Development and Validation of a Novel Mobility Test for Rod-Cone Dystrophies: From Reality to Virtual Reality.

Purpose: To validate a novel mobility test (MOST, MObility Standardized Test) and performance outcomes in real (RL) and virtual (VR) environments to be used for interventional clinical studies in order to characterize vision impairment in rod-cone dystrophies, also known as retinitis pigmentosa (RP).

Design: Prospective, interventional, noninvasive, reliability and validity analysis.

Methods: We designed MOST to be used in both VR and RL and conducted 3 experimental studies with 89 participants to (1) validate the difficulty of the mobility courses (15 controls), (2) determine the optimal number of light levels and training trials (14 participants with RP), and (3) validate the reproducibility (test-retest), reliability (VR/RL), sensitivity, and construct/content validity of the test (30 participants with RP and 30 controls).

Rewarding objects appear larger but not brighter.

Whether reward can accentuate the perception of visual objects, that is, makes them appear larger than they really are, is a long-standing and controversial question. Here, we revisit this issue with a novel two-alternative forced-choice paradigm combining asymmetric reward schedule and task reversal. In a first experiment, participants (n = 27) choose the larger of two unequally rewarded objects in some sessions and the smaller one in other sessions.