• Giaschi, Deborah Eileen

    Titles
    Investigator, BC Children's Hospital
    Professor, Department of Ophthalmology and Visual Sciences, University of British Columbia
    Degrees / Designations
    B.Sc., MA, PhD
    Primary Area of Research
    The M.I.N.D.
    Secondary Area(s) of Research
    Phone
    604-875-2345 ext. 7807
    Fax
    604-875-2683
    Lab Phone
    604-875-2345 ext. 7853
    Mailing Address
    BC Children's Hospital
    Room E300E
    4480 Oak Street
    Vancouver, BC V6H 3V4 

    Affiliate Websites
    Research Areas
    • Visual and auditory perception in children
    • Perceptual deficits in amblyopia and developmental dyslexia
    • Cortical mechanisms involved in visual perception, auditory perception and reading
    Summary
    Visual perceptual abilities develop rapidly in infants, but considerable maturation occurs in preschool and elementary school-aged children. Several things can go wrong during the course of this development and a child may be left with visual deficits that interfere with different aspects of life. Of particular interest are motion and depth perception. The goal of our research is to understand the normal development of the underlying brain structures that control these perceptual abilities and to discover the changes in the brain that result in deficits. We focus specifically on a developmental visual disorder called amblyopia, or lazy eye, and a developmental reading disorder called dyslexia.
    Current Projects

    Evaluation of reading improvement and brain changes following treatment for dyslexia

    There are some children who have difficulty learning to read. This disability is called developmental dyslexia. Children with dyslexia have poor school performance, but they may also develop mental health problems. Therefore, increasing reading skills in childhood is very important to their overall health as adults. The purpose of our research is to evaluate an intensive reading intervention program using behavioural and neuroimaging techniques, and whether these measures can predict success with the intervention program. We are also examining the brain networks associated with reading and reading difficulty.

    Motion perception in children 

    It is rare for a person to totally lack the ability to perceive motion, but certain developmental disorders affect the ability to perceive specific types of motion. In addition, the development of motion perception in children differs for different types of motion. The age at which performance on different visual tasks reaches adult levels may be an indicator of the brain structures and the amount of processing involved. We use computer ‘games’ to obtain information about the typical maturation of motion perception and about the changes in motion perception caused by lazy eye, dyslexia or preterm birth. We are also using functional MRI to study the brain regions involved in these developmental disorders. 

    Predicting patching treatment success in children with amblyopia

    Amblyopia (lazy eye) is a common developmental disorder in which vision is impaired in one eye and cannot be corrected with glasses. An eye turn or an optical problem can cause amblyopia to develop in an otherwise healthy eye. If these problems are detected and treated when a child is young enough, amblyopia can often be prevented or reversed by patching the unaffected fellow eye; however, not all children respond well to this patching therapy. Treatment failures may occur because patching treats only some of the problems in amblyopia. Most amblyopia treatment and research focuses on problems with form perception, such as visual acuity (the smallest character that can be seen on an eye chart). In contrast, our research focuses on problems with motion perception and eye gaze control. We are using customized computer games to identify visual problems that predict treatment success by testing children (age 4 to 7 years) who are about to start patching therapy and children with normal vision. 

    Using depth perception to treat visual disorders

    Amblyopia (lazy eye) and strabismus (crossed eye) are common childhood eye disorders that disrupt binocular visual development and cause changes in the brain. Current treatments for these disorders have failure rates up to 30%, possibly because they are aimed at one rather than both eyes. Stereoscopic depth (3D) perception is an important aspect of binocular vision that may prove to be key for developing more effective treatment options. 'Fine’ 3D perception, in which information from the two eyes is fused to produce the experience of a single image, is relatively well understood. Less is known about ‘coarse’ 3D perception that is obtained from very large depths that cannot be fused into a single image. Our research identifies the sensitive periods for the development of fine and coarse 3D, the brain regions affected by their disruption, and the importance of spared coarse 3D for the treatment of amblyopia and strabismus. 

    Selected Publications

    Meier K, Giaschi D (2014) The maturation of global motion perception depends on the spatial and temporal offsets of the stimulus. Vision Research 95:61-67

    Giaschi D, Lo R, Narasimhan S, Lyons C, Wilcox L. (2013) Sparing of coarse stereopsis in stereodeficient children with a history of amblyopia. Journal of Vision 13(10): 17

    Giaschi D, Narasimhan S, Solski A, Harrison E, Wilcox L. (2013) On the typical development of stereopsis: fine and coarse processing. Vision Research 88: 65-71

    Partanen M, Fitzpatrick K, Madler B, Edgell D, Bjornson B, Giaschi D. (2012) Cortical basis for dichotic pitch perception in developmental dyslexia. Brain and Language 123:104-112

    Narasimhan S, Harrison E, Giaschi D. (2012) Quantitative measurement of interocular suppression in children with amblyopia. Vision Research 66:1-10

    Narasimhan S, Giaschi D. (2012) The effect of dot speed and density on the development of global motion perception. Vision Research 62:102-107

    Secen J, Culham J, Ho C, Giaschi D. (2011) Neural correlates of the multiple-object tracking deficit in amblyopia. Vision Research 51:2517-2527

    Hayward J, Truong G, Partanen M, Giaschi D. (2011) Effects of speed, age and amblyopia on the perception of motion-defined form. Vision Research 51:2216-23

    Ho C, Giaschi D (2009) Low- and high-level motion perception deficits in anisometropic and strabismic amblyopia: evidence from fMRI. Vision Research 49: 2891-901

    Boden C, Giaschi D (2007) M-stream deficits and reading-related visual processes in developmental dyslexia. Psychological Bulletin 133:346-66

    Ho C, Giaschi D, Boden C, Dougherty R, Cline R, Lyons C (2005) Deficient motion perception in the fellow eye of amblyopic children. Vision Research 45:1615-27

    Edwards V, Giaschi D, Dougherty R, Edgell D, Bjornson B, Lyons C, Douglas R (2004) Psychophysical indices of temporal processing abnormalities in children with dyslexia. Developmental Neuropsychology 25:321-54

    Grants
    Honours & Awards

    BC Research Institute for Children’s & Women’s Health Investigatorship Award – 1999-2002

    NSERC Women's Faculty Award – 1994-1999

    Research Group Members
    Christine Chapman – research assistant
    Kim Meier – PhD student
    Marita Partanen – PhD student
    Brian Sum – summer student
    Marcus Watson – postdoctoral fellow
    Angela Zhang – summer student