Effects of letter-reversals training on the discrimination performance of EMR children.

Ninety mentally retarded elementary-school children who committed letter-reversal errors on a pretest were randomly assigned to one of three (one experimental, two control) training conditions consisting of seven sessions given over a 5-week period. Subsequent statistical analyses revealed that for one of four letter-discrimination posttests, the experimental subjects performed significantly better than the placebo control subjects. Differences between the experimental and the method-specific control subjects were in the expected direction but not statistically significant. Aptitude times Treatment interactions for three of the four posttests revealed the training effect to be most pronounced with younger and more retarded children.