PowerPoint presentations are often criticized for the excessive use of text on the slides. In a study of 97 academic scholars, we found that presenters indeed used substantially more text than is advised. Speaking anxiety was found to be related to the time spent on preparing and rehearsing, and time spent on rehearsing is related to the number of words on the slides. Anxious presenters appear to use PowerPoint slides as speaking notes. Presenters should be trained to overcome their speaking anxiety by means other than the abundant use of words on their slides.
Hertz, B., Kerkhof, P., & van Woerkum, C. M. J. (2016). PowerPoint slides as speaking notes: The influence of speaking anxiety on the use of text on slides. Business and Professional Communication Quarterly, 79(3), 348-359. https://doi.org/10.1177/2329490615620416