The impact of aging and hearing status on verbal short-term memory

We determined the impact of hearing status on age-related effects on verbal short-term memory (STM). Rabbit (1991) observed that elderly participants with hearing loss show impaired STM; he suggested that in the case of hearing loss, attentional resources had to be recruited to a larger extent to stimulus perception, reducing the available pool of attentional resources for STM processing. We tested this hypothesis by distinguishing the impact of aging from the impact of hearing status on STM. This was done by administering different verbal STM tasks to elderly and young adult participants matched for hearing threshold, as well as normal-hearing control participants. We observed that elderly participants and hearing-matched young participants showed equal levels of performance in all verbal STM tasks, and performed overall more poorly than the normal-hearing young control participants. These results suggest that mild hearing impairment is a major explanatory factor of reduced STM performance, and importantly, is age-independent. The results are discussed within an interactive framework of STM and attentional processing (Majerus et al., 2009).