The present master thesis analyses the influence of hearing impairment and meaningfulness of stimuli on subjects working memory. The effortfulness hypothesis was examined by measuring the performance of the working memory of people suffering from hearing impairment as well as people with induced hearing impairment. In a further part of the study, the cerebral activity of subjects was analyzed using fMRI while they performed tasks measuring their working memory. A total of 42 subjects were instructed to work on an n-back task in the fMRI scanner. 24 of the subjects had normal hearing abilities while 18 suffered from hearing impairment. These two groups were further separated: One half was presented stimuli at ideal volume conditions while the other half was presented stimuli at a lower volume which induced a hearing impairment. The presentation of the stimuli was performed by means of earphones only providing the stimuli on one side. In the n-back task, each of the subjects was presented a set of defined words and non-words. The analysis of the performance-related data using MANOVA with repeated measurements showed no significant results. Hence, it was not possible to confirm the effortfulness hypothesis in the present study. A further result of the study shows a tendentially significant interaction between stimuli and their presentation volume. In ideal volume conditions, subjects performed better when being presented non-words than when being presented words. In induced hearing impairment conditions the subjects performed better with words than with non-words. The n-back task showed a ceiling effect. Significant differences were found in the analysis of fMRI data.