Ramirez and Mann previously found that 1) poor readers exhibit degraded perception for transient acoustic events in noise and 2) make less effective use of visual articulatory cues relative to age matched controls in identifying consonant-vowel (CV) syllables. Experiment 1 will address concerns about whether the previous findings could be a by-product of reading experience. This follow-up experiment will examine whether reading ability-matched controls will show the same failure to use visual cues exhibited by the dyslexic adults. Experiment 2 will examine poor readers' ability to recognize categorical boundaries between speech sounds that are embedded in noise and whether spectral cues (e.g., amplifications of formants) and dynamic cues (e.g., visual articulatory cues) can help reading impaired subjects recognize categorical boundaries. Ramirez and Mann's previous findings may not be anticipated by Tallal's temporal processing account unless one assumes that deficits in temporal processing are pervasive across sensory modalities. A strong test of Tallars account should, thus, examine poor readers' ability to process transient visual stimuli. Experiment 3 will address this by adapting Demb and Boynton's (1998) work into a psychophysical study examining how poor readers and reading ability matched controls differ in their ability to discriminate visual displays of sinusoidal gratings that vary in temporal frequency. Lastly, experiment 4 attempts to correlate the findings of previous auditory-visual integration studies with the results of fMRI experiments that seek to determine the underlying neurological mechanisms the typify normal and impaired reading populations. ? ?
