Force measurement system and a method of testing a subject

A method of testing a subject, the method comprising the steps of:

• providing reality-altering glasses configured to be worn on a head of a subject, the reality-altering glasses including:
• one or more visual displays configured to generate a virtual screen image for the subject;
• and
• one or more cameras configured to capture one or more video images of an environment surrounding the subject;
• providing a data processing device operatively coupled to the reality-altering glasses, the data processing device configured to manipulate the virtual screen image that is displayed on the one or more visual displays of the reality-altering glasses;
• providing a force measurement assembly configured to receive the subject, the force measurement assembly being operatively coupled to the data processing device, and the force measurement assembly including:
• a surface for receiving at least one portion of the body of the subject;
• and
• at least one force transducer, the at least one force transducer configured to sense one or more measured quantities and output one or more signals that are representative of forces and/or moments being applied to the surface of the force measurement assembly by the subject;
• positioning the subject on the surface of the force measurement assembly;
• positioning the reality-altering glasses on the subject;
• capturing one or more video images of an environment surrounding the subject using the one or more cameras of the reality-altering glasses;
• converting, by using the data processing device, the one or more signals that are representative of the forces and/or moments being applied to the surface of the force measurement assembly by the subject into one or more load output values;
• and
• altering and/or displacing, by using the data processing device, the one or more video images of the environment surrounding the subject based upon the one or more load output values determined from the one or more signals from the force measurement assembly so that, when the one or more video images are displayed to the subject on the one or more visual displays of the reality-altering glasses, the one or more video images no longer depict an accurate representation of the environment surrounding the subject so as to perturb a visual input of the subject during the performance of a balance test where one or more sensory inputs of the subject are modified to determine whether any sensory systems of the subject are deficient or whether the subject is relying too heavily upon one or more of the sensory systems;
• wherein the step of altering and/or displacing the one or more video images of the environment surrounding the subject using the data processing device comprises displacing the one or more video images of the environment surrounding the subject and/or modifying a size of the one or more video images of the environment surrounding the subject based upon a displacement position of the subject determined using the one or more load output values of the force measurement assembly.