This research work forms the first part of a long-term project designed to provide a framework for facilitating hearing aids tuning. The present study focuses on the setting up of automatic measures of speech intelligibility for the recognition of isolated words and sentences. Both materials were degraded in order to simulate presbycusis effects on speech perception. Automatic measures based on an Automatic Speech Recognition (ASR) system were applied to an audio corpus simulating the effects of presbycusis at nine severity stages. The results are compared to reference intelligibility scores collected from 60 French listeners. The aim of this system being to produce measures as close as possible to human behaviour, good performances were achieved since strong correlations between subjective and objective scores are observed.