye Clinic, Catholic University, Rome, Italy.
Tamburrelli
C
C
Porciatti
V
V
Anile
C
C
Porrello
G
G
Mangiola
N
N
D000328:Adult; D004596:Electroretinography; D005074:Evoked Potentials, Visual; D005260:Female; D006801:Humans; D007427:Intracranial Pressure; D008297:Male; D008875:Middle Aged; D010211:Papilledema / Q000503:physiopathology*; D010364:Pattern Recognition, Visual; D014786:Vision Disorders / Q000175:diagnosis