A meta-analysis of studies carried out between 1946 and 1988 concerned with the efficacy of speech and language therapy treatment for aphasic patients.

An examination of the empirical evidence for the efficacy of speech and language therapy treatment for adult aphasic patients is undertaken with the aid of meta-analysis which affords a statistical method of systematic data summary and synthesis. Patient characteristics and treatment outcomes are correlated to identify factors that contribute to the demonstration of a treatment effect. One of the most striking results of this retrospective study was the identification of the overwhelming failure to report data or include, in experimental controls, variables that might crucially affect outcome.