Reading disability: a hemispheric asymmetry--information processing approach.

A visual half-field task using a Sperling partial-report paradigm was presented to 10 reading disabled and 10 control subjects (7 to 14 yr. old). The design was very similar to that described in 1977 by Morrison, Giordani, and Nagy, examining performance of letters placed in a circular array at both the perceptual and short-term memory stage. The reading-disabled subjects performed significantly lower on letter-recognition during both the perceptual and short-term memory processing stages. A hemi-field analysis showed a left visual-field performance decrement for the reading-disabled group during the short-term memory stage. Contrary to previous findings which discount a perceptual deficit, this study indicates that such a deficit may exist and is further accentuated during the short-term memory stage by a decrement in right-hemisphere performance.