Topic — In open office spaces, workers are submitted to an ambient noise that is demonstrably distracting. This phenomenon is described in the scientific literature as the Irrelevant Sound Effect. The actual causes of this effect are misunderstood, which makes finding adequate solutions particularly difficult. In this project we propose to use electrophysiological markers of sound perception and speech intelligibility — measured with electroencephalography, EEG — to uncover what properties of the ambient office noise are triggering the distracting effect. We will then use these same markers to understand how hearing impairment affects work in open office spaces.