The aim of our study is to explore which information is essential to understand virtual signing. For that, we developed an online test. We tested the comprehensibility of four different versions: two degraded versions of a virtual signer (one with non-visible hands and one without movements on head and trunk), a complete version of a virtual signer and a version with a real human signer. Each video shown the description of a picture in French Sign Language (LSF). After seeing the video, participants had to found the picture described among 9 pictures displayed. The originality of our approach was to include two types of confusable pictures on the response board. One was supposed to induce errors by confounding the lexical signs and the other by confounding the spatial structure of the picture. By this method, we explored the effect of hiding hands and blocking trunk and head on the comprehension of lexicon and spatial structure.