Hearing aids are audio capture devices which aim at providing the hearing impaired with better audibility. Most of the state-of-the-art systems involve sensing devices that work independently. However, the availability of a wireless communication link between two hearing aids would allow to perform spatial beamforming such as to provide better rejection of interfering signals. In this paper, we identify and study the above scenario from an information-theoretic viewpoint. We explore the gain provided by collaborating hearing aids as a function of the communication rate. In particular, we derive a closed-form gain-rate formula in the case where a sound source has to be extracted from ambient noise. A similar analysis is provided in the presence of an interfering point source and the corresponding optimal rate allocation is discussed.