A reproducible method to measure the intelligibility of communication systems is required to assess their efficiency. The current study seeks to develop a French version of the Modified Rhyme Test (MRT) [(House, Williams, Heker, and Kryter (1965). J. Acoust. Soc. Am. 37, 158-66], an intelligibility test composed of 50 six-word lists, originally developed for military applications and now widely used. An evaluation of the authors' French MRT was carried out, reproducing the original experimental conditions used by House and colleagues. Very similar results were found between the original MRT and the French MRT, validating the latter for further use and dissemination.

The last version of 3MTM Combat ArmsTM earplugs was designed to meet the hearing protection needs of the French armed forces. This earplug uses triple-flange-design fits in three sizes (small, medium, and large) allowing the best adaptation to all morphologies. The individual choice of the size of the earplug is the major problem to have an adequate protection: how to choose the ideal size? Three methods were assessed in the current study. The first method was based on the observation of tympanometry tips fit. The second was a commercial device allowing to check the attenuation of the earplug in situ. The last one was based on the detection of leak in low frequency with an instrumented earplug. The objective of this study was to compare these three different methods. An assessment test with 106 soldiers was performed. Each soldier was tested with the three methods, in a different order. The results of the different methods are presented and compared.