Abstract
Objective: To better characterize the properties of chromatic VEPs to onset-offset of red-green and blue-yellow equiluminant patterns, and establish normative values for a set of stimuli able to elicit robust and reliable responses, suitable for the clinical application. Methods: Chromatic VEPs have been recorded (Oz lead) from 28 normal subjects (age range 20-53 years) in response to monocular presentation of both red-green and blue- yellow equiluminant sinusoidal gratings. Stimuli were generated by a Cambridge VSG/2 card and displayed on a Barco CCID monitor (14 x 14 deg field size). Spatial frequency, chromaticity, contrast and onset-offset duration were varied. Results: For both red-green and blue-yellow equiluminant stimuli, robust responses have been obtained with gratings of 2 c/deg, presented in onset (300 ms) offset (700 ms) mode, at contrasts ranging from 90 to 6%. In all observers, the VEP waveform consisted mainly of a negative wave at stimulus onset, with a latency rapidly increasing with decreasing contrast. For both red-green and blue-yellow stimuli, the VEP contrast threshold coincided with the psychophysical threshold. Conclusions: The results complement previous studies aimed at characterizing the properties of chromatic VEPs. In addition, normative data are provided for a set of stimulus characteristics suitable for the clinical routine.
Original language | English (US) |
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Pages (from-to) | 772-781 |
Number of pages | 10 |
Journal | Clinical Neurophysiology |
Volume | 110 |
Issue number | 4 |
DOIs | |
State | Published - Apr 1 1999 |
Externally published | Yes |
Keywords
- Chromatic contrast
- Koniocellular
- Luminance contrast
- Magnocellular
- Parvocellular
- VEPs
ASJC Scopus subject areas
- Clinical Neurology
- Radiology Nuclear Medicine and imaging
- Neurology
- Sensory Systems
- Physiology (medical)