Evaluation of an audiovisual-FM system: speechreading performance as a function of distance

A research program was undertaken to evaluate the efficacy of an audiovisual-FM system as a speechreading aid. The present study investigated the effects of the distance between the talker and the speechreader on a visual-speech perception task. Sentences were recorded simultaneously with a conventional Hi8 mm video camera, and with the microcamera of an audiovisual-FM system. The recordings were obtained from two talkers at three different distances: 1.83 m, 3.66 m, and 7.32 m. Sixteen subjects completed a visual-keyword recognition task. The main results of the investigation were as follows: For the recordings obtained with the conventional video camera, there was a significant decrease in speechreading performance as the distance between the talker and the camera increased. For the recordings obtained with the microcamera of the audiovisual-FM system, there were no differences in speechreading as a function of the test distances. The findings of the investigation confirm that in a classroom setting the use of an audiovisual-FM system may constitute an effective way of overcoming the deleterious effects of distance on speechreading performance.