Motion energy analysis (MEA): A primer on the assessment of motion from video.

Nonverbal behavior is a central factor influencing the therapeutic relationship. Despite broad agreement on its importance, empirical studies assessing nonverbal behavior in counseling and psychotherapy are relatively scarce and often limited to few cases. One restraining factor may be the resources needed when assessing nonverbal behavior. Movement dynamics are an exemplary aspect of nonverbal behavior that can be captured with computer vision-a discipline concerned with the automated analysis of footage captured on video. One of the simplest methods requiring no special detectors, devices, or markers on patients or therapists is based on the assessment of differences in sequences of pictures (frames) found in video recordings. Algorithms of so-called frame-differencing methods may be implemented on commonly available computers, and they provide a good, straightforward assessment of, for example, patients' and therapists' movement dynamics in counseling and therapy sessions. Frame-differencing methods in psychology date back 36 years, but their use in counseling and psychotherapy research is only recently gaining momentum. In this introductory article, the use of one specific application suitable for the assessment of human motion from archival video material is presented. Motion energy analysis (MEA) is a procedure particularly appropriate for clinicians and researchers who have access to recordings of sessions or who wish to record their own video material. Focusing on the phenomenon of nonverbal synchrony-the coordination of movement between patient and therapist-a step-by-step demonstration of the stages involved in a successful application of MEA in psychotherapy research is provided. (PsycInfo Database Record (c) 2020 APA, all rights reserved).