The report to Congress by the Interagency Committee on Learning Disabilities, required by the Health Research Extension Act of 1985, Public Law 99-158, provides a review and assessment of Federal research priorities, activities, and findings regarding learning disabilities. Included in the report is information on (1) the number of persons affected by learning disabilities and the demographic data describing them; (2) current research findings on the causes, diagnoses, treatments, and prevention of learning and prevention of learning disabilities; and (3) recommendations for legislation and administrative actions to increase research effectiveness and prioritize research needs. Chapter I provides a summary of Committee activities, while Chapter II summarizes testimony of 23 persons representing various associations and organizations and purposes. Results of a survey of member agencies of the Committee concerning programs, achievements, and perceived needs are contained in the following chapter. Chapter IV contains results of a review of the epidemiologic and survey literature on incidence and characteristics of learning disabilities. Current research findings in the following five areas are reviewed in the next chapter: neurobiology of learning and memory; specific developmental disabilities of reading, writing, and mathematics; developmental language disorders; social skills deficits; and hyperactivity/attention deficit disorder. Chapter VI contains the Committee's recommendations including the need to revise the legislative definition of learning disabilities and the proposal of a revised definition. (DB)