Author Response: Shoulder-Tap Test for Functional Gait Disorders: A Sign of Abnormal Anticipatory Behavior.

Abstract

We welcome the comments by Dr. Geroin et al.1 on our article. We agree that a light touch may be a sufficient stimulus to induce an anticipatory postural response in patients with functional gait disorders, without the need for a “tap.” Although the video linked to our article shows a rapid downward movement of the examiner's hands onto the shoulders, the actual contact with the shoulders is in fact light, lending credence to our esteemed colleagues' observations. Whether there exists a sensory threshold of force, at which an incongruent or inappropriate postural response occurs following a touch to the shoulders, is an interesting question that we hope to be able to address in our future work. In fact, we are extending our work to explore the shoulder-tap test in elderly people with a fear of falling—a common symptom in which abnormal anticipatory behaviors likely exist and identification of such thresholds may be of particular interest.