Despite the ubiquity of multimedia slide presentations in settings where Simultaneous Interpretation (SI) is required, there is limited research about their impact on the process of simultaneous interpreting. This thesis replicates a previous study exploring how visual clarity and lexical density affects simultaneous interpreters' fluency. In this study, student interpreters work with two different versions of slide presentations. The fluency and accuracy of their interpretations was assessed. The NASA TLX and an open-ended questionnaire were also administered. On average, interpretations of speeches that were accompanied by slides with higher lexical density and higher visual clarity led to increased disfluency, confirming results of previous studies, as well as increased accuracy and increased perceived load. This suggests that information displayed in bullet point style format is more difficult for simultaneous interpreters to process. This builds on previous studies indicating that audiences interact with slides presentations very differently from simultaneous interpreters.