A patient describes an unusual distortion in how movement appears to them. Before revealing the answer, decide how you would explore whether this is trailing phenomena.

Ask specifically whether a real, moving object is present and correctly identified throughout the experience, with only the continuity of its motion disrupted, since this preserved identification alongside disrupted motion perception is the defining feature. Ask about the nature of the distortion itself, since a moving object is seen as a sequence of discrete, separate images rather than as smooth, continuous motion. Take a careful history of recent substance use, since trailing phenomena is most classically reported in connection with hallucinogenic drug use, and establish the time course, since it is usually brief and tied to the period of drug intoxication rather than being a stable, lasting change.