This paper (1) highlights the relevance of functional communication as an outcome parameter in Alzheimer disease (AD) clinical trials; (2) identifies studies that have reported functional communication outcome measures in AD clinical trials; (3) critically reviews the scales of functional communication used in recent AD clinical trials by summarizing the sources of information, characteristics, and available psychometric data for these scales; and (4) evaluates whether these measures actually or partially assess functional communication. To provide direction for future research and generate suggestions to assist in the development of a valid and reliable functional communication scale for the needs of AD clinical trials, we have included not only functional communication scales, but also related concepts that give thought-provoking impulses for the development of a functional communication scale. As outcome measures for AD clinical trials, the 6 identified papers use 6 different scales, for functional communication and for related concepts. All of the scales appear to have questionable psychometric properties, but still provide a promising basis for the creation of a functional communication scale. We conclude with concrete suggestions on how to combine the advantages of the existing scales for future research aimed at developing a valid and reliable functional communication scale for the needs of AD clinical trials.