Abstract
This study explored the relation between visual processing and word-decoding ability in a normal reading population. Forty participants were recruited at Arizona State University. Flicker fusion thresholds were assessed with an optical chopper using the method of limits by a 1-deg diameter green (543 nm) test field. Word decoding was measured using reading-word and nonsense-word decoding tests. A non-linguistic decoding measure was obtained using a computer program that consisted of Landolt C targets randomly presented in four cardinal orientations, at 3-radial distances from a focus point, for eight compass points, in a circular pattern. Participants responded by pressing the arrow key on the keyboard that matched the direction the target was facing. The results show a strong correlation between critical flicker fusion thresholds and scores on the reading-word, nonsense-word, and non-linguistic decoding measures. The data suggests that the functional elements of the visual system involved with temporal modulation and spatial processing may affect the ease with which people read.
Highlights
Many theories, causal and non-causal, have been advanced in an effort to explain the frequent co-occurrence of diminished dorsal stream function and linguistic deficits
Scores on the word decoding test were comparable to the original San Diego Quick Assessment measure when transformed as the SDQA test requires [26]
To assess the relationship between Critical Flicker Fusion (CFF) thresholds and decoding, we examined the correlation between these two measures
Summary
Causal and non-causal, have been advanced in an effort to explain the frequent co-occurrence of diminished dorsal stream function and linguistic deficits. The precise role remains unclear, it is generally accepted that some visual system deficits are associated with reading impairments such as dyslexia [1,2]. One such measure that has garnered considerable attention is the Critical Flicker Fusion (CFF) threshold. Lesion studies in non-human primates indicate that processing in the magnocellular visual pathway [5,6] and occipital lobe [7,8] are rate-limiting for CFF. Most neuroscience research in animals points towards flicker fusion being largely mediated by cells in the dorsal visual pathway which are specialized to process high temporal frequencies, respond to lowluminance contrasts, and are involved in motion processing [9,10,11,12,13,14]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call