Clinical relevance of phase of steady-state VEPs to P100 latency of transient VEPs.
Pattern visual evoked potentials (VEPs) to transient and steady-state stimulation were recorded in 10 normal subjects at 4 levels of luminance (180, 57, 22 and 11 cd/m2). VEPs were also recorded in 5 patients with optic neuropathy at a fixed luminance (180 cd/m2). The relationship between P100 latency of transient VEPs (T-VEPs) and the phase of steady-state VEPs (S-VEPs) was analyzed. As luminance decreased in normal subjects, P100 latency was prolonged and the phase lag increased. A significant linear relationship between the P100 latency and phase was found. Patients showed both the prolonged P100 latency and the delayed phase. The simple linear regression line of the phase-P100 latency function of normal subjects closely matched the patients' values. These results suggest that changes in the phase may be equivalent to changes in the P100 latency. S-VEPs, therefore, may be clinically useful in assessing visual function.
Tobimatsu
S
S
Department of Clinical Neurophysiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Tashima-Kurita
S
S
Nakayama-Hiromatsu
M
M
Kato
M
M
D000328:Adult; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications / Q000503:physiopathology; D009902:Optic Neuritis / Q000209:etiology / Q000503:physiopathology; D010775:Photic Stimulation; D011930:Reaction Time