Hollingsworth_2017.pdf (2.02 MB)
The effects of colour on reading and visual correlates in children and adolescents who are profoundly or severely deaf
thesisposted on 2023-08-30, 15:46 authored by Richard S. Hollingsworth
Vision and reading abilities in profound or severely deaf children have consistently been reported to be impaired. Although the nature of reading acquisition in these children has been widely debated, visual functions necessary for reading have rarely been assessed. Coloured overlays have been shown to improve reading in hearing children with reading disabilities, yet no investigation with children who are deaf has been performed. Two visual theories have been proposed to explain the benefit from overlays: visual stress and the magnocellular defect. Visual functions (refractive state, visual acuities and binocular status for near and distance) were measured and compared between children who were deaf and normal hearing. Intelligence quotient was also evaluated. Reading was investigated with the Wilkins Rate of Reading test and a version specifically adapted for children who are deaf (validated in a pilot study). A clinical assessment using intuitive overlays was performed on all participants. Magnocellular functions were examined with Frequency Doubling Technology and Random Dot Kinematograms. Convergence and accommodation were significantly reduced in the deaf participants. Reading speeds were increased with colour only for the deaf participants who chose the yellow overlay, and yellow was the most common choice of colour. Magnocellular responses appear increased globally and in specific areas in the Frequency Doubling Technology test, but only if the participant had previously chosen a yellow overlay. Visual and binocular dysfunction were more prevalent in the deaf participants. This has possible implications with reading difficulties. The most common choice of yellow overlays combined with the selective advantage of yellow in increasing reading speed supported the transient visual stream and the magnocellular defect theory. However, increased sensitivities with the Frequency Doubling Technology test suggest enhancement of the magnocellular pathway which may also be associated with improved peripheral retinal sensitivity and cross modal plasticity of the peripheral retina with children who are deaf.
InstitutionAnglia Ruskin University
- Accepted version