This study evaluated the validity of using an earplug so that information is presented to only one ear of children (N=34) in Alberta, Canada, with learning disabilities as a means of improving listening comprehension. Children were asked to recall stories from the Auditory Comprehension Test (ACT) immediately after hearing the story. The children (ages 8-18) were retested by an impartial researcher, blind to original test results, regarding: (1) the reproducibility of the monaural advantage; (2) the reliability of the monaural advantage over a mean period of 2 years from the original testing; and (3) the inter-rater reliability of scores from the ACT. The results supported the validity of a monaural effect in that the retest group, as a whole, showed a mean advantage of approximately 30 percent in recalling stories when heard in only one ear. Inter-rater reliability was high. Forty-five percent of the children who were prescribed the earplug continued to wear the earplug on a daily basis at followup. Parents', teachers', and childrens' reports at interviews conformed with reports of the effects of an earplug. The earplug was reported as producing improved abilities to attend to and comprehend speech in 45 percent of the samples. Interview forms are appended. (36 references) (DB)