Contrast detection in infants with fragile X syndrome.
Studies have reported that a selective deficit in visual motion processing is present in certain developmental disorders, including Williams syndrome and autism. More recent evidence suggests a visual motion impairment is also present in adults with fragile X syndrome (FXS), the most common form of inherited mental retardation. The goal of the current study was to examine low-level cortical visual processing in infants diagnosed with FXS in order to explore the developmental origin of this putative deficit. We measured contrast detection of first-order (luminance-defined) and second-order (contrast-defined) gratings at two levels of temporal frequency, 0 Hz (static) and 4 Hz (moving). Results indicate that infants with FXS display significantly higher detection thresholds only for the second-order, moving stimuli compared to mental age-matched typically developing controls.
Farzin
F
F
Department of Psychology, University of California, Davis, CA 95618, USA. ffarzin@ucdavis.edu <ffarzin@ucdavis.edu>
Whitney
D
D
Hagerman
R J
RJ
Rivera
S M
SM
D002675:Child, Preschool; D015350:Contrast Sensitivity; D005260:Female; D005600:Fragile X Syndrome / Q000523:psychology*; D006801:Humans; D007223:Infant; D008297:Male; D009039:Motion Perception; D010468:Perceptual Disorders / Q000209:etiology*; D010775:Photic Stimulation / Q000379:methods; D012684:Sensory Thresholds