Objective: To provide an historical overview, description, synthesis, and critique of the Activator Adjusting Instrument (AAI) and Activator Methods Chiropractic Technique of clinical assessment.
Methods: Online resources were searched including Index to Chiropractic Literature, EBSCO Online, MANTIS, CHIROLARS, CINAHL, eJournals, Ovid, MDConsult, Lane Catalog, SU Catalog, and Pubmed. Relevant peer-reviewed studies, commentaries, and reviews were selected. Studies fell into 2 major content areas: instrument adjusting and the analysis system for therapy application. Studies were categorized by research content type: biomechanical, neurophysiological, and clinical. Each study was reviewed in terms of contribution to knowledge and critiqued with regard to quality.
Discussion: More than 100 studies related to the AAI and the technique were found, including studies on the instrument's mechanical effects, and a few studies on clinical efficacy. With regard to the analysis, there is evidence for good reliability on prone leg-length assessment, but to date, there is only 1 study evaluating the Activator Methods Chiropractic Technique analysis.
Conclusion: A body of basic science and clinical research has been generated on the AAI since its first peer-reviewed publication in 1986. The Activator analysis may be a clinically useful tool, but its ultimate scientific validation requires testing using sophisticated research models in the areas of neurophysiology, biomechanics, and statistical analysis.